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Material graph to render target via compute in UE5

This is similar to the Draw Material to Render Target node provided by Unreal but executed through compute.

Get the code

$ shadeup-unreal
 > [COMPUTE] Compute Shader
 > Material Evaluation Render Target

Usage

1. Generate or download the template using the instructions above
2. Rebuild your project
3. Create or navigate to an existing Blueprint
4. Right-click and add the node called “Execute Material RTCompute Shader”

Notes

• The render target you use should be a multiple of 32. If not the sampler might go over the edge and wrap back around (depending on your settings).

Helpful reading

• Render Dependency Graph

Sample snippet

// rtmat.usf

#include "/Engine/Generated/Material.ush"
#include "/Engine/Public/Platform.ush"

RWTexture2D<float3> RenderTarget;

[numthreads(THREADS_X, THREADS_Y, THREADS_Z)]
void RTMatExample(
	uint3 DispatchThreadId : SV_DispatchThreadID,
	uint GroupIndex : SV_GroupIndex )
{
	float4 SvPosition = float4(DispatchThreadId.xy, 0, 0);

	FMaterialPixelParameters MaterialParameters = MakeInitializedMaterialPixelParameters();

	// There are various inputs we can provide to the material graph via FMaterialPixelParameters
	// See: https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Shaders/Private/MaterialTemplate.ush#L262

	MaterialParameters.VertexColor = half4(1, 1, 0, 1);

	FPixelMaterialInputs PixelMaterialInputs = (FPixelMaterialInputs)0;

	// This is the call to the material graph
	CalcMaterialParameters(MaterialParameters, PixelMaterialInputs, SvPosition, true);

	// PixelMaterialInputs is a struct that contains the outputs of the material graph
	// Use the provided helper methods ( GetMaterialXYZ(...) ) to access the outputs
	// See: https://github.com/chendi-YU/UnrealEngine/blob/master/Engine/Shaders/MaterialTemplate.usf#L1298

	RenderTarget[DispatchThreadId.xy] = GetMaterialBaseColor(PixelMaterialInputs);
}