[PD] Syncing an event with refresh rate in GEM
cyrille.henry at la-kitchen.fr
Fri Oct 12 20:17:26 CEST 2007
Roman Haefeli a écrit :
> On Fri, 2007-10-12 at 00:48 +0200, cyrille henry wrote:
>> Thomas O Fredericks a écrit :
>>> "sync to vblank will sync swapping buffer with the screen frame rate, but
>>> that's not the original question.
>>> to my knowledge, there is no possibility to sync gem rendering with the
>>> screen frame rate.
>>> if you fix both at 60Hz, you can have jitter (not a lot, but some)."
>>> You are not technically syncing gem to the screen frame rate.
>>> You are
>>> syncing the open gl redraw to the framerate.
>>> The GPU takes care of that.
>> i don't understand this.
>> if you get gem to render a 60FPS, you will have 60fps based on the pd (cpu) clock.
> i don't know this by reading the code, but for me it would only make
> sense to get the clock from the audio-card, nothing else. this is also
> what i experienced, when pd was running on jackd, while jackd was
> believing to be running at 44100Hz, while it was actually at 48000Hz.
> all [metro]s were too fast and all pitches too high. the only objects,
> that seems to work not with the audio-clock, that come to my mind, are
> [cputime] and [realtime] (is that true?)
>> if you set your screen at 60fps, you will have 60fps based on the gpu.
>> there is no way to make the cpu clock to be exactely the same speed as the gpu clock.
>> so, sometime (specially with big patch), you can have desincronisation between this 2 clocks, even if they should be at the same speed.
>> (there is a also a lot's of jitter in pd clock)
> what makes you think that? i 'd claim, that pd's clock is stable, unless
> you get audio drop-outs.
t b b
you should have only 50.
what i've got is :
(with audio off, nothing else than the gemwin and this 4 object in the patch)
this jitter make it impossible to compute 1 and only 1 frame for each frame on the screen, even with sync on vblank.
> Der fr�he Vogel f�ngt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de
More information about the Pd-list