[SM6] Shader error when using Texture Cube Array in UE 5.5

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1

Hello there, first time posting here.

For context. this shader was tested on UE 5.3, but I get this error when hooking up a Texture Cube Array in 5.5

Any tips would be appreciated!

This is the error message.

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image2770×363 69.4 KB

[SM6] Shader debug info dumped to: “d:\p4\main\projects\TagFighter\UnrealEngine\TagFighter\Saved\ShaderDebugInfo\PCD3D_SM6\M_SpeedTunnel_Cubemap_Particle_492b22692a8dfd\Default\FLocalVertexFactory\TMaterialCHSFNoLightMapPolicyFAnyHitShader\0”
d:\p4\main\projects\TagFighter\UnrealEngine\Engine\Shaders\Private\RayTracing\RayTracingMaterialHitShaders.usf(0): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
error: validation errors
[SM6] d:\p4\main\projects\TagFighter\UnrealEngine\Engine\Binaries\Win64\RayTracingMaterialHitShaders.dxil(2816,9): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
RayTracingMaterialHitShaders.dxil:2816:9: error: Opcode Sample not valid in shader model lib_6_6(closesthit).
[SM6] d:\p4\main\projects\TagFighter\UnrealEngine\Engine\Shaders\Private\RayTracing\RayTracingMaterialHitShaders.usf(0): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
RayTracingMaterialHitShaders.dxil:5257: error: Entry function performs some operation that is incompatible with the shader stage or other entry properties. See other errors for details.
[SM6] d:\p4\main\projects\TagFighter\UnrealEngine\Engine\Shaders\Private\RayTracing\RayTracingMaterialHitShaders.usf(0): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
RayTracingMaterialHitShaders.dxil:5257: error: Function uses features incompatible with the shader stage (closesthit) of the entry function.

2

It seems to be a bug in UE shader.

Open file “\Shaders\Engine\Private\Common.ush” and modify the TextureCubeArraySample function from

MaterialFloat4 TextureCubeArraySample(TextureCubeArray Tex, SamplerState Sampler, float4 UV)
{
	return Tex.Sample(Sampler, UV);
}

to

MaterialFloat4 TextureCubeArraySample(TextureCubeArray Tex, SamplerState Sampler, float4 UV)
{
#if USE_FORCE_TEXTURE_MIP
	return Tex.SampleLevel(Sampler, UV, 0);
#else
	return Tex.Sample(Sampler, UV);
#endif
}

and restart the UE editor.

BTW, it seems that UE do not accept external issues or pull requests. Does anyone know how I can feed back this bug to the official?