UE 5.1 MAWI demo mis-renders mesh shader path
What happens when you set r.Nanite.MeshShaderRasterization to 0, or just use VKD3D_DISABLE_EXTENSIONS=VK_EXT_mesh_shader does that work around this issue?
Looks very similar overall, so that should rule out RADV.
Considering how few real users of mesh shading there are, it isn't impossible that it still has issues. But of course it'd be hilarious if NVidia had the same bug in their driver.
With mesh shaders disabled, it seems to render without these holes.
It's the same under nvidia - including UE 5.2 and MWTropicalRainforest demos - textures flicker - disappear and reappear + artifacts appear
ok I can confirm that under Nvidia excluding Mesh Shader = VKD3D_DISABLE_EXTENSIONS=VK_EXT_mesh_shader there are no these artifacts:
Looked at this a bit, the mesh shaders themselves are all more or less trivial and there are no task shaders involved. Things like MS<->FS interface matching and just basic shader metadata like maximum vertex/primitive count also all look correct. Strongly doubt that mesh shaders themselves are the problem - but they all go through ExecuteIndirect, so the compute shaders generating those draws might be broken.
It just seems to work™ just fine on RADV with current mesa-git though, so there's that.
Hmm, I'm not sure why but for some reason glitches I see on my NV GPU when using mesh shader path seem to be quite a bit more severe? If you excuse the horrible quality:
That was on GeForce RTX 4080 Mobile, 535.86.05 driver, db608963
Hmm, I'm not sure why but for some reason glitches I see on my NV GPU when using mesh shader path seem to be quite a bit more severe? If you excuse the horrible quality:
MAWI.mp4
That was on GeForce RTX 4080 Mobile, 535.86.05 driver, db60896
I confirm it has the same without VKD3D_DISABLE_EXTENSIONS
Fixed on master.
Launch options
VKD3D_DISABLE_EXTENSIONSx1 2023-07VKD3D_DISABLE_EXTENSIONS=VK_EXT_mesh_shaderx1 2023-07VKD3D_DISABLE_EXTENSIONS=VK_EXT_mesh_shader`x1 2023-07
Old issue with downloads links of demo: https://github.com/HansKristian-Work/vkd3d-proton/issues/1599.
Repro video on RADV: https://1drv.ms/u/s!Amz0nBA4PrbSm0Ch0vDm_Akg0UnQ?e=we1bBM
Repro video on NV: https://1drv.ms/u/s!Amz0nBA4PrbSmz8fb2nasNOMMKkg?e=yjcjO1
Looks very similar overall, so that should rule out RADV. With mesh shaders disabled, it seems to render without these holes. Nanite is being used in both paths here which leaves mesh shaders as the likely culprit.