On 06/12/2012 02:25 PM, Olivier Galibert wrote: > On Tue, Jun 12, 2012 at 01:50:08PM +0200, Christoph Bumiller wrote: >>> First question: how many depths should be computed, and for which >>> coordinates? Which of these values is associated with which sample? >> >> One for each sample point. The depth buffer will be multisampled as well. >> Coverage sampling (CSAA) where you have extra coverage samples that do >> NOT (necessarily) correspond to color sample locations are not covered >> by the GL spec, it's vendor-specific. > > Ok. So that means that if the shader writes z, you have to do full > supersampling then. >
No, I don't think that's the case. You get per-sample depth values if you use fixed-pipe depth, but shader-computed depth should simply be replicated (to all samples covered by the shader invocation), like color outputs. > >>> Second question: how many samples should be shaded, and for which >>> coordinates? What is the impact of depth testing failure? >> >> As many as the user requested via glMinSampleShading, and the sample >> locations to choose seem to be up to the implementation. > > Do you know what's usually expected? Center of collapsed samples, one > of the samples, center of the pixel? > > >>> Third question: what happens when a variable has a "sample" qualifier >>> in the fragment shader? Or "centroid"? >> >> "When interpolating variables declared using sample in when MULTISAMPLE >> is enabled, the fragment shader will be invoked separately for each (!) >> covered sample and the variable will be sampled at the corresponding >> sample point." > > So a "sample" anywhere means full supersampling, ok. > > Thanks, > > OG. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev