[GEM-dev] asynchronous pixel buffer objects for recording etc

[cyrille henry]

for information : what is the size of the pixel buffer?

thx
Cyrille

Le 06/06/2010 16:49, Claude Heiland-Allen a écrit :
> Hi list,
>
> Is there any way in current Gem to use asynchronous readback of pixel
> buffer objects to speed up recording (or other GPU<->CPU transfer)?
>
> In one of my projects in plain C/OpenGL I used this technique successfully:
>
> 1) naive (blocking) glReadPixels direct to CPU ram and piped via
> stdout to ppmtoy4m|y4mscaler|mpeg2enc
> -> about 5fps
>
> 2) async glReadPixels to pixel buffer object mapped into the CPU
> with one frame latency and piped via stdout to same encoder
> -> about 20fps
>
> 3) async glReadPixels to PBO to CPU piped via stdout to /dev/null
> -> about 25fps
>
> (laptop with 4GB ram, intel core2 dual core cpu, nvidia g105m gpu,
> tested with 32bit gnu/linux/ubuntu/karmic generic-pae kernel)
>
> Thanks for any tips,
>
>
> Claude