gl

getFloatv(Pname) -> [float()]

Types

?GL_FEEDBACK: Feedback mode. No pixel fragments are produced, and no change to the frame buffer contents is made. Instead, the coordinates and attributes of vertices that would have been drawn if the render mode had been ?GL_RENDER is returned in a feedback buffer, which must be created (see gl:feedbackBuffer/3 ) before feedback mode is entered.

The return value of gl:renderMode is determined by the render mode at the time gl:renderMode is called, rather than by Mode . The values returned for the three render modes are as follows:

?GL_RENDER: 0.

?GL_SELECT: The number of hit records transferred to the select buffer.

?GL_FEEDBACK: The number of values (not vertices) transferred to the feedback buffer.

See the gl:selectBuffer/2 and gl:feedbackBuffer/3 reference pages for more details concerning selection and feedback operation.

See external documentation.

getError() -> enum()

Return error information

gl:getError returns the value of the error flag. Each detectable error is assigned a numeric code and symbolic name. When an error occurs, the error flag is set to the appropriate error code value. No other errors are recorded until gl:getError is called, the error code is returned, and the flag is reset to ?GL_NO_ERROR. If a call to gl:getError returns ?GL_NO_ERROR, there has been no detectable error since the last call to gl:getError , or since the GL was initialized.

To allow for distributed implementations, there may be several error flags. If any single error flag has recorded an error, the value of that flag is returned and that flag is reset to ?GL_NO_ERROR when gl:getError is called. If more than one flag has recorded an error, gl:getError returns and clears an arbitrary error flag value. Thus, gl:getError should always be called in a loop, until it returns ?GL_NO_ERROR , if all error flags are to be reset.

Initially, all error flags are set to ?GL_NO_ERROR.

The following errors are currently defined:

?GL_NO_ERROR: No error has been recorded. The value of this symbolic constant is guaranteed to be 0.

?GL_INVALID_ENUM: An unacceptable value is specified for an enumerated argument. The offending command is ignored and has no other side effect than to set the error flag.

?GL_INVALID_VALUE: A numeric argument is out of range. The offending command is ignored and has no other side effect than to set the error flag.

?GL_INVALID_OPERATION: The specified operation is not allowed in the current state. The offending command is ignored and has no other side effect than to set the error flag.

?GL_INVALID_FRAMEBUFFER_OPERATION: The framebuffer object is not complete. The offending command is ignored and has no other side effect than to set the error flag.

?GL_OUT_OF_MEMORY: There is not enough memory left to execute the command. The state of the GL is undefined, except for the state of the error flags, after this error is recorded.

When an error flag is set, results of a GL operation are undefined only if ?GL_OUT_OF_MEMORY has occurred. In all other cases, the command generating the error is ignored and has no effect on the GL state or frame buffer contents. If the generating command returns a value, it returns 0. If gl:getError itself generates an error, it returns 0.

See external documentation.

getString(Name) -> string()

Types

Name = enum()

Return a string describing the current GL connection

gl:getString returns a pointer to a static string describing some aspect of the current GL connection. Name can be one of the following:

?GL_VENDOR: Returns the company responsible for this GL implementation. This name does not change from release to release.

?GL_RENDERER: Returns the name of the renderer. This name is typically specific to a particular configuration of a hardware platform. It does not change from release to release.

?GL_VERSION: Returns a version or release number.

?GL_SHADING_LANGUAGE_VERSION: Returns a version or release number for the shading language.

gl:getStringi returns a pointer to a static string indexed by Index . Name can be one of the following:

?GL_EXTENSIONS: For gl:getStringi only, returns the extension string supported by the implementation at Index .

Strings ?GL_VENDOR and ?GL_RENDERER together uniquely specify a platform. They do not change from release to release and should be used by platform-recognition algorithms.

The ?GL_VERSION and ?GL_SHADING_LANGUAGE_VERSION strings begin with a version number. The version number uses one of these forms:

major_number.minor_numbermajor_number.minor_number.release_number

Vendor-specific information may follow the version number. Its format depends on the implementation, but a space always separates the version number and the vendor-specific information.

All strings are null-terminated.

See external documentation.

finish() -> ok

Block until all GL execution is complete

gl:finish does not return until the effects of all previously called GL commands are complete. Such effects include all changes to GL state, all changes to connection state, and all changes to the frame buffer contents.

See external documentation.

flush() -> ok

Force execution of GL commands in finite time

Different GL implementations buffer commands in several different locations, including network buffers and the graphics accelerator itself. gl:flush empties all of these buffers, causing all issued commands to be executed as quickly as they are accepted by the actual rendering engine. Though this execution may not be completed in any particular time period, it does complete in finite time.

Because any GL program might be executed over a network, or on an accelerator that buffers commands, all programs should call gl:flush whenever they count on having all of their previously issued commands completed. For example, call gl:flush before waiting for user input that depends on the generated image.

See external documentation.

hint(Target, Mode) -> ok

Types

Target = enum()

Mode = enum()

Specify implementation-specific hints

Certain aspects of GL behavior, when there is room for interpretation, can be controlled with hints. A hint is specified with two arguments. Target is a symbolic constant indicating the behavior to be controlled, and Mode is another symbolic constant indicating the desired behavior. The initial value for each Target is ?GL_DONT_CARE . Mode can be one of the following:

?GL_FASTEST: The most efficient option should be chosen.

?GL_NICEST: The most correct, or highest quality, option should be chosen.

?GL_DONT_CARE: No preference.

Though the implementation aspects that can be hinted are well defined, the interpretation of the hints depends on the implementation. The hint aspects that can be specified with Target , along with suggested semantics, are as follows:

?GL_FRAGMENT_SHADER_DERIVATIVE_HINT: Indicates the accuracy of the derivative calculation for the GL shading language fragment processing built-in functions: ?dFdx , ?dFdy, and ?fwidth.

?GL_LINE_SMOOTH_HINT: Indicates the sampling quality of antialiased lines. If a larger filter function is applied, hinting ?GL_NICEST can result in more pixel fragments being generated during rasterization.

?GL_POLYGON_SMOOTH_HINT: Indicates the sampling quality of antialiased polygons. Hinting ?GL_NICEST can result in more pixel fragments being generated during rasterization, if a larger filter function is applied.

?GL_TEXTURE_COMPRESSION_HINT: Indicates the quality and performance of the compressing texture images. Hinting ?GL_FASTEST indicates that texture images should be compressed as quickly as possible, while ?GL_NICEST indicates that texture images should be compressed with as little image quality loss as possible. ?GL_NICEST should be selected if the texture is to be retrieved by gl:getCompressedTexImage/3 for reuse.

See external documentation.

clearDepth(Depth) -> ok

Types

Depth = clamp()

Specify the clear value for the depth buffer

gl:clearDepth specifies the depth value used by gl:clear/1 to clear the depth buffer. Values specified by gl:clearDepth are clamped to the range [0 1].

See external documentation.

depthFunc(Func) -> ok

Types

Func = enum()

Specify the value used for depth buffer comparisons

gl:depthFunc specifies the function used to compare each incoming pixel depth value with the depth value present in the depth buffer. The comparison is performed only if depth testing is enabled. (See gl:enable/1 and gl:enable/1 of ?GL_DEPTH_TEST .)

Func specifies the conditions under which the pixel will be drawn. The comparison functions are as follows:

?GL_NEVER: Never passes.

?GL_LESS: Passes if the incoming depth value is less than the stored depth value.

?GL_EQUAL: Passes if the incoming depth value is equal to the stored depth value.

?GL_LEQUAL: Passes if the incoming depth value is less than or equal to the stored depth value.

?GL_GREATER: Passes if the incoming depth value is greater than the stored depth value.

?GL_NOTEQUAL: Passes if the incoming depth value is not equal to the stored depth value.

?GL_GEQUAL: Passes if the incoming depth value is greater than or equal to the stored depth value.

?GL_ALWAYS: Always passes.

The initial value of Func is ?GL_LESS. Initially, depth testing is disabled. If depth testing is disabled or if no depth buffer exists, it is as if the depth test always passes.

See external documentation.

depthMask(Flag) -> ok

Types

Flag = 0 | 1

Enable or disable writing into the depth buffer

gl:depthMask specifies whether the depth buffer is enabled for writing. If Flag is ?GL_FALSE, depth buffer writing is disabled. Otherwise, it is enabled. Initially, depth buffer writing is enabled.

See external documentation.

depthRange(Near_val, Far_val) -> ok

Types

Near_val = clamp()

Far_val = clamp()

Specify mapping of depth values from normalized device coordinates to window coordinates

After clipping and division by w, depth coordinates range from -1 to 1, corresponding to the near and far clipping planes. gl:depthRange specifies a linear mapping of the normalized depth coordinates in this range to window depth coordinates. Regardless of the actual depth buffer implementation, window coordinate depth values are treated as though they range from 0 through 1 (like color components). Thus, the values accepted by gl:depthRange are both clamped to this range before they are accepted.

The setting of (0,1) maps the near plane to 0 and the far plane to 1. With this mapping, the depth buffer range is fully utilized.

See external documentation.

clearAccum(Red, Green, Blue, Alpha) -> ok

Types

Red = float()

Green = float()

Blue = float()

Alpha = float()

Specify clear values for the accumulation buffer

gl:clearAccum specifies the red, green, blue, and alpha values used by gl:clear/1 to clear the accumulation buffer.

Values specified by gl:clearAccum are clamped to the range [-1 1].

See external documentation.

accum(Op, Value) -> ok

Types

Op = enum()

Value = float()

Operate on the accumulation buffer

The accumulation buffer is an extended-range color buffer. Images are not rendered into it. Rather, images rendered into one of the color buffers are added to the contents of the accumulation buffer after rendering. Effects such as antialiasing (of points, lines, and polygons), motion blur, and depth of field can be created by accumulating images generated with different transformation matrices.

Each pixel in the accumulation buffer consists of red, green, blue, and alpha values. The number of bits per component in the accumulation buffer depends on the implementation. You can examine this number by calling gl:getBooleanv/1 four times, with arguments ?GL_ACCUM_RED_BITS, ?GL_ACCUM_GREEN_BITS, ?GL_ACCUM_BLUE_BITS, and ?GL_ACCUM_ALPHA_BITS . Regardless of the number of bits per component, the range of values stored by each component is [-1 1]. The accumulation buffer pixels are mapped one-to-one with frame buffer pixels.

gl:accum operates on the accumulation buffer. The first argument, Op , is a symbolic constant that selects an accumulation buffer operation. The second argument, Value , is a floating-point value to be used in that operation. Five operations are specified: ?GL_ACCUM , ?GL_LOAD, ?GL_ADD, ?GL_MULT, and ?GL_RETURN.

All accumulation buffer operations are limited to the area of the current scissor box and applied identically to the red, green, blue, and alpha components of each pixel. If a gl:accum operation results in a value outside the range [-1 1], the contents of an accumulation buffer pixel component are undefined.

The operations are as follows:

?GL_ACCUM: Obtains R, G, B, and A values from the buffer currently selected for reading (see gl:readBuffer/1 ). Each component value is divided by 2 n-1, where n is the number of bits allocated to each color component in the currently selected buffer. The result is a floating-point value in the range [0 1], which is multiplied by Value and added to the corresponding pixel component in the accumulation buffer, thereby updating the accumulation buffer.

?GL_LOAD: Similar to ?GL_ACCUM, except that the current value in the accumulation buffer is not used in the calculation of the new value. That is, the R, G, B, and A values from the currently selected buffer are divided by 2 n-1, multiplied by Value , and then stored in the corresponding accumulation buffer cell, overwriting the current value.

?GL_ADD: Adds Value to each R, G, B, and A in the accumulation buffer.

?GL_MULT: Multiplies each R, G, B, and A in the accumulation buffer by Value and returns the scaled component to its corresponding accumulation buffer location.

?GL_RETURN: Transfers accumulation buffer values to the color buffer or buffers currently selected for writing. Each R, G, B, and A component is multiplied by Value , then multiplied by 2 n-1, clamped to the range [0 2 n-1], and stored in the corresponding display buffer cell. The only fragment operations that are applied to this transfer are pixel ownership, scissor, dithering, and color writemasks.

To clear the accumulation buffer, call gl:clearAccum/4 with R, G, B, and A values to set it to, then call gl:clear/1 with the accumulation buffer enabled.

See external documentation.

matrixMode(Mode) -> ok

Types

Mode = enum()

Specify which matrix is the current matrix

gl:matrixMode sets the current matrix mode. Mode can assume one of four values:

?GL_MODELVIEW: Applies subsequent matrix operations to the modelview matrix stack.

?GL_PROJECTION: Applies subsequent matrix operations to the projection matrix stack.

?GL_TEXTURE: Applies subsequent matrix operations to the texture matrix stack.

?GL_COLOR: Applies subsequent matrix operations to the color matrix stack.

To find out which matrix stack is currently the target of all matrix operations, call gl:getBooleanv/1 with argument ?GL_MATRIX_MODE. The initial value is ?GL_MODELVIEW.

See external documentation.

ortho(Left, Right, Bottom, Top, Near_val, Far_val) -> ok

Types

Left = float()

Right = float()

Bottom = float()

Top = float()

Near_val = float()

Far_val = float()

Multiply the current matrix with an orthographic matrix

gl:ortho describes a transformation that produces a parallel projection. The current matrix (see gl:matrixMode/1 ) is multiplied by this matrix and the result replaces the current matrix, as if gl:multMatrixd/1 were called with the following matrix as its argument:

((2/(right-left)) 0 0(t x) 0(2/(top-bottom)) 0(t y) 0 0(-2/(farVal-nearVal))(t z) 0 0 0 1)

where t x=-((right+left)/(right-left)) t y=-((top+bottom)/(top-bottom)) t z=-((farVal+nearVal)/(farVal-nearVal))

Typically, the matrix mode is ?GL_PROJECTION, and (left bottom-nearVal) and (right top-nearVal) specify the points on the near clipping plane that are mapped to the lower left and upper right corners of the window, respectively, assuming that the eye is located at (0, 0, 0). -farVal specifies the location of the far clipping plane. Both NearVal and FarVal can be either positive or negative.

Use gl:pushMatrix/0 and gl:pushMatrix/0 to save and restore the current matrix stack.

See external documentation.

frustum(Left, Right, Bottom, Top, Near_val, Far_val) -> ok

Types

Left = float()

Right = float()

Bottom = float()

Top = float()

Near_val = float()

Far_val = float()

Multiply the current matrix by a perspective matrix

gl:frustum describes a perspective matrix that produces a perspective projection. The current matrix (see gl:matrixMode/1 ) is multiplied by this matrix and the result replaces the current matrix, as if gl:multMatrixd/1 were called with the following matrix as its argument:

[((2 nearVal)/(right-left)) 0 A 0 0((2 nearVal)/(top-bottom)) B 0 0 0 C D 0 0 -1 0]

A=(right+left)/(right-left)

B=(top+bottom)/(top-bottom)

C=-((farVal+nearVal)/(farVal-nearVal))

D=-((2 farVal nearVal)/(farVal-nearVal))

Typically, the matrix mode is ?GL_PROJECTION, and (left bottom-nearVal) and (right top-nearVal) specify the points on the near clipping plane that are mapped to the lower left and upper right corners of the window, assuming that the eye is located at (0, 0, 0). -farVal specifies the location of the far clipping plane. Both NearVal and FarVal must be positive.

Use gl:pushMatrix/0 and gl:pushMatrix/0 to save and restore the current matrix stack.

See external documentation.

viewport(X, Y, Width, Height) -> ok

Types

X = integer()

Y = integer()

Width = integer()

Height = integer()

Set the viewport

gl:viewport specifies the affine transformation of x and y from normalized device coordinates to window coordinates. Let (x nd y nd) be normalized device coordinates. Then the window coordinates (x w y w) are computed as follows:

x w=(x nd+1) (width/2)+x

y w=(y nd+1) (height/2)+y

Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call gl:getBooleanv/1 with argument ?GL_MAX_VIEWPORT_DIMS.

See external documentation.

pushMatrix() -> ok

Push and pop the current matrix stack

There is a stack of matrices for each of the matrix modes. In ?GL_MODELVIEW mode, the stack depth is at least 32. In the other modes, ?GL_COLOR, ?GL_PROJECTION , and ?GL_TEXTURE, the depth is at least 2. The current matrix in any mode is the matrix on the top of the stack for that mode.

gl:pushMatrix pushes the current matrix stack down by one, duplicating the current matrix. That is, after a gl:pushMatrix call, the matrix on top of the stack is identical to the one below it.

gl:pushMatrix/0 pops the current matrix stack, replacing the current matrix with the one below it on the stack.

Initially, each of the stacks contains one matrix, an identity matrix.

It is an error to push a full matrix stack or to pop a matrix stack that contains only a single matrix. In either case, the error flag is set and no other change is made to GL state.

See external documentation.

popMatrix() -> ok

See pushMatrix/0

loadIdentity() -> ok

Replace the current matrix with the identity matrix

gl:loadIdentity replaces the current matrix with the identity matrix. It is semantically equivalent to calling gl:loadMatrixd/1 with the identity matrix

((1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1))

but in some cases it is more efficient.

See external documentation.

loadMatrixd(M) -> ok

Types

M = matrix()

Replace the current matrix with the specified matrix

gl:loadMatrix replaces the current matrix with the one whose elements are specified by M . The current matrix is the projection matrix, modelview matrix, or texture matrix, depending on the current matrix mode (see gl:matrixMode/1 ).

The current matrix, M, defines a transformation of coordinates. For instance, assume M refers to the modelview matrix. If v=(v[0] v[1] v[2] v[3]) is the set of object coordinates of a vertex, and M points to an array of 16 single- or double-precision floating-point values m={m[0] m[1] ... m[15]}, then the modelview transformation M(v) does the following:

M(v)=(m[0] m[4] m[8] m[12] m[1] m[5] m[9] m[13] m[2] m[6] m[10] m[14] m[3] m[7] m[11] m[15])×(v[0] v[1] v[2] v[3])

Projection and texture transformations are similarly defined.

See external documentation.

loadMatrixf(M) -> ok

Types

M = matrix()

See loadMatrixd/1

multMatrixd(M) -> ok

Types

M = matrix()

Multiply the current matrix with the specified matrix

gl:multMatrix multiplies the current matrix with the one specified using M , and replaces the current matrix with the product.

The current matrix is determined by the current matrix mode (see gl:matrixMode/1 ). It is either the projection matrix, modelview matrix, or the texture matrix.

See external documentation.

multMatrixf(M) -> ok

Types

M = matrix()

See multMatrixd/1

rotated(Angle, X, Y, Z) -> ok

Types

Angle = float()

X = float()

Y = float()

Z = float()

Multiply the current matrix by a rotation matrix

gl:rotate produces a rotation of Angle degrees around the vector (x y z). The current matrix (see gl:matrixMode/1 ) is multiplied by a rotation matrix with the product replacing the current matrix, as if gl:multMatrixd/1 were called with the following matrix as its argument:

(x 2(1-c)+c x y(1-c)-z s x z(1-c)+y s 0 y x(1-c)+z s y 2(1-c)+c y z(1-c)-x s 0 x z(1-c)-y s y z(1-c)+x s z 2(1-c)+c 0 0 0 0 1)

Where c=cos(angle), s=sin(angle), and ||(x y z)||=1 (if not, the GL will normalize this vector).

If the matrix mode is either ?GL_MODELVIEW or ?GL_PROJECTION, all objects drawn after gl:rotate is called are rotated. Use gl:pushMatrix/0 and gl:pushMatrix/0 to save and restore the unrotated coordinate system.

See external documentation.

rotatef(Angle, X, Y, Z) -> ok

Types

Angle = float()

X = float()

Y = float()

Z = float()

See rotated/4

scaled(X, Y, Z) -> ok

Types

X = float()

Y = float()

Z = float()

Multiply the current matrix by a general scaling matrix

gl:scale produces a nonuniform scaling along the x, y, and z axes. The three parameters indicate the desired scale factor along each of the three axes.

The current matrix (see gl:matrixMode/1 ) is multiplied by this scale matrix, and the product replaces the current matrix as if gl:multMatrixd/1 were called with the following matrix as its argument:

(x 0 0 0 0 y 0 0 0 0 z 0 0 0 0 1)

If the matrix mode is either ?GL_MODELVIEW or ?GL_PROJECTION, all objects drawn after gl:scale is called are scaled.

Use gl:pushMatrix/0 and gl:pushMatrix/0 to save and restore the unscaled coordinate system.

See external documentation.

scalef(X, Y, Z) -> ok

Types

X = float()

Y = float()

Z = float()

See scaled/3

translated(X, Y, Z) -> ok

Types

X = float()

Y = float()

Z = float()

Multiply the current matrix by a translation matrix

gl:translate produces a translation by (x y z). The current matrix (see gl:matrixMode/1 ) is multiplied by this translation matrix, with the product replacing the current matrix, as if gl:multMatrixd/1 were called with the following matrix for its argument:

(1 0 0 x 0 1 0 y 0 0 1 z 0 0 0 1)

If the matrix mode is either ?GL_MODELVIEW or ?GL_PROJECTION, all objects drawn after a call to gl:translate are translated.

Use gl:pushMatrix/0 and gl:pushMatrix/0 to save and restore the untranslated coordinate system.

See external documentation.

translatef(X, Y, Z) -> ok

Types

X = float()

Y = float()

Z = float()

See translated/3

isList(List) -> 0 | 1

Types

List = integer()

Determine if a name corresponds to a display list

gl:isList returns ?GL_TRUE if List is the name of a display list and returns ?GL_FALSE if it is not, or if an error occurs.

A name returned by gl:genLists/1 , but not yet associated with a display list by calling gl:newList/2 , is not the name of a display list.

See external documentation.

deleteLists(List, Range) -> ok

Types

List = integer()

Range = integer()

Delete a contiguous group of display lists

gl:deleteLists causes a contiguous group of display lists to be deleted. List is the name of the first display list to be deleted, and Range is the number of display lists to delete. All display lists d with list<= d<= list+range-1 are deleted.

All storage locations allocated to the specified display lists are freed, and the names are available for reuse at a later time. Names within the range that do not have an associated display list are ignored. If Range is 0, nothing happens.

See external documentation.

genLists(Range) -> integer()

Types

Range = integer()

Generate a contiguous set of empty display lists

gl:genLists has one argument, Range . It returns an integer n such that Range contiguous empty display lists, named n, n+1, ..., n+range-1, are created. If Range is 0, if there is no group of Range contiguous names available, or if any error is generated, no display lists are generated, and 0 is returned.

See external documentation.

newList(List, Mode) -> ok

Types

List = integer()

Mode = enum()

Create or replace a display list

Display lists are groups of GL commands that have been stored for subsequent execution. Display lists are created with gl:newList. All subsequent commands are placed in the display list, in the order issued, until gl:endList/0 is called.

gl:newList has two arguments. The first argument, List , is a positive integer that becomes the unique name for the display list. Names can be created and reserved with gl:genLists/1 and tested for uniqueness with gl:isList/1 . The second argument, Mode , is a symbolic constant that can assume one of two values:

?GL_COMPILE: Commands are merely compiled.

?GL_COMPILE_AND_EXECUTE: Commands are executed as they are compiled into the display list.

Certain commands are not compiled into the display list but are executed immediately, regardless of the display-list mode. These commands are gl:areTexturesResident/1 , gl:colorPointer/4 , gl:deleteLists/2 , gl:deleteTextures/1 , gl:enableClientState/1 , gl:edgeFlagPointer/2 , gl:enableClientState/1 , gl:feedbackBuffer/3 , gl:finish/0 , gl:flush/0 , gl:genLists/1 , gl:genTextures/1 , gl:indexPointer/3 , gl:interleavedArrays/3 , gl:isEnabled/1 , gl:isList/1 , gl:isTexture/1 , gl:normalPointer/3 , gl:pushClientAttrib/1 , gl:pixelStoref/2 , gl:pushClientAttrib/1 , gl:readPixels/7 , gl:renderMode/1 , gl:selectBuffer/2 , gl:texCoordPointer/4 , gl:vertexPointer/4 , and all of the gl:getBooleanv/1 commands.

Similarly, gl:texImage1D/8 , gl:texImage2D/9 , and gl:texImage3D/10 are executed immediately and not compiled into the display list when their first argument is ?GL_PROXY_TEXTURE_1D, ?GL_PROXY_TEXTURE_1D, or ?GL_PROXY_TEXTURE_3D , respectively.

When the ARB_imaging extension is supported, gl:histogram/4 executes immediately when its argument is ?GL_PROXY_HISTOGRAM. Similarly, gl:colorTable/6 executes immediately when its first argument is ?GL_PROXY_COLOR_TABLE, ?GL_PROXY_POST_CONVOLUTION_COLOR_TABLE , or ?GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE.

For OpenGL versions 1.3 and greater, or when the ARB_multitexture extension is supported, gl:clientActiveTexture/1 is not compiled into display lists, but executed immediately.

When gl:endList/0 is encountered, the display-list definition is completed by associating the list with the unique name List (specified in the gl:newList command). If a display list with name List already exists, it is replaced only when gl:endList/0 is called.

See external documentation.

endList() -> ok

glBeginList

See external documentation.

callList(List) -> ok

Types

List = integer()

Execute a display list

gl:callList causes the named display list to be executed. The commands saved in the display list are executed in order, just as if they were called without using a display list. If List has not been defined as a display list, gl:callList is ignored.

gl:callList can appear inside a display list. To avoid the possibility of infinite recursion resulting from display lists calling one another, a limit is placed on the nesting level of display lists during display-list execution. This limit is at least 64, and it depends on the implementation.

GL state is not saved and restored across a call to gl:callList. Thus, changes made to GL state during the execution of a display list remain after execution of the display list is completed. Use gl:pushAttrib/1 , gl:pushAttrib/1 , gl:pushMatrix/0 , and gl:pushMatrix/0 to preserve GL state across gl:callList calls.

See external documentation.

callLists(Lists) -> ok

Types

Lists = [integer()]

Execute a list of display lists

gl:callLists causes each display list in the list of names passed as Lists to be executed. As a result, the commands saved in each display list are executed in order, just as if they were called without using a display list. Names of display lists that have not been defined are ignored.

gl:callLists provides an efficient means for executing more than one display list. Type allows lists with various name formats to be accepted. The formats are as follows:

?GL_BYTE: Lists is treated as an array of signed bytes, each in the range -128 through 127.

?GL_UNSIGNED_BYTE: Lists is treated as an array of unsigned bytes, each in the range 0 through 255.

?GL_SHORT: Lists is treated as an array of signed two-byte integers, each in the range -32768 through 32767.

?GL_UNSIGNED_SHORT: Lists is treated as an array of unsigned two-byte integers, each in the range 0 through 65535.

?GL_INT: Lists is treated as an array of signed four-byte integers.

?GL_UNSIGNED_INT: Lists is treated as an array of unsigned four-byte integers.

?GL_FLOAT: Lists is treated as an array of four-byte floating-point values.

?GL_2_BYTES: Lists is treated as an array of unsigned bytes. Each pair of bytes specifies a single display-list name. The value of the pair is computed as 256 times the unsigned value of the first byte plus the unsigned value of the second byte.

?GL_3_BYTES: Lists is treated as an array of unsigned bytes. Each triplet of bytes specifies a single display-list name. The value of the triplet is computed as 65536 times the unsigned value of the first byte, plus 256 times the unsigned value of the second byte, plus the unsigned value of the third byte.

?GL_4_BYTES: Lists is treated as an array of unsigned bytes. Each quadruplet of bytes specifies a single display-list name. The value of the quadruplet is computed as 16777216 times the unsigned value of the first byte, plus 65536 times the unsigned value of the second byte, plus 256 times the unsigned value of the third byte, plus the unsigned value of the fourth byte.

The list of display-list names is not null-terminated. Rather, N specifies how many names are to be taken from Lists .

An additional level of indirection is made available with the gl:listBase/1 command, which specifies an unsigned offset that is added to each display-list name specified in Lists before that display list is executed.

gl:callLists can appear inside a display list. To avoid the possibility of infinite recursion resulting from display lists calling one another, a limit is placed on the nesting level of display lists during display-list execution. This limit must be at least 64, and it depends on the implementation.

GL state is not saved and restored across a call to gl:callLists. Thus, changes made to GL state during the execution of the display lists remain after execution is completed. Use gl:pushAttrib/1 , gl:pushAttrib/1 , gl:pushMatrix/0 , and gl:pushMatrix/0 to preserve GL state across gl:callLists calls.

See external documentation.

listBase(Base) -> ok

Types

Base = integer()

set the display-list base for

gl:callLists/1

gl:callLists/1 specifies an array of offsets. Display-list names are generated by adding Base to each offset. Names that reference valid display lists are executed; the others are ignored.

See external documentation.

begin(Mode) -> ok

Types

Mode = enum()

Delimit the vertices of a primitive or a group of like primitives

gl:'begin' and gl:'begin'/1 delimit the vertices that define a primitive or a group of like primitives. gl:'begin' accepts a single argument that specifies in which of ten ways the vertices are interpreted. Taking n as an integer count starting at one, and N as the total number of vertices specified, the interpretations are as follows:

?GL_POINTS: Treats each vertex as a single point. Vertex n defines point n. N points are drawn.

?GL_LINES: Treats each pair of vertices as an independent line segment. Vertices 2 n-1 and 2 n define line n. N/2 lines are drawn.

?GL_LINE_STRIP: Draws a connected group of line segments from the first vertex to the last. Vertices n and n+1 define line n. N-1 lines are drawn.

?GL_LINE_LOOP: Draws a connected group of line segments from the first vertex to the last, then back to the first. Vertices n and n+1 define line n. The last line, however, is defined by vertices N and 1. N lines are drawn.

?GL_TRIANGLES: Treats each triplet of vertices as an independent triangle. Vertices 3 n-2, 3 n-1, and 3 n define triangle n. N/3 triangles are drawn.

?GL_TRIANGLE_STRIP: Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. For odd n, vertices n, n+1, and n+2 define triangle n. For even n, vertices n+1, n, and n+2 define triangle n. N-2 triangles are drawn.

?GL_TRIANGLE_FAN: Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. Vertices 1, n+1, and n+2 define triangle n. N-2 triangles are drawn.

?GL_QUADS: Treats each group of four vertices as an independent quadrilateral. Vertices 4 n-3, 4 n-2, 4 n-1, and 4 n define quadrilateral n. N/4 quadrilaterals are drawn.

?GL_QUAD_STRIP: Draws a connected group of quadrilaterals. One quadrilateral is defined for each pair of vertices presented after the first pair. Vertices 2 n-1, 2 n, 2 n+2, and 2 n+1 define quadrilateral n. N/2-1 quadrilaterals are drawn. Note that the order in which vertices are used to construct a quadrilateral from strip data is different from that used with independent data.

?GL_POLYGON: Draws a single, convex polygon. Vertices 1 through N define this polygon.

Only a subset of GL commands can be used between gl:'begin' and gl:'begin'/1 . The commands are gl:vertex2d/2 , gl:color3b/3 , gl:secondaryColor3b/3 , gl:indexd/1 , gl:normal3b/3 , gl:fogCoordf/1 , gl:texCoord1d/1 , gl:multiTexCoord1d/2 , gl:vertexAttrib1d/2 , gl:evalCoord1d/1 , gl:evalPoint1/1 , gl:arrayElement/1 , gl:materialf/3 , and gl:edgeFlag/1 . Also, it is acceptable to use gl:callList/1 or gl:callLists/1 to execute display lists that include only the preceding commands. If any other GL command is executed between gl:'begin' and gl:'begin'/1 , the error flag is set and the command is ignored.

Regardless of the value chosen for Mode , there is no limit to the number of vertices that can be defined between gl:'begin' and gl:'begin'/1 . Lines, triangles, quadrilaterals, and polygons that are incompletely specified are not drawn. Incomplete specification results when either too few vertices are provided to specify even a single primitive or when an incorrect multiple of vertices is specified. The incomplete primitive is ignored; the rest are drawn.

The minimum specification of vertices for each primitive is as follows: 1 for a point, 2 for a line, 3 for a triangle, 4 for a quadrilateral, and 3 for a polygon. Modes that require a certain multiple of vertices are ?GL_LINES (2), ?GL_TRIANGLES (3), ?GL_QUADS (4), and ?GL_QUAD_STRIP (2).

See external documentation.

end() -> ok

See 'begin'/1

vertex2d(X, Y) -> ok

Types

X = float()

Y = float()

Specify a vertex

gl:vertex commands are used within gl:'begin'/1 / gl:'begin'/1 pairs to specify point, line, and polygon vertices. The current color, normal, texture coordinates, and fog coordinate are associated with the vertex when gl:vertex is called.

When only x and y are specified, z defaults to 0 and w defaults to 1. When x, y, and z are specified, w defaults to 1.

See external documentation.

vertex2f(X, Y) -> ok

Types

X = float()

Y = float()

See vertex2d/2

vertex2i(X, Y) -> ok

Types

X = integer()

Y = integer()

See vertex2d/2

vertex2s(X, Y) -> ok

Nx = integer()

Ny = integer()

Nz = integer()

Set the current normal vector

The current normal is set to the given coordinates whenever gl:normal is issued. Byte, short, or integer arguments are converted to floating-point format with a linear mapping that maps the most positive representable integer value to 1.0 and the most negative representable integer value to -1.0.

Normals specified with gl:normal need not have unit length. If ?GL_NORMALIZE is enabled, then normals of any length specified with gl:normal are normalized after transformation. If ?GL_RESCALE_NORMAL is enabled, normals are scaled by a scaling factor derived from the modelview matrix. ?GL_RESCALE_NORMAL requires that the originally specified normals were of unit length, and that the modelview matrix contain only uniform scales for proper results. To enable and disable normalization, call gl:enable/1 and gl:enable/1 with either ?GL_NORMALIZE or ?GL_RESCALE_NORMAL. Normalization is initially disabled.

See external documentation.

normal3d(Nx, Ny, Nz) -> ok

Types

Nx = float()

Ny = float()

Nz = float()

See normal3b/3

normal3f(Nx, Ny, Nz) -> ok

Types

Nx = float()

Ny = float()

Nz = float()

See normal3b/3

normal3i(Nx, Ny, Nz) -> ok

Types

Nx = integer()

Ny = integer()

Nz = integer()

See normal3b/3

normal3s(Nx, Ny, Nz) -> ok

Types

Nx = integer()

Ny = integer()

The GL stores both a current single-valued color index and a current four-valued RGBA color. gl:color sets a new four-valued RGBA color. gl:color has two major variants: gl:color3 and gl:color4. gl:color3 variants specify new red, green, and blue values explicitly and set the current alpha value to 1.0 (full intensity) implicitly. gl:color4 variants specify all four color components explicitly.

S = float()

Set the current texture coordinates

gl:texCoord specifies texture coordinates in one, two, three, or four dimensions. gl:texCoord1 sets the current texture coordinates to (s 0 0 1); a call to gl:texCoord2 sets them to (s t 0 1). Similarly, gl:texCoord3 specifies the texture coordinates as (s t r 1), and gl:texCoord4 defines all four components explicitly as (s t r q).

The current texture coordinates are part of the data that is associated with each vertex and with the current raster position. Initially, the values for s, t, r , and q are (0, 0, 0, 1).

See external documentation.

texCoord1f(S) -> ok

Types

S = float()

See texCoord1d/1

texCoord1i(S) -> ok

Types

S = integer()

See texCoord1d/1

texCoord1s(S) -> ok

X = float()

Y = float()

Specify the raster position for pixel operations

The GL maintains a 3D position in window coordinates. This position, called the raster position, is used to position pixel and bitmap write operations. It is maintained with subpixel accuracy. See gl:bitmap/7 , gl:drawPixels/5 , and gl:copyPixels/5 .

The current raster position consists of three window coordinates ( x, y, z), a clip coordinate value ( w), an eye coordinate distance, a valid bit, and associated color data and texture coordinates. The w coordinate is a clip coordinate, because w is not projected to window coordinates. gl:rasterPos4 specifies object coordinates x, y, z, and w explicitly. gl:rasterPos3 specifies object coordinate x, y, and z explicitly, while w is implicitly set to 1. gl:rasterPos2 uses the argument values for x and y while implicitly setting z and w to 0 and 1.

The object coordinates presented by gl:rasterPos are treated just like those of a gl:vertex2d/2 command: They are transformed by the current modelview and projection matrices and passed to the clipping stage. If the vertex is not culled, then it is projected and scaled to window coordinates, which become the new current raster position, and the ?GL_CURRENT_RASTER_POSITION_VALID flag is set. If the vertex is culled, then the valid bit is cleared and the current raster position and associated color and texture coordinates are undefined.

The current raster position also includes some associated color data and texture coordinates. If lighting is enabled, then ?GL_CURRENT_RASTER_COLOR (in RGBA mode) or ?GL_CURRENT_RASTER_INDEX (in color index mode) is set to the color produced by the lighting calculation (see gl:lightf/3 , gl:lightModelf/2 , and gl:shadeModel/1 ). If lighting is disabled, current color (in RGBA mode, state variable ?GL_CURRENT_COLOR) or color index (in color index mode, state variable ?GL_CURRENT_INDEX) is used to update the current raster color. ?GL_CURRENT_RASTER_SECONDARY_COLOR (in RGBA mode) is likewise updated.

Likewise, ?GL_CURRENT_RASTER_TEXTURE_COORDS is updated as a function of ?GL_CURRENT_TEXTURE_COORDS , based on the texture matrix and the texture generation functions (see gl:texGend/3 ). Finally, the distance from the origin of the eye coordinate system to the vertex as transformed by only the modelview matrix replaces ?GL_CURRENT_RASTER_DISTANCE.

Initially, the current raster position is (0, 0, 0, 1), the current raster distance is 0, the valid bit is set, the associated RGBA color is (1, 1, 1, 1), the associated color index is 1, and the associated texture coordinates are (0, 0, 0, 1). In RGBA mode, ?GL_CURRENT_RASTER_INDEX is always 1; in color index mode, the current raster RGBA color always maintains its initial value.

See external documentation.

rasterPos2f(X, Y) -> ok

Types

X = float()

Y = float()

See rasterPos2d/2

rasterPos2i(X, Y) -> ok

Types

X = integer()

Y = integer()

See rasterPos2d/2

rasterPos2s(X, Y) -> ok

X1 = float()

Y1 = float()

X2 = float()

Y2 = float()

Draw a rectangle

gl:rect supports efficient specification of rectangles as two corner points. Each rectangle command takes four arguments, organized either as two consecutive pairs of (x y) coordinates or as two pointers to arrays, each containing an (x y) pair. The resulting rectangle is defined in the z=0 plane.

gl:rect( X1 , Y1 , X2 , Y2 ) is exactly equivalent to the following sequence: glBegin(?GL_POLYGON); glVertex2( X1 , Y1 ); glVertex2( X2 , Y1 ); glVertex2( X2 , Y2 ); glVertex2( X1 , Y2 ); glEnd(); Note that if the second vertex is above and to the right of the first vertex, the rectangle is constructed with a counterclockwise winding.

See external documentation.

rectf(X1, Y1, X2, Y2) -> ok

Types

X1 = float()

Y1 = float()

X2 = float()

Y2 = float()

See rectd/4

recti(X1, Y1, X2, Y2) -> ok

Types

X1 = integer()

Y1 = integer()

X2 = integer()

Y2 = integer()

See rectd/4

rects(X1, Y1, X2, Y2) -> ok

Types

X1 = integer()

Y1 = integer()

gl:vertexPointer specifies the location and data format of an array of vertex coordinates to use when rendering. Size specifies the number of coordinates per vertex, and must be 2, 3, or 4. Type specifies the data type of each coordinate, and Stride specifies the byte stride from one vertex to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see gl:interleavedArrays/3 .)

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while a vertex array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as vertex array client-side state (?GL_VERTEX_ARRAY_BUFFER_BINDING).

When a vertex array is specified, Size , Type , Stride , and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable the vertex array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_VERTEX_ARRAY. If enabled, the vertex array is used when gl:arrayElement/1 , gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements , or gl:drawRangeElements/6 is called.

See external documentation.

normalPointer(Type, Stride, Ptr) -> ok

Types

Type = enum()

Stride = integer()

Ptr = offset() | mem()

Define an array of normals

gl:normalPointer specifies the location and data format of an array of normals to use when rendering. Type specifies the data type of each normal coordinate, and Stride specifies the byte stride from one normal to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see gl:interleavedArrays/3 .)

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while a normal array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as normal vertex array client-side state (?GL_NORMAL_ARRAY_BUFFER_BINDING ).

When a normal array is specified, Type , Stride , and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable the normal array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_NORMAL_ARRAY. If enabled, the normal array is used when gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements, gl:drawRangeElements/6 , or gl:arrayElement/1 is called.

See external documentation.

colorPointer(Size, Type, Stride, Ptr) -> ok

Types

Size = integer()

Type = enum()

Stride = integer()

Ptr = offset() | mem()

Define an array of colors

gl:colorPointer specifies the location and data format of an array of color components to use when rendering. Size specifies the number of components per color, and must be 3 or 4. Type specifies the data type of each color component, and Stride specifies the byte stride from one color to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see gl:interleavedArrays/3 .)

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while a color array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as color vertex array client-side state (?GL_COLOR_ARRAY_BUFFER_BINDING).

When a color array is specified, Size , Type , Stride , and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable the color array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_COLOR_ARRAY. If enabled, the color array is used when gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements, gl:drawRangeElements/6 , or gl:arrayElement/1 is called.

See external documentation.

indexPointer(Type, Stride, Ptr) -> ok

Types

Type = enum()

Stride = integer()

Ptr = offset() | mem()

Define an array of color indexes

gl:indexPointer specifies the location and data format of an array of color indexes to use when rendering. Type specifies the data type of each color index and Stride specifies the byte stride from one color index to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays.

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while a color index array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as color index vertex array client-side state (?GL_INDEX_ARRAY_BUFFER_BINDING ).

When a color index array is specified, Type , Stride , and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable the color index array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_INDEX_ARRAY. If enabled, the color index array is used when gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements , gl:drawRangeElements/6 , or gl:arrayElement/1 is called.

See external documentation.

texCoordPointer(Size, Type, Stride, Ptr) -> ok

Types

Size = integer()

Type = enum()

Stride = integer()

Ptr = offset() | mem()

Define an array of texture coordinates

gl:texCoordPointer specifies the location and data format of an array of texture coordinates to use when rendering. Size specifies the number of coordinates per texture coordinate set, and must be 1, 2, 3, or 4. Type specifies the data type of each texture coordinate, and Stride specifies the byte stride from one texture coordinate set to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see gl:interleavedArrays/3 .)

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while a texture coordinate array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as texture coordinate vertex array client-side state (?GL_TEXTURE_COORD_ARRAY_BUFFER_BINDING ).

When a texture coordinate array is specified, Size , Type , Stride , and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable a texture coordinate array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_TEXTURE_COORD_ARRAY. If enabled, the texture coordinate array is used when gl:arrayElement/1 , gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements, or gl:drawRangeElements/6 is called.

See external documentation.

edgeFlagPointer(Stride, Ptr) -> ok

Types

Stride = integer()

Ptr = offset() | mem()

Define an array of edge flags

gl:edgeFlagPointer specifies the location and data format of an array of boolean edge flags to use when rendering. Stride specifies the byte stride from one edge flag to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays.

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while an edge flag array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as edge flag vertex array client-side state (?GL_EDGE_FLAG_ARRAY_BUFFER_BINDING ).

When an edge flag array is specified, Stride and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable the edge flag array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_EDGE_FLAG_ARRAY. If enabled, the edge flag array is used when gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements , gl:drawRangeElements/6 , or gl:arrayElement/1 is called.

See external documentation.

arrayElement(I) -> ok

Types

I = integer()

Render a vertex using the specified vertex array element

gl:arrayElement commands are used within gl:'begin'/1 / gl:'begin'/1 pairs to specify vertex and attribute data for point, line, and polygon primitives. If ?GL_VERTEX_ARRAY is enabled when gl:arrayElement is called, a single vertex is drawn, using vertex and attribute data taken from location I of the enabled arrays. If ?GL_VERTEX_ARRAY is not enabled, no drawing occurs but the attributes corresponding to the enabled arrays are modified.

Use gl:arrayElement to construct primitives by indexing vertex data, rather than by streaming through arrays of data in first-to-last order. Because each call specifies only a single vertex, it is possible to explicitly specify per-primitive attributes such as a single normal for each triangle.

Changes made to array data between the execution of gl:'begin'/1 and the corresponding execution of gl:'begin'/1 may affect calls to gl:arrayElement that are made within the same gl:'begin'/1 / gl:'begin'/1 period in nonsequential ways. That is, a call to gl:arrayElement that precedes a change to array data may access the changed data, and a call that follows a change to array data may access original data.

See external documentation.

drawArrays(Mode, First, Count) -> ok

Mode = enum()

Select flat or smooth shading

GL primitives can have either flat or smooth shading. Smooth shading, the default, causes the computed colors of vertices to be interpolated as the primitive is rasterized, typically assigning different colors to each resulting pixel fragment. Flat shading selects the computed color of just one vertex and assigns it to all the pixel fragments generated by rasterizing a single primitive. In either case, the computed color of a vertex is the result of lighting if lighting is enabled, or it is the current color at the time the vertex was specified if lighting is disabled.

Flat and smooth shading are indistinguishable for points. Starting when gl:'begin'/1 is issued and counting vertices and primitives from 1, the GL gives each flat-shaded line segment i the computed color of vertex i+1, its second vertex. Counting similarly from 1, the GL gives each flat-shaded polygon the computed color of the vertex listed in the following table. This is the last vertex to specify the polygon in all cases except single polygons, where the first vertex specifies the flat-shaded color.

Primitive Type of Polygon iVertex
Single polygon ( i== 1) 1
Triangle strip i+2
Triangle fan i+2
Independent triangle 3 i
Quad strip 2 i+2
Independent quad 4 i

Flat and smooth shading are specified by gl:shadeModel with Mode set to ?GL_FLAT and ?GL_SMOOTH, respectively.

See external documentation.

lightf(Light, Pname, Param) -> ok

Types

Light = enum()

Pname = enum()

Param = float()

Set light source parameters

gl:light sets the values of individual light source parameters. Light names the light and is a symbolic name of the form ?GL_LIGHT i, where i ranges from 0 to the value of ?GL_MAX_LIGHTS - 1. Pname specifies one of ten light source parameters, again by symbolic name. Params is either a single value or a pointer to an array that contains the new values.

To enable and disable lighting calculation, call gl:enable/1 and gl:enable/1 with argument ?GL_LIGHTING. Lighting is initially disabled. When it is enabled, light sources that are enabled contribute to the lighting calculation. Light source i is enabled and disabled using gl:enable/1 and gl:enable/1 with argument ?GL_LIGHT i.

The ten light parameters are as follows:

?GL_AMBIENT: Params contains four integer or floating-point values that specify the ambient RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient light intensity is (0, 0, 0, 1).

?GL_DIFFUSE: Params contains four integer or floating-point values that specify the diffuse RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial value for ?GL_LIGHT0 is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 1).

?GL_SPECULAR: Params contains four integer or floating-point values that specify the specular RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial value for ?GL_LIGHT0 is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 1).

?GL_POSITION: Params contains four integer or floating-point values that specify the position of the light in homogeneous object coordinates. Both integer and floating-point values are mapped directly. Neither integer nor floating-point values are clamped.

The position is transformed by the modelview matrix when gl:light is called (just as if it were a point), and it is stored in eye coordinates. If the w component of the position is 0, the light is treated as a directional source. Diffuse and specular lighting calculations take the light's direction, but not its actual position, into account, and attenuation is disabled. Otherwise, diffuse and specular lighting calculations are based on the actual location of the light in eye coordinates, and attenuation is enabled. The initial position is (0, 0, 1, 0); thus, the initial light source is directional, parallel to, and in the direction of the -z axis.

?GL_SPOT_DIRECTION: Params contains three integer or floating-point values that specify the direction of the light in homogeneous object coordinates. Both integer and floating-point values are mapped directly. Neither integer nor floating-point values are clamped.

The spot direction is transformed by the upper 3x3 of the modelview matrix when gl:light is called, and it is stored in eye coordinates. It is significant only when ?GL_SPOT_CUTOFF is not 180, which it is initially. The initial direction is (0 0 -1).

?GL_SPOT_EXPONENT: Params is a single integer or floating-point value that specifies the intensity distribution of the light. Integer and floating-point values are mapped directly. Only values in the range [0 128] are accepted.

Effective light intensity is attenuated by the cosine of the angle between the direction of the light and the direction from the light to the vertex being lighted, raised to the power of the spot exponent. Thus, higher spot exponents result in a more focused light source, regardless of the spot cutoff angle (see ?GL_SPOT_CUTOFF, next paragraph). The initial spot exponent is 0, resulting in uniform light distribution.

?GL_SPOT_CUTOFF: Params is a single integer or floating-point value that specifies the maximum spread angle of a light source. Integer and floating-point values are mapped directly. Only values in the range [0 90] and the special value 180 are accepted. If the angle between the direction of the light and the direction from the light to the vertex being lighted is greater than the spot cutoff angle, the light is completely masked. Otherwise, its intensity is controlled by the spot exponent and the attenuation factors. The initial spot cutoff is 180, resulting in uniform light distribution.

?GL_CONSTANT_ATTENUATION

?GL_LINEAR_ATTENUATION

?GL_QUADRATIC_ATTENUATION: Params is a single integer or floating-point value that specifies one of the three light attenuation factors. Integer and floating-point values are mapped directly. Only nonnegative values are accepted. If the light is positional, rather than directional, its intensity is attenuated by the reciprocal of the sum of the constant factor, the linear factor times the distance between the light and the vertex being lighted, and the quadratic factor times the square of the same distance. The initial attenuation factors are (1, 0, 0), resulting in no attenuation.

See external documentation.

lighti(Light, Pname, Param) -> ok

Types

Light = enum()

Pname = enum()

See getLightfv/2

lightModelf(Pname, Param) -> ok

Types

Pname = enum()

Param = float()

Set the lighting model parameters

gl:lightModel sets the lighting model parameter. Pname names a parameter and Params gives the new value. There are three lighting model parameters:

?GL_LIGHT_MODEL_AMBIENT: Params contains four integer or floating-point values that specify the ambient RGBA intensity of the entire scene. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient scene intensity is (0.2, 0.2, 0.2, 1.0).

?GL_LIGHT_MODEL_COLOR_CONTROL: Params must be either ?GL_SEPARATE_SPECULAR_COLOR or ?GL_SINGLE_COLOR. ?GL_SINGLE_COLOR specifies that a single color is generated from the lighting computation for a vertex. ?GL_SEPARATE_SPECULAR_COLOR specifies that the specular color computation of lighting be stored separately from the remainder of the lighting computation. The specular color is summed into the generated fragment's color after the application of texture mapping (if enabled). The initial value is ?GL_SINGLE_COLOR.

?GL_LIGHT_MODEL_LOCAL_VIEWER: Params is a single integer or floating-point value that specifies how specular reflection angles are computed. If Params is 0 (or 0.0), specular reflection angles take the view direction to be parallel to and in the direction of the -z axis, regardless of the location of the vertex in eye coordinates. Otherwise, specular reflections are computed from the origin of the eye coordinate system. The initial value is 0.

?GL_LIGHT_MODEL_TWO_SIDE: Params is a single integer or floating-point value that specifies whether one- or two-sided lighting calculations are done for polygons. It has no effect on the lighting calculations for points, lines, or bitmaps. If Params is 0 (or 0.0), one-sided lighting is specified, and only the front material parameters are used in the lighting equation. Otherwise, two-sided lighting is specified. In this case, vertices of back-facing polygons are lighted using the back material parameters and have their normals reversed before the lighting equation is evaluated. Vertices of front-facing polygons are always lighted using the front material parameters, with no change to their normals. The initial value is 0.

In RGBA mode, the lighted color of a vertex is the sum of the material emission intensity, the product of the material ambient reflectance and the lighting model full-scene ambient intensity, and the contribution of each enabled light source. Each light source contributes the sum of three terms: ambient, diffuse, and specular. The ambient light source contribution is the product of the material ambient reflectance and the light's ambient intensity. The diffuse light source contribution is the product of the material diffuse reflectance, the light's diffuse intensity, and the dot product of the vertex's normal with the normalized vector from the vertex to the light source. The specular light source contribution is the product of the material specular reflectance, the light's specular intensity, and the dot product of the normalized vertex-to-eye and vertex-to-light vectors, raised to the power of the shininess of the material. All three light source contributions are attenuated equally based on the distance from the vertex to the light source and on light source direction, spread exponent, and spread cutoff angle. All dot products are replaced with 0 if they evaluate to a negative value.

The alpha component of the resulting lighted color is set to the alpha value of the material diffuse reflectance.

In color index mode, the value of the lighted index of a vertex ranges from the ambient to the specular values passed to gl:materialf/3 using ?GL_COLOR_INDEXES. Diffuse and specular coefficients, computed with a (.30, .59, .11) weighting of the lights' colors, the shininess of the material, and the same reflection and attenuation equations as in the RGBA case, determine how much above ambient the resulting index is.

See external documentation.

lightModeli(Pname, Param) -> ok

Types

Pname = enum()

Param = integer()

See lightModelf/2

lightModelfv(Pname, Params) -> ok

Types

Pname = enum()

Params = tuple()

See lightModelf/2

lightModeliv(Pname, Params) -> ok

Types

Pname = enum()

Params = tuple()

See lightModelf/2

materialf(Face, Pname, Param) -> ok

Types

Face = enum()

Pname = enum()

Param = float()

Specify material parameters for the lighting model

gl:material assigns values to material parameters. There are two matched sets of material parameters. One, the front-facing set, is used to shade points, lines, bitmaps, and all polygons (when two-sided lighting is disabled), or just front-facing polygons (when two-sided lighting is enabled). The other set, back-facing, is used to shade back-facing polygons only when two-sided lighting is enabled. Refer to the gl:lightModelf/2 reference page for details concerning one- and two-sided lighting calculations.

gl:material takes three arguments. The first, Face , specifies whether the ?GL_FRONT materials, the ?GL_BACK materials, or both ?GL_FRONT_AND_BACK materials will be modified. The second, Pname , specifies which of several parameters in one or both sets will be modified. The third, Params , specifies what value or values will be assigned to the specified parameter.

Material parameters are used in the lighting equation that is optionally applied to each vertex. The equation is discussed in the gl:lightModelf/2 reference page. The parameters that can be specified using gl:material, and their interpretations by the lighting equation, are as follows:

?GL_AMBIENT: Params contains four integer or floating-point values that specify the ambient RGBA reflectance of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient reflectance for both front- and back-facing materials is (0.2, 0.2, 0.2, 1.0).

?GL_DIFFUSE: Params contains four integer or floating-point values that specify the diffuse RGBA reflectance of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial diffuse reflectance for both front- and back-facing materials is (0.8, 0.8, 0.8, 1.0).

?GL_SPECULAR: Params contains four integer or floating-point values that specify the specular RGBA reflectance of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial specular reflectance for both front- and back-facing materials is (0, 0, 0, 1).

?GL_EMISSION: Params contains four integer or floating-point values that specify the RGBA emitted light intensity of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial emission intensity for both front- and back-facing materials is (0, 0, 0, 1).

?GL_SHININESS: Params is a single integer or floating-point value that specifies the RGBA specular exponent of the material. Integer and floating-point values are mapped directly. Only values in the range [0 128] are accepted. The initial specular exponent for both front- and back-facing materials is 0.

?GL_AMBIENT_AND_DIFFUSE: Equivalent to calling gl:material twice with the same parameter values, once with ?GL_AMBIENT and once with ?GL_DIFFUSE.

?GL_COLOR_INDEXES: Params contains three integer or floating-point values specifying the color indices for ambient, diffuse, and specular lighting. These three values, and ?GL_SHININESS, are the only material values used by the color index mode lighting equation. Refer to the gl:lightModelf/2 reference page for a discussion of color index lighting.

See external documentation.

materiali(Face, Pname, Param) -> ok

Types

Face = enum()

Pname = enum()

Param = integer()

See materialf/3

materialfv(Face, Pname, Params) -> ok

Types

Face = enum()

Pname = enum()

Params = tuple()

See materialf/3

materialiv(Face, Pname, Params) -> ok

Types

Face = enum()

Pname = enum()

Params = tuple()

See materialf/3

getMaterialfv(Face, Pname) -> {float(), float(), float(), float()}

Types

Face = enum()

Pname = enum()

Return material parameters

gl:getMaterial returns in Params the value or values of parameter Pname of material Face . Six parameters are defined:

?GL_AMBIENT: Params returns four integer or floating-point values representing the ambient reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1 1], the corresponding integer return value is undefined. The initial value is (0.2, 0.2, 0.2, 1.0)

?GL_DIFFUSE: Params returns four integer or floating-point values representing the diffuse reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1 1], the corresponding integer return value is undefined. The initial value is (0.8, 0.8, 0.8, 1.0).

?GL_SPECULAR: Params returns four integer or floating-point values representing the specular reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1 1], the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1).

?GL_EMISSION: Params returns four integer or floating-point values representing the emitted light intensity of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1 1], the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1).

?GL_SHININESS: Params returns one integer or floating-point value representing the specular exponent of the material. Integer values, when requested, are computed by rounding the internal floating-point value to the nearest integer value. The initial value is 0.

?GL_COLOR_INDEXES: Params returns three integer or floating-point values representing the ambient, diffuse, and specular indices of the material. These indices are used only for color index lighting. (All the other parameters are used only for RGBA lighting.) Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.

See external documentation.

getMaterialiv(Face, Pname) -> {integer(), integer(), integer(), integer()}

Types

Face = enum()

Pname = enum()

See getMaterialfv/2

colorMaterial(Face, Mode) -> ok

Types

Face = enum()

Mode = enum()

Cause a material color to track the current color

gl:colorMaterial specifies which material parameters track the current color. When ?GL_COLOR_MATERIAL is enabled, the material parameter or parameters specified by Mode , of the material or materials specified by Face , track the current color at all times.

To enable and disable ?GL_COLOR_MATERIAL, call gl:enable/1 and gl:enable/1 with argument ?GL_COLOR_MATERIAL. ?GL_COLOR_MATERIAL is initially disabled.

See external documentation.

pixelZoom(Xfactor, Yfactor) -> ok

Types

Xfactor = float()

Yfactor = float()

Specify the pixel zoom factors

gl:pixelZoom specifies values for the x and y zoom factors. During the execution of gl:drawPixels/5 or gl:copyPixels/5 , if ( xr, yr) is the current raster position, and a given element is in the mth row and nth column of the pixel rectangle, then pixels whose centers are in the rectangle with corners at

( xr+n. xfactor, yr+m. yfactor)

( xr+(n+1). xfactor, yr+(m+1). yfactor)

are candidates for replacement. Any pixel whose center lies on the bottom or left edge of this rectangular region is also modified.

Pixel zoom factors are not limited to positive values. Negative zoom factors reflect the resulting image about the current raster position.

See external documentation.

pixelStoref(Pname, Param) -> ok

Types

Pname = enum()

Param = float()

Set pixel storage modes

gl:pixelStore sets pixel storage modes that affect the operation of subsequent gl:readPixels/7 as well as the unpacking of texture patterns (see gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , gl:texSubImage1D/7 ), gl:compressedTexImage1D/7 , gl:compressedTexImage2D/8 , gl:compressedTexImage3D/9 , gl:compressedTexSubImage1D/7 , gl:compressedTexSubImage2D/9 or gl:compressedTexSubImage1D/7 .

Pname is a symbolic constant indicating the parameter to be set, and Param is the new value. Six of the twelve storage parameters affect how pixel data is returned to client memory. They are as follows:

?GL_PACK_SWAP_BYTES: If true, byte ordering for multibyte color components, depth components, or stencil indices is reversed. That is, if a four-byte component consists of bytes b 0, b 1, b 2, b 3, it is stored in memory as b 3, b 2, b 1, b 0 if ?GL_PACK_SWAP_BYTES is true. ?GL_PACK_SWAP_BYTES has no effect on the memory order of components within a pixel, only on the order of bytes within components or indices. For example, the three components of a ?GL_RGB format pixel are always stored with red first, green second, and blue third, regardless of the value of ?GL_PACK_SWAP_BYTES.

?GL_PACK_LSB_FIRST: If true, bits are ordered within a byte from least significant to most significant; otherwise, the first bit in each byte is the most significant one.

?GL_PACK_ROW_LENGTH: If greater than 0, ?GL_PACK_ROW_LENGTH defines the number of pixels in a row. If the first pixel of a row is placed at location p in memory, then the location of the first pixel of the next row is obtained by skipping

k={n l(a/s) |(s n l)/a| s>= a s< a)

components or indices, where n is the number of components or indices in a pixel, l is the number of pixels in a row (?GL_PACK_ROW_LENGTH if it is greater than 0, the width argument to the pixel routine otherwise), a is the value of ?GL_PACK_ALIGNMENT , and s is the size, in bytes, of a single component (if a< s, then it is as if a= s). In the case of 1-bit values, the location of the next row is obtained by skipping

k=8 a |(n l)/(8 a)|

components or indices.

The word component in this description refers to the nonindex values red, green, blue, alpha, and depth. Storage format ?GL_RGB, for example, has three components per pixel: first red, then green, and finally blue.

?GL_PACK_IMAGE_HEIGHT: If greater than 0, ?GL_PACK_IMAGE_HEIGHT defines the number of pixels in an image three-dimensional texture volume, where image is defined by all pixels sharing the same third dimension index. If the first pixel of a row is placed at location p in memory, then the location of the first pixel of the next row is obtained by skipping

k={n l h(a/s) |(s n l h)/a| s>= a s< a)

components or indices, where n is the number of components or indices in a pixel, l is the number of pixels in a row (?GL_PACK_ROW_LENGTH if it is greater than 0, the width argument to gl:texImage3D/10 otherwise), h is the number of rows in a pixel image (?GL_PACK_IMAGE_HEIGHT if it is greater than 0, the height argument to the gl:texImage3D/10 routine otherwise), a is the value of ?GL_PACK_ALIGNMENT , and s is the size, in bytes, of a single component (if a< s, then it is as if a=s).

?GL_PACK_SKIP_PIXELS, ?GL_PACK_SKIP_ROWS, and ?GL_PACK_SKIP_IMAGES

These values are provided as a convenience to the programmer; they provide no functionality that cannot be duplicated simply by incrementing the pointer passed to gl:readPixels/7 . Setting ?GL_PACK_SKIP_PIXELS to i is equivalent to incrementing the pointer by i n components or indices, where n is the number of components or indices in each pixel. Setting ?GL_PACK_SKIP_ROWS to j is equivalent to incrementing the pointer by j m components or indices, where m is the number of components or indices per row, as just computed in the ?GL_PACK_ROW_LENGTH section. Setting ?GL_PACK_SKIP_IMAGES to k is equivalent to incrementing the pointer by k p, where p is the number of components or indices per image, as computed in the ?GL_PACK_IMAGE_HEIGHT section.

?GL_PACK_ALIGNMENT: Specifies the alignment requirements for the start of each pixel row in memory. The allowable values are 1 (byte-alignment), 2 (rows aligned to even-numbered bytes), 4 (word-alignment), and 8 (rows start on double-word boundaries).

The other six of the twelve storage parameters affect how pixel data is read from client memory. These values are significant for gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , and gl:texSubImage1D/7

They are as follows:

?GL_UNPACK_SWAP_BYTES: If true, byte ordering for multibyte color components, depth components, or stencil indices is reversed. That is, if a four-byte component consists of bytes b 0, b 1, b 2, b 3, it is taken from memory as b 3, b 2, b 1, b 0 if ?GL_UNPACK_SWAP_BYTES is true. ?GL_UNPACK_SWAP_BYTES has no effect on the memory order of components within a pixel, only on the order of bytes within components or indices. For example, the three components of a ?GL_RGB format pixel are always stored with red first, green second, and blue third, regardless of the value of ?GL_UNPACK_SWAP_BYTES.

?GL_UNPACK_LSB_FIRST: If true, bits are ordered within a byte from least significant to most significant; otherwise, the first bit in each byte is the most significant one.

?GL_UNPACK_ROW_LENGTH: If greater than 0, ?GL_UNPACK_ROW_LENGTH defines the number of pixels in a row. If the first pixel of a row is placed at location p in memory, then the location of the first pixel of the next row is obtained by skipping

k={n l(a/s) |(s n l)/a| s>= a s< a)

components or indices, where n is the number of components or indices in a pixel, l is the number of pixels in a row (?GL_UNPACK_ROW_LENGTH if it is greater than 0, the width argument to the pixel routine otherwise), a is the value of ?GL_UNPACK_ALIGNMENT , and s is the size, in bytes, of a single component (if a< s, then it is as if a= s). In the case of 1-bit values, the location of the next row is obtained by skipping

k=8 a |(n l)/(8 a)|

components or indices.

?GL_UNPACK_IMAGE_HEIGHT: If greater than 0, ?GL_UNPACK_IMAGE_HEIGHT defines the number of pixels in an image of a three-dimensional texture volume. Where image is defined by all pixel sharing the same third dimension index. If the first pixel of a row is placed at location p in memory, then the location of the first pixel of the next row is obtained by skipping

k={n l h(a/s) |(s n l h)/a| s>= a s< a)

components or indices, where n is the number of components or indices in a pixel, l is the number of pixels in a row (?GL_UNPACK_ROW_LENGTH if it is greater than 0, the width argument to gl:texImage3D/10 otherwise), h is the number of rows in an image (?GL_UNPACK_IMAGE_HEIGHT if it is greater than 0, the height argument to gl:texImage3D/10 otherwise), a is the value of ?GL_UNPACK_ALIGNMENT, and s is the size, in bytes, of a single component (if a< s, then it is as if a=s).

?GL_UNPACK_SKIP_PIXELS and ?GL_UNPACK_SKIP_ROWS

These values are provided as a convenience to the programmer; they provide no functionality that cannot be duplicated by incrementing the pointer passed to gl:texImage1D/8 , gl:texImage2D/9 , gl:texSubImage1D/7 or gl:texSubImage1D/7 . Setting ?GL_UNPACK_SKIP_PIXELS to i is equivalent to incrementing the pointer by i n components or indices, where n is the number of components or indices in each pixel. Setting ?GL_UNPACK_SKIP_ROWS to j is equivalent to incrementing the pointer by j k components or indices, where k is the number of components or indices per row, as just computed in the ?GL_UNPACK_ROW_LENGTH section.

?GL_UNPACK_ALIGNMENT: Specifies the alignment requirements for the start of each pixel row in memory. The allowable values are 1 (byte-alignment), 2 (rows aligned to even-numbered bytes), 4 (word-alignment), and 8 (rows start on double-word boundaries).

The following table gives the type, initial value, and range of valid values for each storage parameter that can be set with gl:pixelStore.

Pname TypeInitial Value Valid Range
?GL_PACK_SWAP_BYTES boolean false true or false
?GL_PACK_LSB_FIRST boolean false true or false
?GL_PACK_ROW_LENGTH integer 0 [0)
?GL_PACK_IMAGE_HEIGHT integer 0 [0)
?GL_PACK_SKIP_ROWS integer 0 [0)
?GL_PACK_SKIP_PIXELS integer 0 [0)
?GL_PACK_SKIP_IMAGES integer 0 [0)
?GL_PACK_ALIGNMENT integer 4 1, 2, 4, or 8
?GL_UNPACK_SWAP_BYTES boolean false true or false
?GL_UNPACK_LSB_FIRST boolean false true or false
?GL_UNPACK_ROW_LENGTH integer 0 [0)
?GL_UNPACK_IMAGE_HEIGHT integer 0 [0)
?GL_UNPACK_SKIP_ROWS integer 0 [0)
?GL_UNPACK_SKIP_PIXELS integer 0 [0)
?GL_UNPACK_SKIP_IMAGES integer 0 [0)
?GL_UNPACK_ALIGNMENT integer 4 1, 2, 4, or 8

gl:pixelStoref can be used to set any pixel store parameter. If the parameter type is boolean, then if Param is 0, the parameter is false; otherwise it is set to true. If Pname is a integer type parameter, Param is rounded to the nearest integer.

Likewise, gl:pixelStorei can also be used to set any of the pixel store parameters. Boolean parameters are set to false if Param is 0 and true otherwise.

See external documentation.

pixelStorei(Pname, Param) -> ok

Types

Pname = enum()

Param = integer()

See pixelStoref/2

pixelTransferf(Pname, Param) -> ok

Types

Pname = enum()

Param = float()

Set pixel transfer modes

gl:pixelTransfer sets pixel transfer modes that affect the operation of subsequent gl:copyPixels/5 , gl:copyTexImage1D/7 , gl:copyTexImage2D/8 , gl:copyTexSubImage1D/6 , gl:copyTexSubImage2D/8 , gl:copyTexSubImage3D/9 , gl:drawPixels/5 , gl:readPixels/7 , gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , and gl:texSubImage1D/7 commands. Additionally, if the ARB_imaging subset is supported, the routines gl:colorTable/6 , gl:colorSubTable/6 , gl:convolutionFilter1D/6 , gl:convolutionFilter2D/7 , gl:histogram/4 , gl:minmax/3 , and gl:separableFilter2D/8 are also affected. The algorithms that are specified by pixel transfer modes operate on pixels after they are read from the frame buffer ( gl:copyPixels/5 gl:copyTexImage1D/7 , gl:copyTexImage2D/8 , gl:copyTexSubImage1D/6 , gl:copyTexSubImage2D/8 , gl:copyTexSubImage3D/9 , and gl:readPixels/7 ), or unpacked from client memory ( gl:drawPixels/5 , gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , and gl:texSubImage1D/7 ). Pixel transfer operations happen in the same order, and in the same manner, regardless of the command that resulted in the pixel operation. Pixel storage modes (see gl:pixelStoref/2 ) control the unpacking of pixels being read from client memory and the packing of pixels being written back into client memory.

Pixel transfer operations handle four fundamental pixel types: color, color index , depth, and stencil. Color pixels consist of four floating-point values with unspecified mantissa and exponent sizes, scaled such that 0 represents zero intensity and 1 represents full intensity. Color indices comprise a single fixed-point value, with unspecified precision to the right of the binary point. Depth pixels comprise a single floating-point value, with unspecified mantissa and exponent sizes, scaled such that 0.0 represents the minimum depth buffer value, and 1.0 represents the maximum depth buffer value. Finally, stencil pixels comprise a single fixed-point value, with unspecified precision to the right of the binary point.

The pixel transfer operations performed on the four basic pixel types are as follows:

Color: Each of the four color components is multiplied by a scale factor, then added to a bias factor. That is, the red component is multiplied by ?GL_RED_SCALE, then added to ?GL_RED_BIAS; the green component is multiplied by ?GL_GREEN_SCALE , then added to ?GL_GREEN_BIAS; the blue component is multiplied by ?GL_BLUE_SCALE , then added to ?GL_BLUE_BIAS; and the alpha component is multiplied by ?GL_ALPHA_SCALE , then added to ?GL_ALPHA_BIAS. After all four color components are scaled and biased, each is clamped to the range [0 1]. All color, scale, and bias values are specified with gl:pixelTransfer.

If ?GL_MAP_COLOR is true, each color component is scaled by the size of the corresponding color-to-color map, then replaced by the contents of that map indexed by the scaled component. That is, the red component is scaled by ?GL_PIXEL_MAP_R_TO_R_SIZE, then replaced by the contents of ?GL_PIXEL_MAP_R_TO_R indexed by itself. The green component is scaled by ?GL_PIXEL_MAP_G_TO_G_SIZE, then replaced by the contents of ?GL_PIXEL_MAP_G_TO_G indexed by itself. The blue component is scaled by ?GL_PIXEL_MAP_B_TO_B_SIZE, then replaced by the contents of ?GL_PIXEL_MAP_B_TO_B indexed by itself. And the alpha component is scaled by ?GL_PIXEL_MAP_A_TO_A_SIZE, then replaced by the contents of ?GL_PIXEL_MAP_A_TO_A indexed by itself. All components taken from the maps are then clamped to the range [0 1]. ?GL_MAP_COLOR is specified with gl:pixelTransfer. The contents of the various maps are specified with gl:pixelMapfv/3 .

If the ARB_imaging extension is supported, each of the four color components may be scaled and biased after transformation by the color matrix. That is, the red component is multiplied by ?GL_POST_COLOR_MATRIX_RED_SCALE, then added to ?GL_POST_COLOR_MATRIX_RED_BIAS ; the green component is multiplied by ?GL_POST_COLOR_MATRIX_GREEN_SCALE, then added to ?GL_POST_COLOR_MATRIX_GREEN_BIAS; the blue component is multiplied by ?GL_POST_COLOR_MATRIX_BLUE_SCALE , then added to ?GL_POST_COLOR_MATRIX_BLUE_BIAS; and the alpha component is multiplied by ?GL_POST_COLOR_MATRIX_ALPHA_SCALE, then added to ?GL_POST_COLOR_MATRIX_ALPHA_BIAS . After all four color components are scaled and biased, each is clamped to the range [0 1].

Similarly, if the ARB_imaging extension is supported, each of the four color components may be scaled and biased after processing by the enabled convolution filter. That is, the red component is multiplied by ?GL_POST_CONVOLUTION_RED_SCALE, then added to ?GL_POST_CONVOLUTION_RED_BIAS ; the green component is multiplied by ?GL_POST_CONVOLUTION_GREEN_SCALE, then added to ?GL_POST_CONVOLUTION_GREEN_BIAS; the blue component is multiplied by ?GL_POST_CONVOLUTION_BLUE_SCALE , then added to ?GL_POST_CONVOLUTION_BLUE_BIAS; and the alpha component is multiplied by ?GL_POST_CONVOLUTION_ALPHA_SCALE, then added to ?GL_POST_CONVOLUTION_ALPHA_BIAS . After all four color components are scaled and biased, each is clamped to the range [0 1].

Color index: Each color index is shifted left by ?GL_INDEX_SHIFT bits; any bits beyond the number of fraction bits carried by the fixed-point index are filled with zeros. If ?GL_INDEX_SHIFT is negative, the shift is to the right, again zero filled. Then ?GL_INDEX_OFFSET is added to the index. ?GL_INDEX_SHIFT and ?GL_INDEX_OFFSET are specified with gl:pixelTransfer.

From this point, operation diverges depending on the required format of the resulting pixels. If the resulting pixels are to be written to a color index buffer, or if they are being read back to client memory in ?GL_COLOR_INDEX format, the pixels continue to be treated as indices. If ?GL_MAP_COLOR is true, each index is masked by 2 n-1 , where n is ?GL_PIXEL_MAP_I_TO_I_SIZE, then replaced by the contents of ?GL_PIXEL_MAP_I_TO_I indexed by the masked value. ?GL_MAP_COLOR is specified with gl:pixelTransfer . The contents of the index map is specified with gl:pixelMapfv/3 .

If the resulting pixels are to be written to an RGBA color buffer, or if they are read back to client memory in a format other than ?GL_COLOR_INDEX, the pixels are converted from indices to colors by referencing the four maps ?GL_PIXEL_MAP_I_TO_R, ?GL_PIXEL_MAP_I_TO_G , ?GL_PIXEL_MAP_I_TO_B, and ?GL_PIXEL_MAP_I_TO_A. Before being dereferenced, the index is masked by 2 n-1, where n is ?GL_PIXEL_MAP_I_TO_R_SIZE for the red map, ?GL_PIXEL_MAP_I_TO_G_SIZE for the green map, ?GL_PIXEL_MAP_I_TO_B_SIZE for the blue map, and ?GL_PIXEL_MAP_I_TO_A_SIZE for the alpha map. All components taken from the maps are then clamped to the range [0 1]. The contents of the four maps is specified with gl:pixelMapfv/3 .

Depth: Each depth value is multiplied by ?GL_DEPTH_SCALE, added to ?GL_DEPTH_BIAS , then clamped to the range [0 1].

Stencil: Each index is shifted ?GL_INDEX_SHIFT bits just as a color index is, then added to ?GL_INDEX_OFFSET. If ?GL_MAP_STENCIL is true, each index is masked by 2 n-1, where n is ?GL_PIXEL_MAP_S_TO_S_SIZE, then replaced by the contents of ?GL_PIXEL_MAP_S_TO_S indexed by the masked value.

The following table gives the type, initial value, and range of valid values for each of the pixel transfer parameters that are set with gl:pixelTransfer.

Pname TypeInitial Value Valid Range
?GL_MAP_COLOR boolean false true/false
?GL_MAP_STENCIL boolean false true/false
?GL_INDEX_SHIFT integer 0 (-)
?GL_INDEX_OFFSET integer 0 (-)
?GL_RED_SCALE float 1 (-)
?GL_GREEN_SCALE float 1 (-)
?GL_BLUE_SCALE float 1 (-)
?GL_ALPHA_SCALE float 1 (-)
?GL_DEPTH_SCALE float 1 (-)
?GL_RED_BIAS float 0 (-)
?GL_GREEN_BIAS float 0 (-)
?GL_BLUE_BIAS float 0 (-)
?GL_ALPHA_BIAS float 0 (-)
?GL_DEPTH_BIAS float 0 (-)
?GL_POST_COLOR_MATRIX_RED_SCALE float 1 (-)
?GL_POST_COLOR_MATRIX_GREEN_SCALE float 1 (-)
?GL_POST_COLOR_MATRIX_BLUE_SCALE float 1 (-)
?GL_POST_COLOR_MATRIX_ALPHA_SCALE float 1 (-)
?GL_POST_COLOR_MATRIX_RED_BIAS float 0 (-)
?GL_POST_COLOR_MATRIX_GREEN_BIAS float 0 (-)
?GL_POST_COLOR_MATRIX_BLUE_BIAS float 0 (-)
?GL_POST_COLOR_MATRIX_ALPHA_BIAS float 0 (-)
?GL_POST_CONVOLUTION_RED_SCALE float 1 (-)
?GL_POST_CONVOLUTION_GREEN_SCALE float 1 (-)
?GL_POST_CONVOLUTION_BLUE_SCALE float 1 (-)
?GL_POST_CONVOLUTION_ALPHA_SCALE float 1 (-)
?GL_POST_CONVOLUTION_RED_BIAS float 0 (-)
?GL_POST_CONVOLUTION_GREEN_BIAS float 0 (-)
?GL_POST_CONVOLUTION_BLUE_BIAS float 0 (-)
?GL_POST_CONVOLUTION_ALPHA_BIAS float 0 (-)

gl:pixelTransferf can be used to set any pixel transfer parameter. If the parameter type is boolean, 0 implies false and any other value implies true. If Pname is an integer parameter, Param is rounded to the nearest integer.

Likewise, gl:pixelTransferi can be used to set any of the pixel transfer parameters. Boolean parameters are set to false if Param is 0 and to true otherwise. Param is converted to floating point before being assigned to real-valued parameters.

See external documentation.

pixelTransferi(Pname, Param) -> ok

Types

Pname = enum()

Param = integer()

See pixelTransferf/2

pixelMapfv(Map, Mapsize, Values) -> ok

Types

Map = enum()

Mapsize = integer()

Values = binary()

Set up pixel transfer maps

gl:pixelMap sets up translation tables, or maps, used by gl:copyPixels/5 , gl:copyTexImage1D/7 , gl:copyTexImage2D/8 , gl:copyTexSubImage1D/6 , gl:copyTexSubImage2D/8 , gl:copyTexSubImage3D/9 , gl:drawPixels/5 , gl:readPixels/7 , gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , and gl:texSubImage1D/7 . Additionally, if the ARB_imaging subset is supported, the routines gl:colorTable/6 , gl:colorSubTable/6 , gl:convolutionFilter1D/6 , gl:convolutionFilter2D/7 , gl:histogram/4 , gl:minmax/3 , and gl:separableFilter2D/8 . Use of these maps is described completely in the gl:pixelTransferf/2 reference page, and partly in the reference pages for the pixel and texture image commands. Only the specification of the maps is described in this reference page.

Map is a symbolic map name, indicating one of ten maps to set. Mapsize specifies the number of entries in the map, and Values is a pointer to an array of Mapsize map values.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a pixel transfer map is specified, Values is treated as a byte offset into the buffer object's data store.

The ten maps are as follows:

?GL_PIXEL_MAP_I_TO_I: Maps color indices to color indices.

?GL_PIXEL_MAP_S_TO_S: Maps stencil indices to stencil indices.

?GL_PIXEL_MAP_I_TO_R: Maps color indices to red components.

?GL_PIXEL_MAP_I_TO_G: Maps color indices to green components.

?GL_PIXEL_MAP_I_TO_B: Maps color indices to blue components.

?GL_PIXEL_MAP_I_TO_A: Maps color indices to alpha components.

?GL_PIXEL_MAP_R_TO_R: Maps red components to red components.

?GL_PIXEL_MAP_G_TO_G: Maps green components to green components.

?GL_PIXEL_MAP_B_TO_B: Maps blue components to blue components.

?GL_PIXEL_MAP_A_TO_A: Maps alpha components to alpha components.

The entries in a map can be specified as single-precision floating-point numbers, unsigned short integers, or unsigned int integers. Maps that store color component values (all but ?GL_PIXEL_MAP_I_TO_I and ?GL_PIXEL_MAP_S_TO_S) retain their values in floating-point format, with unspecified mantissa and exponent sizes. Floating-point values specified by gl:pixelMapfv are converted directly to the internal floating-point format of these maps, then clamped to the range [0,1]. Unsigned integer values specified by gl:pixelMapusv and gl:pixelMapuiv are converted linearly such that the largest representable integer maps to 1.0, and 0 maps to 0.0.

Maps that store indices, ?GL_PIXEL_MAP_I_TO_I and ?GL_PIXEL_MAP_S_TO_S, retain their values in fixed-point format, with an unspecified number of bits to the right of the binary point. Floating-point values specified by gl:pixelMapfv are converted directly to the internal fixed-point format of these maps. Unsigned integer values specified by gl:pixelMapusv and gl:pixelMapuiv specify integer values, with all 0's to the right of the binary point.

The following table shows the initial sizes and values for each of the maps. Maps that are indexed by either color or stencil indices must have Mapsize = 2 n for some n or the results are undefined. The maximum allowable size for each map depends on the implementation and can be determined by calling gl:getBooleanv/1 with argument ?GL_MAX_PIXEL_MAP_TABLE . The single maximum applies to all maps; it is at least 32.

Map Lookup IndexLookup ValueInitial Size Initial Value
?GL_PIXEL_MAP_I_TO_I color index color index 1 0
?GL_PIXEL_MAP_S_TO_S stencil index stencil index 1 0
?GL_PIXEL_MAP_I_TO_R color index R 1 0
?GL_PIXEL_MAP_I_TO_G color index G 1 0
?GL_PIXEL_MAP_I_TO_B color index B 1 0
?GL_PIXEL_MAP_I_TO_A color index A 1 0
?GL_PIXEL_MAP_R_TO_R R R 1 0
?GL_PIXEL_MAP_G_TO_G G G 1 0
?GL_PIXEL_MAP_B_TO_B B B 1 0
?GL_PIXEL_MAP_A_TO_A A A 1 0

See external documentation.

pixelMapuiv(Map, Mapsize, Values) -> ok

Types

Map = enum()

Mapsize = integer()

Values = binary()

See pixelMapfv/3

pixelMapusv(Map, Mapsize, Values) -> ok

Types

Map = enum()

Mapsize = integer()

Values = binary()

See pixelMapfv/3

getPixelMapfv(Map, Values) -> ok

Types

Map = enum()

Values = mem()

Return the specified pixel map

See the gl:pixelMapfv/3 reference page for a description of the acceptable values for the Map parameter. gl:getPixelMap returns in Data the contents of the pixel map specified in Map . Pixel maps are used during the execution of gl:readPixels/7 , gl:drawPixels/5 , gl:copyPixels/5 , gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , gl:copyTexImage1D/7 , gl:copyTexImage2D/8 , gl:copyTexSubImage1D/6 , gl:copyTexSubImage2D/8 , and gl:copyTexSubImage3D/9 . to map color indices, stencil indices, color components, and depth components to other values.

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while a pixel map is requested, Data is treated as a byte offset into the buffer object's data store.

Unsigned integer values, if requested, are linearly mapped from the internal fixed or floating-point representation such that 1.0 maps to the largest representable integer value, and 0.0 maps to 0. Return unsigned integer values are undefined if the map value was not in the range [0,1].

To determine the required size of Map , call gl:getBooleanv/1 with the appropriate symbolic constant.

See external documentation.

getPixelMapuiv(Map, Values) -> ok

Types

Map = enum()

Values = mem()

See getPixelMapfv/2

getPixelMapusv(Map, Values) -> ok

Types

Map = enum()

Values = mem()

See getPixelMapfv/2

bitmap(Width, Height, Xorig, Yorig, Xmove, Ymove, Bitmap) -> ok

Types

Width = integer()

Height = integer()

Xorig = float()

Yorig = float()

Xmove = float()

Ymove = float()

Bitmap = offset() | mem()

Draw a bitmap

A bitmap is a binary image. When drawn, the bitmap is positioned relative to the current raster position, and frame buffer pixels corresponding to 1's in the bitmap are written using the current raster color or index. Frame buffer pixels corresponding to 0's in the bitmap are not modified.

gl:bitmap takes seven arguments. The first pair specifies the width and height of the bitmap image. The second pair specifies the location of the bitmap origin relative to the lower left corner of the bitmap image. The third pair of arguments specifies x and y offsets to be added to the current raster position after the bitmap has been drawn. The final argument is a pointer to the bitmap image itself.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a bitmap image is specified, Bitmap is treated as a byte offset into the buffer object's data store.

The bitmap image is interpreted like image data for the gl:drawPixels/5 command, with Width and Height corresponding to the width and height arguments of that command, and with type set to ?GL_BITMAP and format set to ?GL_COLOR_INDEX . Modes specified using gl:pixelStoref/2 affect the interpretation of bitmap image data; modes specified using gl:pixelTransferf/2 do not.

If the current raster position is invalid, gl:bitmap is ignored. Otherwise, the lower left corner of the bitmap image is positioned at the window coordinates

x w=|x r-x o|

y w=|y r-y o|

where (x r y r) is the raster position and (x o y o) is the bitmap origin. Fragments are then generated for each pixel corresponding to a 1 (one) in the bitmap image. These fragments are generated using the current raster z coordinate, color or color index, and current raster texture coordinates. They are then treated just as if they had been generated by a point, line, or polygon, including texture mapping, fogging, and all per-fragment operations such as alpha and depth testing.

After the bitmap has been drawn, the x and y coordinates of the current raster position are offset by Xmove and Ymove . No change is made to the z coordinate of the current raster position, or to the current raster color, texture coordinates, or index.

See external documentation.

readPixels(X, Y, Width, Height, Format, Type, Pixels) -> ok

Types

X = integer()

Y = integer()

Width = integer()

Height = integer()

Format = enum()

Type = enum()

Pixels = mem()

Read a block of pixels from the frame buffer

gl:readPixels returns pixel data from the frame buffer, starting with the pixel whose lower left corner is at location ( X , Y ), into client memory starting at location Data . Several parameters control the processing of the pixel data before it is placed into client memory. These parameters are set with gl:pixelStoref/2 . This reference page describes the effects on gl:readPixels of most, but not all of the parameters specified by these three commands.

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while a block of pixels is requested, Data is treated as a byte offset into the buffer object's data store rather than a pointer to client memory.

gl:readPixels returns values from each pixel with lower left corner at (x+i y+j) for 0<= i< width and 0<= j< height. This pixel is said to be the ith pixel in the jth row. Pixels are returned in row order from the lowest to the highest row, left to right in each row.

Format specifies the format for the returned pixel values; accepted values are:

?GL_STENCIL_INDEX: Stencil values are read from the stencil buffer. Each index is converted to fixed point, shifted left or right depending on the value and sign of ?GL_INDEX_SHIFT , and added to ?GL_INDEX_OFFSET. If ?GL_MAP_STENCIL is ?GL_TRUE, indices are replaced by their mappings in the table ?GL_PIXEL_MAP_S_TO_S.

?GL_DEPTH_COMPONENT: Depth values are read from the depth buffer. Each component is converted to floating point such that the minimum depth value maps to 0 and the maximum value maps to 1. Each component is then multiplied by ?GL_DEPTH_SCALE, added to ?GL_DEPTH_BIAS , and finally clamped to the range [0 1].

?GL_DEPTH_STENCIL: Values are taken from both the depth and stencil buffers. The Type parameter must be ?GL_UNSIGNED_INT_24_8 or ?GL_FLOAT_32_UNSIGNED_INT_24_8_REV .

?GL_RED

?GL_GREEN

?GL_BLUE

?GL_RGB

?GL_BGR

?GL_RGBA

?GL_BGRA: Finally, the indices or components are converted to the proper format, as specified by Type . If Format is ?GL_STENCIL_INDEX and Type is not ?GL_FLOAT, each index is masked with the mask value given in the following table. If Type is ?GL_FLOAT, then each integer index is converted to single-precision floating-point format.

If Format is ?GL_RED, ?GL_GREEN, ?GL_BLUE, ?GL_RGB, ?GL_BGR , ?GL_RGBA, or ?GL_BGRA and Type is not ?GL_FLOAT, each component is multiplied by the multiplier shown in the following table. If type is ?GL_FLOAT, then each component is passed as is (or converted to the client's single-precision floating-point format if it is different from the one used by the GL).

Type Index MaskComponent Conversion
?GL_UNSIGNED_BYTE 2 8-1(2 8-1) c
?GL_BYTE 2 7-1((2 8-1) c-1)/2
?GL_UNSIGNED_SHORT 2 16-1(2 16-1) c
?GL_SHORT 2 15-1((2 16-1) c-1)/2
?GL_UNSIGNED_INT 2 32-1(2 32-1) c
?GL_INT 2 31-1((2 32-1) c-1)/2
?GL_HALF_FLOAT none c
?GL_FLOAT none c
?GL_UNSIGNED_BYTE_3_3_2 2 N-1(2 N-1) c
?GL_UNSIGNED_BYTE_2_3_3_REV 2 N-1(2 N-1) c
?GL_UNSIGNED_SHORT_5_6_5 2 N-1 (2 N-1) c
?GL_UNSIGNED_SHORT_5_6_5_REV 2 N-1(2 N-1) c
?GL_UNSIGNED_SHORT_4_4_4_4 2 N-1(2 N-1) c
?GL_UNSIGNED_SHORT_4_4_4_4_REV 2 N-1(2 N-1) c
?GL_UNSIGNED_SHORT_5_5_5_1 2 N-1(2 N-1) c
?GL_UNSIGNED_SHORT_1_5_5_5_REV 2 N-1 (2 N-1) c
?GL_UNSIGNED_INT_8_8_8_8 2 N-1(2 N-1) c
?GL_UNSIGNED_INT_8_8_8_8_REV 2 N-1(2 N-1) c
?GL_UNSIGNED_INT_10_10_10_2 2 N-1(2 N-1) c
?GL_UNSIGNED_INT_2_10_10_10_REV 2 N-1(2 N-1) c
?GL_UNSIGNED_INT_24_8 2 N-1(2 N-1) c
?GL_UNSIGNED_INT_10F_11F_11F_REV -- Special
?GL_UNSIGNED_INT_5_9_9_9_REV -- Special
?GL_FLOAT_32_UNSIGNED_INT_24_8_REV none c (Depth Only)

Return values are placed in memory as follows. If Format is ?GL_STENCIL_INDEX , ?GL_DEPTH_COMPONENT, ?GL_RED, ?GL_GREEN, or ?GL_BLUE, a single value is returned and the data for the ith pixel in the jth row is placed in location (j) width+i. ?GL_RGB and ?GL_BGR return three values, ?GL_RGBA and ?GL_BGRA return four values for each pixel, with all values corresponding to a single pixel occupying contiguous space in Data . Storage parameters set by gl:pixelStoref/2 , such as ?GL_PACK_LSB_FIRST and ?GL_PACK_SWAP_BYTES, affect the way that data is written into memory. See gl:pixelStoref/2 for a description.

See external documentation.

drawPixels(Width, Height, Format, Type, Pixels) -> ok

Types

Width = integer()

Height = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

Write a block of pixels to the frame buffer

gl:drawPixels reads pixel data from memory and writes it into the frame buffer relative to the current raster position, provided that the raster position is valid. Use gl:rasterPos2d/2 or gl:windowPos2d/2 to set the current raster position; use gl:getBooleanv/1 with argument ?GL_CURRENT_RASTER_POSITION_VALID to determine if the specified raster position is valid, and gl:getBooleanv/1 with argument ?GL_CURRENT_RASTER_POSITION to query the raster position.

Several parameters define the encoding of pixel data in memory and control the processing of the pixel data before it is placed in the frame buffer. These parameters are set with four commands: gl:pixelStoref/2 , gl:pixelTransferf/2 , gl:pixelMapfv/3 , and gl:pixelZoom/2 . This reference page describes the effects on gl:drawPixels of many, but not all, of the parameters specified by these four commands.

Data is read from Data as a sequence of signed or unsigned bytes, signed or unsigned shorts, signed or unsigned integers, or single-precision floating-point values, depending on Type . When Type is one of ?GL_UNSIGNED_BYTE, ?GL_BYTE, ?GL_UNSIGNED_SHORT , ?GL_SHORT, ?GL_UNSIGNED_INT, ?GL_INT, or ?GL_FLOAT each of these bytes, shorts, integers, or floating-point values is interpreted as one color or depth component, or one index, depending on Format . When Type is one of ?GL_UNSIGNED_BYTE_3_3_2 , ?GL_UNSIGNED_SHORT_5_6_5, ?GL_UNSIGNED_SHORT_4_4_4_4, ?GL_UNSIGNED_SHORT_5_5_5_1 , ?GL_UNSIGNED_INT_8_8_8_8, or ?GL_UNSIGNED_INT_10_10_10_2, each unsigned value is interpreted as containing all the components for a single pixel, with the color components arranged according to Format . When Type is one of ?GL_UNSIGNED_BYTE_2_3_3_REV , ?GL_UNSIGNED_SHORT_5_6_5_REV, ?GL_UNSIGNED_SHORT_4_4_4_4_REV, ?GL_UNSIGNED_SHORT_1_5_5_5_REV , ?GL_UNSIGNED_INT_8_8_8_8_REV, or ?GL_UNSIGNED_INT_2_10_10_10_REV, each unsigned value is interpreted as containing all color components, specified by Format , for a single pixel in a reversed order. Indices are always treated individually. Color components are treated as groups of one, two, three, or four values, again based on Format . Both individual indices and groups of components are referred to as pixels. If Type is ?GL_BITMAP, the data must be unsigned bytes, and Format must be either ?GL_COLOR_INDEX or ?GL_STENCIL_INDEX. Each unsigned byte is treated as eight 1-bit pixels, with bit ordering determined by ?GL_UNPACK_LSB_FIRST (see gl:pixelStoref/2 ).

width×height pixels are read from memory, starting at location Data . By default, these pixels are taken from adjacent memory locations, except that after all Width pixels are read, the read pointer is advanced to the next four-byte boundary. The four-byte row alignment is specified by gl:pixelStoref/2 with argument ?GL_UNPACK_ALIGNMENT , and it can be set to one, two, four, or eight bytes. Other pixel store parameters specify different read pointer advancements, both before the first pixel is read and after all Width pixels are read. See the gl:pixelStoref/2 reference page for details on these options.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a block of pixels is specified, Data is treated as a byte offset into the buffer object's data store.

The width×height pixels that are read from memory are each operated on in the same way, based on the values of several parameters specified by gl:pixelTransferf/2 and gl:pixelMapfv/3 . The details of these operations, as well as the target buffer into which the pixels are drawn, are specific to the format of the pixels, as specified by Format . Format can assume one of 13 symbolic values:

?GL_COLOR_INDEX: Each pixel is a single value, a color index. It is converted to fixed-point format, with an unspecified number of bits to the right of the binary point, regardless of the memory data type. Floating-point values convert to true fixed-point values. Signed and unsigned integer data is converted with all fraction bits set to 0. Bitmap data convert to either 0 or 1.

Each fixed-point index is then shifted left by ?GL_INDEX_SHIFT bits and added to ?GL_INDEX_OFFSET . If ?GL_INDEX_SHIFT is negative, the shift is to the right. In either case, zero bits fill otherwise unspecified bit locations in the result.

If the GL is in RGBA mode, the resulting index is converted to an RGBA pixel with the help of the ?GL_PIXEL_MAP_I_TO_R, ?GL_PIXEL_MAP_I_TO_G, ?GL_PIXEL_MAP_I_TO_B , and ?GL_PIXEL_MAP_I_TO_A tables. If the GL is in color index mode, and if ?GL_MAP_COLOR is true, the index is replaced with the value that it references in lookup table ?GL_PIXEL_MAP_I_TO_I . Whether the lookup replacement of the index is done or not, the integer part of the index is then ANDed with 2 b-1, where b is the number of bits in a color index buffer.

y n=y r+|n/width|

where (x r y r) is the current raster position. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer.

?GL_STENCIL_INDEX: Each pixel is a single value, a stencil index. It is converted to fixed-point format, with an unspecified number of bits to the right of the binary point, regardless of the memory data type. Floating-point values convert to true fixed-point values. Signed and unsigned integer data is converted with all fraction bits set to 0. Bitmap data convert to either 0 or 1.

Each fixed-point index is then shifted left by ?GL_INDEX_SHIFT bits, and added to ?GL_INDEX_OFFSET. If ?GL_INDEX_SHIFT is negative, the shift is to the right. In either case, zero bits fill otherwise unspecified bit locations in the result. If ?GL_MAP_STENCIL is true, the index is replaced with the value that it references in lookup table ?GL_PIXEL_MAP_S_TO_S. Whether the lookup replacement of the index is done or not, the integer part of the index is then ANDed with 2 b-1, where b is the number of bits in the stencil buffer. The resulting stencil indices are then written to the stencil buffer such that the nth index is written to location

x n=x r+n% width

y n=y r+|n/width|

where (x r y r) is the current raster position. Only the pixel ownership test, the scissor test, and the stencil writemask affect these write operations.

?GL_DEPTH_COMPONENT: Each pixel is a single-depth component. Floating-point data is converted directly to an internal floating-point format with unspecified precision. Signed integer data is mapped linearly to the internal floating-point format such that the most positive representable integer value maps to 1.0, and the most negative representable value maps to -1.0. Unsigned integer data is mapped similarly: the largest integer value maps to 1.0, and 0 maps to 0.0. The resulting floating-point depth value is then multiplied by ?GL_DEPTH_SCALE and added to ?GL_DEPTH_BIAS. The result is clamped to the range [0 1].

x n=x r+n% width

y n=y r+|n/width|

?GL_RGBA

?GL_BGRA: Each pixel is a four-component group: For ?GL_RGBA, the red component is first, followed by green, followed by blue, followed by alpha; for ?GL_BGRA the order is blue, green, red and then alpha. Floating-point values are converted directly to an internal floating-point format with unspecified precision. Signed integer values are mapped linearly to the internal floating-point format such that the most positive representable integer value maps to 1.0, and the most negative representable value maps to -1.0. (Note that this mapping does not convert 0 precisely to 0.0.) Unsigned integer data is mapped similarly: The largest integer value maps to 1.0, and 0 maps to 0.0. The resulting floating-point color values are then multiplied by ?GL_c_SCALE and added to ?GL_c_BIAS, where c is RED, GREEN, BLUE, and ALPHA for the respective color components. The results are clamped to the range [0 1].

If ?GL_MAP_COLOR is true, each color component is scaled by the size of lookup table ?GL_PIXEL_MAP_c_TO_c, then replaced by the value that it references in that table. c is R, G, B, or A respectively.

The GL then converts the resulting RGBA colors to fragments by attaching the current raster position z coordinate and texture coordinates to each pixel, then assigning x and y window coordinates to the nth fragment such that

x n=x r+n% width

y n=y r+|n/width|

?GL_RED: Each pixel is a single red component. This component is converted to the internal floating-point format in the same way the red component of an RGBA pixel is. It is then converted to an RGBA pixel with green and blue set to 0, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

?GL_GREEN: Each pixel is a single green component. This component is converted to the internal floating-point format in the same way the green component of an RGBA pixel is. It is then converted to an RGBA pixel with red and blue set to 0, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

?GL_BLUE: Each pixel is a single blue component. This component is converted to the internal floating-point format in the same way the blue component of an RGBA pixel is. It is then converted to an RGBA pixel with red and green set to 0, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

?GL_ALPHA: Each pixel is a single alpha component. This component is converted to the internal floating-point format in the same way the alpha component of an RGBA pixel is. It is then converted to an RGBA pixel with red, green, and blue set to 0. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

?GL_RGB

?GL_BGR: Each pixel is a three-component group: red first, followed by green, followed by blue; for ?GL_BGR, the first component is blue, followed by green and then red. Each component is converted to the internal floating-point format in the same way the red, green, and blue components of an RGBA pixel are. The color triple is converted to an RGBA pixel with alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

?GL_LUMINANCE: Each pixel is a single luminance component. This component is converted to the internal floating-point format in the same way the red component of an RGBA pixel is. It is then converted to an RGBA pixel with red, green, and blue set to the converted luminance value, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

?GL_LUMINANCE_ALPHA: Each pixel is a two-component group: luminance first, followed by alpha. The two components are converted to the internal floating-point format in the same way the red component of an RGBA pixel is. They are then converted to an RGBA pixel with red, green, and blue set to the converted luminance value, and alpha set to the converted alpha value. After this conversion, the pixel is treated as if it had been read as an RGBA pixel.

The following table summarizes the meaning of the valid constants for the type parameter:

TypeCorresponding Type
?GL_UNSIGNED_BYTE unsigned 8-bit integer
?GL_BYTE signed 8-bit integer
?GL_BITMAP single bits in unsigned 8-bit integers
?GL_UNSIGNED_SHORT unsigned 16-bit integer
?GL_SHORT signed 16-bit integer
?GL_UNSIGNED_INT unsigned 32-bit integer
?GL_INT 32-bit integer
?GL_FLOAT single-precision floating-point
?GL_UNSIGNED_BYTE_3_3_2 unsigned 8-bit integer
?GL_UNSIGNED_BYTE_2_3_3_REV unsigned 8-bit integer with reversed component ordering
?GL_UNSIGNED_SHORT_5_6_5 unsigned 16-bit integer
?GL_UNSIGNED_SHORT_5_6_5_REV unsigned 16-bit integer with reversed component ordering
?GL_UNSIGNED_SHORT_4_4_4_4 unsigned 16-bit integer
?GL_UNSIGNED_SHORT_4_4_4_4_REV unsigned 16-bit integer with reversed component ordering
?GL_UNSIGNED_SHORT_5_5_5_1 unsigned 16-bit integer
?GL_UNSIGNED_SHORT_1_5_5_5_REV unsigned 16-bit integer with reversed component ordering
?GL_UNSIGNED_INT_8_8_8_8 unsigned 32-bit integer
?GL_UNSIGNED_INT_8_8_8_8_REV unsigned 32-bit integer with reversed component ordering
?GL_UNSIGNED_INT_10_10_10_2 unsigned 32-bit integer
?GL_UNSIGNED_INT_2_10_10_10_REV unsigned 32-bit integer with reversed component ordering

The rasterization described so far assumes pixel zoom factors of 1. If gl:pixelZoom/2 is used to change the x and y pixel zoom factors, pixels are converted to fragments as follows. If (x r y r) is the current raster position, and a given pixel is in the nth column and mth row of the pixel rectangle, then fragments are generated for pixels whose centers are in the rectangle with corners at

(x r+(zoom x) n y r+(zoom y) m)

(x r+(zoom x)(n+1) y r+(zoom y)(m+1))

where zoom x is the value of ?GL_ZOOM_X and zoom y is the value of ?GL_ZOOM_Y .

See external documentation.

copyPixels(X, Y, Width, Height, Type) -> ok

Types

X = integer()

Y = integer()

Width = integer()

Height = integer()

Type = enum()

Copy pixels in the frame buffer

gl:copyPixels copies a screen-aligned rectangle of pixels from the specified frame buffer location to a region relative to the current raster position. Its operation is well defined only if the entire pixel source region is within the exposed portion of the window. Results of copies from outside the window, or from regions of the window that are not exposed, are hardware dependent and undefined.

X and Y specify the window coordinates of the lower left corner of the rectangular region to be copied. Width and Height specify the dimensions of the rectangular region to be copied. Both Width and Height must not be negative.

Several parameters control the processing of the pixel data while it is being copied. These parameters are set with three commands: gl:pixelTransferf/2 , gl:pixelMapfv/3 , and gl:pixelZoom/2 . This reference page describes the effects on gl:copyPixels of most, but not all, of the parameters specified by these three commands.

gl:copyPixels copies values from each pixel with the lower left-hand corner at (x+i y+j) for 0<= i< width and 0<= j< height. This pixel is said to be the ith pixel in the jth row. Pixels are copied in row order from the lowest to the highest row, left to right in each row.

Type specifies whether color, depth, or stencil data is to be copied. The details of the transfer for each data type are as follows:

?GL_COLOR: Indices or RGBA colors are read from the buffer currently specified as the read source buffer (see gl:readBuffer/1 ). If the GL is in color index mode, each index that is read from this buffer is converted to a fixed-point format with an unspecified number of bits to the right of the binary point. Each index is then shifted left by ?GL_INDEX_SHIFT bits, and added to ?GL_INDEX_OFFSET. If ?GL_INDEX_SHIFT is negative, the shift is to the right. In either case, zero bits fill otherwise unspecified bit locations in the result. If ?GL_MAP_COLOR is true, the index is replaced with the value that it references in lookup table ?GL_PIXEL_MAP_I_TO_I. Whether the lookup replacement of the index is done or not, the integer part of the index is then ANDed with 2 b-1, where b is the number of bits in a color index buffer.

If the GL is in RGBA mode, the red, green, blue, and alpha components of each pixel that is read are converted to an internal floating-point format with unspecified precision. The conversion maps the largest representable component value to 1.0, and component value 0 to 0.0. The resulting floating-point color values are then multiplied by ?GL_c_SCALE and added to ?GL_c_BIAS, where c is RED, GREEN, BLUE, and ALPHA for the respective color components. The results are clamped to the range [0,1]. If ?GL_MAP_COLOR is true, each color component is scaled by the size of lookup table ?GL_PIXEL_MAP_c_TO_c , then replaced by the value that it references in that table. c is R, G, B, or A.

If the ARB_imaging extension is supported, the color values may be additionally processed by color-table lookups, color-matrix transformations, and convolution filters.

The GL then converts the resulting indices or RGBA colors to fragments by attaching the current raster position z coordinate and texture coordinates to each pixel, then assigning window coordinates (x r+i y r+j), where (x r y r) is the current raster position, and the pixel was the ith pixel in the jth row. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer.

?GL_DEPTH: Depth values are read from the depth buffer and converted directly to an internal floating-point format with unspecified precision. The resulting floating-point depth value is then multiplied by ?GL_DEPTH_SCALE and added to ?GL_DEPTH_BIAS . The result is clamped to the range [0,1].

The GL then converts the resulting depth components to fragments by attaching the current raster position color or color index and texture coordinates to each pixel, then assigning window coordinates (x r+i y r+j), where (x r y r) is the current raster position, and the pixel was the ith pixel in the jth row. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer.

?GL_STENCIL: Stencil indices are read from the stencil buffer and converted to an internal fixed-point format with an unspecified number of bits to the right of the binary point. Each fixed-point index is then shifted left by ?GL_INDEX_SHIFT bits, and added to ?GL_INDEX_OFFSET. If ?GL_INDEX_SHIFT is negative, the shift is to the right. In either case, zero bits fill otherwise unspecified bit locations in the result. If ?GL_MAP_STENCIL is true, the index is replaced with the value that it references in lookup table ?GL_PIXEL_MAP_S_TO_S. Whether the lookup replacement of the index is done or not, the integer part of the index is then ANDed with 2 b-1, where b is the number of bits in the stencil buffer. The resulting stencil indices are then written to the stencil buffer such that the index read from the ith location of the jth row is written to location (x r+i y r+j), where (x r y r) is the current raster position. Only the pixel ownership test, the scissor test, and the stencil writemask affect these write operations.

The rasterization described thus far assumes pixel zoom factors of 1.0. If gl:pixelZoom/2 is used to change the x and y pixel zoom factors, pixels are converted to fragments as follows. If (x r y r) is the current raster position, and a given pixel is in the ith location in the jth row of the source pixel rectangle, then fragments are generated for pixels whose centers are in the rectangle with corners at

(x r+(zoom x) i y r+(zoom y) j)

and

(x r+(zoom x)(i+1) y r+(zoom y)(j+1))

where zoom x is the value of ?GL_ZOOM_X and zoom y is the value of ?GL_ZOOM_Y .

See external documentation.

stencilFunc(Func, Ref, Mask) -> ok

Types

Func = enum()

Ref = integer()

Mask = integer()

Set front and back function and reference value for stencil testing

Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. Stencil planes are first drawn into using GL drawing primitives, then geometry and images are rendered using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering.

The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the reference value and the value in the stencil buffer. To enable and disable the test, call gl:enable/1 and gl:enable/1 with argument ?GL_STENCIL_TEST . To specify actions based on the outcome of the stencil test, call gl:stencilOp/3 or gl:stencilOpSeparate/4 .

There can be two separate sets of Func , Ref , and Mask parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. gl:stencilFunc/3 sets both front and back stencil state to the same values. Use gl:stencilFuncSeparate/4 to set front and back stencil state to different values.

Func is a symbolic constant that determines the stencil comparison function. It accepts one of eight values, shown in the following list. Ref is an integer reference value that is used in the stencil comparison. It is clamped to the range [0 2 n-1], where n is the number of bitplanes in the stencil buffer. Mask is bitwise ANDed with both the reference value and the stored stencil value, with the ANDed values participating in the comparison.

If stencil represents the value stored in the corresponding stencil buffer location, the following list shows the effect of each comparison function that can be specified by Func . Only if the comparison succeeds is the pixel passed through to the next stage in the rasterization process (see gl:stencilOp/3 ). All tests treat stencil values as unsigned integers in the range [0 2 n-1], where n is the number of bitplanes in the stencil buffer.

The following values are accepted by Func :

?GL_NEVER: Always fails.

?GL_LESS: Passes if ( Ref & Mask ) < ( stencil & Mask ).

?GL_LEQUAL: Passes if ( Ref & Mask ) <= ( stencil & Mask ).

?GL_GREATER: Passes if ( Ref & Mask ) > ( stencil & Mask ).

?GL_GEQUAL: Passes if ( Ref & Mask ) >= ( stencil & Mask ).

?GL_EQUAL: Passes if ( Ref & Mask ) = ( stencil & Mask ).

?GL_NOTEQUAL: Passes if ( Ref & Mask ) != ( stencil & Mask ).

?GL_ALWAYS: Always passes.

See external documentation.

stencilMask(Mask) -> ok

Types

Mask = integer()

Control the front and back writing of individual bits in the stencil planes

gl:stencilMask controls the writing of individual bits in the stencil planes. The least significant n bits of Mask , where n is the number of bits in the stencil buffer, specify a mask. Where a 1 appears in the mask, it's possible to write to the corresponding bit in the stencil buffer. Where a 0 appears, the corresponding bit is write-protected. Initially, all bits are enabled for writing.

There can be two separate Mask writemasks; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. gl:stencilMask/1 sets both front and back stencil writemasks to the same values. Use gl:stencilMaskSeparate/2 to set front and back stencil writemasks to different values.

See external documentation.

stencilOp(Fail, Zfail, Zpass) -> ok

Types

Fail = enum()

Zfail = enum()

Zpass = enum()

Set front and back stencil test actions

Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. You draw into the stencil planes using GL drawing primitives, then render geometry and images, using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering.

The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the value in the stencil buffer and a reference value. To enable and disable the test, call gl:enable/1 and gl:enable/1 with argument ?GL_STENCIL_TEST ; to control it, call gl:stencilFunc/3 or gl:stencilFuncSeparate/4 .

There can be two separate sets of Sfail , Dpfail , and Dppass parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. gl:stencilOp/3 sets both front and back stencil state to the same values. Use gl:stencilOpSeparate/4 to set front and back stencil state to different values.

gl:stencilOp takes three arguments that indicate what happens to the stored stencil value while stenciling is enabled. If the stencil test fails, no change is made to the pixel's color or depth buffers, and Sfail specifies what happens to the stencil buffer contents. The following eight actions are possible.

?GL_KEEP: Keeps the current value.

?GL_ZERO: Sets the stencil buffer value to 0.

?GL_REPLACE: Sets the stencil buffer value to ref, as specified by gl:stencilFunc/3 .

?GL_INCR: Increments the current stencil buffer value. Clamps to the maximum representable unsigned value.

?GL_INCR_WRAP: Increments the current stencil buffer value. Wraps stencil buffer value to zero when incrementing the maximum representable unsigned value.

?GL_DECR: Decrements the current stencil buffer value. Clamps to 0.

?GL_DECR_WRAP: Decrements the current stencil buffer value. Wraps stencil buffer value to the maximum representable unsigned value when decrementing a stencil buffer value of zero.

?GL_INVERT: Bitwise inverts the current stencil buffer value.

Stencil buffer values are treated as unsigned integers. When incremented and decremented, values are clamped to 0 and 2 n-1, where n is the value returned by querying ?GL_STENCIL_BITS .

The other two arguments to gl:stencilOp specify stencil buffer actions that depend on whether subsequent depth buffer tests succeed ( Dppass ) or fail ( Dpfail ) (see gl:depthFunc/1 ). The actions are specified using the same eight symbolic constants as Sfail . Note that Dpfail is ignored when there is no depth buffer, or when the depth buffer is not enabled. In these cases, Sfail and Dppass specify stencil action when the stencil test fails and passes, respectively.

See external documentation.

clearStencil(S) -> ok

Types

S = integer()

Specify the clear value for the stencil buffer

gl:clearStencil specifies the index used by gl:clear/1 to clear the stencil buffer. S is masked with 2 m-1, where m is the number of bits in the stencil buffer.

See external documentation.

texGend(Coord, Pname, Param) -> ok

Types

Coord = enum()

Pname = enum()

Param = float()

Control the generation of texture coordinates

gl:texGen selects a texture-coordinate generation function or supplies coefficients for one of the functions. Coord names one of the (s, t, r, q ) texture coordinates; it must be one of the symbols ?GL_S, ?GL_T, ?GL_R , or ?GL_Q. Pname must be one of three symbolic constants: ?GL_TEXTURE_GEN_MODE , ?GL_OBJECT_PLANE, or ?GL_EYE_PLANE. If Pname is ?GL_TEXTURE_GEN_MODE , then Params chooses a mode, one of ?GL_OBJECT_LINEAR, ?GL_EYE_LINEAR , ?GL_SPHERE_MAP, ?GL_NORMAL_MAP, or ?GL_REFLECTION_MAP. If Pname is either ?GL_OBJECT_PLANE or ?GL_EYE_PLANE, Params contains coefficients for the corresponding texture generation function.

If the texture generation function is ?GL_OBJECT_LINEAR, the function

g=p 1×x o+p 2×y o+p 3×z o+p 4×w o

is used, where g is the value computed for the coordinate named in Coord , p 1, p 2, p 3, and p 4 are the four values supplied in Params , and x o, y o, z o, and w o are the object coordinates of the vertex. This function can be used, for example, to texture-map terrain using sea level as a reference plane (defined by p 1, p 2, p 3, and p 4). The altitude of a terrain vertex is computed by the ?GL_OBJECT_LINEAR coordinate generation function as its distance from sea level; that altitude can then be used to index the texture image to map white snow onto peaks and green grass onto foothills.

If the texture generation function is ?GL_EYE_LINEAR, the function

g=(p 1)"×x e+(p 2)"×y e+(p 3)"×z e+(p 4)"×w e

is used, where

((p 1)" (p 2)" (p 3)" (p 4)")=(p 1 p 2 p 3 p 4) M -1

and x e, y e, z e, and w e are the eye coordinates of the vertex, p 1, p 2, p 3, and p 4 are the values supplied in Params , and M is the modelview matrix when gl:texGen is invoked. If M is poorly conditioned or singular, texture coordinates generated by the resulting function may be inaccurate or undefined.

Note that the values in Params define a reference plane in eye coordinates. The modelview matrix that is applied to them may not be the same one in effect when the polygon vertices are transformed. This function establishes a field of texture coordinates that can produce dynamic contour lines on moving objects.

If the texture generation function is ?GL_SPHERE_MAP and Coord is either ?GL_S or ?GL_T, s and t texture coordinates are generated as follows. Let u be the unit vector pointing from the origin to the polygon vertex (in eye coordinates). Let n sup prime be the current normal, after transformation to eye coordinates. Let

f=(f x f y f z) T be the reflection vector such that

f=u-2 n" (n") T u

Finally, let m=2 ((f x) 2+(f y) 2+(f z+1) 2). Then the values assigned to the s and t texture coordinates are

s=f x/m+1/2

Coord = enum()

Pname = enum()

Return texture coordinate generation parameters

gl:getTexGen returns in Params selected parameters of a texture coordinate generation function that was specified using gl:texGend/3 . Coord names one of the (s, t, r, q) texture coordinates, using the symbolic constant ?GL_S, ?GL_T, ?GL_R, or ?GL_Q.

Pname specifies one of three symbolic names:

?GL_TEXTURE_GEN_MODE: Params returns the single-valued texture generation function, a symbolic constant. The initial value is ?GL_EYE_LINEAR.

?GL_OBJECT_PLANE: Params returns the four plane equation coefficients that specify object linear-coordinate generation. Integer values, when requested, are mapped directly from the internal floating-point representation.

?GL_EYE_PLANE: Params returns the four plane equation coefficients that specify eye linear-coordinate generation. Integer values, when requested, are mapped directly from the internal floating-point representation. The returned values are those maintained in eye coordinates. They are not equal to the values specified using gl:texGend/3 , unless the modelview matrix was identity when gl:texGend/3 was called.

See external documentation.

getTexGenfv(Coord, Pname) -> {float(), float(), float(), float()}

Types

Coord = enum()

Pname = enum()

See getTexGendv/2

Target = enum()

Pname = enum()

Params = tuple()

Set texture environment parameters

A texture environment specifies how texture values are interpreted when a fragment is textured. When Target is ?GL_TEXTURE_FILTER_CONTROL, Pname must be ?GL_TEXTURE_LOD_BIAS . When Target is ?GL_TEXTURE_ENV, Pname can be ?GL_TEXTURE_ENV_MODE , ?GL_TEXTURE_ENV_COLOR, ?GL_COMBINE_RGB, ?GL_COMBINE_ALPHA, ?GL_RGB_SCALE , ?GL_ALPHA_SCALE, ?GL_SRC0_RGB, ?GL_SRC1_RGB, ?GL_SRC2_RGB, ?GL_SRC0_ALPHA , ?GL_SRC1_ALPHA, or ?GL_SRC2_ALPHA.

If Pname is ?GL_TEXTURE_ENV_MODE, then Params is (or points to) the symbolic name of a texture function. Six texture functions may be specified: ?GL_ADD , ?GL_MODULATE, ?GL_DECAL, ?GL_BLEND, ?GL_REPLACE, or ?GL_COMBINE .

The following table shows the correspondence of filtered texture values R t, G t, B t, A t, L t, I t to texture source components. C s and A s are used by the texture functions described below.

Texture Base Internal Format C s A s
?GL_ALPHA (0, 0, 0) A t
?GL_LUMINANCE ( L t, L t, L t ) 1
?GL_LUMINANCE_ALPHA ( L t, L t, L t ) A t
?GL_INTENSITY ( I t, I t, I t ) I t
?GL_RGB ( R t, G t, B t ) 1
?GL_RGBA ( R t, G t, B t ) A t

A texture function acts on the fragment to be textured using the texture image value that applies to the fragment (see gl:texParameterf/3 ) and produces an RGBA color for that fragment. The following table shows how the RGBA color is produced for each of the first five texture functions that can be chosen. C is a triple of color values (RGB) and A is the associated alpha value. RGBA values extracted from a texture image are in the range [0,1]. The subscript p refers to the color computed from the previous texture stage (or the incoming fragment if processing texture stage 0), the subscript s to the texture source color, the subscript c to the texture environment color, and the subscript v indicates a value produced by the texture function.

Texture Base Internal Format ?Value?GL_REPLACE Function ?GL_MODULATE Function ?GL_DECAL Function ?GL_BLEND Function ?GL_ADD Function
?GL_ALPHA C v= C p C p undefined C p C p
A v= A s A p A s A v=A p A s A p A s
?GL_LUMINANCE C v= C s C p C s undefined C p (1-C s)+C c C s C p+C s
(or 1) A v= A p A p A p A p
?GL_LUMINANCE_ALPHA C v= C s C p C s undefined C p (1-C s)+C c C s C p+C s
(or 2) A v= A s A p A s A p A s A p A s
?GL_INTENSITY C v= C s C p C s undefined C p (1-C s)+C c C s C p+C s
A v= A s A p A s A p (1-A s)+A c A s A p+A s
?GL_RGB C v= C s C p C s C s C p (1-C s)+C c C s C p+C s
(or 3) A v= A p A p A p A p A p
?GL_RGBA C v= C s C p C s C p (1-A s)+C s A s C p (1-C s)+C c C s C p+C s
(or 4) A v= A s A p A s A p A p A s A p A s

If Pname is ?GL_TEXTURE_ENV_MODE, and Params is ?GL_COMBINE, the form of the texture function depends on the values of ?GL_COMBINE_RGB and ?GL_COMBINE_ALPHA .

The following describes how the texture sources, as specified by ?GL_SRC0_RGB, ?GL_SRC1_RGB , ?GL_SRC2_RGB, ?GL_SRC0_ALPHA, ?GL_SRC1_ALPHA, and ?GL_SRC2_ALPHA , are combined to produce a final texture color. In the following tables, ?GL_SRC0_c is represented by Arg0, ?GL_SRC1_c is represented by Arg1, and ?GL_SRC2_c is represented by Arg2.

?GL_COMBINE_RGB accepts any of ?GL_REPLACE, ?GL_MODULATE, ?GL_ADD , ?GL_ADD_SIGNED, ?GL_INTERPOLATE, ?GL_SUBTRACT, ?GL_DOT3_RGB, or ?GL_DOT3_RGBA.

?GL_COMBINE_RGBTexture Function
?GL_REPLACE Arg0
?GL_MODULATE Arg0×Arg1
?GL_ADD Arg0+Arg1
?GL_ADD_SIGNED Arg0+Arg1-0.5
?GL_INTERPOLATE Arg0×Arg2+Arg1×(1- Arg2)
?GL_SUBTRACT Arg0-Arg1
?GL_DOT3_RGB or ?GL_DOT3_RGBA 4×((((Arg0 r)-0.5)×((Arg1 r)-0.5))+(((Arg0 g)-0.5)×((Arg1 g)-0.5))+(((Arg0 b)-0.5)×((Arg1 b)-0.5)))

The scalar results for ?GL_DOT3_RGB and ?GL_DOT3_RGBA are placed into each of the 3 (RGB) or 4 (RGBA) components on output.

Likewise, ?GL_COMBINE_ALPHA accepts any of ?GL_REPLACE, ?GL_MODULATE, ?GL_ADD, ?GL_ADD_SIGNED, ?GL_INTERPOLATE, or ?GL_SUBTRACT. The following table describes how alpha values are combined:

?GL_COMBINE_ALPHATexture Function
?GL_REPLACE Arg0
?GL_MODULATE Arg0×Arg1
?GL_ADD Arg0+Arg1
?GL_ADD_SIGNED Arg0+Arg1-0.5
?GL_INTERPOLATE Arg0×Arg2+Arg1×(1- Arg2)
?GL_SUBTRACT Arg0-Arg1

In the following tables, the value C s represents the color sampled from the currently bound texture, C c represents the constant texture-environment color, C f represents the primary color of the incoming fragment, and C p represents the color computed from the previous texture stage or C f if processing texture stage 0. Likewise, A s, A c, A f, and A p represent the respective alpha values.

The following table describes the values assigned to Arg0, Arg1, and Arg2 based upon the RGB sources and operands:

?GL_SRCn_RGB?GL_OPERANDn_RGBArgument Value
?GL_TEXTURE?GL_SRC_COLOR(C s)
?GL_ONE_MINUS_SRC_COLOR 1-(C s)
?GL_SRC_ALPHA(A s)
?GL_ONE_MINUS_SRC_ALPHA 1-(A s)
?GL_TEXTUREn?GL_SRC_COLOR(C s)
?GL_ONE_MINUS_SRC_COLOR 1-(C s)
?GL_SRC_ALPHA (A s)
?GL_ONE_MINUS_SRC_ALPHA 1-(A s)
?GL_CONSTANT?GL_SRC_COLOR(C c)
?GL_ONE_MINUS_SRC_COLOR 1-(C c)
?GL_SRC_ALPHA(A c)
?GL_ONE_MINUS_SRC_ALPHA 1-(A c)
?GL_PRIMARY_COLOR ?GL_SRC_COLOR(C f)
?GL_ONE_MINUS_SRC_COLOR 1-(C f)
?GL_SRC_ALPHA(A f)
?GL_ONE_MINUS_SRC_ALPHA 1-(A f)
?GL_PREVIOUS?GL_SRC_COLOR (C p)
?GL_ONE_MINUS_SRC_COLOR 1-(C p)
?GL_SRC_ALPHA(A p)
?GL_ONE_MINUS_SRC_ALPHA 1-(A p)

For ?GL_TEXTUREn sources, C s and A s represent the color and alpha, respectively, produced from texture stage n.

The follow table describes the values assigned to Arg0, Arg1, and Arg2 based upon the alpha sources and operands:

?GL_SRCn_ALPHA?GL_OPERANDn_ALPHAArgument Value
?GL_TEXTURE?GL_SRC_ALPHA(A s)
?GL_ONE_MINUS_SRC_ALPHA 1-(A s)
?GL_TEXTUREn ?GL_SRC_ALPHA(A s)
?GL_ONE_MINUS_SRC_ALPHA 1-(A s)
?GL_CONSTANT?GL_SRC_ALPHA(A c)
?GL_ONE_MINUS_SRC_ALPHA 1-(A c)
?GL_PRIMARY_COLOR ?GL_SRC_ALPHA(A f)
?GL_ONE_MINUS_SRC_ALPHA 1-(A f)
?GL_PREVIOUS?GL_SRC_ALPHA(A p)
?GL_ONE_MINUS_SRC_ALPHA 1-(A p)

The RGB and alpha results of the texture function are multipled by the values of ?GL_RGB_SCALE and ?GL_ALPHA_SCALE, respectively, and clamped to the range [0 1].

If Pname is ?GL_TEXTURE_ENV_COLOR, Params is a pointer to an array that holds an RGBA color consisting of four values. Integer color components are interpreted linearly such that the most positive integer maps to 1.0, and the most negative integer maps to -1.0. The values are clamped to the range [0,1] when they are specified. C c takes these four values.

If Pname is ?GL_TEXTURE_LOD_BIAS, the value specified is added to the texture level-of-detail parameter, that selects which mipmap, or mipmaps depending upon the selected ?GL_TEXTURE_MIN_FILTER, will be sampled.

?GL_TEXTURE_ENV_MODE defaults to ?GL_MODULATE and ?GL_TEXTURE_ENV_COLOR defaults to (0, 0, 0, 0).

If Target is ?GL_POINT_SPRITE and Pname is ?GL_COORD_REPLACE, the boolean value specified is used to either enable or disable point sprite texture coordinate replacement. The default value is ?GL_FALSE.

See external documentation.

texEnviv(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = tuple()

See texEnvfv/3

getTexEnvfv(Target, Pname) -> {float(), float(), float(), float()}

Types

Target = enum()

Pname = enum()

Return texture environment parameters

gl:getTexEnv returns in Params selected values of a texture environment that was specified with gl:texEnvfv/3 . Target specifies a texture environment.

When Target is ?GL_TEXTURE_FILTER_CONTROL, Pname must be ?GL_TEXTURE_LOD_BIAS . When Target is ?GL_POINT_SPRITE, Pname must be ?GL_COORD_REPLACE . When Target is ?GL_TEXTURE_ENV, Pname can be ?GL_TEXTURE_ENV_MODE , ?GL_TEXTURE_ENV_COLOR, ?GL_COMBINE_RGB, ?GL_COMBINE_ALPHA, ?GL_RGB_SCALE , ?GL_ALPHA_SCALE, ?GL_SRC0_RGB, ?GL_SRC1_RGB, ?GL_SRC2_RGB, ?GL_SRC0_ALPHA, ?GL_SRC1_ALPHA, or ?GL_SRC2_ALPHA.

Pname names a specific texture environment parameter, as follows:

?GL_TEXTURE_ENV_MODE: Params returns the single-valued texture environment mode, a symbolic constant. The initial value is ?GL_MODULATE.

?GL_TEXTURE_ENV_COLOR: Params returns four integer or floating-point values that are the texture environment color. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer, and -1.0 maps to the most negative representable integer. The initial value is (0, 0, 0, 0).

?GL_TEXTURE_LOD_BIAS: Params returns a single floating-point value that is the texture level-of-detail bias. The initial value is 0.

?GL_COMBINE_RGB: Params returns a single symbolic constant value representing the current RGB combine mode. The initial value is ?GL_MODULATE.

?GL_COMBINE_ALPHA: Params returns a single symbolic constant value representing the current alpha combine mode. The initial value is ?GL_MODULATE.

?GL_SRC0_RGB: Params returns a single symbolic constant value representing the texture combiner zero's RGB source. The initial value is ?GL_TEXTURE.

?GL_SRC1_RGB: Params returns a single symbolic constant value representing the texture combiner one's RGB source. The initial value is ?GL_PREVIOUS.

?GL_SRC2_RGB: Params returns a single symbolic constant value representing the texture combiner two's RGB source. The initial value is ?GL_CONSTANT.

?GL_SRC0_ALPHA: Params returns a single symbolic constant value representing the texture combiner zero's alpha source. The initial value is ?GL_TEXTURE.

?GL_SRC1_ALPHA: Params returns a single symbolic constant value representing the texture combiner one's alpha source. The initial value is ?GL_PREVIOUS.

?GL_SRC2_ALPHA: Params returns a single symbolic constant value representing the texture combiner two's alpha source. The initial value is ?GL_CONSTANT.

?GL_OPERAND0_RGB: Params returns a single symbolic constant value representing the texture combiner zero's RGB operand. The initial value is ?GL_SRC_COLOR.

?GL_OPERAND1_RGB: Params returns a single symbolic constant value representing the texture combiner one's RGB operand. The initial value is ?GL_SRC_COLOR.

?GL_OPERAND2_RGB: Params returns a single symbolic constant value representing the texture combiner two's RGB operand. The initial value is ?GL_SRC_ALPHA.

?GL_OPERAND0_ALPHA: Params returns a single symbolic constant value representing the texture combiner zero's alpha operand. The initial value is ?GL_SRC_ALPHA.

?GL_OPERAND1_ALPHA: Params returns a single symbolic constant value representing the texture combiner one's alpha operand. The initial value is ?GL_SRC_ALPHA.

?GL_OPERAND2_ALPHA: Params returns a single symbolic constant value representing the texture combiner two's alpha operand. The initial value is ?GL_SRC_ALPHA.

?GL_RGB_SCALE: Params returns a single floating-point value representing the current RGB texture combiner scaling factor. The initial value is 1.0.

?GL_ALPHA_SCALE: Params returns a single floating-point value representing the current alpha texture combiner scaling factor. The initial value is 1.0.

?GL_COORD_REPLACE: Params returns a single boolean value representing the current point sprite texture coordinate replacement enable state. The initial value is ?GL_FALSE .

See external documentation.

getTexEnviv(Target, Pname) -> {integer(), integer(), integer(), integer()}

Types

Target = enum()

Pname = enum()

See getTexEnvfv/2

texParameterf(Target, Pname, Param) -> ok

Types

Target = enum()

Pname = enum()

Param = float()

Set texture parameters

gl:texParameter assigns the value or values in Params to the texture parameter specified as Pname . Target defines the target texture, either ?GL_TEXTURE_1D , ?GL_TEXTURE_2D, ?GL_TEXTURE_1D_ARRAY, ?GL_TEXTURE_2D_ARRAY, ?GL_TEXTURE_RECTANGLE , or ?GL_TEXTURE_3D. The following symbols are accepted in Pname :

?GL_TEXTURE_BASE_LEVEL: Specifies the index of the lowest defined mipmap level. This is an integer value. The initial value is 0.

?GL_TEXTURE_BORDER_COLOR: The data in Params specifies four values that define the border values that should be used for border texels. If a texel is sampled from the border of the texture, the values of ?GL_TEXTURE_BORDER_COLOR are interpreted as an RGBA color to match the texture's internal format and substituted for the non-existent texel data. If the texture contains depth components, the first component of ?GL_TEXTURE_BORDER_COLOR is interpreted as a depth value. The initial value is ( 0.0, 0.0, 0.0, 0.0 ).

If the values for ?GL_TEXTURE_BORDER_COLOR are specified with gl:texParameterIiv or gl:texParameterIuiv, the values are stored unmodified with an internal data type of integer. If specified with gl:texParameteriv, they are converted to floating point with the following equation: f=2 c+1 2 b-/1. If specified with gl:texParameterfv , they are stored unmodified as floating-point values.

?GL_TEXTURE_COMPARE_FUNC: Specifies the comparison operator used when ?GL_TEXTURE_COMPARE_MODE is set to ?GL_COMPARE_REF_TO_TEXTURE. Permissible values are:

Texture Comparison FunctionComputed result
?GL_LEQUAL result={1.0 0.0 r<=(D t) r>(D t))
?GL_GEQUAL result={1.0 0.0 r>=(D t) r<(D t))
?GL_LESS result={1.0 0.0 r<(D t) r>=(D t))
?GL_GREATER result={1.0 0.0 r>(D t) r<=(D t))
?GL_EQUAL result={1.0 0.0 r=(D t) r≠ (D t))
?GL_NOTEQUAL result={1.0 0.0 r≠(D t) r=(D t))
?GL_ALWAYS result=1.0
?GL_NEVER result=0.0

where r is the current interpolated texture coordinate, and D t is the depth texture value sampled from the currently bound depth texture. result is assigned to the the red channel.

?GL_TEXTURE_COMPARE_MODE: Specifies the texture comparison mode for currently bound depth textures. That is, a texture whose internal format is ?GL_DEPTH_COMPONENT_* ; see gl:texImage2D/9 ) Permissible values are:

?GL_COMPARE_REF_TO_TEXTURE: Specifies that the interpolated and clamped r texture coordinate should be compared to the value in the currently bound depth texture. See the discussion of ?GL_TEXTURE_COMPARE_FUNC for details of how the comparison is evaluated. The result of the comparison is assigned to the red channel.

?GL_NONE: Specifies that the red channel should be assigned the appropriate value from the currently bound depth texture.

?GL_TEXTURE_LOD_BIAS: Params specifies a fixed bias value that is to be added to the level-of-detail parameter for the texture before texture sampling. The specified value is added to the shader-supplied bias value (if any) and subsequently clamped into the implementation-defined range [( - bias max)(bias max)], where bias max is the value of the implementation defined constant ?GL_MAX_TEXTURE_LOD_BIAS. The initial value is 0.0.

?GL_TEXTURE_MIN_FILTER: The texture minifying function is used whenever the level-of-detail function used when sampling from the texture determines that the texture should be minified. There are six defined minifying functions. Two of them use either the nearest texture elements or a weighted average of multiple texture elements to compute the texture value. The other four use mipmaps.

A mipmap is an ordered set of arrays representing the same image at progressively lower resolutions. If the texture has dimensions 2 n×2 m, there are max(n m)+1 mipmaps. The first mipmap is the original texture, with dimensions 2 n×2 m. Each subsequent mipmap has dimensions 2(k-1)×2(l-1), where 2 k×2 l are the dimensions of the previous mipmap, until either k=0 or l=0. At that point, subsequent mipmaps have dimension 1×2(l-1) or 2(k-1)×1 until the final mipmap, which has dimension 1×1. To define the mipmaps, call gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:copyTexImage1D/7 , or gl:copyTexImage2D/8 with the level argument indicating the order of the mipmaps. Level 0 is the original texture; level max(n m) is the final 1×1 mipmap.

Params supplies a function for minifying the texture as one of the following:

?GL_NEAREST: Returns the value of the texture element that is nearest (in Manhattan distance) to the specified texture coordinates.

?GL_LINEAR: Returns the weighted average of the four texture elements that are closest to the specified texture coordinates. These can include items wrapped or repeated from other parts of a texture, depending on the values of ?GL_TEXTURE_WRAP_S and ?GL_TEXTURE_WRAP_T , and on the exact mapping.

?GL_NEAREST_MIPMAP_NEAREST: Chooses the mipmap that most closely matches the size of the pixel being textured and uses the ?GL_NEAREST criterion (the texture element closest to the specified texture coordinates) to produce a texture value.

?GL_LINEAR_MIPMAP_NEAREST: Chooses the mipmap that most closely matches the size of the pixel being textured and uses the ?GL_LINEAR criterion (a weighted average of the four texture elements that are closest to the specified texture coordinates) to produce a texture value.

?GL_NEAREST_MIPMAP_LINEAR: Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the ?GL_NEAREST criterion (the texture element closest to the specified texture coordinates ) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values.

?GL_LINEAR_MIPMAP_LINEAR: Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the ?GL_LINEAR criterion (a weighted average of the texture elements that are closest to the specified texture coordinates) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values.

As more texture elements are sampled in the minification process, fewer aliasing artifacts will be apparent. While the ?GL_NEAREST and ?GL_LINEAR minification functions can be faster than the other four, they sample only one or multiple texture elements to determine the texture value of the pixel being rendered and can produce moire patterns or ragged transitions. The initial value of ?GL_TEXTURE_MIN_FILTER is ?GL_NEAREST_MIPMAP_LINEAR .

?GL_TEXTURE_MAG_FILTER: The texture magnification function is used whenever the level-of-detail function used when sampling from the texture determines that the texture should be magified. It sets the texture magnification function to either ?GL_NEAREST or ?GL_LINEAR (see below). ?GL_NEAREST is generally faster than ?GL_LINEAR , but it can produce textured images with sharper edges because the transition between texture elements is not as smooth. The initial value of ?GL_TEXTURE_MAG_FILTER is ?GL_LINEAR .

?GL_NEAREST: Returns the value of the texture element that is nearest (in Manhattan distance) to the specified texture coordinates.

?GL_LINEAR: Returns the weighted average of the texture elements that are closest to the specified texture coordinates. These can include items wrapped or repeated from other parts of a texture, depending on the values of ?GL_TEXTURE_WRAP_S and ?GL_TEXTURE_WRAP_T , and on the exact mapping.

?GL_TEXTURE_MIN_LOD: Sets the minimum level-of-detail parameter. This floating-point value limits the selection of highest resolution mipmap (lowest mipmap level). The initial value is -1000.

?GL_TEXTURE_MAX_LOD: Sets the maximum level-of-detail parameter. This floating-point value limits the selection of the lowest resolution mipmap (highest mipmap level). The initial value is 1000.

?GL_TEXTURE_MAX_LEVEL: Sets the index of the highest defined mipmap level. This is an integer value. The initial value is 1000.

?GL_TEXTURE_SWIZZLE_R: Sets the swizzle that will be applied to the r component of a texel before it is returned to the shader. Valid values for Param are ?GL_RED , ?GL_GREEN, ?GL_BLUE, ?GL_ALPHA, ?GL_ZERO and ?GL_ONE. If ?GL_TEXTURE_SWIZZLE_R is ?GL_RED, the value for r will be taken from the first channel of the fetched texel. If ?GL_TEXTURE_SWIZZLE_R is ?GL_GREEN , the value for r will be taken from the second channel of the fetched texel. If ?GL_TEXTURE_SWIZZLE_R is ?GL_BLUE, the value for r will be taken from the third channel of the fetched texel. If ?GL_TEXTURE_SWIZZLE_R is ?GL_ALPHA, the value for r will be taken from the fourth channel of the fetched texel. If ?GL_TEXTURE_SWIZZLE_R is ?GL_ZERO , the value for r will be subtituted with 0.0. If ?GL_TEXTURE_SWIZZLE_R is ?GL_ONE , the value for r will be subtituted with 1.0. The initial value is ?GL_RED.

?GL_TEXTURE_SWIZZLE_G: Sets the swizzle that will be applied to the g component of a texel before it is returned to the shader. Valid values for Param and their effects are similar to those of ?GL_TEXTURE_SWIZZLE_R. The initial value is ?GL_GREEN .

?GL_TEXTURE_SWIZZLE_B: Sets the swizzle that will be applied to the b component of a texel before it is returned to the shader. Valid values for Param and their effects are similar to those of ?GL_TEXTURE_SWIZZLE_R. The initial value is ?GL_BLUE .

?GL_TEXTURE_SWIZZLE_A: Sets the swizzle that will be applied to the a component of a texel before it is returned to the shader. Valid values for Param and their effects are similar to those of ?GL_TEXTURE_SWIZZLE_R. The initial value is ?GL_ALPHA .

?GL_TEXTURE_SWIZZLE_RGBA: Sets the swizzles that will be applied to the r, g, b, and a components of a texel before they are returned to the shader. Valid values for Params and their effects are similar to those of ?GL_TEXTURE_SWIZZLE_R, except that all channels are specified simultaneously. Setting the value of ?GL_TEXTURE_SWIZZLE_RGBA is equivalent (assuming no errors are generated) to setting the parameters of each of ?GL_TEXTURE_SWIZZLE_R , ?GL_TEXTURE_SWIZZLE_G, ?GL_TEXTURE_SWIZZLE_B, and ?GL_TEXTURE_SWIZZLE_A successively.

?GL_TEXTURE_WRAP_S: Sets the wrap parameter for texture coordinate s to either ?GL_CLAMP_TO_EDGE , ?GL_CLAMP_TO_BORDER, ?GL_MIRRORED_REPEAT, or ?GL_REPEAT. ?GL_CLAMP_TO_EDGE causes s coordinates to be clamped to the range [(1 2/N) 1-(1 2/N)], where N is the size of the texture in the direction of clamping. ?GL_CLAMP_TO_BORDER evaluates s coordinates in a similar manner to ?GL_CLAMP_TO_EDGE. However, in cases where clamping would have occurred in ?GL_CLAMP_TO_EDGE mode, the fetched texel data is substituted with the values specified by ?GL_TEXTURE_BORDER_COLOR. ?GL_REPEAT causes the integer part of the s coordinate to be ignored; the GL uses only the fractional part, thereby creating a repeating pattern. ?GL_MIRRORED_REPEAT causes the s coordinate to be set to the fractional part of the texture coordinate if the integer part of s is even; if the integer part of s is odd, then the s texture coordinate is set to 1- frac(s), where frac(s) represents the fractional part of s. Initially, ?GL_TEXTURE_WRAP_S is set to ?GL_REPEAT.

?GL_TEXTURE_WRAP_T: Sets the wrap parameter for texture coordinate t to either ?GL_CLAMP_TO_EDGE , ?GL_CLAMP_TO_BORDER, ?GL_MIRRORED_REPEAT, or ?GL_REPEAT. See the discussion under ?GL_TEXTURE_WRAP_S. Initially, ?GL_TEXTURE_WRAP_T is set to ?GL_REPEAT.

?GL_TEXTURE_WRAP_R: Sets the wrap parameter for texture coordinate r to either ?GL_CLAMP_TO_EDGE , ?GL_CLAMP_TO_BORDER, ?GL_MIRRORED_REPEAT, or ?GL_REPEAT. See the discussion under ?GL_TEXTURE_WRAP_S. Initially, ?GL_TEXTURE_WRAP_R is set to ?GL_REPEAT.

See external documentation.

texParameteri(Target, Pname, Param) -> ok

Types

Target = enum()

Pname = enum()

Param = integer()

See texParameterf/3

texParameterfv(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = tuple()

See texParameterf/3

texParameteriv(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = tuple()

See texParameterf/3

getTexParameterfv(Target, Pname) -> {float(), float(), float(), float()}

Types

Target = enum()

Pname = enum()

Return texture parameter values

gl:getTexParameter returns in Params the value or values of the texture parameter specified as Pname . Target defines the target texture. ?GL_TEXTURE_1D, ?GL_TEXTURE_2D, ?GL_TEXTURE_3D, ?GL_TEXTURE_1D_ARRAY, ?GL_TEXTURE_2D_ARRAY , ?GL_TEXTURE_RECTANGLE, ?GL_TEXTURE_CUBE_MAP, ?GL_TEXTURE_CUBE_MAP_ARRAY specify one-, two-, or three-dimensional, one-dimensional array, two-dimensional array, rectangle, cube-mapped or cube-mapped array texturing, respectively. Pname accepts the same symbols as gl:texParameterf/3 , with the same interpretations:

?GL_TEXTURE_MAG_FILTER: Returns the single-valued texture magnification filter, a symbolic constant. The initial value is ?GL_LINEAR.

?GL_TEXTURE_MIN_FILTER: Returns the single-valued texture minification filter, a symbolic constant. The initial value is ?GL_NEAREST_MIPMAP_LINEAR.

?GL_TEXTURE_MIN_LOD: Returns the single-valued texture minimum level-of-detail value. The initial value is -1000.

?GL_TEXTURE_MAX_LOD: Returns the single-valued texture maximum level-of-detail value. The initial value is 1000.

?GL_TEXTURE_BASE_LEVEL: Returns the single-valued base texture mipmap level. The initial value is 0.

?GL_TEXTURE_MAX_LEVEL: Returns the single-valued maximum texture mipmap array level. The initial value is 1000.

?GL_TEXTURE_SWIZZLE_R: Returns the red component swizzle. The initial value is ?GL_RED .

?GL_TEXTURE_SWIZZLE_G: Returns the green component swizzle. The initial value is ?GL_GREEN .

?GL_TEXTURE_SWIZZLE_B: Returns the blue component swizzle. The initial value is ?GL_BLUE .

?GL_TEXTURE_SWIZZLE_A: Returns the alpha component swizzle. The initial value is ?GL_ALPHA .

?GL_TEXTURE_SWIZZLE_RGBA: Returns the component swizzle for all channels in a single query.

?GL_TEXTURE_WRAP_S: Returns the single-valued wrapping function for texture coordinate s, a symbolic constant. The initial value is ?GL_REPEAT.

?GL_TEXTURE_WRAP_T: Returns the single-valued wrapping function for texture coordinate t, a symbolic constant. The initial value is ?GL_REPEAT.

?GL_TEXTURE_WRAP_R: Returns the single-valued wrapping function for texture coordinate r, a symbolic constant. The initial value is ?GL_REPEAT.

?GL_TEXTURE_BORDER_COLOR: Returns four integer or floating-point numbers that comprise the RGBA color of the texture border. Floating-point values are returned in the range [0 1]. Integer values are returned as a linear mapping of the internal floating-point representation such that 1.0 maps to the most positive representable integer and -1.0 maps to the most negative representable integer. The initial value is (0, 0, 0, 0).

?GL_TEXTURE_COMPARE_MODE: Returns a single-valued texture comparison mode, a symbolic constant. The initial value is ?GL_NONE. See gl:texParameterf/3 .

?GL_TEXTURE_COMPARE_FUNC: Returns a single-valued texture comparison function, a symbolic constant. The initial value is ?GL_LEQUAL. See gl:texParameterf/3 .

In addition to the parameters that may be set with gl:texParameterf/3 , gl:getTexParameter accepts the following read-only parameters:

?GL_TEXTURE_IMMUTABLE_FORMAT: Returns non-zero if the texture has an immutable format. Textures become immutable if their storage is specified with gl:texStorage1D/4 , gl:texStorage2D/5 or gl:texStorage3D/6 . The initial value is ?GL_FALSE .

See external documentation.

getTexParameteriv(Target, Pname) -> {integer(), integer(), integer(), integer()}

Types

Target = enum()

Pname = enum()

See getTexParameterfv/2

getTexLevelParameterfv(Target, Level, Pname) -> {float()}

Types

Target = enum()

Level = integer()

Pname = enum()

Return texture parameter values for a specific level of detail

gl:getTexLevelParameter returns in Params texture parameter values for a specific level-of-detail value, specified as Level . Target defines the target texture, either ?GL_TEXTURE_1D, ?GL_TEXTURE_2D, ?GL_TEXTURE_3D, ?GL_PROXY_TEXTURE_1D , ?GL_PROXY_TEXTURE_2D, ?GL_PROXY_TEXTURE_3D, ?GL_TEXTURE_CUBE_MAP_POSITIVE_X , ?GL_TEXTURE_CUBE_MAP_NEGATIVE_X, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Y, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Y , ?GL_TEXTURE_CUBE_MAP_POSITIVE_Z, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, or ?GL_PROXY_TEXTURE_CUBE_MAP .

?GL_MAX_TEXTURE_SIZE, and ?GL_MAX_3D_TEXTURE_SIZE are not really descriptive enough. It has to report the largest square texture image that can be accommodated with mipmaps and borders, but a long skinny texture, or a texture without mipmaps and borders, may easily fit in texture memory. The proxy targets allow the user to more accurately query whether the GL can accommodate a texture of a given configuration. If the texture cannot be accommodated, the texture state variables, which may be queried with gl:getTexLevelParameter , are set to 0. If the texture can be accommodated, the texture state values will be set as they would be set for a non-proxy target.

Pname specifies the texture parameter whose value or values will be returned.

The accepted parameter names are as follows:

?GL_TEXTURE_WIDTH: Params returns a single value, the width of the texture image. This value includes the border of the texture image. The initial value is 0.

?GL_TEXTURE_HEIGHT: Params returns a single value, the height of the texture image. This value includes the border of the texture image. The initial value is 0.

?GL_TEXTURE_DEPTH: Params returns a single value, the depth of the texture image. This value includes the border of the texture image. The initial value is 0.

?GL_TEXTURE_INTERNAL_FORMAT: Params returns a single value, the internal format of the texture image.

?GL_TEXTURE_RED_TYPE,

?GL_TEXTURE_GREEN_TYPE,

?GL_TEXTURE_BLUE_TYPE,

?GL_TEXTURE_ALPHA_TYPE,

?GL_TEXTURE_DEPTH_TYPE: The data type used to store the component. The types ?GL_NONE , ?GL_SIGNED_NORMALIZED, ?GL_UNSIGNED_NORMALIZED, ?GL_FLOAT, ?GL_INT , and ?GL_UNSIGNED_INT may be returned to indicate signed normalized fixed-point, unsigned normalized fixed-point, floating-point, integer unnormalized, and unsigned integer unnormalized components, respectively.

?GL_TEXTURE_RED_SIZE,

?GL_TEXTURE_GREEN_SIZE,

?GL_TEXTURE_BLUE_SIZE,

?GL_TEXTURE_ALPHA_SIZE,

?GL_TEXTURE_DEPTH_SIZE: The internal storage resolution of an individual component. The resolution chosen by the GL will be a close match for the resolution requested by the user with the component argument of gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:copyTexImage1D/7 , and gl:copyTexImage2D/8 . The initial value is 0.

?GL_TEXTURE_COMPRESSED: Params returns a single boolean value indicating if the texture image is stored in a compressed internal format. The initiali value is ?GL_FALSE .

?GL_TEXTURE_COMPRESSED_IMAGE_SIZE: Params returns a single integer value, the number of unsigned bytes of the compressed texture image that would be returned from gl:getCompressedTexImage/3 .

See external documentation.

getTexLevelParameteriv(Target, Level, Pname) -> {integer()}

Types

Target = enum()

Level = integer()

Pname = enum()

See getTexLevelParameterfv/3

texImage1D(Target, Level, InternalFormat, Width, Border, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

InternalFormat = integer()

Width = integer()

Border = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

Specify a one-dimensional texture image

Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable one-dimensional texturing, call gl:enable/1 and gl:enable/1 with argument ?GL_TEXTURE_1D.

Texture images are defined with gl:texImage1D. The arguments describe the parameters of the texture image, such as width, width of the border, level-of-detail number (see gl:texParameterf/3 ), and the internal resolution and format used to store the image. The last three arguments describe how the image is represented in memory.

If Target is ?GL_PROXY_TEXTURE_1D, no data is read from Data , but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see gl:getError/0 ). To query for an entire mipmap array, use an image array level greater than or equal to 1.

If Target is ?GL_TEXTURE_1D, data is read from Data as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on Type . These values are grouped into sets of one, two, three, or four values, depending on Format , to form elements. Each data byte is treated as eight 1-bit elements, with bit ordering determined by ?GL_UNPACK_LSB_FIRST (see gl:pixelStoref/2 ).

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a texture image is specified, Data is treated as a byte offset into the buffer object's data store.

The first element corresponds to the left end of the texture array. Subsequent elements progress left-to-right through the remaining texels in the texture array. The final element corresponds to the right end of the texture array.

Format determines the composition of each element in Data . It can assume one of these symbolic values:

?GL_RED: Each element is a single red component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_RG: Each element is a single red/green double The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for blue, and 1 for alpha. Each component is then multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_RGB

?GL_BGR: Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1 for alpha. Each component is then multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_RGBA

?GL_BGRA: Each element contains all four components. Each component is multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_DEPTH_COMPONENT: Each element is a single depth value. The GL converts it to floating point, multiplies by the signed scale factor ?GL_DEPTH_SCALE, adds the signed bias ?GL_DEPTH_BIAS, and clamps to the range [0,1].

If an application wants to store the texture at a certain resolution or in a certain format, it can request the resolution and format with InternalFormat . The GL will choose an internal representation that closely approximates that requested by InternalFormat , but it may not match exactly. (The representations specified by ?GL_RED, ?GL_RG , ?GL_RGB and ?GL_RGBA must match exactly.)

InternalFormat may be one of the base internal formats shown in Table 1, below

InternalFormat may also be one of the sized internal formats shown in Table 2, below

Finally, InternalFormat may also be one of the generic or compressed compressed texture formats shown in Table 3 below

If the InternalFormat parameter is one of the generic compressed formats, ?GL_COMPRESSED_RED , ?GL_COMPRESSED_RG, ?GL_COMPRESSED_RGB, or ?GL_COMPRESSED_RGBA, the GL will replace the internal format with the symbolic constant for a specific internal format and compress the texture before storage. If no corresponding internal format is available, or the GL can not compress that image for any reason, the internal format is instead replaced with a corresponding base internal format.

If the InternalFormat parameter is ?GL_SRGB, ?GL_SRGB8, ?GL_SRGB_ALPHA or ?GL_SRGB8_ALPHA8, the texture is treated as if the red, green, or blue components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component c s to a linear component c l is:

c l={ c s/12.92if c s≤ 0.04045( c s+0.055/1.055) 2.4if c s> 0.04045

Assume c s is the sRGB component in the range [0,1].

Use the ?GL_PROXY_TEXTURE_1D target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call gl:getTexLevelParameterfv/3 . If the texture cannot be accommodated, texture state is set to 0.

A one-component texture image uses only the red component of the RGBA color from Data . A two-component image uses the R and A values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components.

Image-based shadowing can be enabled by comparing texture r coordinates to depth texture values to generate a boolean result. See gl:texParameterf/3 for details on texture comparison.

See external documentation.

texImage2D(Target, Level, InternalFormat, Width, Height, Border, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

InternalFormat = integer()

Width = integer()

Height = integer()

Border = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

Specify a two-dimensional texture image

Texturing allows elements of an image array to be read by shaders.

To define texture images, call gl:texImage2D. The arguments describe the parameters of the texture image, such as height, width, width of the border, level-of-detail number (see gl:texParameterf/3 ), and number of color components provided. The last three arguments describe how the image is represented in memory.

If Target is ?GL_PROXY_TEXTURE_2D, ?GL_PROXY_TEXTURE_1D_ARRAY, ?GL_PROXY_TEXTURE_CUBE_MAP , or ?GL_PROXY_TEXTURE_RECTANGLE, no data is read from Data , but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see gl:getError/0 ). To query for an entire mipmap array, use an image array level greater than or equal to 1.

If Target is ?GL_TEXTURE_2D, ?GL_TEXTURE_RECTANGLE or one of the ?GL_TEXTURE_CUBE_MAP targets, data is read from Data as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on Type . These values are grouped into sets of one, two, three, or four values, depending on Format , to form elements. Each data byte is treated as eight 1-bit elements, with bit ordering determined by ?GL_UNPACK_LSB_FIRST (see gl:pixelStoref/2 ).

If Target is ?GL_TEXTURE_1D_ARRAY, data is interpreted as an array of one-dimensional images.

The first element corresponds to the lower left corner of the texture image. Subsequent elements progress left-to-right through the remaining texels in the lowest row of the texture image, and then in successively higher rows of the texture image. The final element corresponds to the upper right corner of the texture image.

Format determines the composition of each element in Data . It can assume one of these symbolic values:

?GL_RG: Each element is a red/green double. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for blue, and 1 for alpha. Each component is then multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_RGB

?GL_RGBA

?GL_BGRA: Each element contains all four components. Each component is multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_DEPTH_STENCIL: Each element is a pair of depth and stencil values. The depth component of the pair is interpreted as in ?GL_DEPTH_COMPONENT. The stencil component is interpreted based on specified the depth + stencil internal format.

InternalFormat may be one of the base internal formats shown in Table 1, below

InternalFormat may also be one of the sized internal formats shown in Table 2, below

Finally, InternalFormat may also be one of the generic or compressed compressed texture formats shown in Table 3 below

If the InternalFormat parameter is ?GL_SRGB, ?GL_SRGB8, ?GL_SRGB_ALPHA , or ?GL_SRGB8_ALPHA8, the texture is treated as if the red, green, or blue components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component c s to a linear component c l is:

c l={ c s/12.92if c s≤ 0.04045( c s+0.055/1.055) 2.4if c s> 0.04045

Assume c s is the sRGB component in the range [0,1].

Use the ?GL_PROXY_TEXTURE_2D, ?GL_PROXY_TEXTURE_1D_ARRAY, ?GL_PROXY_TEXTURE_RECTANGLE , or ?GL_PROXY_TEXTURE_CUBE_MAP target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call gl:getTexLevelParameterfv/3 . If the texture cannot be accommodated, texture state is set to 0.

A one-component texture image uses only the red component of the RGBA color extracted from Data . A two-component image uses the R and G values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components.

Image-based shadowing can be enabled by comparing texture r coordinates to depth texture values to generate a boolean result. See gl:texParameterf/3 for details on texture comparison.

See external documentation.

getTexImage(Target, Level, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

Format = enum()

Type = enum()

Pixels = mem()

Return a texture image

gl:getTexImage returns a texture image into Img . Target specifies whether the desired texture image is one specified by gl:texImage1D/8 (?GL_TEXTURE_1D ), gl:texImage2D/9 (?GL_TEXTURE_1D_ARRAY, ?GL_TEXTURE_RECTANGLE, ?GL_TEXTURE_2D or any of ?GL_TEXTURE_CUBE_MAP_*), or gl:texImage3D/10 (?GL_TEXTURE_2D_ARRAY , ?GL_TEXTURE_3D). Level specifies the level-of-detail number of the desired image. Format and Type specify the format and type of the desired image array. See the reference page for gl:texImage1D/8 for a description of the acceptable values for the Format and Type parameters, respectively.

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while a texture image is requested, Img is treated as a byte offset into the buffer object's data store.

To understand the operation of gl:getTexImage, consider the selected internal four-component texture image to be an RGBA color buffer the size of the image. The semantics of gl:getTexImage are then identical to those of gl:readPixels/7 , with the exception that no pixel transfer operations are performed, when called with the same Format and Type , with x and y set to 0, width set to the width of the texture image and height set to 1 for 1D images, or to the height of the texture image for 2D images.

If the selected texture image does not contain four components, the following mappings are applied. Single-component textures are treated as RGBA buffers with red set to the single-component value, green set to 0, blue set to 0, and alpha set to 1. Two-component textures are treated as RGBA buffers with red set to the value of component zero, alpha set to the value of component one, and green and blue set to 0. Finally, three-component textures are treated as RGBA buffers with red set to component zero, green set to component one, blue set to component two, and alpha set to 1.

To determine the required size of Img , use gl:getTexLevelParameterfv/3 to determine the dimensions of the internal texture image, then scale the required number of pixels by the storage required for each pixel, based on Format and Type . Be sure to take the pixel storage parameters into account, especially ?GL_PACK_ALIGNMENT .

See external documentation.

genTextures(N) -> [integer()]

Types

N = integer()

Generate texture names

gl:genTextures returns N texture names in Textures . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genTextures.

The generated textures have no dimensionality; they assume the dimensionality of the texture target to which they are first bound (see gl:bindTexture/2 ).

Texture names returned by a call to gl:genTextures are not returned by subsequent calls, unless they are first deleted with gl:deleteTextures/1 .

See external documentation.

deleteTextures(Textures) -> ok

Types

Textures = [integer()]

Delete named textures

gl:deleteTextures deletes N textures named by the elements of the array Textures . After a texture is deleted, it has no contents or dimensionality, and its name is free for reuse (for example by gl:genTextures/1 ). If a texture that is currently bound is deleted, the binding reverts to 0 (the default texture).

gl:deleteTextures silently ignores 0's and names that do not correspond to existing textures.

See external documentation.

bindTexture(Target, Texture) -> ok

Types

Target = enum()

Texture = integer()

Bind a named texture to a texturing target

gl:bindTexture lets you create or use a named texture. Calling gl:bindTexture with Target set to ?GL_TEXTURE_1D, ?GL_TEXTURE_2D, ?GL_TEXTURE_3D , or ?GL_TEXTURE_1D_ARRAY, ?GL_TEXTURE_2D_ARRAY, ?GL_TEXTURE_RECTANGLE , ?GL_TEXTURE_CUBE_MAP, ?GL_TEXTURE_2D_MULTISAMPLE or ?GL_TEXTURE_2D_MULTISAMPLE_ARRAY and Texture set to the name of the new texture binds the texture name to the target. When a texture is bound to a target, the previous binding for that target is automatically broken.

Texture names are unsigned integers. The value zero is reserved to represent the default texture for each texture target. Texture names and the corresponding texture contents are local to the shared object space of the current GL rendering context; two rendering contexts share texture names only if they explicitly enable sharing between contexts through the appropriate GL windows interfaces functions.

You must use gl:genTextures/1 to generate a set of new texture names.

When a texture is first bound, it assumes the specified target: A texture first bound to ?GL_TEXTURE_1D becomes one-dimensional texture, a texture first bound to ?GL_TEXTURE_2D becomes two-dimensional texture, a texture first bound to ?GL_TEXTURE_3D becomes three-dimensional texture, a texture first bound to ?GL_TEXTURE_1D_ARRAY becomes one-dimensional array texture, a texture first bound to ?GL_TEXTURE_2D_ARRAY becomes two-dimensional arary texture, a texture first bound to ?GL_TEXTURE_RECTANGLE becomes rectangle texture, a, texture first bound to ?GL_TEXTURE_CUBE_MAP becomes a cube-mapped texture, a texture first bound to ?GL_TEXTURE_2D_MULTISAMPLE becomes a two-dimensional multisampled texture, and a texture first bound to ?GL_TEXTURE_2D_MULTISAMPLE_ARRAY becomes a two-dimensional multisampled array texture. The state of a one-dimensional texture immediately after it is first bound is equivalent to the state of the default ?GL_TEXTURE_1D at GL initialization, and similarly for the other texture types.

While a texture is bound, GL operations on the target to which it is bound affect the bound texture, and queries of the target to which it is bound return state from the bound texture. In effect, the texture targets become aliases for the textures currently bound to them, and the texture name zero refers to the default textures that were bound to them at initialization.

A texture binding created with gl:bindTexture remains active until a different texture is bound to the same target, or until the bound texture is deleted with gl:deleteTextures/1 .

Once created, a named texture may be re-bound to its same original target as often as needed. It is usually much faster to use gl:bindTexture to bind an existing named texture to one of the texture targets than it is to reload the texture image using gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 or another similar function.

See external documentation.

prioritizeTextures(Textures, Priorities) -> ok

Types

Textures = [integer()]

Priorities = [clamp()]

Set texture residence priority

gl:prioritizeTextures assigns the N texture priorities given in Priorities to the N textures named in Textures .

The GL establishes a working set of textures that are resident in texture memory. These textures may be bound to a texture target much more efficiently than textures that are not resident. By specifying a priority for each texture, gl:prioritizeTextures allows applications to guide the GL implementation in determining which textures should be resident.

The priorities given in Priorities are clamped to the range [0 1] before they are assigned. 0 indicates the lowest priority; textures with priority 0 are least likely to be resident. 1 indicates the highest priority; textures with priority 1 are most likely to be resident. However, textures are not guaranteed to be resident until they are used.

gl:prioritizeTextures silently ignores attempts to prioritize texture 0 or any texture name that does not correspond to an existing texture.

gl:prioritizeTextures does not require that any of the textures named by Textures be bound to a texture target. gl:texParameterf/3 may also be used to set a texture's priority, but only if the texture is currently bound. This is the only way to set the priority of a default texture.

See external documentation.

areTexturesResident(Textures) -> {0 | 1, Residences::[0 | 1]}

Types

Textures = [integer()]

Determine if textures are loaded in texture memory

GL establishes a working set of textures that are resident in texture memory. These textures can be bound to a texture target much more efficiently than textures that are not resident.

gl:areTexturesResident queries the texture residence status of the N textures named by the elements of Textures . If all the named textures are resident, gl:areTexturesResident returns ?GL_TRUE, and the contents of Residences are undisturbed. If not all the named textures are resident, gl:areTexturesResident returns ?GL_FALSE, and detailed status is returned in the N elements of Residences . If an element of Residences is ?GL_TRUE, then the texture named by the corresponding element of Textures is resident.

The residence status of a single bound texture may also be queried by calling gl:getTexParameterfv/2 with the target argument set to the target to which the texture is bound, and the pname argument set to ?GL_TEXTURE_RESIDENT. This is the only way that the residence status of a default texture can be queried.

See external documentation.

isTexture(Texture) -> 0 | 1

Types

Texture = integer()

Determine if a name corresponds to a texture

gl:isTexture returns ?GL_TRUE if Texture is currently the name of a texture. If Texture is zero, or is a non-zero value that is not currently the name of a texture, or if an error occurs, gl:isTexture returns ?GL_FALSE.

A name returned by gl:genTextures/1 , but not yet associated with a texture by calling gl:bindTexture/2 , is not the name of a texture.

See external documentation.

texSubImage1D(Target, Level, Xoffset, Width, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Width = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

glTexSubImage

See external documentation.

texSubImage2D(Target, Level, Xoffset, Yoffset, Width, Height, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Yoffset = integer()

Width = integer()

Height = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

glTexSubImage

See external documentation.

copyTexImage1D(Target, Level, Internalformat, X, Y, Width, Border) -> ok

Types

Target = enum()

Level = integer()

Internalformat = enum()

X = integer()

Y = integer()

Width = integer()

Border = integer()

Copy pixels into a 1D texture image

gl:copyTexImage1D defines a one-dimensional texture image with pixels from the current ?GL_READ_BUFFER.

The screen-aligned pixel row with left corner at (x y) and with a length of width+2(border) defines the texture array at the mipmap level specified by Level . Internalformat specifies the internal format of the texture array.

The pixels in the row are processed exactly as if gl:readPixels/7 had been called, but the process stops just before final conversion. At this point all pixel component values are clamped to the range [0 1] and then converted to the texture's internal format for storage in the texel array.

Pixel ordering is such that lower x screen coordinates correspond to lower texture coordinates.

If any of the pixels within the specified row of the current ?GL_READ_BUFFER are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined.

gl:copyTexImage1D defines a one-dimensional texture image with pixels from the current ?GL_READ_BUFFER.

When Internalformat is one of the sRGB types, the GL does not automatically convert the source pixels to the sRGB color space. In this case, the gl:pixelMap function can be used to accomplish the conversion.

See external documentation.

copyTexImage2D(Target, Level, Internalformat, X, Y, Width, Height, Border) -> ok

Types

Target = enum()

Level = integer()

Internalformat = enum()

X = integer()

Y = integer()

Width = integer()

Height = integer()

Border = integer()

Copy pixels into a 2D texture image

gl:copyTexImage2D defines a two-dimensional texture image, or cube-map texture image with pixels from the current ?GL_READ_BUFFER.

The screen-aligned pixel rectangle with lower left corner at ( X , Y ) and with a width of width+2(border) and a height of height+2(border) defines the texture array at the mipmap level specified by Level . Internalformat specifies the internal format of the texture array.

The pixels in the rectangle are processed exactly as if gl:readPixels/7 had been called, but the process stops just before final conversion. At this point all pixel component values are clamped to the range [0 1] and then converted to the texture's internal format for storage in the texel array.

Pixel ordering is such that lower x and y screen coordinates correspond to lower s and t texture coordinates.

If any of the pixels within the specified rectangle of the current ?GL_READ_BUFFER are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined.

See external documentation.

copyTexSubImage1D(Target, Level, Xoffset, X, Y, Width) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

X = integer()

Y = integer()

Width = integer()

Copy a one-dimensional texture subimage

gl:copyTexSubImage1D replaces a portion of a one-dimensional texture image with pixels from the current ?GL_READ_BUFFER (rather than from main memory, as is the case for gl:texSubImage1D/7 ).

The screen-aligned pixel row with left corner at ( X , Y ), and with length Width replaces the portion of the texture array with x indices Xoffset through xoffset +width-1, inclusive. The destination in the texture array may not include any texels outside the texture array as it was originally specified.

The pixels in the row are processed exactly as if gl:readPixels/7 had been called, but the process stops just before final conversion. At this point, all pixel component values are clamped to the range [0 1] and then converted to the texture's internal format for storage in the texel array.

It is not an error to specify a subtexture with zero width, but such a specification has no effect. If any of the pixels within the specified row of the current ?GL_READ_BUFFER are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined.

No change is made to the internalformat, width, or border parameters of the specified texture array or to texel values outside the specified subregion.

See external documentation.

copyTexSubImage2D(Target, Level, Xoffset, Yoffset, X, Y, Width, Height) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Yoffset = integer()

X = integer()

Y = integer()

Width = integer()

Height = integer()

Copy a two-dimensional texture subimage

gl:copyTexSubImage2D replaces a rectangular portion of a two-dimensional texture image or cube-map texture image with pixels from the current ?GL_READ_BUFFER (rather than from main memory, as is the case for gl:texSubImage1D/7 ).

The screen-aligned pixel rectangle with lower left corner at (x y) and with width Width and height Height replaces the portion of the texture array with x indices Xoffset through xoffset+width-1, inclusive, and y indices Yoffset through yoffset+height -1, inclusive, at the mipmap level specified by Level .

The pixels in the rectangle are processed exactly as if gl:readPixels/7 had been called, but the process stops just before final conversion. At this point, all pixel component values are clamped to the range [0 1] and then converted to the texture's internal format for storage in the texel array.

The destination rectangle in the texture array may not include any texels outside the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect.

If any of the pixels within the specified rectangle of the current ?GL_READ_BUFFER are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined.

No change is made to the internalformat, width, height, or border parameters of the specified texture array or to texel values outside the specified subregion.

See external documentation.

map1d(Target, U1, U2, Stride, Order, Points) -> ok

Types

Target = enum()

U1 = float()

U2 = float()

Stride = integer()

Order = integer()

Points = binary()

Target = enum()

Query = enum()

V = mem()

Return evaluator parameters

gl:map1d/6 and gl:map1d/6 define evaluators. gl:getMap returns evaluator parameters. Target chooses a map, Query selects a specific parameter, and V points to storage where the values will be returned.

The acceptable values for the Target parameter are described in the gl:map1d/6 and gl:map1d/6 reference pages.

Query can assume the following values:

?GL_COEFF: V returns the control points for the evaluator function. One-dimensional evaluators return order control points, and two-dimensional evaluators return uorder×vorder control points. Each control point consists of one, two, three, or four integer, single-precision floating-point, or double-precision floating-point values, depending on the type of the evaluator. The GL returns two-dimensional control points in row-major order, incrementing the uorder index quickly and the vorder index after each row. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.

?GL_ORDER: V returns the order of the evaluator function. One-dimensional evaluators return a single value, order. The initial value is 1. Two-dimensional evaluators return two values, uorder and vorder. The initial value is 1,1.

?GL_DOMAIN: V returns the linear u and v mapping parameters. One-dimensional evaluators return two values, u1 and u2, as specified by gl:map1d/6 . Two-dimensional evaluators return four values ( u1, u2, v1, and v2) as specified by gl:map1d/6 . Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.

See external documentation.

getMapfv(Target, Query, V) -> ok

Types

Target = enum()

Query = enum()

V = mem()

See getMapdv/3

getMapiv(Target, Query, V) -> ok

Types

Target = enum()

Query = enum()

V = mem()

See getMapdv/3

evalCoord1d(U) -> ok

Types

U = float()

Evaluate enabled one- and two-dimensional maps

gl:evalCoord1 evaluates enabled one-dimensional maps at argument U . gl:evalCoord2 does the same for two-dimensional maps using two domain values, U and V . To define a map, call gl:map1d/6 and gl:map1d/6 ; to enable and disable it, call gl:enable/1 and gl:enable/1 .

When one of the gl:evalCoord commands is issued, all currently enabled maps of the indicated dimension are evaluated. Then, for each enabled map, it is as if the corresponding GL command had been issued with the computed value. That is, if ?GL_MAP1_INDEX or ?GL_MAP2_INDEX is enabled, a gl:indexd/1 command is simulated. If ?GL_MAP1_COLOR_4 or ?GL_MAP2_COLOR_4 is enabled, a gl:color3b/3 command is simulated. If ?GL_MAP1_NORMAL or ?GL_MAP2_NORMAL is enabled, a normal vector is produced, and if any of ?GL_MAP1_TEXTURE_COORD_1, ?GL_MAP1_TEXTURE_COORD_2 , ?GL_MAP1_TEXTURE_COORD_3, ?GL_MAP1_TEXTURE_COORD_4, ?GL_MAP2_TEXTURE_COORD_1 , ?GL_MAP2_TEXTURE_COORD_2, ?GL_MAP2_TEXTURE_COORD_3, or ?GL_MAP2_TEXTURE_COORD_4 is enabled, then an appropriate gl:texCoord1d/1 command is simulated.

For color, color index, normal, and texture coordinates the GL uses evaluated values instead of current values for those evaluations that are enabled, and current values otherwise, However, the evaluated values do not update the current values. Thus, if gl:vertex2d/2 commands are interspersed with gl:evalCoord commands, the color, normal, and texture coordinates associated with the gl:vertex2d/2 commands are not affected by the values generated by the gl:evalCoord commands, but only by the most recent gl:color3b/3 , gl:indexd/1 , gl:normal3b/3 , and gl:texCoord1d/1 commands.

No commands are issued for maps that are not enabled. If more than one texture evaluation is enabled for a particular dimension (for example, ?GL_MAP2_TEXTURE_COORD_1 and ?GL_MAP2_TEXTURE_COORD_2 ), then only the evaluation of the map that produces the larger number of coordinates (in this case, ?GL_MAP2_TEXTURE_COORD_2) is carried out. ?GL_MAP1_VERTEX_4 overrides ?GL_MAP1_VERTEX_3, and ?GL_MAP2_VERTEX_4 overrides ?GL_MAP2_VERTEX_3 , in the same manner. If neither a three- nor a four-component vertex map is enabled for the specified dimension, the gl:evalCoord command is ignored.

If you have enabled automatic normal generation, by calling gl:enable/1 with argument ?GL_AUTO_NORMAL, gl:evalCoord2 generates surface normals analytically, regardless of the contents or enabling of the ?GL_MAP2_NORMAL map. Let

m=((&PartialD; p)/(&PartialD; u))×((&PartialD; p)/(&PartialD; v))

Then the generated normal n is n=m/(||m||)

If automatic normal generation is disabled, the corresponding normal map ?GL_MAP2_NORMAL , if enabled, is used to produce a normal. If neither automatic normal generation nor a normal map is enabled, no normal is generated for gl:evalCoord2 commands.

See external documentation.

evalCoord1f(U) -> ok

Types

U = float()

See evalCoord1d/1

evalCoord1dv(U) -> ok

Types

U = {U::float()}

Equivalent to evalCoord1d(U).

evalCoord1fv(U) -> ok

U = {U::float(), V::float()}

Equivalent to evalCoord2d(U, V).

evalCoord2fv(U) -> ok

Types

U = {U::float(), V::float()}

Equivalent to evalCoord2f(U, V).

mapGrid1d(Un, U1, U2) -> ok

Types

Un = integer()

U1 = float()

U2 = float()

Define a one- or two-dimensional mesh

gl:mapGrid and gl:evalMesh1/3 are used together to efficiently generate and evaluate a series of evenly-spaced map domain values. gl:evalMesh1/3 steps through the integer domain of a one- or two-dimensional grid, whose range is the domain of the evaluation maps specified by gl:map1d/6 and gl:map1d/6 .

gl:mapGrid1 and gl:mapGrid2 specify the linear grid mappings between the i (or i and j) integer grid coordinates, to the u (or u and v) floating-point evaluation map coordinates. See gl:map1d/6 and gl:map1d/6 for details of how u and v coordinates are evaluated.

gl:mapGrid1 specifies a single linear mapping such that integer grid coordinate 0 maps exactly to U1 , and integer grid coordinate Un maps exactly to U2 . All other integer grid coordinates i are mapped so that

u=i(u2-u1)/un+u1

gl:mapGrid2 specifies two such linear mappings. One maps integer grid coordinate i=0 exactly to U1 , and integer grid coordinate i=un exactly to U2 . The other maps integer grid coordinate j=0 exactly to V1 , and integer grid coordinate j=vn exactly to V2 . Other integer grid coordinates i and j are mapped such that

u=i(u2-u1)/un+u1

v=j(v2-v1)/vn+v1

The mappings specified by gl:mapGrid are used identically by gl:evalMesh1/3 and gl:evalPoint1/1 .

I = integer()

Generate and evaluate a single point in a mesh

gl:mapGrid1d/3 and gl:evalMesh1/3 are used in tandem to efficiently generate and evaluate a series of evenly spaced map domain values. gl:evalPoint can be used to evaluate a single grid point in the same gridspace that is traversed by gl:evalMesh1/3 . Calling gl:evalPoint1 is equivalent to calling glEvalCoord1( i.Δ u+u 1 ); where Δ u=(u 2-u 1)/n

and n, u 1, and u 2 are the arguments to the most recent gl:mapGrid1d/3 command. The one absolute numeric requirement is that if i=n, then the value computed from i.Δ u+u 1 is exactly u 2.

In the two-dimensional case, gl:evalPoint2, let

Δ u=(u 2-u 1)/n

Δ v=(v 2-v 1)/m

where n, u 1, u 2, m, v 1, and v 2 are the arguments to the most recent gl:mapGrid1d/3 command. Then the gl:evalPoint2 command is equivalent to calling glEvalCoord2( i. Δ u+u 1, j.Δ v+v 1 ); The only absolute numeric requirements are that if i=n, then the value computed from i.Δ u+u 1 is exactly u 2, and if j=m, then the value computed from j.Δ v+v 1 is exactly v 2.

See external documentation.

evalPoint2(I, J) -> ok

Types

I = integer()

J = integer()

See evalPoint1/1

evalMesh1(Mode, I1, I2) -> ok

Types

Mode = enum()

I1 = integer()

I2 = integer()

Compute a one- or two-dimensional grid of points or lines

gl:mapGrid1d/3 and gl:evalMesh are used in tandem to efficiently generate and evaluate a series of evenly-spaced map domain values. gl:evalMesh steps through the integer domain of a one- or two-dimensional grid, whose range is the domain of the evaluation maps specified by gl:map1d/6 and gl:map1d/6 . Mode determines whether the resulting vertices are connected as points, lines, or filled polygons.

In the one-dimensional case, gl:evalMesh1, the mesh is generated as if the following code fragment were executed:

glBegin( Type ); for ( i = I1 ; i <= I2 ; i += 1 ) glEvalCoord1( i.Δ u+u 1 ); glEnd(); where

Δ u=(u 2-u 1)/n

and n, u 1, and u 2 are the arguments to the most recent gl:mapGrid1d/3 command. type is ?GL_POINTS if Mode is ?GL_POINT, or ?GL_LINES if Mode is ?GL_LINE.

The one absolute numeric requirement is that if i=n, then the value computed from i.Δ u+u 1 is exactly u 2.

In the two-dimensional case, gl:evalMesh2, let .cp Δ u=(u 2-u 1)/n

Δ v=(v 2-v 1)/m

where n, u 1, u 2, m, v 1, and v 2 are the arguments to the most recent gl:mapGrid1d/3 command. Then, if Mode is ?GL_FILL, the gl:evalMesh2 command is equivalent to:

for ( j = J1 ; j < J2 ; j += 1 ) { glBegin( GL_QUAD_STRIP ); for ( i = I1 ; i <= I2 ; i += 1 ) { glEvalCoord2( i.Δ u+u 1, j.Δ v+v 1 ); glEvalCoord2( i.Δ u+u 1,(j+1).Δ v+v 1 ); } glEnd(); }

If Mode is ?GL_LINE, then a call to gl:evalMesh2 is equivalent to:

for ( j = J1 ; j <= J2 ; j += 1 ) { glBegin( GL_LINE_STRIP ); for ( i = I1 ; i <= I2 ; i += 1 ) glEvalCoord2( i.Δ u+u 1, j.Δ v+v 1 ); glEnd(); } for ( i = I1 ; i <= I2 ; i += 1 ) { glBegin( GL_LINE_STRIP ); for ( j = J1 ; j <= J1 ; j += 1 ) glEvalCoord2( i.Δ u+u 1, j. Δ v+v 1 ); glEnd(); }

And finally, if Mode is ?GL_POINT, then a call to gl:evalMesh2 is equivalent to:

glBegin( GL_POINTS ); for ( j = J1 ; j <= J2 ; j += 1 ) for ( i = I1 ; i <= I2 ; i += 1 ) glEvalCoord2( i.Δ u+u 1, j.Δ v+v 1 ); glEnd();

In all three cases, the only absolute numeric requirements are that if i=n, then the value computed from i.Δ u+u 1 is exactly u 2, and if j=m, then the value computed from j.Δ v+v 1 is exactly v 2.

See external documentation.

evalMesh2(Mode, I1, I2, J1, J2) -> ok

Types

Mode = enum()

I1 = integer()

I2 = integer()

J1 = integer()

J2 = integer()

See evalMesh1/3

fogf(Pname, Param) -> ok

Types

Pname = enum()

Param = float()

Specify fog parameters

Fog is initially disabled. While enabled, fog affects rasterized geometry, bitmaps, and pixel blocks, but not buffer clear operations. To enable and disable fog, call gl:enable/1 and gl:enable/1 with argument ?GL_FOG.

gl:fog assigns the value or values in Params to the fog parameter specified by Pname . The following values are accepted for Pname :

?GL_FOG_MODE: Params is a single integer or floating-point value that specifies the equation to be used to compute the fog blend factor, f. Three symbolic constants are accepted: ?GL_LINEAR, ?GL_EXP, and ?GL_EXP2. The equations corresponding to these symbolic constants are defined below. The initial fog mode is ?GL_EXP.

?GL_FOG_DENSITY: Params is a single integer or floating-point value that specifies density, the fog density used in both exponential fog equations. Only nonnegative densities are accepted. The initial fog density is 1.

?GL_FOG_START: Params is a single integer or floating-point value that specifies start, the near distance used in the linear fog equation. The initial near distance is 0.

?GL_FOG_END: Params is a single integer or floating-point value that specifies end, the far distance used in the linear fog equation. The initial far distance is 1.

?GL_FOG_INDEX: Params is a single integer or floating-point value that specifies i f, the fog color index. The initial fog index is 0.

?GL_FOG_COLOR: Params contains four integer or floating-point values that specify C f, the fog color. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0. Floating-point values are mapped directly. After conversion, all color components are clamped to the range [0 1]. The initial fog color is (0, 0, 0, 0).

?GL_FOG_COORD_SRC: Params contains either of the following symbolic constants: ?GL_FOG_COORD or ?GL_FRAGMENT_DEPTH. ?GL_FOG_COORD specifies that the current fog coordinate should be used as distance value in the fog color computation. ?GL_FRAGMENT_DEPTH specifies that the current fragment depth should be used as distance value in the fog computation.

Fog blends a fog color with each rasterized pixel fragment's post-texturing color using a blending factor f. Factor f is computed in one of three ways, depending on the fog mode. Let c be either the distance in eye coordinate from the origin (in the case that the ?GL_FOG_COORD_SRC is ?GL_FRAGMENT_DEPTH) or the current fog coordinate (in the case that ?GL_FOG_COORD_SRC is ?GL_FOG_COORD). The equation for ?GL_LINEAR fog is f=(end-c)/(end-start)

The equation for ?GL_EXP fog is f=e(-(density. c))

The equation for ?GL_EXP2 fog is f=e(-(density. c)) 2

Regardless of the fog mode, f is clamped to the range [0 1] after it is computed. Then, if the GL is in RGBA color mode, the fragment's red, green, and blue colors, represented by C r, are replaced by

(C r)"=f×C r+(1-f)×C f

Fog does not affect a fragment's alpha component.

In color index mode, the fragment's color index i r is replaced by

(i r)"=i r+(1-f)×i f

See external documentation.

fogi(Pname, Param) -> ok

Types

Pname = enum()

Param = integer()

See fogf/2

fogfv(Pname, Params) -> ok

Types

Pname = enum()

Params = tuple()

See fogf/2

fogiv(Pname, Params) -> ok

Types

Pname = enum()

Params = tuple()

See fogf/2

feedbackBuffer(Size, Type, Buffer) -> ok

Types

Size = integer()

Type = enum()

Buffer = mem()

Controls feedback mode

The gl:feedbackBuffer function controls feedback. Feedback, like selection, is a GL mode. The mode is selected by calling gl:renderMode/1 with ?GL_FEEDBACK. When the GL is in feedback mode, no pixels are produced by rasterization. Instead, information about primitives that would have been rasterized is fed back to the application using the GL.

gl:feedbackBuffer has three arguments: Buffer is a pointer to an array of floating-point values into which feedback information is placed. Size indicates the size of the array. Type is a symbolic constant describing the information that is fed back for each vertex. gl:feedbackBuffer must be issued before feedback mode is enabled (by calling gl:renderMode/1 with argument ?GL_FEEDBACK). Setting ?GL_FEEDBACK without establishing the feedback buffer, or calling gl:feedbackBuffer while the GL is in feedback mode, is an error.

When gl:renderMode/1 is called while in feedback mode, it returns the number of entries placed in the feedback array and resets the feedback array pointer to the base of the feedback buffer. The returned value never exceeds Size . If the feedback data required more room than was available in Buffer , gl:renderMode/1 returns a negative value. To take the GL out of feedback mode, call gl:renderMode/1 with a parameter value other than ?GL_FEEDBACK.

While in feedback mode, each primitive, bitmap, or pixel rectangle that would be rasterized generates a block of values that are copied into the feedback array. If doing so would cause the number of entries to exceed the maximum, the block is partially written so as to fill the array (if there is any room left at all), and an overflow flag is set. Each block begins with a code indicating the primitive type, followed by values that describe the primitive's vertices and associated data. Entries are also written for bitmaps and pixel rectangles. Feedback occurs after polygon culling and gl:polygonMode/2 interpretation of polygons has taken place, so polygons that are culled are not returned in the feedback buffer. It can also occur after polygons with more than three edges are broken up into triangles, if the GL implementation renders polygons by performing this decomposition.

The gl:passThrough/1 command can be used to insert a marker into the feedback buffer. See gl:passThrough/1 .

Following is the grammar for the blocks of values written into the feedback buffer. Each primitive is indicated with a unique identifying value followed by some number of vertices. Polygon entries include an integer value indicating how many vertices follow. A vertex is fed back as some number of floating-point values, as determined by Type . Colors are fed back as four values in RGBA mode and one value in color index mode.

feedbackList ← feedbackItem feedbackList | feedbackItem

point ←?GL_POINT_TOKEN vertex

lineSegment ←?GL_LINE_TOKEN vertex vertex | ?GL_LINE_RESET_TOKEN vertex vertex

polygon ←?GL_POLYGON_TOKEN n polySpec

polySpec ← polySpec vertex | vertex vertex vertex

bitmap ←?GL_BITMAP_TOKEN vertex

pixelRectangle ←?GL_DRAW_PIXEL_TOKEN vertex | ?GL_COPY_PIXEL_TOKEN vertex

passThru ←?GL_PASS_THROUGH_TOKEN value

vertex ← 2d | 3d | 3dColor | 3dColorTexture | 4dColorTexture

2d ← value value

3d ← value value value

3dColor ← value value value color

3dColorTexture ← value value value color tex

4dColorTexture ← value value value value color tex

color ← rgba | index

rgba ← value value value value

index ← value

tex ← value value value value

value is a floating-point number, and n is a floating-point integer giving the number of vertices in the polygon. ?GL_POINT_TOKEN, ?GL_LINE_TOKEN, ?GL_LINE_RESET_TOKEN , ?GL_POLYGON_TOKEN, ?GL_BITMAP_TOKEN, ?GL_DRAW_PIXEL_TOKEN, ?GL_COPY_PIXEL_TOKEN and ?GL_PASS_THROUGH_TOKEN are symbolic floating-point constants. ?GL_LINE_RESET_TOKEN is returned whenever the line stipple pattern is reset. The data returned as a vertex depends on the feedback Type .

The following table gives the correspondence between Type and the number of values per vertex. k is 1 in color index mode and 4 in RGBA mode.

TypeCoordinatesColor TextureTotal Number of Values
?GL_2Dx, y 2
?GL_3D x, y, z 3
?GL_3D_COLOR x, y, z k 3+k
?GL_3D_COLOR_TEXTURE x, y, z k 4 7+k
?GL_4D_COLOR_TEXTUREx, y, z, w k 4 8+k

Feedback vertex coordinates are in window coordinates, except w, which is in clip coordinates. Feedback colors are lighted, if lighting is enabled. Feedback texture coordinates are generated, if texture coordinate generation is enabled. They are always transformed by the texture matrix.

See external documentation.

passThrough(Token) -> ok

Types

Token = float()

Place a marker in the feedback buffer

Feedback is a GL render mode. The mode is selected by calling gl:renderMode/1 with ?GL_FEEDBACK. When the GL is in feedback mode, no pixels are produced by rasterization. Instead, information about primitives that would have been rasterized is fed back to the application using the GL. See the gl:feedbackBuffer/3 reference page for a description of the feedback buffer and the values in it.

gl:passThrough inserts a user-defined marker in the feedback buffer when it is executed in feedback mode. Token is returned as if it were a primitive; it is indicated with its own unique identifying value: ?GL_PASS_THROUGH_TOKEN. The order of gl:passThrough commands with respect to the specification of graphics primitives is maintained.

See external documentation.

selectBuffer(Size, Buffer) -> ok

Types

Size = integer()

Buffer = mem()

Establish a buffer for selection mode values

gl:selectBuffer has two arguments: Buffer is a pointer to an array of unsigned integers, and Size indicates the size of the array. Buffer returns values from the name stack (see gl:initNames/0 , gl:loadName/1 , gl:pushName/1 ) when the rendering mode is ?GL_SELECT (see gl:renderMode/1 ). gl:selectBuffer must be issued before selection mode is enabled, and it must not be issued while the rendering mode is ?GL_SELECT.

A programmer can use selection to determine which primitives are drawn into some region of a window. The region is defined by the current modelview and perspective matrices.

In selection mode, no pixel fragments are produced from rasterization. Instead, if a primitive or a raster position intersects the clipping volume defined by the viewing frustum and the user-defined clipping planes, this primitive causes a selection hit. (With polygons, no hit occurs if the polygon is culled.) When a change is made to the name stack, or when gl:renderMode/1 is called, a hit record is copied to Buffer if any hits have occurred since the last such event (name stack change or gl:renderMode/1 call). The hit record consists of the number of names in the name stack at the time of the event, followed by the minimum and maximum depth values of all vertices that hit since the previous event, followed by the name stack contents, bottom name first.

Depth values (which are in the range [0,1]) are multiplied by 2 32-1, before being placed in the hit record.

An internal index into Buffer is reset to 0 whenever selection mode is entered. Each time a hit record is copied into Buffer , the index is incremented to point to the cell just past the end of the block of names(emthat is, to the next available cell If the hit record is larger than the number of remaining locations in Buffer , as much data as can fit is copied, and the overflow flag is set. If the name stack is empty when a hit record is copied, that record consists of 0 followed by the minimum and maximum depth values.

To exit selection mode, call gl:renderMode/1 with an argument other than ?GL_SELECT . Whenever gl:renderMode/1 is called while the render mode is ?GL_SELECT, it returns the number of hit records copied to Buffer , resets the overflow flag and the selection buffer pointer, and initializes the name stack to be empty. If the overflow bit was set when gl:renderMode/1 was called, a negative hit record count is returned.

See external documentation.

initNames() -> ok

Initialize the name stack

The name stack is used during selection mode to allow sets of rendering commands to be uniquely identified. It consists of an ordered set of unsigned integers. gl:initNames causes the name stack to be initialized to its default empty state.

The name stack is always empty while the render mode is not ?GL_SELECT. Calls to gl:initNames while the render mode is not ?GL_SELECT are ignored.

See external documentation.

loadName(Name) -> ok

Types

Name = integer()

Load a name onto the name stack

The name stack is used during selection mode to allow sets of rendering commands to be uniquely identified. It consists of an ordered set of unsigned integers and is initially empty.

gl:loadName causes Name to replace the value on the top of the name stack.

The name stack is always empty while the render mode is not ?GL_SELECT. Calls to gl:loadName while the render mode is not ?GL_SELECT are ignored.

See external documentation.

pushName(Name) -> ok

Types

Name = integer()

Push and pop the name stack

The name stack is used during selection mode to allow sets of rendering commands to be uniquely identified. It consists of an ordered set of unsigned integers and is initially empty.

gl:pushName causes Name to be pushed onto the name stack. gl:pushName/1 pops one name off the top of the stack.

The maximum name stack depth is implementation-dependent; call ?GL_MAX_NAME_STACK_DEPTH to find out the value for a particular implementation. It is an error to push a name onto a full stack or to pop a name off an empty stack. It is also an error to manipulate the name stack between the execution of gl:'begin'/1 and the corresponding execution of gl:'begin'/1 . In any of these cases, the error flag is set and no other change is made to GL state.

The name stack is always empty while the render mode is not ?GL_SELECT. Calls to gl:pushName or gl:pushName/1 while the render mode is not ?GL_SELECT are ignored.

See external documentation.

popName() -> ok

See pushName/1

blendColor(Red, Green, Blue, Alpha) -> ok

Types

Red = clamp()

Green = clamp()

Blue = clamp()

Alpha = clamp()

Set the blend color

The ?GL_BLEND_COLOR may be used to calculate the source and destination blending factors. The color components are clamped to the range [0 1] before being stored. See gl:blendFunc/2 for a complete description of the blending operations. Initially the ?GL_BLEND_COLOR is set to (0, 0, 0, 0).

See external documentation.

blendEquation(Mode) -> ok

Types

Mode = enum()

Specify the equation used for both the RGB blend equation and the Alpha blend equation

The blend equations determine how a new pixel (the ''source'' color) is combined with a pixel already in the framebuffer (the ''destination'' color). This function sets both the RGB blend equation and the alpha blend equation to a single equation. gl:blendEquationi specifies the blend equation for a single draw buffer whereas gl:blendEquation sets the blend equation for all draw buffers.

These equations use the source and destination blend factors specified by either gl:blendFunc/2 or gl:blendFuncSeparate/4 . See gl:blendFunc/2 or gl:blendFuncSeparate/4 for a description of the various blend factors.

In the equations that follow, source and destination color components are referred to as (R s G s B s A s) and (R d G d B d A d), respectively. The result color is referred to as (R r G r B r A r). The source and destination blend factors are denoted (s R s G s B s A) and (d R d G d B d A), respectively. For these equations all color components are understood to have values in the range [0 1].

Mode RGB ComponentsAlpha Component
?GL_FUNC_ADD Rr=R s s R+R d d R Gr=G s s G+G d d G Br=B s s B+B d d B Ar=A s s A+A d d A
?GL_FUNC_SUBTRACT Rr=R s s R-R d d R Gr=G s s G-G d d G Br=B s s B-B d d B Ar=A s s A-A d d A
?GL_FUNC_REVERSE_SUBTRACT Rr=R d d R-R s s R Gr=G d d G-G s s G Br=B d d B-B s s B Ar=A d d A-A s s A
?GL_MIN Rr=min(R s R d) Gr=min(G s G d) Br=min(B s B d) Ar=min (A s A d)
?GL_MAX Rr=max(R s R d) Gr=max(G s G d) Br=max(B s B d) Ar=max(A s A d)

The results of these equations are clamped to the range [0 1].

The ?GL_MIN and ?GL_MAX equations are useful for applications that analyze image data (image thresholding against a constant color, for example). The ?GL_FUNC_ADD equation is useful for antialiasing and transparency, among other things.

Initially, both the RGB blend equation and the alpha blend equation are set to ?GL_FUNC_ADD .

See external documentation.

drawRangeElements(Mode, Start, End, Count, Type, Indices) -> ok

Types

Mode = enum()

Start = integer()

End = integer()

Count = integer()

Type = enum()

Indices = offset() | mem()

Render primitives from array data

gl:drawRangeElements is a restricted form of gl:drawElements/4 . Mode , Start , End , and Count match the corresponding arguments to gl:drawElements/4 , with the additional constraint that all values in the arrays Count must lie between Start and End , inclusive.

Implementations denote recommended maximum amounts of vertex and index data, which may be queried by calling gl:getBooleanv/1 with argument ?GL_MAX_ELEMENTS_VERTICES and ?GL_MAX_ELEMENTS_INDICES . If end-start+1 is greater than the value of ?GL_MAX_ELEMENTS_VERTICES, or if Count is greater than the value of ?GL_MAX_ELEMENTS_INDICES, then the call may operate at reduced performance. There is no requirement that all vertices in the range [start end] be referenced. However, the implementation may partially process unused vertices, reducing performance from what could be achieved with an optimal index set.

When gl:drawRangeElements is called, it uses Count sequential elements from an enabled array, starting at Start to construct a sequence of geometric primitives. Mode specifies what kind of primitives are constructed, and how the array elements construct these primitives. If more than one array is enabled, each is used.

Vertex attributes that are modified by gl:drawRangeElements have an unspecified value after gl:drawRangeElements returns. Attributes that aren't modified maintain their previous values.

See external documentation.

texImage3D(Target, Level, InternalFormat, Width, Height, Depth, Border, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

InternalFormat = integer()

Width = integer()

Height = integer()

Depth = integer()

Border = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

Specify a three-dimensional texture image

Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable three-dimensional texturing, call gl:enable/1 and gl:enable/1 with argument ?GL_TEXTURE_3D.

To define texture images, call gl:texImage3D. The arguments describe the parameters of the texture image, such as height, width, depth, width of the border, level-of-detail number (see gl:texParameterf/3 ), and number of color components provided. The last three arguments describe how the image is represented in memory.

If Target is ?GL_PROXY_TEXTURE_3D, no data is read from Data , but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see gl:getError/0 ). To query for an entire mipmap array, use an image array level greater than or equal to 1.

If Target is ?GL_TEXTURE_3D, data is read from Data as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on Type . These values are grouped into sets of one, two, three, or four values, depending on Format , to form elements. Each data byte is treated as eight 1-bit elements, with bit ordering determined by ?GL_UNPACK_LSB_FIRST (see gl:pixelStoref/2 ).

Format determines the composition of each element in Data . It can assume one of these symbolic values:

?GL_RG: Each element is a red and green pair. The GL converts each to floating point and assembles it into an RGBA element by attaching 0 for blue, and 1 for alpha. Each component is then multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

?GL_RGB

?GL_RGBA

?GL_BGRA: Each element contains all four components. Each component is multiplied by the signed scale factor ?GL_c_SCALE, added to the signed bias ?GL_c_BIAS, and clamped to the range [0,1].

InternalFormat may be one of the base internal formats shown in Table 1, below

InternalFormat may also be one of the sized internal formats shown in Table 2, below

Finally, InternalFormat may also be one of the generic or compressed compressed texture formats shown in Table 3 below

If the InternalFormat parameter is ?GL_SRGB, ?GL_SRGB8, ?GL_SRGB_ALPHA , or ?GL_SRGB8_ALPHA8, the texture is treated as if the red, green, blue, or luminance components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component c s to a linear component c l is:

c l={ c s/12.92if c s≤ 0.04045( c s+0.055/1.055) 2.4if c s> 0.04045

Assume c s is the sRGB component in the range [0,1].

Use the ?GL_PROXY_TEXTURE_3D target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call gl:getTexLevelParameterfv/3 . If the texture cannot be accommodated, texture state is set to 0.

A one-component texture image uses only the red component of the RGBA color extracted from Data . A two-component image uses the R and A values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components.

See external documentation.

texSubImage3D(Target, Level, Xoffset, Yoffset, Zoffset, Width, Height, Depth, Format, Type, Pixels) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Yoffset = integer()

Zoffset = integer()

Width = integer()

Height = integer()

Depth = integer()

Format = enum()

Type = enum()

Pixels = offset() | mem()

glTexSubImage

See external documentation.

copyTexSubImage3D(Target, Level, Xoffset, Yoffset, Zoffset, X, Y, Width, Height) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Yoffset = integer()

Zoffset = integer()

X = integer()

Y = integer()

Width = integer()

Height = integer()

Copy a three-dimensional texture subimage

gl:copyTexSubImage3D replaces a rectangular portion of a three-dimensional texture image with pixels from the current ?GL_READ_BUFFER (rather than from main memory, as is the case for gl:texSubImage1D/7 ).

The screen-aligned pixel rectangle with lower left corner at ( X , Y ) and with width Width and height Height replaces the portion of the texture array with x indices Xoffset through xoffset+width-1, inclusive, and y indices Yoffset through yoffset+height-1, inclusive, at z index Zoffset and at the mipmap level specified by Level .

No change is made to the internalformat, width, height, depth, or border parameters of the specified texture array or to texel values outside the specified subregion.

See external documentation.

colorTable(Target, Internalformat, Width, Format, Type, Table) -> ok

Types

Target = enum()

Internalformat = enum()

Width = integer()

Format = enum()

Type = enum()

Table = offset() | mem()

Define a color lookup table

gl:colorTable may be used in two ways: to test the actual size and color resolution of a lookup table given a particular set of parameters, or to load the contents of a color lookup table. Use the targets ?GL_PROXY_* for the first case and the other targets for the second case.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a color table is specified, Data is treated as a byte offset into the buffer object's data store.

If Target is ?GL_COLOR_TABLE, ?GL_POST_CONVOLUTION_COLOR_TABLE, or ?GL_POST_COLOR_MATRIX_COLOR_TABLE , gl:colorTable builds a color lookup table from an array of pixels. The pixel array specified by Width , Format , Type , and Data is extracted from memory and processed just as if gl:drawPixels/5 were called, but processing stops after the final expansion to RGBA is completed.

The four scale parameters and the four bias parameters that are defined for the table are then used to scale and bias the R, G, B, and A components of each pixel. (Use gl:colorTableParameter to set these scale and bias parameters.)

Next, the R, G, B, and A values are clamped to the range [0 1]. Each pixel is then converted to the internal format specified by Internalformat . This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows:

Internal FormatRedGreen BlueAlphaLuminanceIntensity
?GL_ALPHA A
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

Finally, the red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in the color table. They form a one-dimensional table with indices in the range [0 width-1].

If Target is ?GL_PROXY_*, gl:colorTable recomputes and stores the values of the proxy color table's state variables ?GL_COLOR_TABLE_FORMAT, ?GL_COLOR_TABLE_WIDTH , ?GL_COLOR_TABLE_RED_SIZE, ?GL_COLOR_TABLE_GREEN_SIZE, ?GL_COLOR_TABLE_BLUE_SIZE , ?GL_COLOR_TABLE_ALPHA_SIZE, ?GL_COLOR_TABLE_LUMINANCE_SIZE, and ?GL_COLOR_TABLE_INTENSITY_SIZE . There is no effect on the image or state of any actual color table. If the specified color table is too large to be supported, then all the proxy state variables listed above are set to zero. Otherwise, the color table could be supported by gl:colorTable using the corresponding non-proxy target, and the proxy state variables are set as if that target were being defined.

The proxy state variables can be retrieved by calling gl:getColorTableParameterfv/2 with a target of ?GL_PROXY_*. This allows the application to decide if a particular gl:colorTable command would succeed, and to determine what the resulting color table attributes would be.

If a color table is enabled, and its width is non-zero, then its contents are used to replace a subset of the components of each RGBA pixel group, based on the internal format of the table.

Each pixel group has color components (R, G, B, A) that are in the range [0.0 1.0]. The color components are rescaled to the size of the color lookup table to form an index. Then a subset of the components based on the internal format of the table are replaced by the table entry selected by that index. If the color components and contents of the table are represented as follows:

RepresentationMeaning
r Table index computed from R
g Table index computed from G
b Table index computed from B
a Table index computed from A
L[i] Luminance value at table index i
I[i] Intensity value at table index i
R[i] Red value at table index i
G[i] Green value at table index i
B[i] Blue value at table index i
A[i] Alpha value at table index i

then the result of color table lookup is as follows:

Resulting Texture Components
Table Internal Format RGBA
?GL_ALPHARGBA[a]
?GL_LUMINANCEL[r]L[g]L[b]At
?GL_LUMINANCE_ALPHA L[r]L[g]L[b]A[a]
?GL_INTENSITY I[r]I[g]I[b]I[a]
?GL_RGBR[r] G[g]B[b]A
?GL_RGBAR[r] G[g]B[b]A[a]

When ?GL_COLOR_TABLE is enabled, the colors resulting from the pixel map operation (if it is enabled) are mapped by the color lookup table before being passed to the convolution operation. The colors resulting from the convolution operation are modified by the post convolution color lookup table when ?GL_POST_CONVOLUTION_COLOR_TABLE is enabled. These modified colors are then sent to the color matrix operation. Finally, if ?GL_POST_COLOR_MATRIX_COLOR_TABLE is enabled, the colors resulting from the color matrix operation are mapped by the post color matrix color lookup table before being used by the histogram operation.

See external documentation.

colorTableParameterfv(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = {float(), float(), float(), float()}

Set color lookup table parameters

gl:colorTableParameter is used to specify the scale factors and bias terms applied to color components when they are loaded into a color table. Target indicates which color table the scale and bias terms apply to; it must be set to ?GL_COLOR_TABLE, ?GL_POST_CONVOLUTION_COLOR_TABLE , or ?GL_POST_COLOR_MATRIX_COLOR_TABLE.

Pname must be ?GL_COLOR_TABLE_SCALE to set the scale factors. In this case, Params points to an array of four values, which are the scale factors for red, green, blue, and alpha, in that order.

Pname must be ?GL_COLOR_TABLE_BIAS to set the bias terms. In this case, Params points to an array of four values, which are the bias terms for red, green, blue, and alpha, in that order.

The color tables themselves are specified by calling gl:colorTable/6 .

See external documentation.

colorTableParameteriv(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = {integer(), integer(), integer(), integer()}

See colorTableParameterfv/3

copyColorTable(Target, Internalformat, X, Y, Width) -> ok

Types

Target = enum()

Internalformat = enum()

X = integer()

Y = integer()

Width = integer()

Copy pixels into a color table

gl:copyColorTable loads a color table with pixels from the current ?GL_READ_BUFFER (rather than from main memory, as is the case for gl:colorTable/6 ).

The screen-aligned pixel rectangle with lower-left corner at ( X , Y ) having width Width and height 1 is loaded into the color table. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined.

The pixels in the rectangle are processed just as if gl:readPixels/7 were called, with Internalformat set to RGBA, but processing stops after the final conversion to RGBA.

The four scale parameters and the four bias parameters that are defined for the table are then used to scale and bias the R, G, B, and A components of each pixel. The scale and bias parameters are set by calling gl:colorTableParameterfv/3 .

Internal FormatRedGreen BlueAlphaLuminanceIntensity
?GL_ALPHA A
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

See external documentation.

getColorTable(Target, Format, Type, Table) -> ok

Types

Target = enum()

Format = enum()

Type = enum()

Table = mem()

Retrieve contents of a color lookup table

gl:getColorTable returns in Table the contents of the color table specified by Target . No pixel transfer operations are performed, but pixel storage modes that are applicable to gl:readPixels/7 are performed.

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while a histogram table is requested, Table is treated as a byte offset into the buffer object's data store.

Color components that are requested in the specified Format , but which are not included in the internal format of the color lookup table, are returned as zero. The assignments of internal color components to the components requested by Format are

Internal ComponentResulting Component
Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red
Intensity Red

See external documentation.

getColorTableParameterfv(Target, Pname) -> {float(), float(), float(), float()}

Types

Target = enum()

Pname = enum()

Get color lookup table parameters

Returns parameters specific to color table Target .

When Pname is set to ?GL_COLOR_TABLE_SCALE or ?GL_COLOR_TABLE_BIAS, gl:getColorTableParameter returns the color table scale or bias parameters for the table specified by Target . For these queries, Target must be set to ?GL_COLOR_TABLE , ?GL_POST_CONVOLUTION_COLOR_TABLE, or ?GL_POST_COLOR_MATRIX_COLOR_TABLE and Params points to an array of four elements, which receive the scale or bias factors for red, green, blue, and alpha, in that order.

gl:getColorTableParameter can also be used to retrieve the format and size parameters for a color table. For these queries, set Target to either the color table target or the proxy color table target. The format and size parameters are set by gl:colorTable/6 .

The following table lists the format and size parameters that may be queried. For each symbolic constant listed below for Pname , Params must point to an array of the given length and receive the values indicated.

ParameterNMeaning
?GL_COLOR_TABLE_FORMAT 1 Internal format (e.g., ?GL_RGBA)
?GL_COLOR_TABLE_WIDTH 1 Number of elements in table
?GL_COLOR_TABLE_RED_SIZE 1 Size of red component, in bits
?GL_COLOR_TABLE_GREEN_SIZE 1 Size of green component
?GL_COLOR_TABLE_BLUE_SIZE 1 Size of blue component
?GL_COLOR_TABLE_ALPHA_SIZE 1 Size of alpha component
?GL_COLOR_TABLE_LUMINANCE_SIZE 1 Size of luminance component
?GL_COLOR_TABLE_INTENSITY_SIZE 1 Size of intensity component

See external documentation.

getColorTableParameteriv(Target, Pname) -> {integer(), integer(), integer(), integer()}

Types

Target = enum()

Pname = enum()

See getColorTableParameterfv/2

colorSubTable(Target, Start, Count, Format, Type, Data) -> ok

Types

Target = enum()

Start = integer()

Count = integer()

Format = enum()

Type = enum()

Data = offset() | mem()

Respecify a portion of a color table

gl:colorSubTable is used to respecify a contiguous portion of a color table previously defined using gl:colorTable/6 . The pixels referenced by Data replace the portion of the existing table from indices Start to start+count-1, inclusive. This region may not include any entries outside the range of the color table as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a portion of a color table is respecified, Data is treated as a byte offset into the buffer object's data store.

See external documentation.

copyColorSubTable(Target, Start, X, Y, Width) -> ok

Types

Target = enum()

Start = integer()

X = integer()

Y = integer()

Width = integer()

Respecify a portion of a color table

gl:copyColorSubTable is used to respecify a contiguous portion of a color table previously defined using gl:colorTable/6 . The pixels copied from the framebuffer replace the portion of the existing table from indices Start to start+x-1, inclusive. This region may not include any entries outside the range of the color table, as was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect.

See external documentation.

convolutionFilter1D(Target, Internalformat, Width, Format, Type, Image) -> ok

Types

Target = enum()

Internalformat = enum()

Width = integer()

Format = enum()

Type = enum()

Image = offset() | mem()

Define a one-dimensional convolution filter

gl:convolutionFilter1D builds a one-dimensional convolution filter kernel from an array of pixels.

The pixel array specified by Width , Format , Type , and Data is extracted from memory and processed just as if gl:drawPixels/5 were called, but processing stops after the final expansion to RGBA is completed.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a convolution filter is specified, Data is treated as a byte offset into the buffer object's data store.

The R, G, B, and A components of each pixel are next scaled by the four 1D ?GL_CONVOLUTION_FILTER_SCALE parameters and biased by the four 1D ?GL_CONVOLUTION_FILTER_BIAS parameters. (The scale and bias parameters are set by gl:convolutionParameterf/3 using the ?GL_CONVOLUTION_1D target and the names ?GL_CONVOLUTION_FILTER_SCALE and ?GL_CONVOLUTION_FILTER_BIAS . The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process.

Each pixel is then converted to the internal format specified by Internalformat . This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows:

Internal FormatRedGreen BlueAlphaLuminanceIntensity
?GL_ALPHA A
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. They form a one-dimensional filter kernel image indexed with coordinate i such that i starts at 0 and increases from left to right. Kernel location i is derived from the ith pixel, counting from 0.

Note that after a convolution is performed, the resulting color components are also scaled by their corresponding ?GL_POST_CONVOLUTION_c_SCALE parameters and biased by their corresponding ?GL_POST_CONVOLUTION_c_BIAS parameters (where c takes on the values RED, GREEN, BLUE, and ALPHA). These parameters are set by gl:pixelTransferf/2 .

See external documentation.

convolutionFilter2D(Target, Internalformat, Width, Height, Format, Type, Image) -> ok

Types

Target = enum()

Internalformat = enum()

Width = integer()

Height = integer()

Format = enum()

Type = enum()

Image = offset() | mem()

Define a two-dimensional convolution filter

gl:convolutionFilter2D builds a two-dimensional convolution filter kernel from an array of pixels.

The pixel array specified by Width , Height , Format , Type , and Data is extracted from memory and processed just as if gl:drawPixels/5 were called, but processing stops after the final expansion to RGBA is completed.

The R, G, B, and A components of each pixel are next scaled by the four 2D ?GL_CONVOLUTION_FILTER_SCALE parameters and biased by the four 2D ?GL_CONVOLUTION_FILTER_BIAS parameters. (The scale and bias parameters are set by gl:convolutionParameterf/3 using the ?GL_CONVOLUTION_2D target and the names ?GL_CONVOLUTION_FILTER_SCALE and ?GL_CONVOLUTION_FILTER_BIAS . The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process.

Internal FormatRedGreen BlueAlphaLuminanceIntensity
?GL_ALPHA A
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. They form a two-dimensional filter kernel image indexed with coordinates i and j such that i starts at zero and increases from left to right, and j starts at zero and increases from bottom to top. Kernel location i,j is derived from the Nth pixel, where N is i+j* Width .

See external documentation.

convolutionParameterf(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = tuple()

Set convolution parameters

gl:convolutionParameter sets the value of a convolution parameter.

Target selects the convolution filter to be affected: ?GL_CONVOLUTION_1D, ?GL_CONVOLUTION_2D , or ?GL_SEPARABLE_2D for the 1D, 2D, or separable 2D filter, respectively.

Pname selects the parameter to be changed. ?GL_CONVOLUTION_FILTER_SCALE and ?GL_CONVOLUTION_FILTER_BIAS affect the definition of the convolution filter kernel; see gl:convolutionFilter1D/6 , gl:convolutionFilter2D/7 , and gl:separableFilter2D/8 for details. In these cases, Params v is an array of four values to be applied to red, green, blue, and alpha values, respectively. The initial value for ?GL_CONVOLUTION_FILTER_SCALE is (1, 1, 1, 1), and the initial value for ?GL_CONVOLUTION_FILTER_BIAS is (0, 0, 0, 0).

A Pname value of ?GL_CONVOLUTION_BORDER_MODE controls the convolution border mode. The accepted modes are:

?GL_REDUCE: The image resulting from convolution is smaller than the source image. If the filter width is Wf and height is Hf, and the source image width is Ws and height is Hs, then the convolved image width will be Ws-Wf+1 and height will be Hs-Hf +1. (If this reduction would generate an image with zero or negative width and/or height, the output is simply null, with no error generated.) The coordinates of the image resulting from convolution are zero through Ws-Wf in width and zero through Hs-Hf in height.

?GL_CONSTANT_BORDER: The image resulting from convolution is the same size as the source image, and processed as if the source image were surrounded by pixels with their color specified by the ?GL_CONVOLUTION_BORDER_COLOR.

?GL_REPLICATE_BORDER: The image resulting from convolution is the same size as the source image, and processed as if the outermost pixel on the border of the source image were replicated.

See external documentation.

convolutionParameterfv(Target::enum(), Pname::enum(), Params) -> ok

Types

Params = {Params::tuple()}

Equivalent to convolutionParameterf(Target, Pname, Params).

convolutionParameteri(Target, Pname, Params) -> ok

Types

Target = enum()

Pname = enum()

Params = tuple()

See convolutionParameterf/3

convolutionParameteriv(Target::enum(), Pname::enum(), Params) -> ok

Types

Params = {Params::tuple()}

Equivalent to convolutionParameteri(Target, Pname, Params).

copyConvolutionFilter1D(Target, Internalformat, X, Y, Width) -> ok

Types

Target = enum()

Internalformat = enum()

X = integer()

Y = integer()

Width = integer()

Copy pixels into a one-dimensional convolution filter

gl:copyConvolutionFilter1D defines a one-dimensional convolution filter kernel with pixels from the current ?GL_READ_BUFFER (rather than from main memory, as is the case for gl:convolutionFilter1D/6 ).

The screen-aligned pixel rectangle with lower-left corner at ( X , Y ), width Width and height 1 is used to define the convolution filter. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined.

The pixels in the rectangle are processed exactly as if gl:readPixels/7 had been called with format set to RGBA, but the process stops just before final conversion. The R, G, B, and A components of each pixel are next scaled by the four 1D ?GL_CONVOLUTION_FILTER_SCALE parameters and biased by the four 1D ?GL_CONVOLUTION_FILTER_BIAS parameters. (The scale and bias parameters are set by gl:convolutionParameterf/3 using the ?GL_CONVOLUTION_1D target and the names ?GL_CONVOLUTION_FILTER_SCALE and ?GL_CONVOLUTION_FILTER_BIAS . The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process.

Internal FormatRedGreen BlueAlphaLuminanceIntensity
?GL_ALPHA A
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format.

Pixel ordering is such that lower x screen coordinates correspond to lower i filter image coordinates.

See external documentation.

copyConvolutionFilter2D(Target, Internalformat, X, Y, Width, Height) -> ok

Types

Target = enum()

Internalformat = enum()

X = integer()

Y = integer()

Width = integer()

Height = integer()

Copy pixels into a two-dimensional convolution filter

gl:copyConvolutionFilter2D defines a two-dimensional convolution filter kernel with pixels from the current ?GL_READ_BUFFER (rather than from main memory, as is the case for gl:convolutionFilter2D/7 ).

The screen-aligned pixel rectangle with lower-left corner at ( X , Y ), width Width and height Height is used to define the convolution filter. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined.

The pixels in the rectangle are processed exactly as if gl:readPixels/7 had been called with format set to RGBA, but the process stops just before final conversion. The R, G, B, and A components of each pixel are next scaled by the four 2D ?GL_CONVOLUTION_FILTER_SCALE parameters and biased by the four 2D ?GL_CONVOLUTION_FILTER_BIAS parameters. (The scale and bias parameters are set by gl:convolutionParameterf/3 using the ?GL_CONVOLUTION_2D target and the names ?GL_CONVOLUTION_FILTER_SCALE and ?GL_CONVOLUTION_FILTER_BIAS . The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process.

Internal FormatRedGreen BlueAlphaLuminanceIntensity
?GL_ALPHA A
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format.

Pixel ordering is such that lower x screen coordinates correspond to lower i filter image coordinates, and lower y screen coordinates correspond to lower j filter image coordinates.

See external documentation.

getConvolutionFilter(Target, Format, Type, Image) -> ok

Types

Target = enum()

Format = enum()

Type = enum()

Image = mem()

Get current 1D or 2D convolution filter kernel

gl:getConvolutionFilter returns the current 1D or 2D convolution filter kernel as an image. The one- or two-dimensional image is placed in Image according to the specifications in Format and Type . No pixel transfer operations are performed on this image, but the relevant pixel storage modes are applied.

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while a convolution filter is requested, Image is treated as a byte offset into the buffer object's data store.

Color components that are present in Format but not included in the internal format of the filter are returned as zero. The assignments of internal color components to the components of Format are as follows.

Internal Component Resulting Component
Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red
Intensity Red

See external documentation.

getConvolutionParameterfv(Target, Pname) -> {float(), float(), float(), float()}

Types

Target = enum()

Pname = enum()

Get convolution parameters

gl:getConvolutionParameter retrieves convolution parameters. Target determines which convolution filter is queried. Pname determines which parameter is returned:

?GL_CONVOLUTION_BORDER_MODE: The convolution border mode. See gl:convolutionParameterf/3 for a list of border modes.

?GL_CONVOLUTION_BORDER_COLOR: The current convolution border color. Params must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha border colors.

?GL_CONVOLUTION_FILTER_SCALE: The current filter scale factors. Params must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha filter scale factors in that order.

?GL_CONVOLUTION_FILTER_BIAS: The current filter bias factors. Params must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha filter bias terms in that order.

?GL_CONVOLUTION_FORMAT: The current internal format. See gl:convolutionFilter1D/6 , gl:convolutionFilter2D/7 , and gl:separableFilter2D/8 for lists of allowable formats.

?GL_CONVOLUTION_WIDTH: The current filter image width.

?GL_CONVOLUTION_HEIGHT: The current filter image height.

?GL_MAX_CONVOLUTION_WIDTH: The maximum acceptable filter image width.

?GL_MAX_CONVOLUTION_HEIGHT: The maximum acceptable filter image height.

See external documentation.

getConvolutionParameteriv(Target, Pname) -> {integer(), integer(), integer(), integer()}

Types

Target = enum()

Pname = enum()

See getConvolutionParameterfv/2

separableFilter2D(Target, Internalformat, Width, Height, Format, Type, Row, Column) -> ok

Types

Target = enum()

Internalformat = enum()

Width = integer()

Height = integer()

Format = enum()

Type = enum()

Row = offset() | mem()

Column = offset() | mem()

Define a separable two-dimensional convolution filter

gl:separableFilter2D builds a two-dimensional separable convolution filter kernel from two arrays of pixels.

The pixel arrays specified by ( Width , Format , Type , Row ) and ( Height , Format , Type , Column ) are processed just as if they had been passed to gl:drawPixels/5 , but processing stops after the final expansion to RGBA is completed.

If a non-zero named buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target (see gl:bindBuffer/2 ) while a convolution filter is specified, Row and Column are treated as byte offsets into the buffer object's data store.

Next, the R, G, B, and A components of all pixels in both arrays are scaled by the four separable 2D ?GL_CONVOLUTION_FILTER_SCALE parameters and biased by the four separable 2D ?GL_CONVOLUTION_FILTER_BIAS parameters. (The scale and bias parameters are set by gl:convolutionParameterf/3 using the ?GL_SEPARABLE_2D target and the names ?GL_CONVOLUTION_FILTER_SCALE and ?GL_CONVOLUTION_FILTER_BIAS. The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process.

Internal FormatRed GreenBlueAlphaLuminance Intensity
?GL_LUMINANCE R
?GL_LUMINANCE_ALPHA A R
?GL_INTENSITY R
?GL_RGB R G B
?GL_RGBA R G B A

The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. They form two one-dimensional filter kernel images. The row image is indexed by coordinate i starting at zero and increasing from left to right. Each location in the row image is derived from element i of Row . The column image is indexed by coordinate j starting at zero and increasing from bottom to top. Each location in the column image is derived from element j of Column .

See external documentation.

getHistogram(Target, Reset, Format, Type, Values) -> ok

Types

Target = enum()

Reset = 0 | 1

Format = enum()

Type = enum()

Values = mem()

Get histogram table

gl:getHistogram returns the current histogram table as a one-dimensional image with the same width as the histogram. No pixel transfer operations are performed on this image, but pixel storage modes that are applicable to 1D images are honored.

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while a histogram table is requested, Values is treated as a byte offset into the buffer object's data store.

Color components that are requested in the specified Format , but which are not included in the internal format of the histogram, are returned as zero. The assignments of internal color components to the components requested by Format are:

Internal ComponentResulting Component
Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red

See external documentation.

getHistogramParameterfv(Target, Pname) -> {float()}

Types

Target = enum()

Pname = enum()

Get histogram parameters

gl:getHistogramParameter is used to query parameter values for the current histogram or for a proxy. The histogram state information may be queried by calling gl:getHistogramParameter with a Target of ?GL_HISTOGRAM (to obtain information for the current histogram table) or ?GL_PROXY_HISTOGRAM (to obtain information from the most recent proxy request) and one of the following values for the Pname argument:

ParameterDescription
?GL_HISTOGRAM_WIDTH Histogram table width
?GL_HISTOGRAM_FORMAT Internal format
?GL_HISTOGRAM_RED_SIZE Red component counter size, in bits
?GL_HISTOGRAM_GREEN_SIZE Green component counter size, in bits
?GL_HISTOGRAM_BLUE_SIZE Blue component counter size, in bits
?GL_HISTOGRAM_ALPHA_SIZE Alpha component counter size, in bits
?GL_HISTOGRAM_LUMINANCE_SIZE Luminance component counter size, in bits
?GL_HISTOGRAM_SINK Value of the sink parameter

See external documentation.

getHistogramParameteriv(Target, Pname) -> {integer()}

Types

Target = enum()

Pname = enum()

See getHistogramParameterfv/2

getMinmax(Target, Reset, Format, Types, Values) -> ok

Types

Target = enum()

Reset = 0 | 1

Format = enum()

Types = enum()

Values = mem()

Get minimum and maximum pixel values

gl:getMinmax returns the accumulated minimum and maximum pixel values (computed on a per-component basis) in a one-dimensional image of width 2. The first set of return values are the minima, and the second set of return values are the maxima. The format of the return values is determined by Format , and their type is determined by Types .

If a non-zero named buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target (see gl:bindBuffer/2 ) while minimum and maximum pixel values are requested, Values is treated as a byte offset into the buffer object's data store.

No pixel transfer operations are performed on the return values, but pixel storage modes that are applicable to one-dimensional images are performed. Color components that are requested in the specified Format , but that are not included in the internal format of the minmax table, are returned as zero. The assignment of internal color components to the components requested by Format are as follows:

Internal ComponentResulting Component
Red Red
Green Green
Blue Blue
Alpha Alpha
Luminance Red

If Reset is ?GL_TRUE, the minmax table entries corresponding to the return values are reset to their initial values. Minimum and maximum values that are not returned are not modified, even if Reset is ?GL_TRUE.

See external documentation.

getMinmaxParameterfv(Target, Pname) -> {float()}

Types

Target = enum()

Pname = enum()

Get minmax parameters

gl:getMinmaxParameter retrieves parameters for the current minmax table by setting Pname to one of the following values:

ParameterDescription
?GL_MINMAX_FORMAT Internal format of minmax table
?GL_MINMAX_SINK Value of the sink parameter

See external documentation.

getMinmaxParameteriv(Target, Pname) -> {integer()}

Types

Target = enum()

Pname = enum()

See getMinmaxParameterfv/2

histogram(Target, Width, Internalformat, Sink) -> ok

Types

Target = enum()

Width = integer()

Internalformat = enum()

Sink = 0 | 1

Define histogram table

When ?GL_HISTOGRAM is enabled, RGBA color components are converted to histogram table indices by clamping to the range [0,1], multiplying by the width of the histogram table, and rounding to the nearest integer. The table entries selected by the RGBA indices are then incremented. (If the internal format of the histogram table includes luminance, then the index derived from the R color component determines the luminance table entry to be incremented.) If a histogram table entry is incremented beyond its maximum value, then its value becomes undefined. (This is not an error.)

Histogramming is performed only for RGBA pixels (though these may be specified originally as color indices and converted to RGBA by index table lookup). Histogramming is enabled with gl:enable/1 and disabled with gl:enable/1 .

When Target is ?GL_HISTOGRAM, gl:histogram redefines the current histogram table to have Width entries of the format specified by Internalformat . The entries are indexed 0 through width-1, and all entries are initialized to zero. The values in the previous histogram table, if any, are lost. If Sink is ?GL_TRUE , then pixels are discarded after histogramming; no further processing of the pixels takes place, and no drawing, texture loading, or pixel readback will result.

When Target is ?GL_PROXY_HISTOGRAM, gl:histogram computes all state information as if the histogram table were to be redefined, but does not actually define the new table. If the requested histogram table is too large to be supported, then the state information will be set to zero. This provides a way to determine if a histogram table with the given parameters can be supported.

See external documentation.

minmax(Target, Internalformat, Sink) -> ok

Types

Target = enum()

Internalformat = enum()

Sink = 0 | 1

Define minmax table

When ?GL_MINMAX is enabled, the RGBA components of incoming pixels are compared to the minimum and maximum values for each component, which are stored in the two-element minmax table. (The first element stores the minima, and the second element stores the maxima.) If a pixel component is greater than the corresponding component in the maximum element, then the maximum element is updated with the pixel component value. If a pixel component is less than the corresponding component in the minimum element, then the minimum element is updated with the pixel component value. (In both cases, if the internal format of the minmax table includes luminance, then the R color component of incoming pixels is used for comparison.) The contents of the minmax table may be retrieved at a later time by calling gl:getMinmax/5 . The minmax operation is enabled or disabled by calling gl:enable/1 or gl:enable/1 , respectively, with an argument of ?GL_MINMAX .

gl:minmax redefines the current minmax table to have entries of the format specified by Internalformat . The maximum element is initialized with the smallest possible component values, and the minimum element is initialized with the largest possible component values. The values in the previous minmax table, if any, are lost. If Sink is ?GL_TRUE , then pixels are discarded after minmax; no further processing of the pixels takes place, and no drawing, texture loading, or pixel readback will result.

See external documentation.

resetHistogram(Target) -> ok

Types

Target = enum()

Reset histogram table entries to zero

gl:resetHistogram resets all the elements of the current histogram table to zero.

See external documentation.

resetMinmax(Target) -> ok

Types

Target = enum()

Reset minmax table entries to initial values

gl:resetMinmax resets the elements of the current minmax table to their initial values: the maximum element receives the minimum possible component values, and the minimum element receives the maximum possible component values.

See external documentation.

activeTexture(Texture) -> ok

Types

Texture = enum()

Select active texture unit

gl:activeTexture selects which texture unit subsequent texture state calls will affect. The number of texture units an implementation supports is implementation dependent, but must be at least 80.

See external documentation.

sampleCoverage(Value, Invert) -> ok

Types

Value = clamp()

Invert = 0 | 1

Specify multisample coverage parameters

Multisampling samples a pixel multiple times at various implementation-dependent subpixel locations to generate antialiasing effects. Multisampling transparently antialiases points, lines, polygons, and images if it is enabled.

Value is used in constructing a temporary mask used in determining which samples will be used in resolving the final fragment color. This mask is bitwise-anded with the coverage mask generated from the multisampling computation. If the Invert flag is set, the temporary mask is inverted (all bits flipped) and then the bitwise-and is computed.

If an implementation does not have any multisample buffers available, or multisampling is disabled, rasterization occurs with only a single sample computing a pixel's final RGB color.

Provided an implementation supports multisample buffers, and multisampling is enabled, then a pixel's final color is generated by combining several samples per pixel. Each sample contains color, depth, and stencil information, allowing those operations to be performed on each sample.

See external documentation.

compressedTexImage3D(Target, Level, Internalformat, Width, Height, Depth, Border, ImageSize, Data) -> ok

Types

Target = enum()

Level = integer()

Internalformat = enum()

Width = integer()

Height = integer()

Depth = integer()

Border = integer()

ImageSize = integer()

Data = offset() | mem()

Specify a three-dimensional texture image in a compressed format

Texturing allows elements of an image array to be read by shaders.

gl:compressedTexImage3D loads a previously defined, and retrieved, compressed three-dimensional texture image if Target is ?GL_TEXTURE_3D (see gl:texImage3D/10 ).

If Target is ?GL_TEXTURE_2D_ARRAY, Data is treated as an array of compressed 2D textures.

If Target is ?GL_PROXY_TEXTURE_3D or ?GL_PROXY_TEXTURE_2D_ARRAY, no data is read from Data , but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see gl:getError/0 ). To query for an entire mipmap array, use an image array level greater than or equal to 1.

Internalformat must be a known compressed image format (such as ?GL_RGTC) or an extension-specified compressed-texture format. When a texture is loaded with gl:texImage2D/9 using a generic compressed texture format (e.g., ?GL_COMPRESSED_RGB), the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using gl:compressedTexImage3D, query the compressed texture image's size and format using gl:getTexLevelParameterfv/3 .

If the compressed data are arranged into fixed-size blocks of texels, the pixel storage modes can be used to select a sub-rectangle from a larger containing rectangle. These pixel storage modes operate in the same way as they do for gl:texImage1D/8 . In the following description, denote by b s, b w, b h, and b d, the values of pixel storage modes ?GL_UNPACK_COMPRESSED_BLOCK_SIZE, ?GL_UNPACK_COMPRESSED_BLOCK_WIDTH, ?GL_UNPACK_COMPRESSED_BLOCK_HEIGHT , and ?GL_UNPACK_COMPRESSED_BLOCK_DEPTH, respectively. b s is the compressed block size in bytes; b w, b h, and b d are the compressed block width, height, and depth in pixels.

By default the pixel storage modes ?GL_UNPACK_ROW_LENGTH, ?GL_UNPACK_SKIP_ROWS , ?GL_UNPACK_SKIP_PIXELS, ?GL_UNPACK_IMAGE_HEIGHT and ?GL_UNPACK_SKIP_IMAGES are ignored for compressed images. To enable ?GL_UNPACK_SKIP_PIXELS and ?GL_UNPACK_ROW_LENGTH , b s and b w must both be non-zero. To also enable ?GL_UNPACK_SKIP_ROWS and ?GL_UNPACK_IMAGE_HEIGHT , b h must be non-zero. To also enable ?GL_UNPACK_SKIP_IMAGES, b d must be non-zero. All parameters must be consistent with the compressed format to produce the desired results.

When selecting a sub-rectangle from a compressed image: the value of ?GL_UNPACK_SKIP_PIXELS must be a multiple of b w;the value of ?GL_UNPACK_SKIP_ROWS must be a multiple of b w;the value of ?GL_UNPACK_SKIP_IMAGES must be a multiple of b w.

ImageSize must be equal to:

b s×|width b/w|×|height b/h|×|depth b/d|

See external documentation.

compressedTexImage2D(Target, Level, Internalformat, Width, Height, Border, ImageSize, Data) -> ok

Types

Target = enum()

Level = integer()

Internalformat = enum()

Width = integer()

Height = integer()

Border = integer()

ImageSize = integer()

Data = offset() | mem()

Specify a two-dimensional texture image in a compressed format

Texturing allows elements of an image array to be read by shaders.

gl:compressedTexImage2D loads a previously defined, and retrieved, compressed two-dimensional texture image if Target is ?GL_TEXTURE_2D, or one of the cube map faces such as ?GL_TEXTURE_CUBE_MAP_POSITIVE_X. (see gl:texImage2D/9 ).

If Target is ?GL_TEXTURE_1D_ARRAY, Data is treated as an array of compressed 1D textures.

If Target is ?GL_PROXY_TEXTURE_2D, ?GL_PROXY_TEXTURE_1D_ARRAY or ?GL_PROXY_CUBE_MAP , no data is read from Data , but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see gl:getError/0 ). To query for an entire mipmap array, use an image array level greater than or equal to 1.

Internalformat must be a known compressed image format (such as ?GL_RGTC) or an extension-specified compressed-texture format. When a texture is loaded with gl:texImage2D/9 using a generic compressed texture format (e.g., ?GL_COMPRESSED_RGB), the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using gl:compressedTexImage2D, query the compressed texture image's size and format using gl:getTexLevelParameterfv/3 .

If the compressed data are arranged into fixed-size blocks of texels, the pixel storage modes can be used to select a sub-rectangle from a larger containing rectangle. These pixel storage modes operate in the same way as they do for gl:texImage2D/9 . In the following description, denote by b s, b w, b h, and b d, the values of pixel storage modes ?GL_UNPACK_COMPRESSED_BLOCK_SIZE, ?GL_UNPACK_COMPRESSED_BLOCK_WIDTH, ?GL_UNPACK_COMPRESSED_BLOCK_HEIGHT , and ?GL_UNPACK_COMPRESSED_BLOCK_DEPTH, respectively. b s is the compressed block size in bytes; b w, b h, and b d are the compressed block width, height, and depth in pixels.

When selecting a sub-rectangle from a compressed image: the value of ?GL_UNPACK_SKIP_PIXELS must be a multiple of b w;the value of ?GL_UNPACK_SKIP_ROWS must be a multiple of b w.

ImageSize must be equal to:

b s×|width b/w|×|height b/h|

See external documentation.

compressedTexImage1D(Target, Level, Internalformat, Width, Border, ImageSize, Data) -> ok

Types

Target = enum()

Level = integer()

Internalformat = enum()

Width = integer()

Border = integer()

ImageSize = integer()

Data = offset() | mem()

Specify a one-dimensional texture image in a compressed format

Texturing allows elements of an image array to be read by shaders.

gl:compressedTexImage1D loads a previously defined, and retrieved, compressed one-dimensional texture image if Target is ?GL_TEXTURE_1D (see gl:texImage1D/8 ).

Internalformat must be an extension-specified compressed-texture format. When a texture is loaded with gl:texImage1D/8 using a generic compressed texture format (e.g., ?GL_COMPRESSED_RGB) the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using gl:compressedTexImage1D , query the compressed texture image's size and format using gl:getTexLevelParameterfv/3 .

When selecting a sub-rectangle from a compressed image: the value of ?GL_UNPACK_SKIP_PIXELS must be a multiple of b w;

ImageSize must be equal to:

b s×|width b/w|

See external documentation.

compressedTexSubImage3D(Target, Level, Xoffset, Yoffset, Zoffset, Width, Height, Depth, Format, ImageSize, Data) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Yoffset = integer()

Zoffset = integer()

Width = integer()

Height = integer()

Depth = integer()

Format = enum()

ImageSize = integer()

Data = offset() | mem()

Specify a three-dimensional texture subimage in a compressed format

Texturing allows elements of an image array to be read by shaders.

gl:compressedTexSubImage3D redefines a contiguous subregion of an existing three-dimensional texture image. The texels referenced by Data replace the portion of the existing texture array with x indices Xoffset and xoffset+width-1, and the y indices Yoffset and yoffset+height-1, and the z indices Zoffset and zoffset+depth-1, inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect.

Internalformat must be a known compressed image format (such as ?GL_RGTC) or an extension-specified compressed-texture format. The Format of the compressed texture image is selected by the GL implementation that compressed it (see gl:texImage3D/10 ) and should be queried at the time the texture was compressed with gl:getTexLevelParameterfv/3 .

See external documentation.

compressedTexSubImage2D(Target, Level, Xoffset, Yoffset, Width, Height, Format, ImageSize, Data) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Yoffset = integer()

Width = integer()

Height = integer()

Format = enum()

ImageSize = integer()

Data = offset() | mem()

Specify a two-dimensional texture subimage in a compressed format

Texturing allows elements of an image array to be read by shaders.

gl:compressedTexSubImage2D redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by Data replace the portion of the existing texture array with x indices Xoffset and xoffset+width-1, and the y indices Yoffset and yoffset+height-1, inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect.

Internalformat must be a known compressed image format (such as ?GL_RGTC) or an extension-specified compressed-texture format. The Format of the compressed texture image is selected by the GL implementation that compressed it (see gl:texImage2D/9 ) and should be queried at the time the texture was compressed with gl:getTexLevelParameterfv/3 .

See external documentation.

compressedTexSubImage1D(Target, Level, Xoffset, Width, Format, ImageSize, Data) -> ok

Types

Target = enum()

Level = integer()

Xoffset = integer()

Width = integer()

Format = enum()

ImageSize = integer()

Data = offset() | mem()

Specify a one-dimensional texture subimage in a compressed format

Texturing allows elements of an image array to be read by shaders.

gl:compressedTexSubImage1D redefines a contiguous subregion of an existing one-dimensional texture image. The texels referenced by Data replace the portion of the existing texture array with x indices Xoffset and xoffset+width-1, inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect.

Internalformat must be a known compressed image format (such as ?GL_RGTC) or an extension-specified compressed-texture format. The Format of the compressed texture image is selected by the GL implementation that compressed it (see gl:texImage1D/8 ), and should be queried at the time the texture was compressed with gl:getTexLevelParameterfv/3 .

See external documentation.

getCompressedTexImage(Target, Lod, Img) -> ok

Types

Target = enum()

Lod = integer()

Img = mem()

Return a compressed texture image

gl:getCompressedTexImage returns the compressed texture image associated with Target and Lod into Img . Img should be an array of ?GL_TEXTURE_COMPRESSED_IMAGE_SIZE bytes. Target specifies whether the desired texture image was one specified by gl:texImage1D/8 (?GL_TEXTURE_1D), gl:texImage2D/9 (?GL_TEXTURE_2D or any of ?GL_TEXTURE_CUBE_MAP_* ), or gl:texImage3D/10 (?GL_TEXTURE_3D). Lod specifies the level-of-detail number of the desired image.

To minimize errors, first verify that the texture is compressed by calling gl:getTexLevelParameterfv/3 with argument ?GL_TEXTURE_COMPRESSED. If the texture is compressed, then determine the amount of memory required to store the compressed texture by calling gl:getTexLevelParameterfv/3 with argument ?GL_TEXTURE_COMPRESSED_IMAGE_SIZE. Finally, retrieve the internal format of the texture by calling gl:getTexLevelParameterfv/3 with argument ?GL_TEXTURE_INTERNAL_FORMAT . To store the texture for later use, associate the internal format and size with the retrieved texture image. These data can be used by the respective texture or subtexture loading routine used for loading Target textures.

See external documentation.

clientActiveTexture(Texture) -> ok

Types

Texture = enum()

Select active texture unit

gl:clientActiveTexture selects the vertex array client state parameters to be modified by gl:texCoordPointer/4 , and enabled or disabled with gl:enableClientState/1 or gl:enableClientState/1 , respectively, when called with a parameter of ?GL_TEXTURE_COORD_ARRAY .

See external documentation.

multiTexCoord1d(Target, S) -> ok

Types

Target = enum()

S = float()

Set the current texture coordinates

M = matrix()

Replace the current matrix with the specified row-major ordered matrix

gl:loadTransposeMatrix replaces the current matrix with the one whose elements are specified by M . The current matrix is the projection matrix, modelview matrix, or texture matrix, depending on the current matrix mode (see gl:matrixMode/1 ).

M(v)=(m[0] m[1] m[2] m[3] m[4] m[5] m[6] m[7] m[8] m[9] m[10] m[11] m[12] m[13] m[14] m[15])×(v[0] v[1] v[2] v[3])

Projection and texture transformations are similarly defined.

Calling gl:loadTransposeMatrix with matrix M is identical in operation to gl:loadMatrixd/1 with M T, where T represents the transpose.

See external documentation.

loadTransposeMatrixd(M) -> ok

Types

M = matrix()

See loadTransposeMatrixf/1

multTransposeMatrixf(M) -> ok

Types

M = matrix()

Multiply the current matrix with the specified row-major ordered matrix

gl:multTransposeMatrix multiplies the current matrix with the one specified using M , and replaces the current matrix with the product.

The current matrix is determined by the current matrix mode (see gl:matrixMode/1 ). It is either the projection matrix, modelview matrix, or the texture matrix.

See external documentation.

multTransposeMatrixd(M) -> ok

Types

M = matrix()

See multTransposeMatrixf/1

blendFuncSeparate(SfactorRGB, DfactorRGB, SfactorAlpha, DfactorAlpha) -> ok

Types

SfactorRGB = enum()

DfactorRGB = enum()

SfactorAlpha = enum()

DfactorAlpha = enum()

Specify pixel arithmetic for RGB and alpha components separately

gl:blendFuncSeparate defines the operation of blending for all draw buffers when it is enabled. gl:blendFuncSeparatei defines the operation of blending for a single draw buffer specified by Buf when enabled for that draw buffer. SrcRGB specifies which method is used to scale the source RGB-color components. DstRGB specifies which method is used to scale the destination RGB-color components. Likewise, SrcAlpha specifies which method is used to scale the source alpha color component, and DstAlpha specifies which method is used to scale the destination alpha component. The possible methods are described in the following table. Each method defines four scale factors, one each for red, green, blue, and alpha.

In the table and in subsequent equations, first source, second source and destination color components are referred to as (R s0 G s0 B s0 A s0), (R s1 G s1 B s1 A s1), and (R d G d B d A d), respectively. The color specified by gl:blendColor/4 is referred to as (R c G c B c A c). They are understood to have integer values between 0 and (k R k G k B k A), where

k c=2(m c)-1

and (m R m G m B m A) is the number of red, green, blue, and alpha bitplanes.

Source and destination scale factors are referred to as (s R s G s B s A) and (d R d G d B d A). All scale factors have range [0 1].

ParameterRGB FactorAlpha Factor
?GL_ZERO(0 0 0) 0
?GL_ONE (1 1 1) 1
?GL_SRC_COLOR(R s0 k/R G s0 k/G B s0 k/B) A s0 k/A
?GL_ONE_MINUS_SRC_COLOR(1 1 1 1)-(R s0 k/R G s0 k/G B s0 k/B) 1-A s0 k/A
?GL_DST_COLOR(R d k/R G d k/G B d k/B) A d k/A
?GL_ONE_MINUS_DST_COLOR (1 1 1)-(R d k/R G d k/G B d k/B) 1-A d k/A
?GL_SRC_ALPHA(A s0 k/A A s0 k/A A s0 k/A) A s0 k/A
?GL_ONE_MINUS_SRC_ALPHA(1 1 1)-(A s0 k/A A s0 k/A A s0 k/A ) 1-A s0 k/A
?GL_DST_ALPHA(A d k/A A d k/A A d k/A) A d k/A
?GL_ONE_MINUS_DST_ALPHA (1 1 1)-(A d k/A A d k/A A d k/A) 1-A d k/A
?GL_CONSTANT_COLOR(R c G c B c) A c
?GL_ONE_MINUS_CONSTANT_COLOR(1 1 1)-(R c G c B c) 1-A c
?GL_CONSTANT_ALPHA(A c A c A c) A c
?GL_ONE_MINUS_CONSTANT_ALPHA (1 1 1)-(A c A c A c) 1-A c
?GL_SRC_ALPHA_SATURATE(i i i) 1
?GL_SRC1_COLOR(R s1 k/R G s1 k/G B s1 k/B) A s1 k/A
?GL_ONE_MINUS_SRC_COLOR (1 1 1 1)-(R s1 k/R G s1 k/G B s1 k/B) 1-A s1 k/A
?GL_SRC1_ALPHA(A s1 k/A A s1 k/A A s1 k/A) A s1 k/A
?GL_ONE_MINUS_SRC_ALPHA(1 1 1)-(A s1 k/A A s1 k/A A s1 k/A ) 1-A s1 k/A

In the table,

i=min(A s 1-(A d))

To determine the blended RGBA values of a pixel, the system uses the following equations:

R d=min(k R R s s R+R d d R) G d=min(k G G s s G+G d d G) B d=min(k B B s s B+B d d B) A d=min(k A A s s A+A d d A)

Despite the apparent precision of the above equations, blending arithmetic is not exactly specified, because blending operates with imprecise integer color values. However, a blend factor that should be equal to 1 is guaranteed not to modify its multiplicand, and a blend factor equal to 0 reduces its multiplicand to 0. For example, when SrcRGB is ?GL_SRC_ALPHA , DstRGB is ?GL_ONE_MINUS_SRC_ALPHA, and A s is equal to k A, the equations reduce to simple replacement:

R d=R s G d=G s B d=B s A d=A s

See external documentation.

multiDrawArrays(Mode, First, Count) -> ok

Types

Mode = enum()

First = [integer()] | mem()

Count = [integer()] | mem()

Render multiple sets of primitives from array data

gl:multiDrawArrays specifies multiple sets of geometric primitives with very few subroutine calls. Instead of calling a GL procedure to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and colors and use them to construct a sequence of primitives with a single call to gl:multiDrawArrays.

gl:multiDrawArrays behaves identically to gl:drawArrays/3 except that Primcount separate ranges of elements are specified instead.

When gl:multiDrawArrays is called, it uses Count sequential elements from each enabled array to construct a sequence of geometric primitives, beginning with element First . Mode specifies what kind of primitives are constructed, and how the array elements construct those primitives.

Vertex attributes that are modified by gl:multiDrawArrays have an unspecified value after gl:multiDrawArrays returns. Attributes that aren't modified remain well defined.

See external documentation.

pointParameterf(Pname, Param) -> ok

Types

Pname = enum()

Param = float()

Specify point parameters

The following values are accepted for Pname :

?GL_POINT_FADE_THRESHOLD_SIZE: Params is a single floating-point value that specifies the threshold value to which point sizes are clamped if they exceed the specified value. The default value is 1.0.

?GL_POINT_SPRITE_COORD_ORIGIN: Params is a single enum specifying the point sprite texture coordinate origin, either ?GL_LOWER_LEFT or ?GL_UPPER_LEFT. The default value is ?GL_UPPER_LEFT.

See external documentation.

pointParameterfv(Pname, Params) -> ok

Types

Pname = enum()

Params = tuple()

See pointParameterf/2

pointParameteri(Pname, Param) -> ok

Types

Pname = enum()

Param = integer()

See pointParameterf/2

pointParameteriv(Pname, Params) -> ok

Types

Pname = enum()

Params = tuple()

See pointParameterf/2

fogCoordf(Coord) -> ok

Types

Coord = float()

Set the current fog coordinates

gl:fogCoord specifies the fog coordinate that is associated with each vertex and the current raster position. The value specified is interpolated and used in computing the fog color (see gl:fogf/2 ).

See external documentation.

fogCoordfv(Coord) -> ok

Types

Coord = {Coord::float()}

Equivalent to fogCoordf(Coord).

fogCoordd(Coord) -> ok

Types

Size = integer()

Type = enum()

Stride = integer()

Pointer = offset() | mem()

Define an array of secondary colors

gl:secondaryColorPointer specifies the location and data format of an array of color components to use when rendering. Size specifies the number of components per color, and must be 3. Type specifies the data type of each color component, and Stride specifies the byte stride from one color to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays.

If a non-zero named buffer object is bound to the ?GL_ARRAY_BUFFER target (see gl:bindBuffer/2 ) while a secondary color array is specified, Pointer is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (?GL_ARRAY_BUFFER_BINDING ) is saved as secondary color vertex array client-side state (?GL_SECONDARY_COLOR_ARRAY_BUFFER_BINDING ).

When a secondary color array is specified, Size , Type , Stride , and Pointer are saved as client-side state, in addition to the current vertex array buffer object binding.

To enable and disable the secondary color array, call gl:enableClientState/1 and gl:enableClientState/1 with the argument ?GL_SECONDARY_COLOR_ARRAY. If enabled, the secondary color array is used when gl:arrayElement/1 , gl:drawArrays/3 , gl:multiDrawArrays/3 , gl:drawElements/4 , see glMultiDrawElements, or gl:drawRangeElements/6 is called.

See external documentation.

windowPos2d(X, Y) -> ok

Types

X = float()

Y = float()

Specify the raster position in window coordinates for pixel operations

gl:windowPos2 specifies the x and y coordinates, while z is implicitly set to 0. gl:windowPos3 specifies all three coordinates. The w coordinate of the current raster position is always set to 1.0.

gl:windowPos directly updates the x and y coordinates of the current raster position with the values specified. That is, the values are neither transformed by the current modelview and projection matrices, nor by the viewport-to-window transform. The z coordinate of the current raster position is updated in the following manner:

z={n f(n+z×(f-n)) if z<= 0 if z>= 1(otherwise))

where n is ?GL_DEPTH_RANGE's near value, and f is ?GL_DEPTH_RANGE's far value. See gl:depthRange/2 .

N = integer()

Generate query object names

gl:genQueries returns N query object names in Ids . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genQueries.

Query object names returned by a call to gl:genQueries are not returned by subsequent calls, unless they are first deleted with gl:deleteQueries/1 .

No query objects are associated with the returned query object names until they are first used by calling gl:beginQuery/2 .

See external documentation.

deleteQueries(Ids) -> ok

Types

Ids = [integer()]

Delete named query objects

gl:deleteQueries deletes N query objects named by the elements of the array Ids . After a query object is deleted, it has no contents, and its name is free for reuse (for example by gl:genQueries/1 ).

gl:deleteQueries silently ignores 0's and names that do not correspond to existing query objects.

See external documentation.

isQuery(Id) -> 0 | 1

Types

Id = integer()

Determine if a name corresponds to a query object

gl:isQuery returns ?GL_TRUE if Id is currently the name of a query object. If Id is zero, or is a non-zero value that is not currently the name of a query object, or if an error occurs, gl:isQuery returns ?GL_FALSE.

A name returned by gl:genQueries/1 , but not yet associated with a query object by calling gl:beginQuery/2 , is not the name of a query object.

See external documentation.

beginQuery(Target, Id) -> ok

Types

Target = enum()

Id = integer()

Delimit the boundaries of a query object

gl:beginQuery and gl:beginQuery/2 delimit the boundaries of a query object. Query must be a name previously returned from a call to gl:genQueries/1 . If a query object with name Id does not yet exist it is created with the type determined by Target . Target must be one of ?GL_SAMPLES_PASSED, ?GL_ANY_SAMPLES_PASSED, ?GL_PRIMITIVES_GENERATED , ?GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN, or ?GL_TIME_ELAPSED. The behavior of the query object depends on its type and is as follows.

If Target is ?GL_SAMPLES_PASSED, Id must be an unused name, or the name of an existing occlusion query object. When gl:beginQuery is executed, the query object's samples-passed counter is reset to 0. Subsequent rendering will increment the counter for every sample that passes the depth test. If the value of ?GL_SAMPLE_BUFFERS is 0, then the samples-passed count is incremented by 1 for each fragment. If the value of ?GL_SAMPLE_BUFFERS is 1, then the samples-passed count is incremented by the number of samples whose coverage bit is set. However, implementations, at their discression may instead increase the samples-passed count by the value of ?GL_SAMPLES if any sample in the fragment is covered. When gl:endQuery is executed, the samples-passed counter is assigned to the query object's result value. This value can be queried by calling gl:getQueryObjectiv/2 with Pname ?GL_QUERY_RESULT.

If Target is ?GL_ANY_SAMPLES_PASSED, Id must be an unused name, or the name of an existing boolean occlusion query object. When gl:beginQuery is executed, the query object's samples-passed flag is reset to ?GL_FALSE. Subsequent rendering causes the flag to be set to ?GL_TRUE if any sample passes the depth test. When gl:endQuery is executed, the samples-passed flag is assigned to the query object's result value. This value can be queried by calling gl:getQueryObjectiv/2 with Pname ?GL_QUERY_RESULT.

If Target is ?GL_PRIMITIVES_GENERATED, Id must be an unused name, or the name of an existing primitive query object previously bound to the ?GL_PRIMITIVES_GENERATED query binding. When gl:beginQuery is executed, the query object's primitives-generated counter is reset to 0. Subsequent rendering will increment the counter once for every vertex that is emitted from the geometry shader, or from the vertex shader if no geometry shader is present. When gl:endQuery is executed, the primitives-generated counter is assigned to the query object's result value. This value can be queried by calling gl:getQueryObjectiv/2 with Pname ?GL_QUERY_RESULT.

Types

Target = enum()

Buffer = integer()

Bind a named buffer object

gl:bindBuffer binds a buffer object to the specified buffer binding point. Calling gl:bindBuffer with Target set to one of the accepted symbolic constants and Buffer set to the name of a buffer object binds that buffer object name to the target. If no buffer object with name Buffer exists, one is created with that name. When a buffer object is bound to a target, the previous binding for that target is automatically broken.

Buffer object names are unsigned integers. The value zero is reserved, but there is no default buffer object for each buffer object target. Instead, Buffer set to zero effectively unbinds any buffer object previously bound, and restores client memory usage for that buffer object target (if supported for that target). Buffer object names and the corresponding buffer object contents are local to the shared object space of the current GL rendering context; two rendering contexts share buffer object names only if they explicitly enable sharing between contexts through the appropriate GL windows interfaces functions.

gl:genBuffers/1 must be used to generate a set of unused buffer object names.

The state of a buffer object immediately after it is first bound is an unmapped zero-sized memory buffer with ?GL_READ_WRITE access and ?GL_STATIC_DRAW usage.

While a non-zero buffer object name is bound, GL operations on the target to which it is bound affect the bound buffer object, and queries of the target to which it is bound return state from the bound buffer object. While buffer object name zero is bound, as in the initial state, attempts to modify or query state on the target to which it is bound generates an ?GL_INVALID_OPERATION error.

When a non-zero buffer object is bound to the ?GL_ARRAY_BUFFER target, the vertex array pointer parameter is interpreted as an offset within the buffer object measured in basic machine units.

When a non-zero buffer object is bound to the ?GL_DRAW_INDIRECT_BUFFER target, parameters for draws issued through gl:drawArraysIndirect/2 and gl:drawElementsIndirect/3 are sourced from that buffer object.

While a non-zero buffer object is bound to the ?GL_ELEMENT_ARRAY_BUFFER target, the indices parameter of gl:drawElements/4 , gl:drawElementsInstanced/5 , gl:drawElementsBaseVertex/5 , gl:drawRangeElements/6 , gl:drawRangeElementsBaseVertex/7 , see glMultiDrawElements , or see glMultiDrawElementsBaseVertex is interpreted as an offset within the buffer object measured in basic machine units.

While a non-zero buffer object is bound to the ?GL_PIXEL_PACK_BUFFER target, the following commands are affected: gl:getCompressedTexImage/3 , gl:getTexImage/5 , and gl:readPixels/7 . The pointer parameter is interpreted as an offset within the buffer object measured in basic machine units.

While a non-zero buffer object is bound to the ?GL_PIXEL_UNPACK_BUFFER target, the following commands are affected: gl:compressedTexImage1D/7 , gl:compressedTexImage2D/8 , gl:compressedTexImage3D/9 , gl:compressedTexSubImage1D/7 , gl:compressedTexSubImage2D/9 , gl:compressedTexSubImage3D/11 , gl:texImage1D/8 , gl:texImage2D/9 , gl:texImage3D/10 , gl:texSubImage1D/7 , gl:texSubImage1D/7 , and gl:texSubImage1D/7 . The pointer parameter is interpreted as an offset within the buffer object measured in basic machine units.

The buffer targets ?GL_COPY_READ_BUFFER and ?GL_COPY_WRITE_BUFFER are provided to allow gl:copyBufferSubData/5 to be used without disturbing the state of other bindings. However, gl:copyBufferSubData/5 may be used with any pair of buffer binding points.

The ?GL_TRANSFORM_FEEDBACK_BUFFER buffer binding point may be passed to gl:bindBuffer , but will not directly affect transform feedback state. Instead, the indexed ?GL_TRANSFORM_FEEDBACK_BUFFER bindings must be used through a call to gl:bindBufferBase/3 or gl:bindBufferRange/5 . This will affect the generic ?GL_TRANSFORM_FEEDABCK_BUFFER binding.

Likewise, the ?GL_UNIFORM_BUFFER and ?GL_ATOMIC_COUNTER_BUFFER buffer binding points may be used, but do not directly affect uniform buffer or atomic counter buffer state, respectively. gl:bindBufferBase/3 or gl:bindBufferRange/5 must be used to bind a buffer to an indexed uniform buffer or atomic counter buffer binding point.

A buffer object binding created with gl:bindBuffer remains active until a different buffer object name is bound to the same target, or until the bound buffer object is deleted with gl:deleteBuffers/1 .

Once created, a named buffer object may be re-bound to any target as often as needed. However, the GL implementation may make choices about how to optimize the storage of a buffer object based on its initial binding target.

See external documentation.

deleteBuffers(Buffers) -> ok

Types

Buffers = [integer()]

Delete named buffer objects

gl:deleteBuffers deletes N buffer objects named by the elements of the array Buffers . After a buffer object is deleted, it has no contents, and its name is free for reuse (for example by gl:genBuffers/1 ). If a buffer object that is currently bound is deleted, the binding reverts to 0 (the absence of any buffer object).

gl:deleteBuffers silently ignores 0's and names that do not correspond to existing buffer objects.

See external documentation.

genBuffers(N) -> [integer()]

Types

N = integer()

Generate buffer object names

gl:genBuffers returns N buffer object names in Buffers . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genBuffers .

Buffer object names returned by a call to gl:genBuffers are not returned by subsequent calls, unless they are first deleted with gl:deleteBuffers/1 .

No buffer objects are associated with the returned buffer object names until they are first bound by calling gl:bindBuffer/2 .

See external documentation.

isBuffer(Buffer) -> 0 | 1

Types

Buffer = integer()

Determine if a name corresponds to a buffer object

gl:isBuffer returns ?GL_TRUE if Buffer is currently the name of a buffer object. If Buffer is zero, or is a non-zero value that is not currently the name of a buffer object, or if an error occurs, gl:isBuffer returns ?GL_FALSE .

A name returned by gl:genBuffers/1 , but not yet associated with a buffer object by calling gl:bindBuffer/2 , is not the name of a buffer object.

See external documentation.

bufferData(Target, Size, Data, Usage) -> ok

Types

Target = enum()

Size = integer()

Data = offset() | mem()

Usage = enum()

Creates and initializes a buffer object's data store

gl:bufferData creates a new data store for the buffer object currently bound to Target . Any pre-existing data store is deleted. The new data store is created with the specified Size in bytes and Usage . If Data is not ?NULL, the data store is initialized with data from this pointer. In its initial state, the new data store is not mapped, it has a ?NULL mapped pointer, and its mapped access is ?GL_READ_WRITE .

Usage is a hint to the GL implementation as to how a buffer object's data store will be accessed. This enables the GL implementation to make more intelligent decisions that may significantly impact buffer object performance. It does not, however, constrain the actual usage of the data store. Usage can be broken down into two parts: first, the frequency of access (modification and usage), and second, the nature of that access. The frequency of access may be one of these:

STREAM: The data store contents will be modified once and used at most a few times.

STATIC: The data store contents will be modified once and used many times.

DYNAMIC: The data store contents will be modified repeatedly and used many times.

The nature of access may be one of these:

DRAW: The data store contents are modified by the application, and used as the source for GL drawing and image specification commands.

READ: The data store contents are modified by reading data from the GL, and used to return that data when queried by the application.

COPY: The data store contents are modified by reading data from the GL, and used as the source for GL drawing and image specification commands.

See external documentation.

bufferSubData(Target, Offset, Size, Data) -> ok

Types

Target = enum()

Offset = integer()

Size = integer()

Data = offset() | mem()

Updates a subset of a buffer object's data store

gl:bufferSubData redefines some or all of the data store for the buffer object currently bound to Target . Data starting at byte offset Offset and extending for Size bytes is copied to the data store from the memory pointed to by Data . An error is thrown if Offset and Size together define a range beyond the bounds of the buffer object's data store.

See external documentation.

getBufferSubData(Target, Offset, Size, Data) -> ok

Types

Target = enum()

Offset = integer()

Size = integer()

Data = mem()

Returns a subset of a buffer object's data store

gl:getBufferSubData returns some or all of the data from the buffer object currently bound to Target . Data starting at byte offset Offset and extending for Size bytes is copied from the data store to the memory pointed to by Data . An error is thrown if the buffer object is currently mapped, or if Offset and Size together define a range beyond the bounds of the buffer object's data store.

See external documentation.

getBufferParameteriv(Target, Pname) -> integer()

Types

Target = enum()

Pname = enum()

Return parameters of a buffer object

gl:getBufferParameteriv returns in Data a selected parameter of the buffer object specified by Target .

Value names a specific buffer object parameter, as follows:

?GL_BUFFER_ACCESS: Params returns the access policy set while mapping the buffer object. The initial value is ?GL_READ_WRITE.

?GL_BUFFER_MAPPED: Params returns a flag indicating whether the buffer object is currently mapped. The initial value is ?GL_FALSE.

?GL_BUFFER_SIZE: Params returns the size of the buffer object, measured in bytes. The initial value is 0.

?GL_BUFFER_USAGE: Params returns the buffer object's usage pattern. The initial value is ?GL_STATIC_DRAW.

See external documentation.

blendEquationSeparate(ModeRGB, ModeAlpha) -> ok

Types

ModeRGB = enum()

ModeAlpha = enum()

Set the RGB blend equation and the alpha blend equation separately

The blend equations determines how a new pixel (the ''source'' color) is combined with a pixel already in the framebuffer (the ''destination'' color). These functions specifie one blend equation for the RGB-color components and one blend equation for the alpha component. gl:blendEquationSeparatei specifies the blend equations for a single draw buffer whereas gl:blendEquationSeparate sets the blend equations for all draw buffers.

The blend equations use the source and destination blend factors specified by either gl:blendFunc/2 or gl:blendFuncSeparate/4 . See gl:blendFunc/2 or gl:blendFuncSeparate/4 for a description of the various blend factors.

The results of these equations are clamped to the range [0 1].

Initially, both the RGB blend equation and the alpha blend equation are set to ?GL_FUNC_ADD .

See external documentation.

drawBuffers(Bufs) -> ok

Types

Bufs = [enum()]

Specifies a list of color buffers to be drawn into

gl:drawBuffers defines an array of buffers into which outputs from the fragment shader data will be written. If a fragment shader writes a value to one or more user defined output variables, then the value of each variable will be written into the buffer specified at a location within Bufs corresponding to the location assigned to that user defined output. The draw buffer used for user defined outputs assigned to locations greater than or equal to N is implicitly set to ?GL_NONE and any data written to such an output is discarded.

The symbolic constants contained in Bufs may be any of the following:

?GL_NONE: The fragment shader output value is not written into any color buffer.

?GL_FRONT_LEFT: The fragment shader output value is written into the front left color buffer.

?GL_FRONT_RIGHT: The fragment shader output value is written into the front right color buffer.

?GL_BACK_LEFT: The fragment shader output value is written into the back left color buffer.

?GL_BACK_RIGHT: The fragment shader output value is written into the back right color buffer.

?GL_COLOR_ATTACHMENTn: The fragment shader output value is written into the nth color attachment of the current framebuffer. n may range from 0 to the value of ?GL_MAX_COLOR_ATTACHMENTS.

Except for ?GL_NONE, the preceding symbolic constants may not appear more than once in Bufs . The maximum number of draw buffers supported is implementation dependent and can be queried by calling gl:getBooleanv/1 with the argument ?GL_MAX_DRAW_BUFFERS .

See external documentation.

stencilOpSeparate(Face, Sfail, Dpfail, Dppass) -> ok

Types

Face = enum()

Sfail = enum()

Dpfail = enum()

Dppass = enum()

Set front and/or back stencil test actions

There can be two separate sets of Sfail , Dpfail , and Dppass parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. gl:stencilOp/3 sets both front and back stencil state to the same values, as if gl:stencilOpSeparate/4 were called with Face set to ?GL_FRONT_AND_BACK.

gl:stencilOpSeparate takes three arguments that indicate what happens to the stored stencil value while stenciling is enabled. If the stencil test fails, no change is made to the pixel's color or depth buffers, and Sfail specifies what happens to the stencil buffer contents. The following eight actions are possible.

?GL_KEEP: Keeps the current value.

?GL_ZERO: Sets the stencil buffer value to 0.

?GL_REPLACE: Sets the stencil buffer value to ref, as specified by gl:stencilFunc/3 .

?GL_INCR: Increments the current stencil buffer value. Clamps to the maximum representable unsigned value.

?GL_INCR_WRAP: Increments the current stencil buffer value. Wraps stencil buffer value to zero when incrementing the maximum representable unsigned value.

?GL_DECR: Decrements the current stencil buffer value. Clamps to 0.

?GL_DECR_WRAP: Decrements the current stencil buffer value. Wraps stencil buffer value to the maximum representable unsigned value when decrementing a stencil buffer value of zero.

?GL_INVERT: Bitwise inverts the current stencil buffer value.

Stencil buffer values are treated as unsigned integers. When incremented and decremented, values are clamped to 0 and 2 n-1, where n is the value returned by querying ?GL_STENCIL_BITS .

The other two arguments to gl:stencilOpSeparate specify stencil buffer actions that depend on whether subsequent depth buffer tests succeed ( Dppass ) or fail ( Dpfail ) (see gl:depthFunc/1 ). The actions are specified using the same eight symbolic constants as Sfail . Note that Dpfail is ignored when there is no depth buffer, or when the depth buffer is not enabled. In these cases, Sfail and Dppass specify stencil action when the stencil test fails and passes, respectively.

See external documentation.

stencilFuncSeparate(Face, Func, Ref, Mask) -> ok

Types

Face = enum()

Func = enum()

Ref = integer()

Mask = integer()

Set front and/or back function and reference value for stencil testing

There can be two separate sets of Func , Ref , and Mask parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. gl:stencilFunc/3 sets both front and back stencil state to the same values, as if gl:stencilFuncSeparate/4 were called with Face set to ?GL_FRONT_AND_BACK.

The following values are accepted by Func :

?GL_NEVER: Always fails.

?GL_LESS: Passes if ( Ref & Mask ) < ( stencil & Mask ).

?GL_LEQUAL: Passes if ( Ref & Mask ) <= ( stencil & Mask ).

?GL_GREATER: Passes if ( Ref & Mask ) > ( stencil & Mask ).

?GL_GEQUAL: Passes if ( Ref & Mask ) >= ( stencil & Mask ).

?GL_EQUAL: Passes if ( Ref & Mask ) = ( stencil & Mask ).

?GL_NOTEQUAL: Passes if ( Ref & Mask ) != ( stencil & Mask ).

?GL_ALWAYS: Always passes.

See external documentation.

stencilMaskSeparate(Face, Mask) -> ok

Types

Face = enum()

Mask = integer()

Control the front and/or back writing of individual bits in the stencil planes

gl:stencilMaskSeparate controls the writing of individual bits in the stencil planes. The least significant n bits of Mask , where n is the number of bits in the stencil buffer, specify a mask. Where a 1 appears in the mask, it's possible to write to the corresponding bit in the stencil buffer. Where a 0 appears, the corresponding bit is write-protected. Initially, all bits are enabled for writing.

There can be two separate Mask writemasks; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. gl:stencilMask/1 sets both front and back stencil writemasks to the same values, as if gl:stencilMaskSeparate/2 were called with Face set to ?GL_FRONT_AND_BACK.

See external documentation.

attachShader(Program, Shader) -> ok

Types

Program = integer()

Shader = integer()

Attaches a shader object to a program object

In order to create a complete shader program, there must be a way to specify the list of things that will be linked together. Program objects provide this mechanism. Shaders that are to be linked together in a program object must first be attached to that program object. gl:attachShader attaches the shader object specified by Shader to the program object specified by Program . This indicates that Shader will be included in link operations that will be performed on Program .

All operations that can be performed on a shader object are valid whether or not the shader object is attached to a program object. It is permissible to attach a shader object to a program object before source code has been loaded into the shader object or before the shader object has been compiled. It is permissible to attach multiple shader objects of the same type because each may contain a portion of the complete shader. It is also permissible to attach a shader object to more than one program object. If a shader object is deleted while it is attached to a program object, it will be flagged for deletion, and deletion will not occur until gl:detachShader/2 is called to detach it from all program objects to which it is attached.

See external documentation.

bindAttribLocation(Program, Index, Name) -> ok

Types

Program = integer()

Index = integer()

Name = string()

Associates a generic vertex attribute index with a named attribute variable

gl:bindAttribLocation is used to associate a user-defined attribute variable in the program object specified by Program with a generic vertex attribute index. The name of the user-defined attribute variable is passed as a null terminated string in Name . The generic vertex attribute index to be bound to this variable is specified by Index . When Program is made part of current state, values provided via the generic vertex attribute Index will modify the value of the user-defined attribute variable specified by Name .

If Name refers to a matrix attribute variable, Index refers to the first column of the matrix. Other matrix columns are then automatically bound to locations Index+1 for a matrix of type mat2; Index+1 and Index+2 for a matrix of type mat3; and Index+1 , Index+2 , and Index+3 for a matrix of type mat4 .

This command makes it possible for vertex shaders to use descriptive names for attribute variables rather than generic variables that are numbered from 0 to ?GL_MAX_VERTEX_ATTRIBS -1. The values sent to each generic attribute index are part of current state. If a different program object is made current by calling gl:useProgram/1 , the generic vertex attributes are tracked in such a way that the same values will be observed by attributes in the new program object that are also bound to Index .

Attribute variable name-to-generic attribute index bindings for a program object can be explicitly assigned at any time by calling gl:bindAttribLocation. Attribute bindings do not go into effect until gl:linkProgram/1 is called. After a program object has been linked successfully, the index values for generic attributes remain fixed (and their values can be queried) until the next link command occurs.

Any attribute binding that occurs after the program object has been linked will not take effect until the next time the program object is linked.

See external documentation.

compileShader(Shader) -> ok

Types

Shader = integer()

Compiles a shader object

gl:compileShader compiles the source code strings that have been stored in the shader object specified by Shader .

The compilation status will be stored as part of the shader object's state. This value will be set to ?GL_TRUE if the shader was compiled without errors and is ready for use, and ?GL_FALSE otherwise. It can be queried by calling gl:getShaderiv/2 with arguments Shader and ?GL_COMPILE_STATUS.

Compilation of a shader can fail for a number of reasons as specified by the OpenGL Shading Language Specification. Whether or not the compilation was successful, information about the compilation can be obtained from the shader object's information log by calling gl:getShaderInfoLog/2 .

See external documentation.

createProgram() -> integer()

Creates a program object

gl:createProgram creates an empty program object and returns a non-zero value by which it can be referenced. A program object is an object to which shader objects can be attached. This provides a mechanism to specify the shader objects that will be linked to create a program. It also provides a means for checking the compatibility of the shaders that will be used to create a program (for instance, checking the compatibility between a vertex shader and a fragment shader). When no longer needed as part of a program object, shader objects can be detached.

One or more executables are created in a program object by successfully attaching shader objects to it with gl:attachShader/2 , successfully compiling the shader objects with gl:compileShader/1 , and successfully linking the program object with gl:linkProgram/1 . These executables are made part of current state when gl:useProgram/1 is called. Program objects can be deleted by calling gl:deleteProgram/1 . The memory associated with the program object will be deleted when it is no longer part of current rendering state for any context.

See external documentation.

createShader(Type) -> integer()

Index = integer()

Enable or disable a generic vertex attribute array

gl:enableVertexAttribArray enables the generic vertex attribute array specified by Index . gl:disableVertexAttribArray disables the generic vertex attribute array specified by Index . By default, all client-side capabilities are disabled, including all generic vertex attribute arrays. If enabled, the values in the generic vertex attribute array will be accessed and used for rendering when calls are made to vertex array commands such as gl:drawArrays/3 , gl:drawElements/4 , gl:drawRangeElements/6 , see glMultiDrawElements , or gl:multiDrawArrays/3 .

See external documentation.

enableVertexAttribArray(Index) -> ok

Types

Index = integer()

See disableVertexAttribArray/1

getActiveAttrib(Program, Index, BufSize) -> {Size::integer(), Type::enum(), Name::string()}

Types

Program = integer()

Index = integer()

BufSize = integer()

Returns information about an active attribute variable for the specified program object

gl:getActiveAttrib returns information about an active attribute variable in the program object specified by Program . The number of active attributes can be obtained by calling gl:getProgramiv/2 with the value ?GL_ACTIVE_ATTRIBUTES. A value of 0 for Index selects the first active attribute variable. Permissible values for Index range from 0 to the number of active attribute variables minus 1.

A vertex shader may use either built-in attribute variables, user-defined attribute variables, or both. Built-in attribute variables have a prefix of "gl_" and reference conventional OpenGL vertex attribtes (e.g., Gl_Vertex , Gl_Normal , etc., see the OpenGL Shading Language specification for a complete list.) User-defined attribute variables have arbitrary names and obtain their values through numbered generic vertex attributes. An attribute variable (either built-in or user-defined) is considered active if it is determined during the link operation that it may be accessed during program execution. Therefore, Program should have previously been the target of a call to gl:linkProgram/1 , but it is not necessary for it to have been linked successfully.

The size of the character buffer required to store the longest attribute variable name in Program can be obtained by calling gl:getProgramiv/2 with the value ?GL_ACTIVE_ATTRIBUTE_MAX_LENGTH . This value should be used to allocate a buffer of sufficient size to store the returned attribute name. The size of this character buffer is passed in BufSize , and a pointer to this character buffer is passed in Name .

gl:getActiveAttrib returns the name of the attribute variable indicated by Index , storing it in the character buffer specified by Name . The string returned will be null terminated. The actual number of characters written into this buffer is returned in Length , and this count does not include the null termination character. If the length of the returned string is not required, a value of ?NULL can be passed in the Length argument.

The Type argument specifies a pointer to a variable into which the attribute variable's data type will be written. The symbolic constants ?GL_FLOAT, ?GL_FLOAT_VEC2, ?GL_FLOAT_VEC3, ?GL_FLOAT_VEC4, ?GL_FLOAT_MAT2, ?GL_FLOAT_MAT3, ?GL_FLOAT_MAT4, ?GL_FLOAT_MAT2x3, ?GL_FLOAT_MAT2x4, ?GL_FLOAT_MAT3x2 , ?GL_FLOAT_MAT3x4, ?GL_FLOAT_MAT4x2, ?GL_FLOAT_MAT4x3, ?GL_INT , ?GL_INT_VEC2, ?GL_INT_VEC3, ?GL_INT_VEC4, ?GL_UNSIGNED_INT_VEC , ?GL_UNSIGNED_INT_VEC2, ?GL_UNSIGNED_INT_VEC3, ?GL_UNSIGNED_INT_VEC4, ?DOUBLE, ?DOUBLE_VEC2, ?DOUBLE_VEC3, ?DOUBLE_VEC4, ?DOUBLE_MAT2 , ?DOUBLE_MAT3, ?DOUBLE_MAT4, ?DOUBLE_MAT2x3, ?DOUBLE_MAT2x4, ?DOUBLE_MAT3x2, ?DOUBLE_MAT3x4, ?DOUBLE_MAT4x2, or ?DOUBLE_MAT4x3 may be returned. The Size argument will return the size of the attribute, in units of the type returned in Type .

The list of active attribute variables may include both built-in attribute variables (which begin with the prefix "gl_") as well as user-defined attribute variable names.

This function will return as much information as it can about the specified active attribute variable. If no information is available, Length will be 0, and Name will be an empty string. This situation could occur if this function is called after a link operation that failed. If an error occurs, the return values Length , Size , Type , and Name will be unmodified.

See external documentation.

getActiveUniform(Program, Index, BufSize) -> {Size::integer(), Type::enum(), Name::string()}

Types

Program = integer()

Index = integer()

BufSize = integer()

Returns information about an active uniform variable for the specified program object

gl:getActiveUniform returns information about an active uniform variable in the program object specified by Program . The number of active uniform variables can be obtained by calling gl:getProgramiv/2 with the value ?GL_ACTIVE_UNIFORMS. A value of 0 for Index selects the first active uniform variable. Permissible values for Index range from 0 to the number of active uniform variables minus 1.

Shaders may use either built-in uniform variables, user-defined uniform variables, or both. Built-in uniform variables have a prefix of "gl_" and reference existing OpenGL state or values derived from such state (e.g., Gl_DepthRangeParameters , see the OpenGL Shading Language specification for a complete list.) User-defined uniform variables have arbitrary names and obtain their values from the application through calls to gl:uniform1f/2 . A uniform variable (either built-in or user-defined) is considered active if it is determined during the link operation that it may be accessed during program execution. Therefore, Program should have previously been the target of a call to gl:linkProgram/1 , but it is not necessary for it to have been linked successfully.

The size of the character buffer required to store the longest uniform variable name in Program can be obtained by calling gl:getProgramiv/2 with the value ?GL_ACTIVE_UNIFORM_MAX_LENGTH . This value should be used to allocate a buffer of sufficient size to store the returned uniform variable name. The size of this character buffer is passed in BufSize , and a pointer to this character buffer is passed in Name.

gl:getActiveUniform returns the name of the uniform variable indicated by Index , storing it in the character buffer specified by Name . The string returned will be null terminated. The actual number of characters written into this buffer is returned in Length , and this count does not include the null termination character. If the length of the returned string is not required, a value of ?NULL can be passed in the Length argument.

The Type argument will return a pointer to the uniform variable's data type. The symbolic constants returned for uniform types are shown in the table below.

Returned Symbolic ContantShader Uniform Type
?GL_FLOAT?float
?GL_FLOAT_VEC2 ?vec2
?GL_FLOAT_VEC3?vec3
?GL_FLOAT_VEC4?vec4
?GL_DOUBLE ?double
?GL_DOUBLE_VEC2?dvec2
?GL_DOUBLE_VEC3?dvec3
?GL_DOUBLE_VEC4 ?dvec4
?GL_INT?int
?GL_INT_VEC2?ivec2
?GL_INT_VEC3?ivec3
?GL_INT_VEC4?ivec4
?GL_UNSIGNED_INT ?unsigned int
?GL_UNSIGNED_INT_VEC2?uvec2
?GL_UNSIGNED_INT_VEC3?uvec3
?GL_UNSIGNED_INT_VEC4 ?uvec4
?GL_BOOL?bool
?GL_BOOL_VEC2?bvec2
?GL_BOOL_VEC3 ?bvec3
?GL_BOOL_VEC4?bvec4
?GL_FLOAT_MAT2?mat2
?GL_FLOAT_MAT3 ?mat3
?GL_FLOAT_MAT4?mat4
?GL_FLOAT_MAT2x3?mat2x3
?GL_FLOAT_MAT2x4 ?mat2x4
?GL_FLOAT_MAT3x2?mat3x2
?GL_FLOAT_MAT3x4?mat3x4
?GL_FLOAT_MAT4x2 ?mat4x2
?GL_FLOAT_MAT4x3?mat4x3
?GL_DOUBLE_MAT2?dmat2
?GL_DOUBLE_MAT3 ?dmat3
?GL_DOUBLE_MAT4?dmat4
?GL_DOUBLE_MAT2x3?dmat2x3
?GL_DOUBLE_MAT2x4 ?dmat2x4
?GL_DOUBLE_MAT3x2?dmat3x2
?GL_DOUBLE_MAT3x4?dmat3x4
?GL_DOUBLE_MAT4x2 ?dmat4x2
?GL_DOUBLE_MAT4x3?dmat4x3
?GL_SAMPLER_1D?sampler1D
?GL_SAMPLER_2D ?sampler2D
?GL_SAMPLER_3D?sampler3D
?GL_SAMPLER_CUBE?samplerCube
?GL_SAMPLER_1D_SHADOW ?sampler1DShadow
?GL_SAMPLER_2D_SHADOW?sampler2DShadow
?GL_SAMPLER_1D_ARRAY?sampler1DArray
?GL_SAMPLER_2D_ARRAY?sampler2DArray
?GL_SAMPLER_1D_ARRAY_SHADOW ?sampler1DArrayShadow
?GL_SAMPLER_2D_ARRAY_SHADOW ?sampler2DArrayShadow
?GL_SAMPLER_2D_MULTISAMPLE ?sampler2DMS
?GL_SAMPLER_2D_MULTISAMPLE_ARRAY?sampler2DMSArray
?GL_SAMPLER_CUBE_SHADOW?samplerCubeShadow
?GL_SAMPLER_BUFFER?samplerBuffer
?GL_SAMPLER_2D_RECT ?sampler2DRect
?GL_SAMPLER_2D_RECT_SHADOW ?sampler2DRectShadow
?GL_INT_SAMPLER_1D?isampler1D
?GL_INT_SAMPLER_2D?isampler2D
?GL_INT_SAMPLER_3D ?isampler3D
?GL_INT_SAMPLER_CUBE?isamplerCube
?GL_INT_SAMPLER_1D_ARRAY?isampler1DArray
?GL_INT_SAMPLER_2D_ARRAY?isampler2DArray
?GL_INT_SAMPLER_2D_MULTISAMPLE ?isampler2DMS
?GL_INT_SAMPLER_2D_MULTISAMPLE_ARRAY ?isampler2DMSArray
?GL_INT_SAMPLER_BUFFER?isamplerBuffer
?GL_INT_SAMPLER_2D_RECT?isampler2DRect
?GL_UNSIGNED_INT_SAMPLER_1D?usampler1D
?GL_UNSIGNED_INT_SAMPLER_2D ?usampler2D
?GL_UNSIGNED_INT_SAMPLER_3D?usampler3D
?GL_UNSIGNED_INT_SAMPLER_CUBE?usamplerCube
?GL_UNSIGNED_INT_SAMPLER_1D_ARRAY?usampler2DArray
?GL_UNSIGNED_INT_SAMPLER_2D_ARRAY?usampler2DArray
?GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE?usampler2DMS
?GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE_ARRAY?usampler2DMSArray
?GL_UNSIGNED_INT_SAMPLER_BUFFER?usamplerBuffer
?GL_UNSIGNED_INT_SAMPLER_2D_RECT?usampler2DRect
?GL_IMAGE_1D?image1D
?GL_IMAGE_2D ?image2D
?GL_IMAGE_3D?image3D
?GL_IMAGE_2D_RECT?image2DRect
?GL_IMAGE_CUBE ?imageCube
?GL_IMAGE_BUFFER?imageBuffer
?GL_IMAGE_1D_ARRAY?image1DArray
?GL_IMAGE_2D_ARRAY?image2DArray
?GL_IMAGE_2D_MULTISAMPLE ?image2DMS
?GL_IMAGE_2D_MULTISAMPLE_ARRAY ?image2DMSArray
?GL_INT_IMAGE_1D?iimage1D
?GL_INT_IMAGE_2D?iimage2D
?GL_INT_IMAGE_3D ?iimage3D
?GL_INT_IMAGE_2D_RECT?iimage2DRect
?GL_INT_IMAGE_CUBE?iimageCube
?GL_INT_IMAGE_BUFFER ?iimageBuffer
?GL_INT_IMAGE_1D_ARRAY?iimage1DArray
?GL_INT_IMAGE_2D_ARRAY?iimage2DArray
?GL_INT_IMAGE_2D_MULTISAMPLE?iimage2DMS
?GL_INT_IMAGE_2D_MULTISAMPLE_ARRAY ?iimage2DMSArray
?GL_UNSIGNED_INT_IMAGE_1D ?uimage1D
?GL_UNSIGNED_INT_IMAGE_2D?uimage2D
?GL_UNSIGNED_INT_IMAGE_3D?uimage3D
?GL_UNSIGNED_INT_IMAGE_2D_RECT?uimage2DRect
?GL_UNSIGNED_INT_IMAGE_CUBE ?uimageCube
?GL_UNSIGNED_INT_IMAGE_BUFFER ?uimageBuffer
?GL_UNSIGNED_INT_IMAGE_1D_ARRAY?uimage1DArray
?GL_UNSIGNED_INT_IMAGE_2D_ARRAY?uimage2DArray
?GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE?uimage2DMS
?GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE_ARRAY?uimage2DMSArray
?GL_UNSIGNED_INT_ATOMIC_COUNTER?atomic_uint

If one or more elements of an array are active, the name of the array is returned in Name , the type is returned in Type , and the Size parameter returns the highest array element index used, plus one, as determined by the compiler and/or linker. Only one active uniform variable will be reported for a uniform array.

Uniform variables that are declared as structures or arrays of structures will not be returned directly by this function. Instead, each of these uniform variables will be reduced to its fundamental components containing the "." and "[]" operators such that each of the names is valid as an argument to gl:getUniformLocation/2 . Each of these reduced uniform variables is counted as one active uniform variable and is assigned an index. A valid name cannot be a structure, an array of structures, or a subcomponent of a vector or matrix.

The size of the uniform variable will be returned in Size . Uniform variables other than arrays will have a size of 1. Structures and arrays of structures will be reduced as described earlier, such that each of the names returned will be a data type in the earlier list. If this reduction results in an array, the size returned will be as described for uniform arrays; otherwise, the size returned will be 1.

The list of active uniform variables may include both built-in uniform variables (which begin with the prefix "gl_") as well as user-defined uniform variable names.

This function will return as much information as it can about the specified active uniform variable. If no information is available, Length will be 0, and Name will be an empty string. This situation could occur if this function is called after a link operation that failed. If an error occurs, the return values Length , Size , Type , and Name will be unmodified.

See external documentation.

getAttachedShaders(Program, MaxCount) -> [integer()]

Types

Program = integer()

MaxCount = integer()

Returns the handles of the shader objects attached to a program object

gl:getAttachedShaders returns the names of the shader objects attached to Program . The names of shader objects that are attached to Program will be returned in Shaders. The actual number of shader names written into Shaders is returned in Count. If no shader objects are attached to Program , Count is set to 0. The maximum number of shader names that may be returned in Shaders is specified by MaxCount .

If the number of names actually returned is not required (for instance, if it has just been obtained by calling gl:getProgramiv/2 ), a value of ?NULL may be passed for count. If no shader objects are attached to Program , a value of 0 will be returned in Count . The actual number of attached shaders can be obtained by calling gl:getProgramiv/2 with the value ?GL_ATTACHED_SHADERS.

See external documentation.

getAttribLocation(Program, Name) -> integer()

Types

Program = integer()

Name = string()

Returns the location of an attribute variable

gl:getAttribLocation queries the previously linked program object specified by Program for the attribute variable specified by Name and returns the index of the generic vertex attribute that is bound to that attribute variable. If Name is a matrix attribute variable, the index of the first column of the matrix is returned. If the named attribute variable is not an active attribute in the specified program object or if Name starts with the reserved prefix "gl_", a value of -1 is returned.

The association between an attribute variable name and a generic attribute index can be specified at any time by calling gl:bindAttribLocation/3 . Attribute bindings do not go into effect until gl:linkProgram/1 is called. After a program object has been linked successfully, the index values for attribute variables remain fixed until the next link command occurs. The attribute values can only be queried after a link if the link was successful. gl:getAttribLocation returns the binding that actually went into effect the last time gl:linkProgram/1 was called for the specified program object. Attribute bindings that have been specified since the last link operation are not returned by gl:getAttribLocation.

See external documentation.

getProgramiv(Program, Pname) -> integer()

Types

Program = integer()

Pname = enum()

Returns a parameter from a program object

gl:getProgram returns in Params the value of a parameter for a specific program object. The following parameters are defined:

?GL_DELETE_STATUS: Params returns ?GL_TRUE if Program is currently flagged for deletion, and ?GL_FALSE otherwise.

?GL_LINK_STATUS: Params returns ?GL_TRUE if the last link operation on Program was successful, and ?GL_FALSE otherwise.

?GL_VALIDATE_STATUS: Params returns ?GL_TRUE or if the last validation operation on Program was successful, and ?GL_FALSE otherwise.

?GL_INFO_LOG_LENGTH: Params returns the number of characters in the information log for Program including the null termination character (i.e., the size of the character buffer required to store the information log). If Program has no information log, a value of 0 is returned.

?GL_ATTACHED_SHADERS: Params returns the number of shader objects attached to Program .

?GL_ACTIVE_ATOMIC_COUNTER_BUFFERS: Params returns the number of active attribute atomic counter buffers used by Program .

?GL_ACTIVE_ATTRIBUTES: Params returns the number of active attribute variables for Program .

?GL_ACTIVE_ATTRIBUTE_MAX_LENGTH: Params returns the length of the longest active attribute name for Program , including the null termination character (i.e., the size of the character buffer required to store the longest attribute name). If no active attributes exist, 0 is returned.

?GL_ACTIVE_UNIFORMS: Params returns the number of active uniform variables for Program .

?GL_ACTIVE_UNIFORM_MAX_LENGTH: Params returns the length of the longest active uniform variable name for Program , including the null termination character (i.e., the size of the character buffer required to store the longest uniform variable name). If no active uniform variables exist, 0 is returned.

?GL_PROGRAM_BINARY_LENGTH: Params returns the length of the program binary, in bytes that will be returned by a call to gl:getProgramBinary/2 . When a progam's ?GL_LINK_STATUS is ?GL_FALSE, its program binary length is zero.

?GL_TRANSFORM_FEEDBACK_BUFFER_MODE: Params returns a symbolic constant indicating the buffer mode used when transform feedback is active. This may be ?GL_SEPARATE_ATTRIBS or ?GL_INTERLEAVED_ATTRIBS.

?GL_TRANSFORM_FEEDBACK_VARYINGS: Params returns the number of varying variables to capture in transform feedback mode for the program.

?GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH: Params returns the length of the longest variable name to be used for transform feedback, including the null-terminator.

?GL_GEOMETRY_VERTICES_OUT: Params returns the maximum number of vertices that the geometry shader in Program will output.

?GL_GEOMETRY_INPUT_TYPE: Params returns a symbolic constant indicating the primitive type accepted as input to the geometry shader contained in Program .

?GL_GEOMETRY_OUTPUT_TYPE: Params returns a symbolic constant indicating the primitive type that will be output by the geometry shader contained in Program .

See external documentation.

getProgramInfoLog(Program, BufSize) -> string()

Types

Program = integer()

BufSize = integer()

Returns the information log for a program object

gl:getProgramInfoLog returns the information log for the specified program object. The information log for a program object is modified when the program object is linked or validated. The string that is returned will be null terminated.

gl:getProgramInfoLog returns in InfoLog as much of the information log as it can, up to a maximum of MaxLength characters. The number of characters actually returned, excluding the null termination character, is specified by Length . If the length of the returned string is not required, a value of ?NULL can be passed in the Length argument. The size of the buffer required to store the returned information log can be obtained by calling gl:getProgramiv/2 with the value ?GL_INFO_LOG_LENGTH .

The information log for a program object is either an empty string, or a string containing information about the last link operation, or a string containing information about the last validation operation. It may contain diagnostic messages, warning messages, and other information. When a program object is created, its information log will be a string of length 0.

See external documentation.

getShaderiv(Shader, Pname) -> integer()

Types

Shader = integer()

Pname = enum()

Returns a parameter from a shader object

gl:getShader returns in Params the value of a parameter for a specific shader object. The following parameters are defined:

?GL_SHADER_TYPE: Params returns ?GL_VERTEX_SHADER if Shader is a vertex shader object, ?GL_GEOMETRY_SHADER if Shader is a geometry shader object, and ?GL_FRAGMENT_SHADER if Shader is a fragment shader object.

?GL_DELETE_STATUS: Params returns ?GL_TRUE if Shader is currently flagged for deletion, and ?GL_FALSE otherwise.

?GL_COMPILE_STATUS: Params returns ?GL_TRUE if the last compile operation on Shader was successful, and ?GL_FALSE otherwise.

?GL_INFO_LOG_LENGTH: Params returns the number of characters in the information log for Shader including the null termination character (i.e., the size of the character buffer required to store the information log). If Shader has no information log, a value of 0 is returned.

?GL_SHADER_SOURCE_LENGTH: Params returns the length of the concatenation of the source strings that make up the shader source for the Shader , including the null termination character. (i.e., the size of the character buffer required to store the shader source). If no source code exists, 0 is returned.

See external documentation.

getShaderInfoLog(Shader, BufSize) -> string()

Types

Shader = integer()

BufSize = integer()

Returns the information log for a shader object

gl:getShaderInfoLog returns the information log for the specified shader object. The information log for a shader object is modified when the shader is compiled. The string that is returned will be null terminated.

gl:getShaderInfoLog returns in InfoLog as much of the information log as it can, up to a maximum of MaxLength characters. The number of characters actually returned, excluding the null termination character, is specified by Length . If the length of the returned string is not required, a value of ?NULL can be passed in the Length argument. The size of the buffer required to store the returned information log can be obtained by calling gl:getShaderiv/2 with the value ?GL_INFO_LOG_LENGTH .

The information log for a shader object is a string that may contain diagnostic messages, warning messages, and other information about the last compile operation. When a shader object is created, its information log will be a string of length 0.

See external documentation.

getShaderSource(Shader, BufSize) -> string()

Types

Shader = integer()

BufSize = integer()

Returns the source code string from a shader object

gl:getShaderSource returns the concatenation of the source code strings from the shader object specified by Shader . The source code strings for a shader object are the result of a previous call to gl:shaderSource/2 . The string returned by the function will be null terminated.

gl:getShaderSource returns in Source as much of the source code string as it can, up to a maximum of BufSize characters. The number of characters actually returned, excluding the null termination character, is specified by Length . If the length of the returned string is not required, a value of ?NULL can be passed in the Length argument. The size of the buffer required to store the returned source code string can be obtained by calling gl:getShaderiv/2 with the value ?GL_SHADER_SOURCE_LENGTH .

See external documentation.

getUniformLocation(Program, Name) -> integer()

Types

Program = integer()

Name = string()

Returns the location of a uniform variable

gl:getUniformLocation returns an integer that represents the location of a specific uniform variable within a program object. Name must be a null terminated string that contains no white space. Name must be an active uniform variable name in Program that is not a structure, an array of structures, or a subcomponent of a vector or a matrix. This function returns -1 if Name does not correspond to an active uniform variable in Program , if Name starts with the reserved prefix "gl_", or if Name is associated with an atomic counter or a named uniform block.

Uniform variables that are structures or arrays of structures may be queried by calling gl:getUniformLocation for each field within the structure. The array element operator "[]" and the structure field operator "." may be used in Name in order to select elements within an array or fields within a structure. The result of using these operators is not allowed to be another structure, an array of structures, or a subcomponent of a vector or a matrix. Except if the last part of Name indicates a uniform variable array, the location of the first element of an array can be retrieved by using the name of the array, or by using the name appended by "[0]".

The actual locations assigned to uniform variables are not known until the program object is linked successfully. After linking has occurred, the command gl:getUniformLocation can be used to obtain the location of a uniform variable. This location value can then be passed to gl:uniform1f/2 to set the value of the uniform variable or to gl:getUniformfv/2 in order to query the current value of the uniform variable. After a program object has been linked successfully, the index values for uniform variables remain fixed until the next link command occurs. Uniform variable locations and values can only be queried after a link if the link was successful.

See external documentation.

getUniformfv(Program, Location) -> matrix()

Types

Program = integer()

Location = integer()

Returns the value of a uniform variable

gl:getUniform returns in Params the value(s) of the specified uniform variable. The type of the uniform variable specified by Location determines the number of values returned. If the uniform variable is defined in the shader as a boolean, int, or float, a single value will be returned. If it is defined as a vec2, ivec2, or bvec2, two values will be returned. If it is defined as a vec3, ivec3, or bvec3, three values will be returned, and so on. To query values stored in uniform variables declared as arrays, call gl:getUniform for each element of the array. To query values stored in uniform variables declared as structures, call gl:getUniform for each field in the structure. The values for uniform variables declared as a matrix will be returned in column major order.

The locations assigned to uniform variables are not known until the program object is linked. After linking has occurred, the command gl:getUniformLocation/2 can be used to obtain the location of a uniform variable. This location value can then be passed to gl:getUniform in order to query the current value of the uniform variable. After a program object has been linked successfully, the index values for uniform variables remain fixed until the next link command occurs. The uniform variable values can only be queried after a link if the link was successful.

See external documentation.

getUniformiv(Program, Location) -> {integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer()}

Types

Program = integer()

Location = integer()

See getUniformfv/2

getVertexAttribdv(Index, Pname) -> {float(), float(), float(), float()}

Types

Index = integer()

Pname = enum()

Return a generic vertex attribute parameter

gl:getVertexAttrib returns in Params the value of a generic vertex attribute parameter. The generic vertex attribute to be queried is specified by Index , and the parameter to be queried is specified by Pname .

The accepted parameter names are as follows:

?GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING: Params returns a single value, the name of the buffer object currently bound to the binding point corresponding to generic vertex attribute array Index . If no buffer object is bound, 0 is returned. The initial value is 0.

?GL_VERTEX_ATTRIB_ARRAY_ENABLED: Params returns a single value that is non-zero (true) if the vertex attribute array for Index is enabled and 0 (false) if it is disabled. The initial value is ?GL_FALSE.

?GL_VERTEX_ATTRIB_ARRAY_SIZE: Params returns a single value, the size of the vertex attribute array for Index . The size is the number of values for each element of the vertex attribute array, and it will be 1, 2, 3, or 4. The initial value is 4.

?GL_VERTEX_ATTRIB_ARRAY_STRIDE: Params returns a single value, the array stride for (number of bytes between successive elements in) the vertex attribute array for Index . A value of 0 indicates that the array elements are stored sequentially in memory. The initial value is 0.

?GL_VERTEX_ATTRIB_ARRAY_TYPE: Params returns a single value, a symbolic constant indicating the array type for the vertex attribute array for Index . Possible values are ?GL_BYTE, ?GL_UNSIGNED_BYTE, ?GL_SHORT, ?GL_UNSIGNED_SHORT , ?GL_INT, ?GL_UNSIGNED_INT, ?GL_FLOAT, and ?GL_DOUBLE. The initial value is ?GL_FLOAT.

?GL_VERTEX_ATTRIB_ARRAY_NORMALIZED: Params returns a single value that is non-zero (true) if fixed-point data types for the vertex attribute array indicated by Index are normalized when they are converted to floating point, and 0 (false) otherwise. The initial value is ?GL_FALSE.

?GL_VERTEX_ATTRIB_ARRAY_INTEGER: Params returns a single value that is non-zero (true) if fixed-point data types for the vertex attribute array indicated by Index have integer data types, and 0 (false) otherwise. The initial value is 0 (?GL_FALSE).

?GL_VERTEX_ATTRIB_ARRAY_DIVISOR: Params returns a single value that is the frequency divisor used for instanced rendering. See gl:vertexAttribDivisor/2 . The initial value is 0.

?GL_CURRENT_VERTEX_ATTRIB: Params returns four values that represent the current value for the generic vertex attribute specified by index. Generic vertex attribute 0 is unique in that it has no current state, so an error will be generated if Index is 0. The initial value for all other generic vertex attributes is (0,0,0,1).

gl:getVertexAttribdv and gl:getVertexAttribfv return the current attribute values as four single-precision floating-point values; gl:getVertexAttribiv reads them as floating-point values and converts them to four integer values; gl:getVertexAttribIiv and gl:getVertexAttribIuiv read and return them as signed or unsigned integer values, respectively; gl:getVertexAttribLdv reads and returns them as four double-precision floating-point values.

All of the parameters except ?GL_CURRENT_VERTEX_ATTRIB represent state stored in the currently bound vertex array object.

See external documentation.

getVertexAttribfv(Index, Pname) -> {float(), float(), float(), float()}

Types

Index = integer()

Pname = enum()

See getVertexAttribdv/2

getVertexAttribiv(Index, Pname) -> {integer(), integer(), integer(), integer()}

Program = integer()

Links a program object

gl:linkProgram links the program object specified by Program . If any shader objects of type ?GL_VERTEX_SHADER are attached to Program , they will be used to create an executable that will run on the programmable vertex processor. If any shader objects of type ?GL_GEOMETRY_SHADER are attached to Program , they will be used to create an executable that will run on the programmable geometry processor. If any shader objects of type ?GL_FRAGMENT_SHADER are attached to Program , they will be used to create an executable that will run on the programmable fragment processor.

The status of the link operation will be stored as part of the program object's state. This value will be set to ?GL_TRUE if the program object was linked without errors and is ready for use, and ?GL_FALSE otherwise. It can be queried by calling gl:getProgramiv/2 with arguments Program and ?GL_LINK_STATUS.

As a result of a successful link operation, all active user-defined uniform variables belonging to Program will be initialized to 0, and each of the program object's active uniform variables will be assigned a location that can be queried by calling gl:getUniformLocation/2 . Also, any active user-defined attribute variables that have not been bound to a generic vertex attribute index will be bound to one at this time.

Linking of a program object can fail for a number of reasons as specified in the OpenGL Shading Language Specification . The following lists some of the conditions that will cause a link error.

The number of active attribute variables supported by the implementation has been exceeded.

The storage limit for uniform variables has been exceeded.

The number of active uniform variables supported by the implementation has been exceeded.

The main function is missing for the vertex, geometry or fragment shader.

A varying variable actually used in the fragment shader is not declared in the same way (or is not declared at all) in the vertex shader, or geometry shader shader if present.

A reference to a function or variable name is unresolved.

A shared global is declared with two different types or two different initial values.

One or more of the attached shader objects has not been successfully compiled.

Binding a generic attribute matrix caused some rows of the matrix to fall outside the allowed maximum of ?GL_MAX_VERTEX_ATTRIBS.

Not enough contiguous vertex attribute slots could be found to bind attribute matrices.

The program object contains objects to form a fragment shader but does not contain objects to form a vertex shader.

The program object contains objects to form a geometry shader but does not contain objects to form a vertex shader.

The program object contains objects to form a geometry shader and the input primitive type, output primitive type, or maximum output vertex count is not specified in any compiled geometry shader object.

The program object contains objects to form a geometry shader and the input primitive type, output primitive type, or maximum output vertex count is specified differently in multiple geometry shader objects.

The number of active outputs in the fragment shader is greater than the value of ?GL_MAX_DRAW_BUFFERS .

The program has an active output assigned to a location greater than or equal to the value of ?GL_MAX_DUAL_SOURCE_DRAW_BUFFERS and has an active output assigned an index greater than or equal to one.

More than one varying out variable is bound to the same number and index.

The explicit binding assigments do not leave enough space for the linker to automatically assign a location for a varying out array, which requires multiple contiguous locations.

The Count specified by gl:transformFeedbackVaryings/3 is non-zero, but the program object has no vertex or geometry shader.

Any variable name specified to gl:transformFeedbackVaryings/3 in the Varyings array is not declared as an output in the vertex shader (or the geometry shader, if active).

Any two entries in the Varyings array given gl:transformFeedbackVaryings/3 specify the same varying variable.

The total number of components to capture in any transform feedback varying variable is greater than the constant ?GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS and the buffer mode is ?SEPARATE_ATTRIBS.

When a program object has been successfully linked, the program object can be made part of current state by calling gl:useProgram/1 . Whether or not the link operation was successful, the program object's information log will be overwritten. The information log can be retrieved by calling gl:getProgramInfoLog/2 .

gl:linkProgram will also install the generated executables as part of the current rendering state if the link operation was successful and the specified program object is already currently in use as a result of a previous call to gl:useProgram/1 . If the program object currently in use is relinked unsuccessfully, its link status will be set to ?GL_FALSE , but the executables and associated state will remain part of the current state until a subsequent call to gl:useProgram removes it from use. After it is removed from use, it cannot be made part of current state until it has been successfully relinked.

If Program contains shader objects of type ?GL_VERTEX_SHADER, and optionally of type ?GL_GEOMETRY_SHADER, but does not contain shader objects of type ?GL_FRAGMENT_SHADER , the vertex shader executable will be installed on the programmable vertex processor, the geometry shader executable, if present, will be installed on the programmable geometry processor, but no executable will be installed on the fragment processor. The results of rasterizing primitives with such a program will be undefined.

The program object's information log is updated and the program is generated at the time of the link operation. After the link operation, applications are free to modify attached shader objects, compile attached shader objects, detach shader objects, delete shader objects, and attach additional shader objects. None of these operations affects the information log or the program that is part of the program object.

See external documentation.

shaderSource(Shader, String) -> ok

Types

Shader = integer()

String = iolist()

Replaces the source code in a shader object

gl:shaderSource sets the source code in Shader to the source code in the array of strings specified by String . Any source code previously stored in the shader object is completely replaced. The number of strings in the array is specified by Count . If Length is ?NULL, each string is assumed to be null terminated. If Length is a value other than ?NULL, it points to an array containing a string length for each of the corresponding elements of String . Each element in the Length array may contain the length of the corresponding string (the null character is not counted as part of the string length) or a value less than 0 to indicate that the string is null terminated. The source code strings are not scanned or parsed at this time; they are simply copied into the specified shader object.

See external documentation.

useProgram(Program) -> ok

Types

Program = integer()

Installs a program object as part of current rendering state

gl:useProgram installs the program object specified by Program as part of current rendering state. One or more executables are created in a program object by successfully attaching shader objects to it with gl:attachShader/2 , successfully compiling the shader objects with gl:compileShader/1 , and successfully linking the program object with gl:linkProgram/1 .

A program object will contain an executable that will run on the vertex processor if it contains one or more shader objects of type ?GL_VERTEX_SHADER that have been successfully compiled and linked. A program object will contain an executable that will run on the geometry processor if it contains one or more shader objects of type ?GL_GEOMETRY_SHADER that have been successfully compiled and linked. Similarly, a program object will contain an executable that will run on the fragment processor if it contains one or more shader objects of type ?GL_FRAGMENT_SHADER that have been successfully compiled and linked.

While a program object is in use, applications are free to modify attached shader objects, compile attached shader objects, attach additional shader objects, and detach or delete shader objects. None of these operations will affect the executables that are part of the current state. However, relinking the program object that is currently in use will install the program object as part of the current rendering state if the link operation was successful (see gl:linkProgram/1 ). If the program object currently in use is relinked unsuccessfully, its link status will be set to ?GL_FALSE, but the executables and associated state will remain part of the current state until a subsequent call to gl:useProgram removes it from use. After it is removed from use, it cannot be made part of current state until it has been successfully relinked.

If Program is zero, then the current rendering state refers to an invalid program object and the results of shader execution are undefined. However, this is not an error.

If Program does not contain shader objects of type ?GL_FRAGMENT_SHADER, an executable will be installed on the vertex, and possibly geometry processors, but the results of fragment shader execution will be undefined.

See external documentation.

uniform1f(Location, V0) -> ok

Types

Location = integer()

V0 = float()

Specify the value of a uniform variable for the current program object

gl:uniform modifies the value of a uniform variable or a uniform variable array. The location of the uniform variable to be modified is specified by Location , which should be a value returned by gl:getUniformLocation/2 . gl:uniform operates on the program object that was made part of current state by calling gl:useProgram/1 .

The commands gl:uniform{1|2|3|4}{f|i|ui} are used to change the value of the uniform variable specified by Location using the values passed as arguments. The number specified in the command should match the number of components in the data type of the specified uniform variable (e.g., 1 for float, int, unsigned int, bool; 2 for vec2, ivec2, uvec2, bvec2, etc.). The suffix f indicates that floating-point values are being passed; the suffix i indicates that integer values are being passed; the suffix ui indicates that unsigned integer values are being passed, and this type should also match the data type of the specified uniform variable. The i variants of this function should be used to provide values for uniform variables defined as int, ivec2 , ivec3, ivec4, or arrays of these. The ui variants of this function should be used to provide values for uniform variables defined as unsigned int, uvec2, uvec3, uvec4, or arrays of these. The f variants should be used to provide values for uniform variables of type float, vec2, vec3, vec4, or arrays of these. Either the i, ui or f variants may be used to provide values for uniform variables of type bool, bvec2 , bvec3, bvec4, or arrays of these. The uniform variable will be set to false if the input value is 0 or 0.0f, and it will be set to true otherwise.

Types

Location = integer()

Transpose = 0 | 1

Value = [{float(), float(), float(), float(), float(), float(), float(), float(), float()}]

uniformMatrix4fv(Location, Transpose, Value) -> ok

Types

Location = integer()

Transpose = 0 | 1

Value = [{float(), float(), float(), float(), float(), float(), float(), float(), float(), float(), float(), float(), float(), float(), float(), float()}]

validateProgram(Program) -> ok

Types

Program = integer()

Validates a program object

gl:validateProgram checks to see whether the executables contained in Program can execute given the current OpenGL state. The information generated by the validation process will be stored in Program 's information log. The validation information may consist of an empty string, or it may be a string containing information about how the current program object interacts with the rest of current OpenGL state. This provides a way for OpenGL implementers to convey more information about why the current program is inefficient, suboptimal, failing to execute, and so on.

The status of the validation operation will be stored as part of the program object's state. This value will be set to ?GL_TRUE if the validation succeeded, and ?GL_FALSE otherwise. It can be queried by calling gl:getProgramiv/2 with arguments Program and ?GL_VALIDATE_STATUS. If validation is successful, Program is guaranteed to execute given the current state. Otherwise, Program is guaranteed to not execute.

This function is typically useful only during application development. The informational string stored in the information log is completely implementation dependent; therefore, an application should not expect different OpenGL implementations to produce identical information strings.

See external documentation.

vertexAttrib1d(Index, X) -> ok

Types

Index = integer()

X = float()

Specifies the value of a generic vertex attribute

The gl:vertexAttrib family of entry points allows an application to pass generic vertex attributes in numbered locations.

Generic attributes are defined as four-component values that are organized into an array. The first entry of this array is numbered 0, and the size of the array is specified by the implementation-dependent constant ?GL_MAX_VERTEX_ATTRIBS. Individual elements of this array can be modified with a gl:vertexAttrib call that specifies the index of the element to be modified and a value for that element.

These commands can be used to specify one, two, three, or all four components of the generic vertex attribute specified by Index . A 1 in the name of the command indicates that only one value is passed, and it will be used to modify the first component of the generic vertex attribute. The second and third components will be set to 0, and the fourth component will be set to 1. Similarly, a 2 in the name of the command indicates that values are provided for the first two components, the third component will be set to 0, and the fourth component will be set to 1. A 3 in the name of the command indicates that values are provided for the first three components and the fourth component will be set to 1, whereas a 4 in the name indicates that values are provided for all four components.

The letters s, f, i, d, ub, us, and ui indicate whether the arguments are of type short, float, int, double, unsigned byte, unsigned short, or unsigned int. When v is appended to the name, the commands can take a pointer to an array of such values.

Additional capitalized letters can indicate further alterations to the default behavior of the glVertexAttrib function:

The commands containing N indicate that the arguments will be passed as fixed-point values that are scaled to a normalized range according to the component conversion rules defined by the OpenGL specification. Signed values are understood to represent fixed-point values in the range [-1,1], and unsigned values are understood to represent fixed-point values in the range [0,1].

The commands containing I indicate that the arguments are extended to full signed or unsigned integers.

The commands containing P indicate that the arguments are stored as packed components within a larger natural type.

The commands containing L indicate that the arguments are full 64-bit quantities and should be passed directly to shader inputs declared as 64-bit double precision types.

OpenGL Shading Language attribute variables are allowed to be of type mat2, mat3, or mat4. Attributes of these types may be loaded using the gl:vertexAttrib entry points. Matrices must be loaded into successive generic attribute slots in column major order, with one column of the matrix in each generic attribute slot.

A user-defined attribute variable declared in a vertex shader can be bound to a generic attribute index by calling gl:bindAttribLocation/3 . This allows an application to use more descriptive variable names in a vertex shader. A subsequent change to the specified generic vertex attribute will be immediately reflected as a change to the corresponding attribute variable in the vertex shader.

Index = integer()

X = integer()

Y = integer()

Z = integer()

W = integer()

vertexAttrib4Nubv(Index::integer(), V) -> ok

Index = integer()

X = float()

Y = float()

Z = float()

Types

Index = integer()

X = integer()

Y = integer()

Z = integer()

W = integer()

vertexAttrib4sv(Index::integer(), V) -> ok

Index = integer()

Size = integer()

Type = enum()

Normalized = 0 | 1

Stride = integer()

Pointer = offset() | mem()

Define an array of generic vertex attribute data

gl:vertexAttribPointer, gl:vertexAttribIPointer and gl:vertexAttribLPointer specify the location and data format of the array of generic vertex attributes at index Index to use when rendering. Size specifies the number of components per attribute and must be 1, 2, 3, 4, or ?GL_BGRA. Type specifies the data type of each component, and Stride specifies the byte stride from one attribute to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays.

For gl:vertexAttribPointer, if Normalized is set to ?GL_TRUE, it indicates that values stored in an integer format are to be mapped to the range [-1,1] (for signed values) or [0,1] (for unsigned values) when they are accessed and converted to floating point. Otherwise, values will be converted to floats directly without normalization.

For gl:vertexAttribIPointer, only the integer types ?GL_BYTE, ?GL_UNSIGNED_BYTE , ?GL_SHORT, ?GL_UNSIGNED_SHORT, ?GL_INT, ?GL_UNSIGNED_INT are accepted. Values are always left as integer values.

gl:vertexAttribLPointer specifies state for a generic vertex attribute array associated with a shader attribute variable declared with 64-bit double precision components. Type must be ?GL_DOUBLE. Index , Size , and Stride behave as described for gl:vertexAttribPointer and gl:vertexAttribIPointer.

See external documentation.

getBooleani_v(Target, Index) -> [0 | 1]

Types

Target = enum()

Index = integer()

getIntegeri_v(Target, Index) -> [integer()]

Types

Target = enum()

Index = integer()

enablei(Target, Index) -> ok

PrimitiveMode = enum()

Start transform feedback operation

Transform feedback mode captures the values of varying variables written by the vertex shader (or, if active, the geometry shader). Transform feedback is said to be active after a call to gl:beginTransformFeedback until a subsequent call to gl:beginTransformFeedback/1 . Transform feedback commands must be paired.

If no geometry shader is present, while transform feedback is active the Mode parameter to gl:drawArrays/3 must match those specified in the following table:

Transform Feedback PrimitiveMode Allowed Render Primitive Modes
?GL_POINTS?GL_POINTS
?GL_LINES?GL_LINES, ?GL_LINE_LOOP, ?GL_LINE_STRIP , ?GL_LINES_ADJACENCY, ?GL_LINE_STRIP_ADJACENCY
?GL_TRIANGLES ?GL_TRIANGLES, ?GL_TRIANGLE_STRIP, ?GL_TRIANGLE_FAN, ?GL_TRIANGLES_ADJACENCY , ?GL_TRIANGLE_STRIP_ADJACENCY

If a geometry shader is present, the output primitive type from the geometry shader must match those provided in the following table:

Transform Feedback PrimitiveMode Allowed Geometry Shader Output Primitive Type
?GL_POINTS?points
?GL_LINES ?line_strip
?GL_TRIANGLES?triangle_strip

See external documentation.

endTransformFeedback() -> ok

See beginTransformFeedback/1

bindBufferRange(Target, Index, Buffer, Offset, Size) -> ok

Types

Target = enum()

Index = integer()

Buffer = integer()

Offset = integer()

Size = integer()

Bind a range within a buffer object to an indexed buffer target

gl:bindBufferRange binds a range the buffer object Buffer represented by Offset and Size to the binding point at index Index of the array of targets specified by Target . Each Target represents an indexed array of buffer binding points, as well as a single general binding point that can be used by other buffer manipulation functions such as gl:bindBuffer/2 or see glMapBuffer. In addition to binding a range of Buffer to the indexed buffer binding target, gl:bindBufferBase also binds the range to the generic buffer binding point specified by Target .

Offset specifies the offset in basic machine units into the buffer object Buffer and Size specifies the amount of data that can be read from the buffer object while used as an indexed target.

See external documentation.

bindBufferBase(Target, Index, Buffer) -> ok

Types

Target = enum()

Index = integer()

Buffer = integer()

Bind a buffer object to an indexed buffer target

gl:bindBufferBase binds the buffer object Buffer to the binding point at index Index of the array of targets specified by Target . Each Target represents an indexed array of buffer binding points, as well as a single general binding point that can be used by other buffer manipulation functions such as gl:bindBuffer/2 or see glMapBuffer. In addition to binding Buffer to the indexed buffer binding target, gl:bindBufferBase also binds Buffer to the generic buffer binding point specified by Target .

See external documentation.

transformFeedbackVaryings(Program, Varyings, BufferMode) -> ok

Types

Program = integer()

Varyings = iolist()

BufferMode = enum()

Specify values to record in transform feedback buffers

The names of the vertex or geometry shader outputs to be recorded in transform feedback mode are specified using gl:transformFeedbackVaryings. When a geometry shader is active, transform feedback records the values of selected geometry shader output variables from the emitted vertices. Otherwise, the values of the selected vertex shader outputs are recorded.

The state set by gl:tranformFeedbackVaryings is stored and takes effect next time gl:linkProgram/1 is called on Program . When gl:linkProgram/1 is called, Program is linked so that the values of the specified varying variables for the vertices of each primitive generated by the GL are written to a single buffer object if BufferMode is ?GL_INTERLEAVED_ATTRIBS or multiple buffer objects if BufferMode is ?GL_SEPARATE_ATTRIBS .

In addition to the errors generated by gl:transformFeedbackVaryings, the program Program will fail to link if:

The count specified by gl:transformFeedbackVaryings is non-zero, but the program object has no vertex or geometry shader.

Any variable name specified in the Varyings array is not declared as an output in the vertex shader (or the geometry shader, if active).

Any two entries in the Varyings array specify the same varying variable.

The total number of components to capture in any varying variable in Varyings is greater than the constant ?GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS and the buffer mode is ?GL_SEPARATE_ATTRIBS.

The total number of components to capture is greater than the constant ?GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS and the buffer mode is ?GL_INTERLEAVED_ATTRIBS.

See external documentation.

getTransformFeedbackVarying(Program, Index, BufSize) -> {Size::integer(), Type::enum(), Name::string()}

Types

Program = integer()

Index = integer()

BufSize = integer()

Retrieve information about varying variables selected for transform feedback

Information about the set of varying variables in a linked program that will be captured during transform feedback may be retrieved by calling gl:getTransformFeedbackVarying. gl:getTransformFeedbackVarying provides information about the varying variable selected by Index . An Index of 0 selects the first varying variable specified in the Varyings array passed to gl:transformFeedbackVaryings/3 , and an Index of ?GL_TRANSFORM_FEEDBACK_VARYINGS-1 selects the last such variable.

The name of the selected varying is returned as a null-terminated string in Name . The actual number of characters written into Name , excluding the null terminator, is returned in Length . If Length is NULL, no length is returned. The maximum number of characters that may be written into Name , including the null terminator, is specified by BufSize .

The length of the longest varying name in program is given by ?GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH , which can be queried with gl:getProgramiv/2 .

For the selected varying variable, its type is returned into Type . The size of the varying is returned into Size . The value in Size is in units of the type returned in Type . The type returned can be any of the scalar, vector, or matrix attribute types returned by gl:getActiveAttrib/3 . If an error occurred, the return parameters Length , Size , Type and Name will be unmodified. This command will return as much information about the varying variables as possible. If no information is available, Length will be set to zero and Name will be an empty string. This situation could arise if gl:getTransformFeedbackVarying is called after a failed link.

See external documentation.

clampColor(Target, Clamp) -> ok

Types

Target = enum()

Clamp = enum()

specify whether data read via

gl:readPixels/7 should be clamped

gl:clampColor controls color clamping that is performed during gl:readPixels/7 . Target must be ?GL_CLAMP_READ_COLOR. If Clamp is ?GL_TRUE, read color clamping is enabled; if Clamp is ?GL_FALSE, read color clamping is disabled. If Clamp is ?GL_FIXED_ONLY, read color clamping is enabled only if the selected read buffer has fixed point components and disabled otherwise.

See external documentation.

beginConditionalRender(Id, Mode) -> ok

Types

Id = integer()

Mode = enum()

Start conditional rendering

Conditional rendering is started using gl:beginConditionalRender and ended using gl:endConditionalRender . During conditional rendering, all vertex array commands, as well as gl:clear/1 and gl:clearBufferiv/3 have no effect if the (?GL_SAMPLES_PASSED) result of the query object Id is zero, or if the (?GL_ANY_SAMPLES_PASSED) result is ?GL_FALSE . The results of commands setting the current vertex state, such as gl:vertexAttrib1d/2 are undefined. If the (?GL_SAMPLES_PASSED) result is non-zero or if the (?GL_ANY_SAMPLES_PASSED ) result is ?GL_TRUE, such commands are not discarded. The Id parameter to gl:beginConditionalRender must be the name of a query object previously returned from a call to gl:genQueries/1 . Mode specifies how the results of the query object are to be interpreted. If Mode is ?GL_QUERY_WAIT, the GL waits for the results of the query to be available and then uses the results to determine if subsequent rendering commands are discarded. If Mode is ?GL_QUERY_NO_WAIT, the GL may choose to unconditionally execute the subsequent rendering commands without waiting for the query to complete.

If Mode is ?GL_QUERY_BY_REGION_WAIT, the GL will also wait for occlusion query results and discard rendering commands if the result of the occlusion query is zero. If the query result is non-zero, subsequent rendering commands are executed, but the GL may discard the results of the commands for any region of the framebuffer that did not contribute to the sample count in the specified occlusion query. Any such discarding is done in an implementation-dependent manner, but the rendering command results may not be discarded for any samples that contributed to the occlusion query sample count. If Mode is ?GL_QUERY_BY_REGION_NO_WAIT, the GL operates as in ?GL_QUERY_BY_REGION_WAIT , but may choose to unconditionally execute the subsequent rendering commands without waiting for the query to complete.

See external documentation.

endConditionalRender() -> ok

See beginConditionalRender/2

vertexAttribIPointer(Index, Size, Type, Stride, Pointer) -> ok

Types

Index = integer()

Size = integer()

Type = enum()

vertexAttribI4i(Index, X, Y, Z, W) -> ok

Types

Index = integer()

X = integer()

Y = integer()

Z = integer()

W = integer()

vertexAttribI1ui(Index, X) -> ok

Types

Index = integer()

X = integer()

vertexAttribI2ui(Index, X, Y) -> ok

Types

Index = integer()

X = integer()

Y = integer()

vertexAttribI3ui(Index, X, Y, Z) -> ok

Types

Index = integer()

X = integer()

Y = integer()

Z = integer()

vertexAttribI4ui(Index, X, Y, Z, W) -> ok

Types

Index = integer()

X = integer()

Y = integer()

Z = integer()

Program = integer()

Color = integer()

Name = string()

Bind a user-defined varying out variable to a fragment shader color number

gl:bindFragDataLocation explicitly specifies the binding of the user-defined varying out variable Name to fragment shader color number ColorNumber for program Program . If Name was bound previously, its assigned binding is replaced with ColorNumber . Name must be a null-terminated string. ColorNumber must be less than ?GL_MAX_DRAW_BUFFERS .

The bindings specified by gl:bindFragDataLocation have no effect until Program is next linked. Bindings may be specified at any time after Program has been created. Specifically, they may be specified before shader objects are attached to the program. Therefore, any name may be specified in Name , including a name that is never used as a varying out variable in any fragment shader object. Names beginning with ?gl_ are reserved by the GL.

In addition to the errors generated by gl:bindFragDataLocation, the program Program will fail to link if:

The number of active outputs is greater than the value ?GL_MAX_DRAW_BUFFERS.

More than one varying out variable is bound to the same color number.

See external documentation.

getFragDataLocation(Program, Name) -> integer()

Types

Program = integer()

Name = string()

Query the bindings of color numbers to user-defined varying out variables

gl:getFragDataLocation retrieves the assigned color number binding for the user-defined varying out variable Name for program Program . Program must have previously been linked. Name must be a null-terminated string. If Name is not the name of an active user-defined varying out fragment shader variable within Program , -1 will be returned.

See external documentation.

uniform1ui(Location, V0) -> ok

Types

Location = integer()

V0 = integer()

uniform2ui(Location, V0, V1) -> ok

Types

Location = integer()

V0 = integer()

V1 = integer()

uniform3ui(Location, V0, V1, V2) -> ok

Types

Location = integer()

V0 = integer()

V1 = integer()

V2 = integer()

uniform4ui(Location, V0, V1, V2, V3) -> ok

Types

Location = integer()

V0 = integer()

V1 = integer()

Types

Target = enum()

Pname = enum()

Params = tuple()

glTexParameterI

See external documentation.

getTexParameterIiv(Target, Pname) -> {integer(), integer(), integer(), integer()}

Types

Drawbuffer = integer()

Depth = float()

Stencil = integer()

glClearBufferfi

See external documentation.

getStringi(Name, Index) -> string()

Types

Name = enum()

Index = integer()

See getString/1

drawArraysInstanced(Mode, First, Count, Primcount) -> ok

Types

Mode = enum()

First = integer()

Count = integer()

Primcount = integer()

glDrawArraysInstance

See external documentation.

drawElementsInstanced(Mode, Count, Type, Indices, Primcount) -> ok

Types

Mode = enum()

Count = integer()

Type = enum()

Indices = offset() | mem()

Primcount = integer()

glDrawElementsInstance

See external documentation.

texBuffer(Target, Internalformat, Buffer) -> ok

Types

Target = enum()

Internalformat = enum()

Buffer = integer()

Attach the storage for a buffer object to the active buffer texture

gl:texBuffer attaches the storage for the buffer object named Buffer to the active buffer texture, and specifies the internal format for the texel array found in the attached buffer object. If Buffer is zero, any buffer object attached to the buffer texture is detached and no new buffer object is attached. If Buffer is non-zero, it must be the name of an existing buffer object. Target must be ?GL_TEXTURE_BUFFER . Internalformat specifies the storage format, and must be one of the following sized internal formats:

Component
Sized Internal FormatBase Type ComponentsNorm0123
?GL_R8ubyte1YESR00 1
?GL_R16ushort1YESR 001
?GL_R16Fhalf1NO R001
?GL_R32Ffloat 1NOR001
?GL_R8I byte1NOR001
?GL_R16I short1NOR001
?GL_R32Iint1NOR001
?GL_R8UIubyte1NOR0 01
?GL_R16UIushort1NO R001
?GL_R32UIuint1 NOR001
?GL_RG8ubyte 2YESRG01
?GL_RG16 ushort2YESRG01
?GL_RG16Fhalf2NORG0 1
?GL_RG32Ffloat2NORG 01
?GL_RG8Ibyte2NO RG01
?GL_RG16Ishort 2NORG01
?GL_RG32I int2NORG01
?GL_RG8UI ubyte2NORG01
?GL_RG16UIushort2NORG0 1
?GL_RG32UIuint2NORG 01
?GL_RGB32Ffloat3NO RGB1
?GL_RGB32Iint 3NORGB1
?GL_RGB32UI uint3NORGB1
?GL_RGBA8uint4YESRGB A
?GL_RGBA16short4YESR GBA
?GL_RGBA16Fhalf4NO RGBA
?GL_RGBA32Ffloat 4NORGBA
?GL_RGBA8I byte4NORGBA
?GL_RGBA16Ishort4NORGB A
?GL_RGBA32Iint4NORG BA
?GL_RGBA8UIubyte4NO RGBA
?GL_RGBA16UIushort 4NORGBA
?GL_RGBA32UI uint4NORGBA

When a buffer object is attached to a buffer texture, the buffer object's data store is taken as the texture's texel array. The number of texels in the buffer texture's texel array is given by buffer_size components×sizeof( base_type/)

where buffer_size is the size of the buffer object, in basic machine units and components and base type are the element count and base data type for elements, as specified in the table above. The number of texels in the texel array is then clamped to the implementation-dependent limit ?GL_MAX_TEXTURE_BUFFER_SIZE. When a buffer texture is accessed in a shader, the results of a texel fetch are undefined if the specified texel coordinate is negative, or greater than or equal to the clamped number of texels in the texel array.

See external documentation.

primitiveRestartIndex(Index) -> ok

Types

Index = integer()

Specify the primitive restart index

gl:primitiveRestartIndex specifies a vertex array element that is treated specially when primitive restarting is enabled. This is known as the primitive restart index.

When one of the Draw* commands transfers a set of generic attribute array elements to the GL, if the index within the vertex arrays corresponding to that set is equal to the primitive restart index, then the GL does not process those elements as a vertex. Instead, it is as if the drawing command ended with the immediately preceding transfer, and another drawing command is immediately started with the same parameters, but only transferring the immediately following element through the end of the originally specified elements.

When either gl:drawElementsBaseVertex/5 , gl:drawElementsInstancedBaseVertex/6 or see glMultiDrawElementsBaseVertex is used, the primitive restart comparison occurs before the basevertex offset is added to the array index.

See external documentation.

getInteger64i_v(Target, Index) -> [integer()]

Types

Target = enum()

Index = integer()

getBufferParameteri64v(Target, Pname) -> [integer()]

Types

Target = enum()

Pname = enum()

glGetBufferParameteri64v

See external documentation.

framebufferTexture(Target, Attachment, Texture, Level) -> ok

Types

Target = enum()

Attachment = enum()

Texture = integer()

Level = integer()

Attach a level of a texture object as a logical buffer to the currently bound framebuffer object

gl:framebufferTexture, gl:framebufferTexture1D, gl:framebufferTexture2D, and gl:framebufferTexture attach a selected mipmap level or image of a texture object as one of the logical buffers of the framebuffer object currently bound to Target . Target must be ?GL_DRAW_FRAMEBUFFER, ?GL_READ_FRAMEBUFFER, or ?GL_FRAMEBUFFER . ?GL_FRAMEBUFFER is equivalent to ?GL_DRAW_FRAMEBUFFER.

Attachment specifies the logical attachment of the framebuffer and must be ?GL_COLOR_ATTACHMENT i, ?GL_DEPTH_ATTACHMENT, ?GL_STENCIL_ATTACHMENT or ?GL_DEPTH_STENCIL_ATTACHMMENT . i in ?GL_COLOR_ATTACHMENTi may range from zero to the value of ?GL_MAX_COLOR_ATTACHMENTS - 1. Attaching a level of a texture to ?GL_DEPTH_STENCIL_ATTACHMENT is equivalent to attaching that level to both the ?GL_DEPTH_ATTACHMENTand the ?GL_STENCIL_ATTACHMENT attachment points simultaneously.

Textarget specifies what type of texture is named by Texture , and for cube map textures, specifies the face that is to be attached. If Texture is not zero, it must be the name of an existing texture with type Textarget , unless it is a cube map texture, in which case Textarget must be ?GL_TEXTURE_CUBE_MAP_POSITIVE_X ?GL_TEXTURE_CUBE_MAP_NEGATIVE_X, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Y, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Y , ?GL_TEXTURE_CUBE_MAP_POSITIVE_Z, or ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.

If Texture is non-zero, the specified Level of the texture object named Texture is attached to the framebfufer attachment point named by Attachment . For gl:framebufferTexture1D , gl:framebufferTexture2D, and gl:framebufferTexture3D, Texture must be zero or the name of an existing texture with a target of Textarget , or Texture must be the name of an existing cube-map texture and Textarget must be one of ?GL_TEXTURE_CUBE_MAP_POSITIVE_X , ?GL_TEXTURE_CUBE_MAP_POSITIVE_Y, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Z, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_X , ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, or ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.

If Textarget is ?GL_TEXTURE_RECTANGLE, ?GL_TEXTURE_2D_MULTISAMPLE, or ?GL_TEXTURE_2D_MULTISAMPLE_ARRAY, then Level must be zero. If Textarget is ?GL_TEXTURE_3D, then level must be greater than or equal to zero and less than or equal to log2 of the value of ?GL_MAX_3D_TEXTURE_SIZE. If Textarget is one of ?GL_TEXTURE_CUBE_MAP_POSITIVE_X, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Y, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Z , ?GL_TEXTURE_CUBE_MAP_NEGATIVE_X, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, or ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Z , then Level must be greater than or equal to zero and less than or equal to log2 of the value of ?GL_MAX_CUBE_MAP_TEXTURE_SIZE. For all other values of Textarget , Level must be greater than or equal to zero and no larger than log2 of the value of ?GL_MAX_TEXTURE_SIZE.

Layer specifies the layer of a 2-dimensional image within a 3-dimensional texture.

For gl:framebufferTexture1D, if Texture is not zero, then Textarget must be ?GL_TEXTURE_1D. For gl:framebufferTexture2D, if Texture is not zero, Textarget must be one of ?GL_TEXTURE_2D, ?GL_TEXTURE_RECTANGLE , ?GL_TEXTURE_CUBE_MAP_POSITIVE_X, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Y, ?GL_TEXTURE_CUBE_MAP_POSITIVE_Z , ?GL_TEXTURE_CUBE_MAP_NEGATIVE_X, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, ?GL_TEXTURE_CUBE_MAP_NEGATIVE_Z , or ?GL_TEXTURE_2D_MULTISAMPLE. For gl:framebufferTexture3D, if Texture is not zero, then Textarget must be ?GL_TEXTURE_3D.

See external documentation.

vertexAttribDivisor(Index, Divisor) -> ok

Types

Index = integer()

Divisor = integer()

Modify the rate at which generic vertex attributes advance during instanced rendering

gl:vertexAttribDivisor modifies the rate at which generic vertex attributes advance when rendering multiple instances of primitives in a single draw call. If Divisor is zero, the attribute at slot Index advances once per vertex. If Divisor is non-zero, the attribute advances once per Divisor instances of the set(s) of vertices being rendered. An attribute is referred to as instanced if its ?GL_VERTEX_ATTRIB_ARRAY_DIVISOR value is non-zero.

Index must be less than the value of ?GL_MAX_VERTEX_ATTRIBUTES.

See external documentation.

minSampleShading(Value) -> ok

Types

Value = clamp()

Specifies minimum rate at which sample shaing takes place

gl:minSampleShading specifies the rate at which samples are shaded within a covered pixel. Sample-rate shading is enabled by calling gl:enable/1 with the parameter ?GL_SAMPLE_SHADING . If ?GL_MULTISAMPLE or ?GL_SAMPLE_SHADING is disabled, sample shading has no effect. Otherwise, an implementation must provide at least as many unique color values for each covered fragment as specified by Value times Samples where Samples is the value of ?GL_SAMPLES for the current framebuffer. At least 1 sample for each covered fragment is generated.

A Value of 1.0 indicates that each sample in the framebuffer should be indpendently shaded. A Value of 0.0 effectively allows the GL to ignore sample rate shading. Any value between 0.0 and 1.0 allows the GL to shade only a subset of the total samples within each covered fragment. Which samples are shaded and the algorithm used to select that subset of the fragment's samples is implementation dependent.

See external documentation.

blendEquationi(Buf, Mode) -> ok

Types

Buf = integer()

Mode = enum()

See blendEquation/1

blendEquationSeparatei(Buf, ModeRGB, ModeAlpha) -> ok

Types

Buf = integer()

ModeRGB = enum()

ModeAlpha = enum()

See blendEquationSeparate/2

blendFunci(Buf, Src, Dst) -> ok

Types

Buf = integer()

Src = enum()

Dst = enum()

glBlendFunci

See external documentation.

blendFuncSeparatei(Buf, SrcRGB, DstRGB, SrcAlpha, DstAlpha) -> ok

Types

Buf = integer()

SrcRGB = enum()

DstRGB = enum()

Target = enum()

Format = enum()

String = string()

glProgramStringARB

See external documentation.

bindProgramARB(Target, Program) -> ok

Types

Target = enum()

programEnvParameter4fARB(Target, Index, X, Y, Z, W) -> ok

Types

Target = enum()

Index = integer()

X = float()

Y = float()

Z = float()

W = float()

glProgramEnvParameterARB

See external documentation.

programEnvParameter4fvARB(Target, Index, Params) -> ok

Types

Target = enum()

Index = integer()

Params = {float(), float(), float(), float()}

glProgramEnvParameterARB

See external documentation.

programLocalParameter4dARB(Target, Index, X, Y, Z, W) -> ok

Types

Target = enum()

Index = integer()

X = float()

Y = float()

Z = float()

W = float()

glProgramLocalParameterARB

See external documentation.

programLocalParameter4dvARB(Target, Index, Params) -> ok

Types

Target = enum()

Index = integer()

Params = {float(), float(), float(), float()}

glProgramLocalParameterARB

See external documentation.

programLocalParameter4fARB(Target, Index, X, Y, Z, W) -> ok

Types

Target = enum()

Index = integer()

X = float()

Y = float()

Z = float()

W = float()

glProgramLocalParameterARB

See external documentation.

programLocalParameter4fvARB(Target, Index, Params) -> ok

Types

Target = enum()

Types

Target = enum()

Pname = enum()

glGetBufferParameterARB

See external documentation.

deleteObjectARB(Obj) -> ok

Types

attachObjectARB(ContainerObj, Obj) -> ok

Types

ContainerObj = integer()

Obj = integer()

glAttachObjectARB

See external documentation.

linkProgramARB(ProgramObj) -> ok

Types

ProgramObj = integer()

glLinkProgramARB

See external documentation.

useProgramObjectARB(ProgramObj) -> ok

Types

ProgramObj = integer()

glUseProgramObjectARB

See external documentation.

validateProgramARB(ProgramObj) -> ok

ProgramObj = integer()

Index = integer()

MaxLength = integer()

glGetActiveUniformARB

See external documentation.

getUniformfvARB(ProgramObj, Location) -> matrix()

Types

ProgramObj = integer()

Location = integer()

glGetUniformARB

See external documentation.

getUniformivARB(ProgramObj, Location) -> {integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer()}

Types

ProgramObj = integer()

Location = integer()

glGetUniformARB

See external documentation.

getShaderSourceARB(Obj, MaxLength) -> string()

ProgramObj = integer()

Name = string()

glGetAttribLocationARB

See external documentation.

isRenderbuffer(Renderbuffer) -> 0 | 1

N = integer()

Generate renderbuffer object names

gl:genRenderbuffers returns N renderbuffer object names in Renderbuffers . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genRenderbuffers .

Renderbuffer object names returned by a call to gl:genRenderbuffers are not returned by subsequent calls, unless they are first deleted with gl:deleteRenderbuffers/1 .

The names returned in Renderbuffers are marked as used, for the purposes of gl:genRenderbuffers only, but they acquire state and type only when they are first bound.

See external documentation.

renderbufferStorage(Target, Internalformat, Width, Height) -> ok

Types

Target = enum()

Internalformat = enum()

Width = integer()

Height = integer()

Establish data storage, format and dimensions of a renderbuffer object's image

gl:renderbufferStorage is equivalent to calling gl:renderbufferStorageMultisample/5 with the Samples set to zero.

Upon success, gl:renderbufferStorage deletes any existing data store for the renderbuffer image and the contents of the data store after calling gl:renderbufferStorage are undefined.

See external documentation.

getRenderbufferParameteriv(Target, Pname) -> integer()

Types

Target = enum()

Pname = enum()

Retrieve information about a bound renderbuffer object

gl:getRenderbufferParameteriv retrieves information about a bound renderbuffer object. Target specifies the target of the query operation and must be ?GL_RENDERBUFFER . Pname specifies the parameter whose value to query and must be one of ?GL_RENDERBUFFER_WIDTH , ?GL_RENDERBUFFER_HEIGHT, ?GL_RENDERBUFFER_INTERNAL_FORMAT, ?GL_RENDERBUFFER_RED_SIZE , ?GL_RENDERBUFFER_GREEN_SIZE, ?GL_RENDERBUFFER_BLUE_SIZE, ?GL_RENDERBUFFER_ALPHA_SIZE , ?GL_RENDERBUFFER_DEPTH_SIZE, ?GL_RENDERBUFFER_DEPTH_SIZE, ?GL_RENDERBUFFER_STENCIL_SIZE , or ?GL_RENDERBUFFER_SAMPLES.

Upon a successful return from gl:getRenderbufferParameteriv, if Pname is ?GL_RENDERBUFFER_WIDTH , ?GL_RENDERBUFFER_HEIGHT, ?GL_RENDERBUFFER_INTERNAL_FORMAT, or ?GL_RENDERBUFFER_SAMPLES , then Params will contain the width in pixels, the height in pixels, the internal format, or the number of samples, respectively, of the image of the renderbuffer currently bound to Target .

If Pname is ?GL_RENDERBUFFER_RED_SIZE, ?GL_RENDERBUFFER_GREEN_SIZE, ?GL_RENDERBUFFER_BLUE_SIZE, ?GL_RENDERBUFFER_ALPHA_SIZE, ?GL_RENDERBUFFER_DEPTH_SIZE , or ?GL_RENDERBUFFER_STENCIL_SIZE, then Params will contain the actual resolutions (not the resolutions specified when the image array was defined) for the red, green, blue, alpha depth, or stencil components, respectively, of the image of the renderbuffer currently bound to Target .

See external documentation.

isFramebuffer(Framebuffer) -> 0 | 1

Types

Framebuffer = integer()

Determine if a name corresponds to a framebuffer object

gl:isFramebuffer returns ?GL_TRUE if Framebuffer is currently the name of a framebuffer object. If Framebuffer is zero, or if ?framebuffer is not the name of a framebuffer object, or if an error occurs, gl:isFramebuffer returns ?GL_FALSE. If Framebuffer is a name returned by gl:genFramebuffers/1 , by that has not yet been bound through a call to gl:bindFramebuffer/2 , then the name is not a framebuffer object and gl:isFramebuffer returns ?GL_FALSE.

See external documentation.

bindFramebuffer(Target, Framebuffer) -> ok

Types

Target = enum()

Framebuffer = integer()

Bind a framebuffer to a framebuffer target

gl:bindFramebuffer binds the framebuffer object with name Framebuffer to the framebuffer target specified by Target . Target must be either ?GL_DRAW_FRAMEBUFFER , ?GL_READ_FRAMEBUFFER or ?GL_FRAMEBUFFER. If a framebuffer object is bound to ?GL_DRAW_FRAMEBUFFER or ?GL_READ_FRAMEBUFFER, it becomes the target for rendering or readback operations, respectively, until it is deleted or another framebuffer is bound to the corresponding bind point. Calling gl:bindFramebuffer with Target set to ?GL_FRAMEBUFFER binds Framebuffer to both the read and draw framebuffer targets. Framebuffer is the name of a framebuffer object previously returned from a call to gl:genFramebuffers/1 , or zero to break the existing binding of a framebuffer object to Target .

See external documentation.

deleteFramebuffers(Framebuffers) -> ok

Types

Framebuffers = [integer()]

Delete framebuffer objects

gl:deleteFramebuffers deletes the N framebuffer objects whose names are stored in the array addressed by Framebuffers . The name zero is reserved by the GL and is silently ignored, should it occur in Framebuffers , as are other unused names. Once a framebuffer object is deleted, its name is again unused and it has no attachments. If a framebuffer that is currently bound to one or more of the targets ?GL_DRAW_FRAMEBUFFER or ?GL_READ_FRAMEBUFFER is deleted, it is as though gl:bindFramebuffer/2 had been executed with the corresponding Target and Framebuffer zero.

See external documentation.

genFramebuffers(N) -> [integer()]

Types

N = integer()

Generate framebuffer object names

gl:genFramebuffers returns N framebuffer object names in Ids . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genFramebuffers .

Framebuffer object names returned by a call to gl:genFramebuffers are not returned by subsequent calls, unless they are first deleted with gl:deleteFramebuffers/1 .

The names returned in Ids are marked as used, for the purposes of gl:genFramebuffers only, but they acquire state and type only when they are first bound.

See external documentation.

checkFramebufferStatus(Target) -> enum()

Types

Target = enum()

Check the completeness status of a framebuffer

gl:checkFramebufferStatus queries the completeness status of the framebuffer object currently bound to Target . Target must be ?GL_DRAW_FRAMEBUFFER, ?GL_READ_FRAMEBUFFER or ?GL_FRAMEBUFFER. ?GL_FRAMEBUFFER is equivalent to ?GL_DRAW_FRAMEBUFFER .

The return value is ?GL_FRAMEBUFFER_COMPLETE if the framebuffer bound to Target is complete. Otherwise, the return value is determined as follows:

?GL_FRAMEBUFFER_UNDEFINED is returned if Target is the default framebuffer, but the default framebuffer does not exist.

?GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT is returned if any of the framebuffer attachment points are framebuffer incomplete.

?GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT is returned if the framebuffer does not have at least one image attached to it.

?GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER is returned if the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is ?GL_NONE for any color attachment point(s) named by ?GL_DRAWBUFFERi.

?GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER is returned if ?GL_READ_BUFFER is not ?GL_NONE and the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is ?GL_NONE for the color attachment point named by ?GL_READ_BUFFER.

?GL_FRAMEBUFFER_UNSUPPORTED is returned if the combination of internal formats of the attached images violates an implementation-dependent set of restrictions.

?GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE is returned if the value of ?GL_RENDERBUFFER_SAMPLES is not the same for all attached renderbuffers; if the value of ?GL_TEXTURE_SAMPLES is the not same for all attached textures; or, if the attached images are a mix of renderbuffers and textures, the value of ?GL_RENDERBUFFER_SAMPLES does not match the value of ?GL_TEXTURE_SAMPLES .

?GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE is also returned if the value of ?GL_TEXTURE_FIXED_SAMPLE_LOCATIONS is not the same for all attached textures; or, if the attached images are a mix of renderbuffers and textures, the value of ?GL_TEXTURE_FIXED_SAMPLE_LOCATIONS is not ?GL_TRUE for all attached textures.

?GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS is returned if any framebuffer attachment is layered, and any populated attachment is not layered, or if all populated color attachments are not from textures of the same target.

Additionally, if an error occurs, zero is returned.

See external documentation.

framebufferTexture1D(Target, Attachment, Textarget, Texture, Level) -> ok

Types

Target = enum()

Attachment = enum()

Textarget = enum()

Texture = integer()

Level = integer()

framebufferTexture2D(Target, Attachment, Textarget, Texture, Level) -> ok

Types

Target = enum()

Attachment = enum()

Textarget = enum()

Texture = integer()

Level = integer()

framebufferTexture3D(Target, Attachment, Textarget, Texture, Level, Zoffset) -> ok

Types

Target = enum()

Attachment = enum()

Textarget = enum()

Texture = integer()

Level = integer()

Zoffset = integer()

framebufferRenderbuffer(Target, Attachment, Renderbuffertarget, Renderbuffer) -> ok

Types

Target = enum()

Attachment = enum()

Renderbuffertarget = enum()

Renderbuffer = integer()

Attach a renderbuffer as a logical buffer to the currently bound framebuffer object

gl:framebufferRenderbuffer attaches a renderbuffer as one of the logical buffers of the currently bound framebuffer object. Renderbuffer is the name of the renderbuffer object to attach and must be either zero, or the name of an existing renderbuffer object of type Renderbuffertarget . If Renderbuffer is not zero and if gl:framebufferRenderbuffer is successful, then the renderbuffer name Renderbuffer will be used as the logical buffer identified by Attachment of the framebuffer currently bound to Target .

The value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE for the specified attachment point is set to ?GL_RENDERBUFFER and the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME is set to Renderbuffer . All other state values of the attachment point specified by Attachment are set to their default values. No change is made to the state of the renderbuuffer object and any previous attachment to the Attachment logical buffer of the framebuffer Target is broken.

Calling gl:framebufferRenderbuffer with the renderbuffer name zero will detach the image, if any, identified by Attachment , in the framebuffer currently bound to Target . All state values of the attachment point specified by attachment in the object bound to target are set to their default values.

Setting Attachment to the value ?GL_DEPTH_STENCIL_ATTACHMENT is a special case causing both the depth and stencil attachments of the framebuffer object to be set to Renderbuffer , which should have the base internal format ?GL_DEPTH_STENCIL .

See external documentation.

getFramebufferAttachmentParameteriv(Target, Attachment, Pname) -> integer()

Types

Target = enum()

Attachment = enum()

Pname = enum()

Retrieve information about attachments of a bound framebuffer object

gl:getFramebufferAttachmentParameter returns information about attachments of a bound framebuffer object. Target specifies the framebuffer binding point and must be ?GL_DRAW_FRAMEBUFFER, ?GL_READ_FRAMEBUFFER or ?GL_FRAMEBUFFER. ?GL_FRAMEBUFFER is equivalent to ?GL_DRAW_FRAMEBUFFER.

If the default framebuffer is bound to Target then Attachment must be one of ?GL_FRONT_LEFT, ?GL_FRONT_RIGHT, ?GL_BACK_LEFT, or ?GL_BACK_RIGHT , identifying a color buffer, ?GL_DEPTH, identifying the depth buffer, or ?GL_STENCIL , identifying the stencil buffer.

If a framebuffer object is bound, then Attachment must be one of ?GL_COLOR_ATTACHMENT i, ?GL_DEPTH_ATTACHMENT, ?GL_STENCIL_ATTACHMENT, or ?GL_DEPTH_STENCIL_ATTACHMENT . i in ?GL_COLOR_ATTACHMENTi must be in the range zero to the value of ?GL_MAX_COLOR_ATTACHMENTS - 1.

If Attachment is ?GL_DEPTH_STENCIL_ATTACHMENT and different objects are bound to the depth and stencil attachment points of Target the query will fail. If the same object is bound to both attachment points, information about that object will be returned.

Upon successful return from gl:getFramebufferAttachmentParameteriv, if Pname is ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, then Params will contain one of ?GL_NONE , ?GL_FRAMEBUFFER_DEFAULT, ?GL_TEXTURE, or ?GL_RENDERBUFFER, identifying the type of object which contains the attached image. Other values accepted for Pname depend on the type of object, as described below.

If the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is ?GL_NONE, no framebuffer is bound to Target . In this case querying Pname ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME will return zero, and all other queries will generate an error.

If the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is not ?GL_NONE, these queries apply to all other framebuffer types:

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE, ?GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE , ?GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE, ?GL_FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE , ?GL_FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE, or ?GL_FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE , then Params will contain the number of bits in the corresponding red, green, blue, alpha, depth, or stencil component of the specified attachment. Zero is returned if the requested component is not present in Attachment .

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE, Params will contain the format of components of the specified attachment, one of ?GL_FLOAT, GL_INT , GL_UNSIGNED_INT , GL_SIGNED_NORMALIZED , or GL_UNSIGNED_NORMALIZED for floating-point, signed integer, unsigned integer, signed normalized fixed-point, or unsigned normalized fixed-point components respectively. Only color buffers may have integer components.

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING, Param will contain the encoding of components of the specified attachment, one of ?GL_LINEAR or ?GL_SRGB for linear or sRGB-encoded components, respectively. Only color buffer components may be sRGB-encoded; such components are treated as described in sections 4.1.7 and 4.1.8. For the default framebuffer, color encoding is determined by the implementation. For framebuffer objects, components are sRGB-encoded if the internal format of a color attachment is one of the color-renderable SRGB formats.

If the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is ?GL_RENDERBUFFER, then:

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME, Params will contain the name of the renderbuffer object which contains the attached image.

If the value of ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is ?GL_TEXTURE, then:

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME, then Params will contain the name of the texture object which contains the attached image.

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL, then Params will contain the mipmap level of the texture object which contains the attached image.

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE and the texture object named ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME is a cube map texture, then Params will contain the cube map face of the cubemap texture object which contains the attached image. Otherwise Params will contain the value zero.

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER and the texture object named ?GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME is a layer of a three-dimensional texture or a one-or two-dimensional array texture, then Params will contain the number of the texture layer which contains the attached image. Otherwise Params will contain the value zero.

If Pname is ?GL_FRAMEBUFFER_ATTACHMENT_LAYERED, then Params will contain ?GL_TRUE if an entire level of a three-dimesional texture, cube map texture, or one-or two-dimensional array texture is attached. Otherwise, Params will contain ?GL_FALSE.

Any combinations of framebuffer type and Pname not described above will generate an error.

See external documentation.

generateMipmap(Target) -> ok

Types

Target = enum()

Generate mipmaps for a specified texture target

gl:generateMipmap generates mipmaps for the texture attached to Target of the active texture unit. For cube map textures, a ?GL_INVALID_OPERATION error is generated if the texture attached to Target is not cube complete.

Mipmap generation replaces texel array levels level base+1 through q with arrays derived from the level base array, regardless of their previous contents. All other mimap arrays, including the level base array, are left unchanged by this computation.

The internal formats of the derived mipmap arrays all match those of the level base array. The contents of the derived arrays are computed by repeated, filtered reduction of the level base array. For one- and two-dimensional texture arrays, each layer is filtered independently.

See external documentation.

blitFramebuffer(SrcX0, SrcY0, SrcX1, SrcY1, DstX0, DstY0, DstX1, DstY1, Mask, Filter) -> ok

Types

SrcX0 = integer()

SrcY0 = integer()

SrcX1 = integer()

SrcY1 = integer()

DstX0 = integer()

DstY0 = integer()

DstX1 = integer()

DstY1 = integer()

Mask = integer()

Filter = enum()

Copy a block of pixels from the read framebuffer to the draw framebuffer

gl:blitFramebuffer transfers a rectangle of pixel values from one region of the read framebuffer to another region in the draw framebuffer. Mask is the bitwise OR of a number of values indicating which buffers are to be copied. The values are ?GL_COLOR_BUFFER_BIT , ?GL_DEPTH_BUFFER_BIT, and ?GL_STENCIL_BUFFER_BIT. The pixels corresponding to these buffers are copied from the source rectangle bounded by the locations ( SrcX0 ; SrcY0 ) and ( SrcX1 ; SrcY1 ) to the destination rectangle bounded by the locations ( DstX0 ; DstY0 ) and ( DstX1 ; DstY1 ). The lower bounds of the rectangle are inclusive, while the upper bounds are exclusive.

The actual region taken from the read framebuffer is limited to the intersection of the source buffers being transferred, which may include the color buffer selected by the read buffer, the depth buffer, and/or the stencil buffer depending on mask. The actual region written to the draw framebuffer is limited to the intersection of the destination buffers being written, which may include multiple draw buffers, the depth buffer, and/or the stencil buffer depending on mask. Whether or not the source or destination regions are altered due to these limits, the scaling and offset applied to pixels being transferred is performed as though no such limits were present.

If the sizes of the source and destination rectangles are not equal, Filter specifies the interpolation method that will be applied to resize the source image , and must be ?GL_NEAREST or ?GL_LINEAR. ?GL_LINEAR is only a valid interpolation method for the color buffer. If Filter is not ?GL_NEAREST and Mask includes ?GL_DEPTH_BUFFER_BIT or ?GL_STENCIL_BUFFER_BIT, no data is transferred and a ?GL_INVALID_OPERATION error is generated.

If Filter is ?GL_LINEAR and the source rectangle would require sampling outside the bounds of the source framebuffer, values are read as if the ?GL_CLAMP_TO_EDGE texture wrapping mode were applied.

When the color buffer is transferred, values are taken from the read buffer of the read framebuffer and written to each of the draw buffers of the draw framebuffer.

If the source and destination rectangles overlap or are the same, and the read and draw buffers are the same, the result of the operation is undefined.

See external documentation.

renderbufferStorageMultisample(Target, Samples, Internalformat, Width, Height) -> ok

Types

Target = enum()

Samples = integer()

Internalformat = enum()

Width = integer()

Height = integer()

Establish data storage, format, dimensions and sample count of a renderbuffer object's image

gl:renderbufferStorageMultisample establishes the data storage, format, dimensions and number of samples of a renderbuffer object's image.

The target of the operation, specified by Target must be ?GL_RENDERBUFFER. Internalformat specifies the internal format to be used for the renderbuffer object's storage and must be a color-renderable, depth-renderable, or stencil-renderable format. Width and Height are the dimensions, in pixels, of the renderbuffer. Both Width and Height must be less than or equal to the value of ?GL_MAX_RENDERBUFFER_SIZE . Samples specifies the number of samples to be used for the renderbuffer object's image, and must be less than or equal to the value of ?GL_MAX_SAMPLES. If Internalformat is a signed or unsigned integer format then Samples must be less than or equal to the value of ?GL_MAX_INTEGER_SAMPLES.

Upon success, gl:renderbufferStorageMultisample deletes any existing data store for the renderbuffer image and the contents of the data store after calling gl:renderbufferStorageMultisample are undefined.

See external documentation.

framebufferTextureLayer(Target, Attachment, Texture, Level, Layer) -> ok

Types

Target = enum()

Attachment = enum()

Texture = integer()

Level = integer()

Layer = integer()

framebufferTextureFaceARB(Target, Attachment, Texture, Level, Face) -> ok

Types

Target = enum()

Attachment = enum()

Texture = integer()

Level = integer()

Face = enum()

flushMappedBufferRange(Target, Offset, Length) -> ok

Types

Target = enum()

Offset = integer()

Length = integer()

Indicate modifications to a range of a mapped buffer

gl:flushMappedBufferRange indicates that modifications have been made to a range of a mapped buffer. The buffer must previously have been mapped with the ?GL_MAP_FLUSH_EXPLICIT flag. Offset and Length indicate the modified subrange of the mapping, in basic units. The specified subrange to flush is relative to the start of the currently mapped range of the buffer. gl:flushMappedBufferRange may be called multiple times to indicate distinct subranges of the mapping which require flushing.

See external documentation.

bindVertexArray(Array) -> ok

Types

Array = integer()

Bind a vertex array object

gl:bindVertexArray binds the vertex array object with name Array . Array is the name of a vertex array object previously returned from a call to gl:genVertexArrays/1 , or zero to break the existing vertex array object binding.

If no vertex array object with name Array exists, one is created when Array is first bound. If the bind is successful no change is made to the state of the vertex array object, and any previous vertex array object binding is broken.

See external documentation.

deleteVertexArrays(Arrays) -> ok

Types

Arrays = [integer()]

Delete vertex array objects

gl:deleteVertexArrays deletes N vertex array objects whose names are stored in the array addressed by Arrays . Once a vertex array object is deleted it has no contents and its name is again unused. If a vertex array object that is currently bound is deleted, the binding for that object reverts to zero and the default vertex array becomes current. Unused names in Arrays are silently ignored, as is the value zero.

See external documentation.

genVertexArrays(N) -> [integer()]

Types

N = integer()

Generate vertex array object names

gl:genVertexArrays returns N vertex array object names in Arrays . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genVertexArrays .

Vertex array object names returned by a call to gl:genVertexArrays are not returned by subsequent calls, unless they are first deleted with gl:deleteVertexArrays/1 .

The names returned in Arrays are marked as used, for the purposes of gl:genVertexArrays only, but they acquire state and type only when they are first bound.

See external documentation.

isVertexArray(Array) -> 0 | 1

Types

Array = integer()

Determine if a name corresponds to a vertex array object

gl:isVertexArray returns ?GL_TRUE if Array is currently the name of a renderbuffer object. If Renderbuffer is zero, or if Array is not the name of a renderbuffer object, or if an error occurs, gl:isVertexArray returns ?GL_FALSE . If Array is a name returned by gl:genVertexArrays/1 , by that has not yet been bound through a call to gl:bindVertexArray/1 , then the name is not a vertex array object and gl:isVertexArray returns ?GL_FALSE.

See external documentation.

getUniformIndices(Program, UniformNames) -> [integer()]

Types

Program = integer()

UniformNames = iolist()

Retrieve the index of a named uniform block

gl:getUniformIndices retrieves the indices of a number of uniforms within Program .

Program must be the name of a program object for which the command gl:linkProgram/1 must have been called in the past, although it is not required that gl:linkProgram/1 must have succeeded. The link could have failed because the number of active uniforms exceeded the limit.

UniformCount indicates both the number of elements in the array of names UniformNames and the number of indices that may be written to UniformIndices .

UniformNames contains a list of UniformCount name strings identifying the uniform names to be queried for indices. For each name string in UniformNames , the index assigned to the active uniform of that name will be written to the corresponding element of UniformIndices . If a string in UniformNames is not the name of an active uniform, the special value ?GL_INVALID_INDEX will be written to the corresponding element of UniformIndices .

If an error occurs, nothing is written to UniformIndices .

See external documentation.

getActiveUniformsiv(Program, UniformIndices, Pname) -> [integer()]

Types

Program = integer()

UniformIndices = [integer()]

Pname = enum()

glGetActiveUniforms

See external documentation.

getActiveUniformName(Program, UniformIndex, BufSize) -> string()

Types

Program = integer()

UniformIndex = integer()

BufSize = integer()

Query the name of an active uniform

gl:getActiveUniformName returns the name of the active uniform at UniformIndex within Program . If UniformName is not NULL, up to BufSize characters (including a nul-terminator) will be written into the array whose address is specified by UniformName . If Length is not NULL, the number of characters that were (or would have been) written into UniformName (not including the nul-terminator) will be placed in the variable whose address is specified in Length . If Length is NULL, no length is returned. The length of the longest uniform name in Program is given by the value of ?GL_ACTIVE_UNIFORM_MAX_LENGTH, which can be queried with gl:getProgramiv/2 .

If gl:getActiveUniformName is not successful, nothing is written to Length or UniformName .

Program must be the name of a program for which the command gl:linkProgram/1 has been issued in the past. It is not necessary for Program to have been linked successfully. The link could have failed because the number of active uniforms exceeded the limit.

UniformIndex must be an active uniform index of the program Program , in the range zero to ?GL_ACTIVE_UNIFORMS - 1. The value of ?GL_ACTIVE_UNIFORMS can be queried with gl:getProgramiv/2 .

See external documentation.

getUniformBlockIndex(Program, UniformBlockName) -> integer()

Types

Program = integer()

UniformBlockName = string()

Retrieve the index of a named uniform block

gl:getUniformBlockIndex retrieves the index of a uniform block within Program .

UniformBlockName must contain a nul-terminated string specifying the name of the uniform block.

gl:getUniformBlockIndex returns the uniform block index for the uniform block named UniformBlockName of Program . If UniformBlockName does not identify an active uniform block of Program , gl:getUniformBlockIndex returns the special identifier, ?GL_INVALID_INDEX. Indices of the active uniform blocks of a program are assigned in consecutive order, beginning with zero.

See external documentation.

getActiveUniformBlockiv(Program, UniformBlockIndex, Pname, Params) -> ok

Types

Program = integer()

UniformBlockIndex = integer()

Pname = enum()

Params = mem()

Query information about an active uniform block

gl:getActiveUniformBlockiv retrieves information about an active uniform block within Program .

UniformBlockIndex is an active uniform block index of Program , and must be less than the value of ?GL_ACTIVE_UNIFORM_BLOCKS.

Upon success, the uniform block parameter(s) specified by Pname are returned in Params . If an error occurs, nothing will be written to Params .

If Pname is ?GL_UNIFORM_BLOCK_BINDING, then the index of the uniform buffer binding point last selected by the uniform block specified by UniformBlockIndex for Program is returned. If no uniform block has been previously specified, zero is returned.

If Pname is ?GL_UNIFORM_BLOCK_DATA_SIZE, then the implementation-dependent minimum total buffer object size, in basic machine units, required to hold all active uniforms in the uniform block identified by UniformBlockIndex is returned. It is neither guaranteed nor expected that a given implementation will arrange uniform values as tightly packed in a buffer object. The exception to this is the std140 uniform block layout , which guarantees specific packing behavior and does not require the application to query for offsets and strides. In this case the minimum size may still be queried, even though it is determined in advance based only on the uniform block declaration.

If Pname is ?GL_UNIFORM_BLOCK_NAME_LENGTH, then the total length (including the nul terminator) of the name of the uniform block identified by UniformBlockIndex is returned.

If Pname is ?GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, then the number of active uniforms in the uniform block identified by UniformBlockIndex is returned.

If Pname is ?GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, then a list of the active uniform indices for the uniform block identified by UniformBlockIndex is returned. The number of elements that will be written to Params is the value of ?GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS for UniformBlockIndex .

If Pname is ?GL_UNIFORM_BLOCK_REFERENCED_BY_VERTEX_SHADER, ?GL_UNIFORM_BLOCK_REFERENCED_BY_GEOMETRY_SHADER , or ?GL_UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER, then a boolean value indicating whether the uniform block identified by UniformBlockIndex is referenced by the vertex, geometry, or fragment programming stages of program, respectively, is returned.

See external documentation.

getActiveUniformBlockName(Program, UniformBlockIndex, BufSize) -> string()

Types

Program = integer()

UniformBlockIndex = integer()

BufSize = integer()

Retrieve the name of an active uniform block

gl:getActiveUniformBlockName retrieves the name of the active uniform block at UniformBlockIndex within Program .

UniformBlockIndex is an active uniform block index of Program , and must be less than the value of ?GL_ACTIVE_UNIFORM_BLOCKS.

Upon success, the name of the uniform block identified by UnifomBlockIndex is returned into UniformBlockName . The name is nul-terminated. The actual number of characters written into UniformBlockName , excluding the nul terminator, is returned in Length . If Length is NULL, no length is returned.

BufSize contains the maximum number of characters (including the nul terminator) that will be written into UniformBlockName .

If an error occurs, nothing will be written to UniformBlockName or Length .

See external documentation.

uniformBlockBinding(Program, UniformBlockIndex, UniformBlockBinding) -> ok

Types

Program = integer()

UniformBlockIndex = integer()

UniformBlockBinding = integer()

Assign a binding point to an active uniform block

Binding points for active uniform blocks are assigned using gl:uniformBlockBinding. Each of a program's active uniform blocks has a corresponding uniform buffer binding point. Program is the name of a program object for which the command gl:linkProgram/1 has been issued in the past.

If successful, gl:uniformBlockBinding specifies that Program will use the data store of the buffer object bound to the binding point UniformBlockBinding to extract the values of the uniforms in the uniform block identified by UniformBlockIndex .

When a program object is linked or re-linked, the uniform buffer object binding point assigned to each of its active uniform blocks is reset to zero.

See external documentation.

copyBufferSubData(ReadTarget, WriteTarget, ReadOffset, WriteOffset, Size) -> ok

Types

ReadTarget = enum()

WriteTarget = enum()

ReadOffset = integer()

WriteOffset = integer()

Size = integer()

Copy part of the data store of a buffer object to the data store of another buffer object

gl:copyBufferSubData copies part of the data store attached to Readtarget to the data store attached to Writetarget . The number of basic machine units indicated by Size is copied from the source, at offset Readoffset to the destination at Writeoffset , also in basic machine units.

Readtarget and Writetarget must be ?GL_ARRAY_BUFFER, ?GL_COPY_READ_BUFFER , ?GL_COPY_WRITE_BUFFER, ?GL_ELEMENT_ARRAY_BUFFER, ?GL_PIXEL_PACK_BUFFER , ?GL_PIXEL_UNPACK_BUFFER, ?GL_TEXTURE_BUFFER, ?GL_TRANSFORM_FEEDBACK_BUFFER or ?GL_UNIFORM_BUFFER. Any of these targets may be used, although the targets ?GL_COPY_READ_BUFFER and ?GL_COPY_WRITE_BUFFER are provided specifically to allow copies between buffers without disturbing other GL state.

Readoffset , Writeoffset and Size must all be greater than or equal to zero. Furthermore, Readoffset + Size must not exceeed the size of the buffer object bound to Readtarget , and Readoffset + Size must not exceeed the size of the buffer bound to Writetarget . If the same buffer object is bound to both Readtarget and Writetarget , then the ranges specified by Readoffset , Writeoffset and Size must not overlap.

See external documentation.

drawElementsBaseVertex(Mode, Count, Type, Indices, Basevertex) -> ok

Types

Mode = enum()

Count = integer()

Type = enum()

Indices = offset() | mem()

Basevertex = integer()

Render primitives from array data with a per-element offset

gl:drawElementsBaseVertex behaves identically to gl:drawElements/4 except that the ith element transferred by the corresponding draw call will be taken from element Indices [i] + Basevertex of each enabled array. If the resulting value is larger than the maximum value representable by Type , it is as if the calculation were upconverted to 32-bit unsigned integers (with wrapping on overflow conditions). The operation is undefined if the sum would be negative.

See external documentation.

drawRangeElementsBaseVertex(Mode, Start, End, Count, Type, Indices, Basevertex) -> ok

Types

Mode = enum()

Start = integer()

End = integer()

Count = integer()

Type = enum()

Indices = offset() | mem()

Basevertex = integer()

Render primitives from array data with a per-element offset

gl:drawRangeElementsBaseVertex is a restricted form of gl:drawElementsBaseVertex/5 . Mode , Start , End , Count and Basevertex match the corresponding arguments to gl:drawElementsBaseVertex/5 , with the additional constraint that all values in the array Indices must lie between Start and End , inclusive, prior to adding Basevertex . Index values lying outside the range [ Start , End ] are treated in the same way as gl:drawElementsBaseVertex/5 . The i th element transferred by the corresponding draw call will be taken from element Indices [i] + Basevertex of each enabled array. If the resulting value is larger than the maximum value representable by Type , it is as if the calculation were upconverted to 32-bit unsigned integers (with wrapping on overflow conditions). The operation is undefined if the sum would be negative.

See external documentation.

drawElementsInstancedBaseVertex(Mode, Count, Type, Indices, Primcount, Basevertex) -> ok

Types

Mode = enum()

Count = integer()

Type = enum()

Indices = offset() | mem()

Primcount = integer()

Basevertex = integer()

Render multiple instances of a set of primitives from array data with a per-element offset

gl:drawElementsInstancedBaseVertex behaves identically to gl:drawElementsInstanced/5 except that the ith element transferred by the corresponding draw call will be taken from element Indices [i] + Basevertex of each enabled array. If the resulting value is larger than the maximum value representable by Type , it is as if the calculation were upconverted to 32-bit unsigned integers (with wrapping on overflow conditions). The operation is undefined if the sum would be negative.

See external documentation.

provokingVertex(Mode) -> ok

Types

Mode = enum()

Specifiy the vertex to be used as the source of data for flat shaded varyings

Flatshading a vertex shader varying output means to assign all vetices of the primitive the same value for that output. The vertex from which these values is derived is known as the provoking vertex and gl:provokingVertex specifies which vertex is to be used as the source of data for flat shaded varyings.

ProvokeMode must be either ?GL_FIRST_VERTEX_CONVENTION or ?GL_LAST_VERTEX_CONVENTION , and controls the selection of the vertex whose values are assigned to flatshaded varying outputs. The interpretation of these values for the supported primitive types is:

Primitive Type of PolygoniFirst Vertex Convention Last Vertex Convention
point i i
independent line 2i - 1 2i
line loop i

i + 1, if i < n

1, if i = n
line strip ii + 1
independent triangle 3i - 2 3i
triangle strip ii + 2
triangle fan i + 1 i + 2
line adjacency 4i - 2 4i - 1
line strip adjacency i + 1 i + 2
triangle adjacency 6i - 5 6i - 1
triangle strip adjacency 2i - 1 2i + 3

If a vertex or geometry shader is active, user-defined varying outputs may be flatshaded by using the flat qualifier when declaring the output.

See external documentation.

fenceSync(Condition, Flags) -> integer()

Types

Condition = enum()

Flags = integer()

If an error occurs, gl:waitSync does not cause the GL server to block.

See external documentation.

getInteger64v(Pname) -> [integer()]

Types

Pname = enum()

getSynciv(Sync, Pname, BufSize) -> [integer()]

Types

Sync = integer()

Pname = enum()

BufSize = integer()

Query the properties of a sync object

gl:getSynciv retrieves properties of a sync object. Sync specifies the name of the sync object whose properties to retrieve.

On success, gl:getSynciv replaces up to BufSize integers in Values with the corresponding property values of the object being queried. The actual number of integers replaced is returned in the variable whose address is specified in Length . If Length is NULL, no length is returned.

If Pname is ?GL_OBJECT_TYPE, a single value representing the specific type of the sync object is placed in Values . The only type supported is ?GL_SYNC_FENCE .

If Pname is ?GL_SYNC_STATUS, a single value representing the status of the sync object (?GL_SIGNALED or ?GL_UNSIGNALED) is placed in Values .

If Pname is ?GL_SYNC_CONDITION, a single value representing the condition of the sync object is placed in Values . The only condition supported is ?GL_SYNC_GPU_COMMANDS_COMPLETE .

If Pname is ?GL_SYNC_FLAGS, a single value representing the flags with which the sync object was created is placed in Values . No flags are currently supported

Flags is expected to be used in future extensions to the sync objects..

If an error occurs, nothing will be written to Values or Length .

See external documentation.

texImage2DMultisample(Target, Samples, Internalformat, Width, Height, Fixedsamplelocations) -> ok

Types

Target = enum()

Samples = integer()

Internalformat = integer()

Width = integer()

Height = integer()

Fixedsamplelocations = 0 | 1

Establish the data storage, format, dimensions, and number of samples of a multisample texture's image

gl:texImage2DMultisample establishes the data storage, format, dimensions and number of samples of a multisample texture's image.

Target must be ?GL_TEXTURE_2D_MULTISAMPLE or ?GL_PROXY_TEXTURE_2D_MULTISAMPLE . Width and Height are the dimensions in texels of the texture, and must be in the range zero to ?GL_MAX_TEXTURE_SIZE - 1. Samples specifies the number of samples in the image and must be in the range zero to ?GL_MAX_SAMPLES - 1.

Internalformat must be a color-renderable, depth-renderable, or stencil-renderable format.

If Fixedsamplelocations is ?GL_TRUE, the image will use identical sample locations and the same number of samples for all texels in the image, and the sample locations will not depend on the internal format or size of the image.

When a multisample texture is accessed in a shader, the access takes one vector of integers describing which texel to fetch and an integer corresponding to the sample numbers describing which sample within the texel to fetch. No standard sampling instructions are allowed on the multisample texture targets.

See external documentation.

texImage3DMultisample(Target, Samples, Internalformat, Width, Height, Depth, Fixedsamplelocations) -> ok

Types

Target = enum()

Samples = integer()

Internalformat = integer()

Width = integer()

Height = integer()

Depth = integer()

Fixedsamplelocations = 0 | 1

Establish the data storage, format, dimensions, and number of samples of a multisample texture's image

gl:texImage3DMultisample establishes the data storage, format, dimensions and number of samples of a multisample texture's image.

Target must be ?GL_TEXTURE_2D_MULTISAMPLE_ARRAY or ?GL_PROXY_TEXTURE_2D_MULTISAMPLE_ARRAY . Width and Height are the dimensions in texels of the texture, and must be in the range zero to ?GL_MAX_TEXTURE_SIZE - 1. Depth is the number of array slices in the array texture's image. Samples specifies the number of samples in the image and must be in the range zero to ?GL_MAX_SAMPLES - 1.

Internalformat must be a color-renderable, depth-renderable, or stencil-renderable format.

See external documentation.

getMultisamplefv(Pname, Index) -> {float(), float()}

Types

Pname = enum()

Index = integer()

Retrieve the location of a sample

gl:getMultisamplefv queries the location of a given sample. Pname specifies the sample parameter to retrieve and must be ?GL_SAMPLE_POSITION. Index corresponds to the sample for which the location should be returned. The sample location is returned as two floating-point values in Val[0] and Val[1] , each between 0 and 1, corresponding to the X and Y locations respectively in the GL pixel space of that sample. (0.5, 0.5) this corresponds to the pixel center. Index must be between zero and the value of ?GL_SAMPLES - 1.

If the multisample mode does not have fixed sample locations, the returned values may only reflect the locations of samples within some pixels.

See external documentation.

sampleMaski(Index, Mask) -> ok

Types

Index = integer()

Mask = integer()

Set the value of a sub-word of the sample mask

gl:sampleMaski sets one 32-bit sub-word of the multi-word sample mask, ?GL_SAMPLE_MASK_VALUE .

MaskIndex specifies which 32-bit sub-word of the sample mask to update, and Mask specifies the new value to use for that sub-word. MaskIndex must be less than the value of ?GL_MAX_SAMPLE_MASK_WORDS. Bit B of mask word M corresponds to sample 32 x M + B.

See external documentation.

namedStringARB(Type, Name, String) -> ok

Types

Type = enum()

Name = string()

String = string()

glNamedStringARB

See external documentation.

deleteNamedStringARB(Name) -> ok

Types

Name = string()

glDeleteNamedStringARB

See external documentation.

compileShaderIncludeARB(Shader, Path) -> ok

Types

Shader = integer()

Path = iolist()

glCompileShaderIncludeARB

See external documentation.

isNamedStringARB(Name) -> 0 | 1

Program = integer()

ColorNumber = integer()

Index = integer()

Name = string()

glBindFragDataLocationIndexe

See external documentation.

getFragDataIndex(Program, Name) -> integer()

Types

Program = integer()

Name = string()

Query the bindings of color indices to user-defined varying out variables

gl:getFragDataIndex returns the index of the fragment color to which the variable Name was bound when the program object Program was last linked. If Name is not a varying out variable of Program , or if an error occurs, -1 will be returned.

See external documentation.

genSamplers(Count) -> [integer()]

Types

Count = integer()

Generate sampler object names

gl:genSamplers returns N sampler object names in Samplers . There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to gl:genSamplers .

Sampler object names returned by a call to gl:genSamplers are not returned by subsequent calls, unless they are first deleted with gl:deleteSamplers/1 .

The names returned in Samplers are marked as used, for the purposes of gl:genSamplers only, but they acquire state and type only when they are first bound.

See external documentation.

deleteSamplers(Samplers) -> ok

Types

Samplers = [integer()]

Delete named sampler objects

gl:deleteSamplers deletes N sampler objects named by the elements of the array Ids . After a sampler object is deleted, its name is again unused. If a sampler object that is currently bound to a sampler unit is deleted, it is as though gl:bindSampler/2 is called with unit set to the unit the sampler is bound to and sampler zero. Unused names in samplers are silently ignored, as is the reserved name zero.

See external documentation.

isSampler(Sampler) -> 0 | 1

Types

Sampler = integer()

Determine if a name corresponds to a sampler object

gl:isSampler returns ?GL_TRUE if Id is currently the name of a sampler object. If Id is zero, or is a non-zero value that is not currently the name of a sampler object, or if an error occurs, gl:isSampler returns ?GL_FALSE.

A name returned by gl:genSamplers/1 , is the name of a sampler object.

See external documentation.

bindSampler(Unit, Sampler) -> ok

Types

Unit = integer()

Sampler = integer()

Bind a named sampler to a texturing target

gl:bindSampler binds Sampler to the texture unit at index Unit . Sampler must be zero or the name of a sampler object previously returned from a call to gl:genSamplers/1 . Unit must be less than the value of ?GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS.

When a sampler object is bound to a texture unit, its state supersedes that of the texture object bound to that texture unit. If the sampler name zero is bound to a texture unit, the currently bound texture's sampler state becomes active. A single sampler object may be bound to multiple texture units simultaneously.

See external documentation.

samplerParameteri(Sampler, Pname, Param) -> ok

Types

Sampler = integer()

Pname = enum()

Param = integer()

Set sampler parameters

gl:samplerParameter assigns the value or values in Params to the sampler parameter specified as Pname . Sampler specifies the sampler object to be modified, and must be the name of a sampler object previously returned from a call to gl:genSamplers/1 . The following symbols are accepted in Pname :

?GL_TEXTURE_MIN_FILTER: The texture minifying function is used whenever the pixel being textured maps to an area greater than one texture element. There are six defined minifying functions. Two of them use the nearest one or nearest four texture elements to compute the texture value. The other four use mipmaps.

Params supplies a function for minifying the texture as one of the following:

?GL_NEAREST: Returns the value of the texture element that is nearest (in Manhattan distance) to the center of the pixel being textured.

?GL_LINEAR: Returns the weighted average of the four texture elements that are closest to the center of the pixel being textured. These can include border texture elements, depending on the values of ?GL_TEXTURE_WRAP_S and ?GL_TEXTURE_WRAP_T, and on the exact mapping.

?GL_NEAREST_MIPMAP_NEAREST: Chooses the mipmap that most closely matches the size of the pixel being textured and uses the ?GL_NEAREST criterion (the texture element nearest to the center of the pixel) to produce a texture value.

?GL_NEAREST_MIPMAP_LINEAR: Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the ?GL_NEAREST criterion (the texture element nearest to the center of the pixel) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values.

?GL_LINEAR_MIPMAP_LINEAR: Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the ?GL_LINEAR criterion (a weighted average of the four texture elements that are closest to the center of the pixel) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values.

As more texture elements are sampled in the minification process, fewer aliasing artifacts will be apparent. While the ?GL_NEAREST and ?GL_LINEAR minification functions can be faster than the other four, they sample only one or four texture elements to determine the texture value of the pixel being rendered and can produce moire patterns or ragged transitions. The initial value of ?GL_TEXTURE_MIN_FILTER is ?GL_NEAREST_MIPMAP_LINEAR .

?GL_TEXTURE_MAG_FILTER: The texture magnification function is used when the pixel being textured maps to an area less than or equal to one texture element. It sets the texture magnification function to either ?GL_NEAREST or ?GL_LINEAR (see below). ?GL_NEAREST is generally faster than ?GL_LINEAR, but it can produce textured images with sharper edges because the transition between texture elements is not as smooth. The initial value of ?GL_TEXTURE_MAG_FILTER is ?GL_LINEAR.

?GL_NEAREST: Returns the value of the texture element that is nearest (in Manhattan distance) to the center of the pixel being textured.

?GL_TEXTURE_MIN_LOD: Sets the minimum level-of-detail parameter. This floating-point value limits the selection of highest resolution mipmap (lowest mipmap level). The initial value is -1000.

?GL_TEXTURE_MAX_LOD: Sets the maximum level-of-detail parameter. This floating-point value limits the selection of the lowest resolution mipmap (highest mipmap level). The initial value is 1000.

?GL_TEXTURE_WRAP_S: Sets the wrap parameter for texture coordinate s to either ?GL_CLAMP_TO_EDGE , ?GL_MIRRORED_REPEAT, or ?GL_REPEAT. ?GL_CLAMP_TO_BORDER causes the s coordinate to be clamped to the range [(-1 2/N) 1+(1 2/N)], where N is the size of the texture in the direction of clamping.?GL_CLAMP_TO_EDGE causes s coordinates to be clamped to the range [(1 2/N) 1-(1 2/N)], where N is the size of the texture in the direction of clamping. ?GL_REPEAT causes the integer part of the s coordinate to be ignored; the GL uses only the fractional part, thereby creating a repeating pattern. ?GL_MIRRORED_REPEAT causes the s coordinate to be set to the fractional part of the texture coordinate if the integer part of s is even; if the integer part of s is odd, then the s texture coordinate is set to 1-frac(s), where frac(s) represents the fractional part of s. Initially, ?GL_TEXTURE_WRAP_S is set to ?GL_REPEAT.

?GL_TEXTURE_WRAP_T: Sets the wrap parameter for texture coordinate t to either ?GL_CLAMP_TO_EDGE , ?GL_MIRRORED_REPEAT, or ?GL_REPEAT. See the discussion under ?GL_TEXTURE_WRAP_S . Initially, ?GL_TEXTURE_WRAP_T is set to ?GL_REPEAT.

?GL_TEXTURE_WRAP_R: Sets the wrap parameter for texture coordinate r to either ?GL_CLAMP_TO_EDGE , ?GL_MIRRORED_REPEAT, or ?GL_REPEAT. See the discussion under ?GL_TEXTURE_WRAP_S . Initially, ?GL_TEXTURE_WRAP_R is set to ?GL_REPEAT.

?GL_TEXTURE_COMPARE_MODE: Specifies the texture comparison mode for currently bound textures. That is, a texture whose internal format is ?GL_DEPTH_COMPONENT_*; see gl:texImage2D/9 ) Permissible values are:

?GL_COMPARE_REF_TO_TEXTURE: Specifies that the interpolated and clamped r texture coordinate should be compared to the value in the currently bound texture. See the discussion of ?GL_TEXTURE_COMPARE_FUNC for details of how the comparison is evaluated. The result of the comparison is assigned to the red channel.

Types

Sampler = integer()

Pname = enum()

Return sampler parameter values

gl:getSamplerParameter returns in Params the value or values of the sampler parameter specified as Pname . Sampler defines the target sampler, and must be the name of an existing sampler object, returned from a previous call to gl:genSamplers/1 . Pname accepts the same symbols as gl:samplerParameteri/3 , with the same interpretations:

?GL_TEXTURE_MAG_FILTER: Returns the single-valued texture magnification filter, a symbolic constant. The initial value is ?GL_LINEAR.

?GL_TEXTURE_MIN_FILTER: Returns the single-valued texture minification filter, a symbolic constant. The initial value is ?GL_NEAREST_MIPMAP_LINEAR.

?GL_TEXTURE_MIN_LOD: Returns the single-valued texture minimum level-of-detail value. The initial value is -1000.

?GL_TEXTURE_MAX_LOD: Returns the single-valued texture maximum level-of-detail value. The initial value is 1000.

?GL_TEXTURE_WRAP_S: Returns the single-valued wrapping function for texture coordinate s, a symbolic constant. The initial value is ?GL_REPEAT.

?GL_TEXTURE_WRAP_T: Returns the single-valued wrapping function for texture coordinate t, a symbolic constant. The initial value is ?GL_REPEAT.

?GL_TEXTURE_WRAP_R: Returns the single-valued wrapping function for texture coordinate r, a symbolic constant. The initial value is ?GL_REPEAT.

?GL_TEXTURE_COMPARE_MODE: Returns a single-valued texture comparison mode, a symbolic constant. The initial value is ?GL_NONE. See gl:samplerParameteri/3 .

?GL_TEXTURE_COMPARE_FUNC: Returns a single-valued texture comparison function, a symbolic constant. The initial value is ?GL_LEQUAL. See gl:samplerParameteri/3 .

See external documentation.

getSamplerParameterIiv(Sampler, Pname) -> [integer()]

Types

Sampler = integer()

Pname = enum()

See getSamplerParameteriv/2

getSamplerParameterfv(Sampler, Pname) -> [float()]

Types

Sampler = integer()

Pname = enum()

See getSamplerParameteriv/2

getSamplerParameterIuiv(Sampler, Pname) -> [integer()]

Types

Sampler = integer()

Pname = enum()

glGetSamplerParameterI

See external documentation.

queryCounter(Id, Target) -> ok

Types

Id = integer()

Target = enum()

Record the GL time into a query object after all previous commands have reached the GL server but have not yet necessarily executed.

gl:queryCounter causes the GL to record the current time into the query object named Id . Target must be ?GL_TIMESTAMP. The time is recorded after all previous commands on the GL client and server state and the framebuffer have been fully realized. When the time is recorded, the query result for that object is marked available. gl:queryCounter timer queries can be used within a gl:beginQuery/2 / gl:beginQuery/2 block where the target is ?GL_TIME_ELAPSED and it does not affect the result of that query object.

See external documentation.

getQueryObjecti64v(Id, Pname) -> integer()

Types

Id = integer()

Pname = enum()

glGetQueryObjecti64v

See external documentation.

getQueryObjectui64v(Id, Pname) -> integer()

Types

Id = integer()

Pname = enum()

glGetQueryObjectui64v

See external documentation.

drawArraysIndirect(Mode, Indirect) -> ok

Types

Mode = enum()

Indirect = offset() | mem()

Render primitives from array data, taking parameters from memory

gl:drawArraysIndirect specifies multiple geometric primitives with very few subroutine calls. gl:drawArraysIndirect behaves similarly to gl:drawArraysInstancedBaseInstance/5 , execept that the parameters to gl:drawArraysInstancedBaseInstance/5 are stored in memory at the address given by Indirect .

The parameters addressed by Indirect are packed into a structure that takes the form (in C): typedef struct { uint count; uint primCount; uint first; uint baseInstance; } DrawArraysIndirectCommand; const DrawArraysIndirectCommand *cmd = (const DrawArraysIndirectCommand *)indirect; glDrawArraysInstancedBaseInstance(mode, cmd->first, cmd->count, cmd->primCount, cmd->baseInstance);

If a buffer is bound to the ?GL_DRAW_INDIRECT_BUFFER binding at the time of a call to gl:drawArraysIndirect, Indirect is interpreted as an offset, in basic machine units, into that buffer and the parameter data is read from the buffer rather than from client memory.

In contrast to gl:drawArraysInstancedBaseInstance/5 , the first member of the parameter structure is unsigned, and out-of-range indices do not generate an error.

Vertex attributes that are modified by gl:drawArraysIndirect have an unspecified value after gl:drawArraysIndirect returns. Attributes that aren't modified remain well defined.

See external documentation.

drawElementsIndirect(Mode, Type, Indirect) -> ok

Types

Mode = enum()

Type = enum()

Indirect = offset() | mem()

Render indexed primitives from array data, taking parameters from memory

gl:drawElementsIndirect specifies multiple indexed geometric primitives with very few subroutine calls. gl:drawElementsIndirect behaves similarly to gl:drawElementsInstancedBaseVertexBaseInstance/7 , execpt that the parameters to gl:drawElementsInstancedBaseVertexBaseInstance/7 are stored in memory at the address given by Indirect .

The parameters addressed by Indirect are packed into a structure that takes the form (in C): typedef struct { uint count; uint primCount; uint firstIndex; uint baseVertex; uint baseInstance; } DrawElementsIndirectCommand;

gl:drawElementsIndirect is equivalent to: void glDrawElementsIndirect(GLenum mode, GLenum type, const void * indirect) { const DrawElementsIndirectCommand *cmd = (const DrawElementsIndirectCommand *)indirect; glDrawElementsInstancedBaseVertexBaseInstance(mode, cmd->count, type, cmd->firstIndex + size-of-type, cmd->primCount, cmd->baseVertex, cmd->baseInstance); }

If a buffer is bound to the ?GL_DRAW_INDIRECT_BUFFER binding at the time of a call to gl:drawElementsIndirect, Indirect is interpreted as an offset, in basic machine units, into that buffer and the parameter data is read from the buffer rather than from client memory.

Note that indices stored in client memory are not supported. If no buffer is bound to the ?GL_ELEMENT_ARRAY_BUFFER binding, an error will be generated.

The results of the operation are undefined if the reservedMustBeZero member of the parameter structure is non-zero. However, no error is generated in this case.

Vertex attributes that are modified by gl:drawElementsIndirect have an unspecified value after gl:drawElementsIndirect returns. Attributes that aren't modified remain well defined.

See external documentation.

uniform1d(Location, X) -> ok

Types

Location = integer()

X = float()

uniform2d(Location, X, Y) -> ok

Types

Location = integer()

X = float()

Y = float()

uniform3d(Location, X, Y, Z) -> ok

Types

Location = integer()

X = float()

Y = float()

Z = float()

uniform4d(Location, X, Y, Z, W) -> ok

Types

Location = integer()

X = float()

Y = float()

Z = float()

W = float()

uniform1dv(Location, Value) -> ok

Types

Location = integer()

Value = [float()]

uniform2dv(Location, Value) -> ok

Types

Location = integer()

Value = [{float(), float()}]

uniform3dv(Location, Value) -> ok

Types

Location = integer()

Value = [{float(), float(), float()}]

uniform4dv(Location, Value) -> ok

Program = integer()

Location = integer()

See getUniformfv/2

getSubroutineUniformLocation(Program, Shadertype, Name) -> integer()

Types

Program = integer()

Shadertype = enum()

Name = string()

Retrieve the location of a subroutine uniform of a given shader stage within a program

gl:getSubroutineUniformLocation returns the location of the subroutine uniform variable Name in the shader stage of type Shadertype attached to Program , with behavior otherwise identical to gl:getUniformLocation/2 .

If Name is not the name of a subroutine uniform in the shader stage, -1 is returned, but no error is generated. If Name is the name of a subroutine uniform in the shader stage, a value between zero and the value of ?GL_ACTIVE_SUBROUTINE_LOCATIONS minus one will be returned. Subroutine locations are assigned using consecutive integers in the range from zero to the value of ?GL_ACTIVE_SUBROUTINE_LOCATIONS minus one for the shader stage. For active subroutine uniforms declared as arrays, the declared array elements are assigned consecutive locations.

See external documentation.

getSubroutineIndex(Program, Shadertype, Name) -> integer()

Shadertype = enum()

Indices = [integer()]

Load active subroutine uniforms

gl:uniformSubroutines loads all active subroutine uniforms for shader stage Shadertype of the current program with subroutine indices from Indices , storing Indices[i] into the uniform at location I . Count must be equal to the value of ?GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS for the program currently in use at shader stage Shadertype . Furthermore, all values in Indices must be less than the value of ?GL_ACTIVE_SUBROUTINES for the shader stage.

See external documentation.

getUniformSubroutineuiv(Shadertype, Location) -> {integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer(), integer()}

Types

Shadertype = enum()

Location = integer()

Retrieve the value of a subroutine uniform of a given shader stage of the current program

gl:getUniformSubroutine retrieves the value of the subroutine uniform at location Location for shader stage Shadertype of the current program. Location must be less than the value of ?GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS for the shader currently in use at shader stage Shadertype . The value of the subroutine uniform is returned in Values .

See external documentation.

getProgramStageiv(Program, Shadertype, Pname) -> integer()

Types

Program = integer()

Shadertype = enum()

Pname = enum()

Retrieve properties of a program object corresponding to a specified shader stage

gl:getProgramStage queries a parameter of a shader stage attached to a program object. Program contains the name of the program to which the shader is attached. Shadertype specifies the stage from which to query the parameter. Pname specifies which parameter should be queried. The value or values of the parameter to be queried is returned in the variable whose address is given in Values .

If Pname is ?GL_ACTIVE_SUBROUTINE_UNIFORMS, the number of active subroutine variables in the stage is returned in Values .

If Pname is ?GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS, the number of active subroutine variable locations in the stage is returned in Values .

If Pname is ?GL_ACTIVE_SUBROUTINES, the number of active subroutines in the stage is returned in Values .

If Pname is ?GL_ACTIVE_SUBROUTINE_UNIFORM_MAX_LENGTH, the length of the longest subroutine uniform for the stage is returned in Values .

If Pname is ?GL_ACTIVE_SUBROUTINE_MAX_LENGTH, the length of the longest subroutine name for the stage is returned in Values . The returned name length includes space for the null-terminator.

If there is no shader present of type Shadertype , the returned value will be consistent with a shader containing no subroutines or subroutine uniforms.

See external documentation.

patchParameteri(Pname, Value) -> ok

Types

Pname = enum()

Value = integer()

Specifies the parameters for patch primitives

gl:patchParameter specifies the parameters that will be used for patch primitives. Pname specifies the parameter to modify and must be either ?GL_PATCH_VERTICES, ?GL_PATCH_DEFAULT_OUTER_LEVEL or ?GL_PATCH_DEFAULT_INNER_LEVEL. For gl:patchParameteri, Value specifies the new value for the parameter specified by Pname . For gl:patchParameterfv, Values specifies the address of an array containing the new values for the parameter specified by Pname .

When Pname is ?GL_PATCH_VERTICES, Value specifies the number of vertices that will be used to make up a single patch primitive. Patch primitives are consumed by the tessellation control shader (if present) and subsequently used for tessellation. When primitives are specified using gl:drawArrays/3 or a similar function, each patch will be made from Parameter control points, each represented by a vertex taken from the enabeld vertex arrays. Parameter must be greater than zero, and less than or equal to the value of ?GL_MAX_PATCH_VERTICES.

When Pname is ?GL_PATCH_DEFAULT_OUTER_LEVEL or ?GL_PATCH_DEFAULT_INNER_LEVEL , Values contains the address of an array contiaining the default outer or inner tessellation levels, respectively, to be used when no tessellation control shader is present.

See external documentation.

patchParameterfv(Pname, Values) -> ok

Types

Pname = enum()

Values = [float()]

See patchParameteri/2

bindTransformFeedback(Target, Id) -> ok

Types

Target = enum()

Id = integer()

Bind a transform feedback object

gl:bindTransformFeedback binds the transform feedback object with name Id to the current GL state. Id must be a name previously returned from a call to gl:genTransformFeedbacks/1 . If Id has not previously been bound, a new transform feedback object with name Id and initialized with with the default transform state vector is created.

In the initial state, a default transform feedback object is bound and treated as a transform feedback object with a name of zero. If the name zero is subsequently bound, the default transform feedback object is again bound to the GL state.

While a transform feedback buffer object is bound, GL operations on the target to which it is bound affect the bound transform feedback object, and queries of the target to which a transform feedback object is bound return state from the bound object. When buffer objects are bound for transform feedback, they are attached to the currently bound transform feedback object. Buffer objects are used for trans- form feedback only if they are attached to the currently bound transform feedback object.

See external documentation.

deleteTransformFeedbacks(Ids) -> ok

Types

Ids = [integer()]

Delete transform feedback objects

gl:deleteTransformFeedbacks deletes the N transform feedback objects whose names are stored in the array Ids . Unused names in Ids are ignored, as is the name zero. After a transform feedback object is deleted, its name is again unused and it has no contents. If an active transform feedback object is deleted, its name immediately becomes unused, but the underlying object is not deleted until it is no longer active.

See external documentation.

genTransformFeedbacks(N) -> [integer()]

Types

N = integer()

Reserve transform feedback object names

gl:genTransformFeedbacks returns N previously unused transform feedback object names in Ids . These names are marked as used, for the purposes of gl:genTransformFeedbacks only, but they acquire transform feedback state only when they are first bound.

See external documentation.

isTransformFeedback(Id) -> 0 | 1

Types

Id = integer()

Determine if a name corresponds to a transform feedback object

gl:isTransformFeedback returns ?GL_TRUE if Id is currently the name of a transform feedback object. If Id is zero, or if ?id is not the name of a transform feedback object, or if an error occurs, gl:isTransformFeedback returns ?GL_FALSE. If Id is a name returned by gl:genTransformFeedbacks/1 , but that has not yet been bound through a call to gl:bindTransformFeedback/2 , then the name is not a transform feedback object and gl:isTransformFeedback returns ?GL_FALSE .

See external documentation.

pauseTransformFeedback() -> ok

Pause transform feedback operations

gl:pauseTransformFeedback pauses transform feedback operations on the currently active transform feedback object. When transform feedback operations are paused, transform feedback is still considered active and changing most transform feedback state related to the object results in an error. However, a new transform feedback object may be bound while transform feedback is paused.

See external documentation.

resumeTransformFeedback() -> ok

Resume transform feedback operations

gl:resumeTransformFeedback resumes transform feedback operations on the currently active transform feedback object. When transform feedback operations are paused, transform feedback is still considered active and changing most transform feedback state related to the object results in an error. However, a new transform feedback object may be bound while transform feedback is paused.

See external documentation.

drawTransformFeedback(Mode, Id) -> ok

Types

Mode = enum()

Id = integer()

Render primitives using a count derived from a transform feedback object

gl:drawTransformFeedback draws primitives of a type specified by Mode using a count retrieved from the transform feedback specified by Id . Calling gl:drawTransformFeedback is equivalent to calling gl:drawArrays/3 with Mode as specified, First set to zero, and Count set to the number of vertices captured on vertex stream zero the last time transform feedback was active on the transform feedback object named by Id .

See external documentation.

drawTransformFeedbackStream(Mode, Id, Stream) -> ok

Types

Mode = enum()

Id = integer()

Stream = integer()

Shaders = [integer()]

Binaryformat = enum()

Binary = binary()

Load pre-compiled shader binaries

gl:shaderBinary loads pre-compiled shader binary code into the Count shader objects whose handles are given in Shaders . Binary points to Length bytes of binary shader code stored in client memory. BinaryFormat specifies the format of the pre-compiled code.

The binary image contained in Binary will be decoded according to the extension specification defining the specified BinaryFormat token. OpenGL does not define any specific binary formats, but it does provide a mechanism to obtain token vaues for such formats provided by such extensions.

Depending on the types of the shader objects in Shaders , gl:shaderBinary will individually load binary vertex or fragment shaders, or load an executable binary that contains an optimized pair of vertex and fragment shaders stored in the same binary.

See external documentation.

getShaderPrecisionFormat(Shadertype, Precisiontype) -> {Range::{integer(), integer()}, Precision::integer()}

Types

Shadertype = enum()

Precisiontype = enum()

Retrieve the range and precision for numeric formats supported by the shader compiler

gl:getShaderPrecisionFormat retrieves the numeric range and precision for the implementation's representation of quantities in different numeric formats in specified shader type. ShaderType specifies the type of shader for which the numeric precision and range is to be retrieved and must be one of ?GL_VERTEX_SHADER or ?GL_FRAGMENT_SHADER. PrecisionType specifies the numeric format to query and must be one of ?GL_LOW_FLOAT, ?GL_MEDIUM_FLOAT ?GL_HIGH_FLOAT, ?GL_LOW_INT, ?GL_MEDIUM_INT, or ?GL_HIGH_INT.

Range points to an array of two integers into which the format's numeric range will be returned. If min and max are the smallest values representable in the format, then the values returned are defined to be: Range [0] = floor(log2(|min|)) and Range [1] = floor(log2(|max|)).

Precision specifies the address of an integer into which will be written the log2 value of the number of bits of precision of the format. If the smallest representable value greater than 1 is 1 + eps, then the integer addressed by Precision will contain floor(-log2(eps)).

See external documentation.

depthRangef(N, F) -> ok

Types

N = clamp()

F = clamp()

See depthRange/2

clearDepthf(D) -> ok

Types

D = clamp()

glClearDepthf

See external documentation.

Pipeline = integer()

Stages = integer()

Program = integer()

Bind stages of a program object to a program pipeline

gl:useProgramStages binds executables from a program object associated with a specified set of shader stages to the program pipeline object given by Pipeline . Pipeline specifies the program pipeline object to which to bind the executables. Stages contains a logical combination of bits indicating the shader stages to use within Program with the program pipeline object Pipeline . Stages must be a logical combination of ?GL_VERTEX_SHADER_BIT, ?GL_TESS_CONTROL_SHADER_BIT, ?GL_TESS_EVALUATION_SHADER_BIT , ?GL_GEOMETRY_SHADER_BIT, and ?GL_FRAGMENT_SHADER_BIT. Additionally, the special value ?GL_ALL_SHADER_BITS may be specified to indicate that all executables contained in Program should be installed in Pipeline .

If Program refers to a program object with a valid shader attached for an indicated shader stage, gl:useProgramStages installs the executable code for that stage in the indicated program pipeline object Pipeline . If Program is zero, or refers to a program object with no valid shader executable for a given stage, it is as if the pipeline object has no programmable stage configured for the indicated shader stages. If Stages contains bits other than those listed above, and is not equal to ?GL_ALL_SHADER_BITS , an error is generated.

See external documentation.

activeShaderProgram(Pipeline, Program) -> ok

Types

Pipeline = integer()

Program = integer()

Set the active program object for a program pipeline object

gl:activeShaderProgram sets the linked program named by Program to be the active program for the program pipeline object Pipeline . The active program in the active program pipeline object is the target of calls to gl:uniform1f/2 when no program has been made current through a call to gl:useProgram/1 .

See external documentation.

createShaderProgramv(Type, Strings) -> integer()

Types

Type = enum()

Strings = iolist()

glCreateShaderProgramv

See external documentation.

bindProgramPipeline(Pipeline) -> ok

Types

Pipeline = integer()

Bind a program pipeline to the current context

gl:bindProgramPipeline binds a program pipeline object to the current context. Pipeline must be a name previously returned from a call to gl:genProgramPipelines/1 . If no program pipeline exists with name Pipeline then a new pipeline object is created with that name and initialized to the default state vector.

When a program pipeline object is bound using gl:bindProgramPipeline, any previous binding is broken and is replaced with a binding to the specified pipeline object. If Pipeline is zero, the previous binding is broken and is not replaced, leaving no pipeline object bound. If no current program object has been established by gl:useProgram/1 , the program objects used for each stage and for uniform updates are taken from the bound program pipeline object, if any. If there is a current program object established by gl:useProgram/1 , the bound program pipeline object has no effect on rendering or uniform updates. When a bound program pipeline object is used for rendering, individual shader executables are taken from its program objects.

See external documentation.

deleteProgramPipelines(Pipelines) -> ok

Types

Pipelines = [integer()]

Delete program pipeline objects

gl:deleteProgramPipelines deletes the N program pipeline objects whose names are stored in the array Pipelines . Unused names in Pipelines are ignored, as is the name zero. After a program pipeline object is deleted, its name is again unused and it has no contents. If program pipeline object that is currently bound is deleted, the binding for that object reverts to zero and no program pipeline object becomes current.

See external documentation.

genProgramPipelines(N) -> [integer()]

Types

N = integer()

Reserve program pipeline object names

gl:genProgramPipelines returns N previously unused program pipeline object names in Pipelines . These names are marked as used, for the purposes of gl:genProgramPipelines only, but they acquire program pipeline state only when they are first bound.

See external documentation.

isProgramPipeline(Pipeline) -> 0 | 1

Types

Pipeline = integer()

Determine if a name corresponds to a program pipeline object

gl:isProgramPipeline returns ?GL_TRUE if Pipeline is currently the name of a program pipeline object. If Pipeline is zero, or if ?pipeline is not the name of a program pipeline object, or if an error occurs, gl:isProgramPipeline returns ?GL_FALSE. If Pipeline is a name returned by gl:genProgramPipelines/1 , but that has not yet been bound through a call to gl:bindProgramPipeline/1 , then the name is not a program pipeline object and gl:isProgramPipeline returns ?GL_FALSE .

See external documentation.

getProgramPipelineiv(Pipeline, Pname) -> integer()

Types

Pipeline = integer()

Pname = enum()

Retrieve properties of a program pipeline object

gl:getProgramPipelineiv retrieves the value of a property of the program pipeline object Pipeline . Pname specifies the name of the parameter whose value to retrieve. The value of the parameter is written to the variable whose address is given by Params .

If Pname is ?GL_ACTIVE_PROGRAM, the name of the active program object of the program pipeline object is returned in Params .

If Pname is ?GL_VERTEX_SHADER, the name of the current program object for the vertex shader type of the program pipeline object is returned in Params .

If Pname is ?GL_TESS_CONTROL_SHADER, the name of the current program object for the tessellation control shader type of the program pipeline object is returned in Params .

If Pname is ?GL_TESS_EVALUATION_SHADER, the name of the current program object for the tessellation evaluation shader type of the program pipeline object is returned in Params .

If Pname is ?GL_GEOMETRY_SHADER, the name of the current program object for the geometry shader type of the program pipeline object is returned in Params .

If Pname is ?GL_FRAGMENT_SHADER, the name of the current program object for the fragment shader type of the program pipeline object is returned in Params .

If Pname is ?GL_INFO_LOG_LENGTH, the length of the info log, including the null terminator, is returned in Params . If there is no info log, zero is returned.

See external documentation.

programUniform1i(Program, Location, V0) -> ok

Types

Program = integer()

Location = integer()

V0 = integer()

Specify the value of a uniform variable for a specified program object

gl:programUniform modifies the value of a uniform variable or a uniform variable array. The location of the uniform variable to be modified is specified by Location , which should be a value returned by gl:getUniformLocation/2 . gl:programUniform operates on the program object specified by Program .

The commands gl:programUniform{1|2|3|4}{f|i|ui} are used to change the value of the uniform variable specified by Location using the values passed as arguments. The number specified in the command should match the number of components in the data type of the specified uniform variable (e.g., 1 for float, int, unsigned int, bool; 2 for vec2, ivec2, uvec2, bvec2, etc.). The suffix f indicates that floating-point values are being passed; the suffix i indicates that integer values are being passed; the suffix ui indicates that unsigned integer values are being passed, and this type should also match the data type of the specified uniform variable. The i variants of this function should be used to provide values for uniform variables defined as int, ivec2 , ivec3, ivec4, or arrays of these. The ui variants of this function should be used to provide values for uniform variables defined as unsigned int, uvec2, uvec3, uvec4, or arrays of these. The f variants should be used to provide values for uniform variables of type float, vec2, vec3, vec4, or arrays of these. Either the i, ui or f variants may be used to provide values for uniform variables of type bool, bvec2 , bvec3, bvec4, or arrays of these. The uniform variable will be set to false if the input value is 0 or 0.0f, and it will be set to true otherwise.

All active uniform variables defined in a program object are initialized to 0 when the program object is linked successfully. They retain the values assigned to them by a call to gl:programUniform until the next successful link operation occurs on the program object, when they are once again initialized to 0.

Program = integer()

Location = integer()

V0 = integer()

V1 = integer()

V2 = integer()

V3 = integer()

programUniform4iv(Program, Location, Value) -> ok

Types

Program = integer()

Location = integer()

Value = [{integer(), integer(), integer(), integer()}]

programUniform4f(Program, Location, V0, V1, V2, V3) -> ok

Types

Program = integer()

Location = integer()

V0 = float()

V1 = float()

V2 = float()

V3 = float()

programUniform4fv(Program, Location, Value) -> ok

Types

Program = integer()

Location = integer()

Value = [{float(), float(), float(), float()}]

programUniform4d(Program, Location, V0, V1, V2, V3) -> ok

Types

Program = integer()

Location = integer()

V0 = float()

V1 = float()

V2 = float()

V3 = float()

programUniform4dv(Program, Location, Value) -> ok

Types

Program = integer()

Location = integer()

Value = [{float(), float(), float(), float()}]

programUniform4ui(Program, Location, V0, V1, V2, V3) -> ok

Types

Program = integer()

Location = integer()

V0 = integer()

V1 = integer()

V2 = integer()

V3 = integer()