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shadocko
06-08-2010, 03:37 AM
Hello,

I think I found a bug with glDisable(GL_MULTISAMPLE) while rendering to a multisample texture with more than 4 samples per pixel/texel on nVidia cards.
I could observe it on both 8800GTX and GTX280 with latest stable drivers. All samples don't contain the same color after rendering. People reported it to work as expected on ATi at least one ATi card.
This prevents me from successfully implementing a stencil routed K-buffer in OpenGL with more than 4 samples, when it seems feasible in DX.

The problem is exposed in this thread (http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=278722) with code to reproduce it.

Some users suggested that could have to do with 16xMSAA being implemented in HW as the addition of 4xMSAA and 4xSSAA on nVidia GPUs before GT4xx.

Am I wrong in my interpretation of the spec that every sub-samples should receive the same colour or is it a bug?

Does anybody have a workaround for this?

Alfonse Reinheart
06-08-2010, 01:02 PM
Am I wrong in my interpretation of the spec that every sub-samples should receive the same colour or is it a bug?

No, the spec is very clear on what's supposed to happen when you render to a multisampled buffer with GL_MULTISAMPLE disabled.