Glitchy hair rendering with VRS in Senua's Saga: Hellblade 2

[runar-work]

When VRS is enabled in Senua's Saga: Hellblade 2, there are hair rendering glitches on certain NPCs.

Original report: https://github.com/ValveSoftware/Proton/issues/7754#issuecomment-2132070672

System information

• GPU: RTX 3070
• Driver: I tested with 550.78 and 555.42.02
• Wine version: 1716845527 experimental-bleeding-edge-9.0-99996-20240527-p01a60c-w7374ef-d7df801-v32ca00
• VKD3D-Proton version: https://github.com/HansKristian-Work/vkd3d-proton/commit/32ca00164e74cbbe500117b2d54a9aae5bd4ba80

Captures

Renderdoc capture

[K0bin]

I took a quick look at it. It reproduced with the renderdoc capture but I couldn't see anything wrong with the problematic draw.

Looking at the first draw where these black squares show up:

• shader outputs are roughly the same between an affected pixel and a neighboring unaffected one
• depth test & stencil test are both fine
• No discard/demote in the fragment shader
• Shading rate of the pipeline: 1x1, combine ops: Keep, Max
• It doesn't write the shading rate in either the vertex or fragment shader
• no TCS, TES or GS shader
• the affected (black) pixels match up with non-zero pixels in the shading rate attachment (values are 1, 4, 5)
• unaffected (correct) pixels match up with black (zero) pixels in the shading rate attachment