Strange issues with flickering triangles

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7 comments, last by EmptyVoid 15 years, 7 months ago
So I have this issue that only appears on nVidia cards..... and seems to be related to the way multiple frames are drawn (capturing one frame in PIX doesn't exhibit the issue) On a solid mesh, some trangles randomly flicker on and off, like they are being culled somewhere (but the depth buffer appears to still be written to).... this only happens on shaders that use ps_3_0.... I'm at a bit of a loss .... anyone experienced anything similar?
Blah....
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Sounds like Z-buffer precision issues to me. What format is your depth buffer, and what are your near and far clip planes set to in your projection matrix? You want the near clip plane as far as possible (And definitely non-zero, ideally 0.1f or further), and the far clip as close as possible (No higher than around 1000.0f for a 16-bit depth buffer).
thanks for the reply...

hoever, highly unlikely to be depth buffer precision problem, the problem occurs on entire polygons(any size) ....throughout the scene. (also, the problem disappears when a replayed in a PIX capture frame) And changing the near/far planes doesn't help.

so strange...... introducing an artificial CPU stall between frames removes the problem... but this is obviously an unworkable solution :P


/annoyed
Blah....
What does the reference rasteriser do? If it works, then it's probably a driver bug.
You could be overwriting a portion of a vertex buffer which is currently in use. This would explain the randomness, also why an artificial stall makes the problem go away.
I had the same problem.

Introducing an artificial CPU stall between frames removed the problem for me as well but that would never work for my project since it was already going way to slow. I never figured it out and just upgraded to DX10 since there was no way to fix it. Now I found another bug in DX10 that creates a memory leak, I don't like being one of the only people to find huge bugs in DX...
This is your life, and it's ending one minute at a time. - Fight club
Bump because I want to know how to fix this to.
This is your life, and it's ending one minute at a time. - Fight club
can we see any screenshot?
... nothing impossible ...
Yes screen shots would be a good idea.
This is your life, and it's ending one minute at a time. - Fight club

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