I have recently started GLSL and I have a few questions 1) I have some fragment shaders which do some image processing stuff and run at 45 fps. However when i use a pbuffer to do all the image processing instead of directly doing it on the framebuffer, my fps drops to 21 fps. 2) I have a 6800 GT which has a fillrate of 2900MPixels/sec. However my image processing program which essentially computes a 5 point gaussian average for many iterations, has fillrate of roughly 290MPixels/sec. Is it ok or is there something really wrong with my program 3) Is Cg much faster than GLSL 4) My GPU has 16 pipelines, is it possible to limit it to use only 4 so as to emulate an older GPU? 5) Are there ne manuals available for estimating the clock cycles of each gpu instructions Thanks a lot Shireesh

1/ look into FBO its replaced pbuffers
2/ no idea
3/ no, though glsl operates in 32bit color as standard + i believe cg operates in 16bit as standard (thus big difference there, but both can use both16+32bit data types)
4/search for nvemulate

Hi can ne one give me some performance comparision between FBO and PBuffers. I got some code from the net but there doesn't seem to be much of a difference.

More GLSL woes

My program, which does some elementary image processing stuff, is totally fragment centric. I had to support some 16 bit *grayscale* images for that so i thought it was time to move to render to texture. This is the result

. 8bit rgb images run at 45 fps
. 8bit rgb images with RT run at 22 fps
. 16 bit gray images with RT run at 2 fps.

I am using the RenderTexture library from Mark Harris. Is this possible???
Please help.

Shireesh