Timing between Application and Draw process
Mark Visconti (visconti++at++cis.ohio-state.edu)
Tue, 29 Nov 1994 15:03:45 -0500 (EST)
I'm running Performer 1.2 on a 3 pipe 8 processor Onyx. I have a question
about timing and the synchronization of the application, draw, and cull
processes in multiprocessor mode (APP_CULL_DRAW). I'm running LOCKed at
a frame rate of 60Hz.
Initially, in the application process I used pfGetTime() after pfFrame()
to get times for individual frames. The frame time was about 16.6-16.7ms
which made sense. I have been working on some other code with which I used
similar timing methods. It was reporting 16.7ms/frame, but obviously running
at 30Hz. I added a pfGetTime() to the draw process and was rewarded by
seeing frametimes of 33ms from the Draw process and 16.7 from the application
process. I didn't think that the application and draw (and cull) processes
could run at different frame rates. Aren't the processes locked to one
another (1APP frame per 1 CULL per 1 DRAW) ? Or are they just synchronized
on frame boundaries ? Does this mean that the application process can run a
simulation at 60Hz while the draw process only runs it at 10Hz ?
Thanks for any help you can supply,
Mark Visconti
visconti++at++cis.ohio-state.edu
LTSI, WPAFB, Dayton, OH
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