Writing shaders

Shaders are written in HLSL and compiled with DXC for every backend. The editor reloads them automatically when they change.

Adding a shader

Shaders live in Source/Shaders/. Write your .hlsl file, then register it in Config/Shaders.hmf:

ShaderDefinition "MyEffect" {
    VS = "MyEffect/MyEffect.hlsl"
    PS = "MyEffect/MyEffect.hlsl"
}

Paths are relative to Source/Shaders/. The keys are the stages:

Key	Stage
VS	Vertex shader
PS	Pixel shader
CS	Compute shader
RGS, CHS, MS	Ray tracing: ray generation, closest hit, and miss

Shader variants are declared at the top of the file:

PERMUTE(HBAO_ENABLED)
PERMUTE(LIGHT_TYPE, CLUSTERED, DIRECTIONAL, POINT, SPOT, AREA_RECT);

With just a name, it's an on/off variant. With a list of values, each variant defines one of them, such as LIGHT_TYPE_POINT:

#ifdef LIGHT_TYPE_DIRECTIONAL
    // directional light only
#endif

STATIC(NAME, value) sets a fixed define.

Shipping builds use precompiled shaders. Packaging does this automatically. To run it yourself:

PrecompileShaders.exe --platform=windows

Add --api=vulkan or --api=dx12 to pick a backend, or --filter=MyEffect to limit it to matching shaders.