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KhronosGroup / Vulkan-Docs

The Vulkan API Specification and related tools
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rasterizerDiscardEnable disable need to not write to a geometry shader pointsize #2347

Closed spencer-lunarg closed 5 months ago

spencer-lunarg commented 5 months ago

moved from https://github.com/KhronosGroup/Vulkan-ValidationLayers/issues/5129

Do these VUs still happen when rasterization is disabled (VkPipelineRasterizationStateCreateInfo::rasterizerDiscardEnable = VK_TRUE) such as when using transform feedback.

image

oddhack commented 5 months ago

@spencer-lunarg was the resolution that you will document this in a NOTE in the spec?

spencer-lunarg commented 5 months ago

Discussed in the WG meeting today

We could see this being allowed, but it is such a edge case and would need lots of tests for things like if someone wanted to write the point size info out to the transform feedback, etc.

The original issue was created before VK_KHR_maintenance5 which provides a default value and solves this problem in a proper way.

With this, the WG decided unless there is a very good use case, we are happy to leave this VU as is.

was the resolution that you will document this in a NOTE in the spec?

No, the VU is doing what it should, for everywhere we implicitly assume not mentioning rasterizerDiscardEnable is the same as rasterizerDiscardEnable not mattering