[erlang-questions] writing a delay loop without now()
Fri Feb 20 09:35:04 CET 2009
> I have a graphical application that runs at a fixed frame
> rate (60 frames per second). The processing takes up part
> of the frame, then I need to make sure that roughly 16,667
> microseconds have passed before displaying the next frame.
> os:sleep() is VERY coarse and inconsistent across
> platforms. On some platforms os:sleep(1) is the same as
> sleep:(32000). Using a timeout value with receive gives
> the same results (that's actually how os:sleep is
> implemented). erlang:statistics(wall_clock) is just as
I may not have had quite such stringent realtime
requirements as you, but I've achieved this sort of thing
- calculating time left to the start of next frame
- using timer:send_after/2 to send myself a special message
at start of next frame
- going into a blocking receive of the special message
Two variants of this are:
- using a separate process that produces the "start of
frame" messages, using the same principle
- using timer:send_interval/2, which amounts to using OTP's
built-in separate process that produces regular messages.
Have you tried such approaches?
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