From the Vulkan 1.1.107 spec:
Sample shading is enabled for a graphics pipeline:
- If the interface of the fragment shader entry point of the
graphics pipeline includes an input variable decorated with
SampleId or SamplePosition. In this case minSampleShadingFactor
takes the value 1.0.
- Else if the sampleShadingEnable member of the
VkPipelineMultisampleStateCreateInfo structure specified when
creating the graphics pipeline is set to VK_TRUE. In this case
minSampleShadingFactor takes the value of
VkPipelineMultisampleStateCreateInfo::minSampleShading.
Otherwise, sample shading is considered disabled.
In other words, if sampleShadingEnable is set to VK_FALSE, we should
ignore minSampleShading.
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
* harmless to compute it and then let dead-code take care of it.
*/
if (ms_info->rasterizationSamples > 1) {
- key->persample_interp =
+ key->persample_interp = ms_info->sampleShadingEnable &&
(ms_info->minSampleShading * ms_info->rasterizationSamples) > 1;
key->multisample_fbo = true;
}
- key->frag_coord_adds_sample_pos = ms_info->sampleShadingEnable;
+ key->frag_coord_adds_sample_pos = key->persample_interp;
}
}