On Tue, Jun 12, 2012 at 1:34 PM, Christoph Bumiller <e0425...@student.tuwien.ac.at> wrote: > On 06/12/2012 06:52 PM, Jerome Glisse wrote: >> On Tue, Jun 12, 2012 at 8:39 AM, Christoph Bumiller >> <e0425...@student.tuwien.ac.at> wrote: >>> 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. >> >> I don't think thats how it wors, each sample will have its color and >> depth value no matter if fixed pipeline or not. When resolving the > > Sorry, "fixed-pipe" was misleading, I meant the z-value from the > rasterizer (which can be regarded as fixed functionality), not "without > (custom) shaders". > > If the shader is only invoked once for each fragment (i.e. > MinSampleShading == 1), all the samples that belong to that fragment > will share the same color and depth values. >
So i think we agree but according to spec MinSampleShading=1 -> the fragment shader is run once for each sample. MinSampleShading value is a fraction of x/MIN_SAMPLE_SHADING_VALUE_ARB So if you have 8 sample surface and you set MinSampleShading to 0.5 you will get the fragment shader invoked for 4 sample. Note that according to spec implementation might ignore the fraction and only cover the case MinSampleShading==1 Cheers, Jerome _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
