Using a modified version of the DXC compiler inside Unity to gain access to Rasterizer Order Views

[DomagojKudek]

Hi all,

I'm trying to use Rasterizer Order Views (ROVs) in Unity, a DX 11.3 feature that requires Shader Model 5.1.

Since Unity caps its shader model at 5.0, it's impossible to specify anything higher than that.

I had an idea that maybe I can modify the DXC code, build that new version and replace the .dll files in Unity to "hack" my way through this limitation.

I'm running Unity 2023.2.20, URP 16 on Vulkan.

Currently I'm getting this error from the DXC compiler :

fatal error: generated SPIR-V is invalid: Opcode BeginInvocationInterlockEXT requires one of these capabilities: FragmentShaderSampleInterlockEXT FragmentShaderShadingRateInterlockEXT FragmentShaderPixelInterlockEXT (on vulkan)

I tried hard-coding that extension and those capabilities, shader model 6, and even the command line arguments but haven't managed to successfully compile my ShaderLab (HLSL) shaders.

Any tips on editing the DXC to successfully use ROVs in HLSL shaders?

[s-perron]

@cassiebeckley Do you know how we add those capabilities? I thought they should be automatically added when the ROVs are used.

[s-perron]

Here is a simple example, and the capability is added: https://godbolt.org/z/3n75Wae8r.