Nvidia glReadPixels() driver bug ?


I am using glReadPixels() to readout my framebuffer. When doing this in SLI anitialiasing mode the usuall black level of the alpha values are at 50% grey. A glCopyTexSubImage2D() call however works fine.
Of cause in SLI single-GPU rendering mode glReadPixels() works too.

SLI with two 7800GTX, Dual Opteron, NVidia 81.95 driver.

Any help on this would be appreciated!

Sounds like a bug, have you reported this to NVIDIA?

Not yet. I will try to build a testcase first. Don’t know if some other code is influencing this beavior. It seems an obvious bug, so I though I’d ask…