On Wed, 2014-09-03 at 15:00 -0700, Jordan Justen wrote: > On 2014-09-03 10:41:02, Kenneth Graunke wrote: > > On Tuesday, September 02, 2014 06:16:01 PM Samuel Iglesias Gonsálvez wrote: > > > Hello, > > > > > > Two weeks ago, Iago and myself sent a batch of patches that added > > > geometry shader support for SandyBridge [0]. > > > > > > Recently, we rebased our patches against master [1] and found > > > that some things are not working properly any more. Particularly, we > > > have plenty of cases where we only get a black screen when using a > > > geometry shader, and in these cases it seems as if some outputs of the > > > geometry shader got "lost" by the time they become inputs in the > > > fragment shader (some input varyings in the fragment shader that come > > > from the outputs of the geometry seem to be zeroed). The values we > > > output in the geometry shader are correct though, since they are > > > correctly captured by transform feedback. > > > > > > A bisect shows that the commit that introduced this problem is > > > 2f28a0dc231 i965: Implement fast color clears using meta operations [2]. > > > > > > Reverting this commit fixes the problem for us. The revert also fixes > > > piglit's bin/gl-3.2-layered-rendering-clear-color* tests in SandyBridge > > > [3]. > > > > > > So the question is whether the commit mentioned above introduces a > > > regression that should be fixed somewhere or if our code needs to be > > > updated to adapt to changes introduced by that commit in some way. > > > > > > Best regards, > > > > > > Sam > > > > Hi Sam, > > > > Layered clears now use GL_AMD_vertex_shader_layered. If you expose > > the extension, then gl-3.2-layered-rendering-clear-color starts > > passing again. Otherwise, the vertex shader code to set gl_LayerID > > = gl_InstanceID is #ifdef'd out, so only layer 0 would get affected. > >
Exposing the extension fixes the issue for our tests and piglit's bin/gl-3.2-layered-rendering-clear-color* tests :-) > > I'm not sure if we can expose that extension without GL 3.2, so you > > might just put the patch to enable it (simply editing > > intel_extensions.c) near the end of your series. Perhaps Jordan > > will know if we can just turn it on now. > > Yes, We should be able to enable GL_AMD_vertex_shader_layered for gen6 > now. But, it really only makes sense to enable it at the same time as > enabling 3.2 so the glFramebufferTexture function is available. > > Due to this meta quirk, it sounds like we should enable them both in > the same patch. (Or, perhaps the extension in the patch just before > 3.2. ??) We are going to add it in the same patch where OpenGL 3.2 is enabled. Thanks! Sam
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