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

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