I know this question has cropped up before but maybe something is now possible that wasn't previously...
Is there a faster alternative to glreadpixels? It is currently taking 75% of my processing.
I am calculating the average amount of colour in an image (for my radiosity engine). glReadPixels seems faster than using glGetTexImage.
Is there some way of doing it on the GPU since it seems that getting the image back to system RAM is what is causing the slowness.
I am not familiar with pixel shaders or cg and I was wondering if they would allow me to read the frame buffer (or a texture) and perform the necessary calculation on the GPU.
Thanks for any help.