Merge pull request #1039 from Unity-Technologies/temp-fix-fo-cluster-decal

temp fix fo cluster decal

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/DecalUtilities.hlsl

     return _DecalDatas[j];
 }
 
+// Caution: We can't compute LOD inside a dynamic loop. The gradient are not accessible.
+// we need to find a way to calculate mips. For now just fetch first mip of the decals
-	src.xyz =  mul(decalToWorld, UnpackNormalmapRGorAG(SAMPLE_TEXTURE2D_ARRAY_LOD(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex, ComputeTextureLOD(texCoords)))) * 0.5f + 0.5f;
+	src.xyz =  mul(decalToWorld, UnpackNormalmapRGorAG(SAMPLE_TEXTURE2D_ARRAY_LOD(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex, 0 /* ComputeTextureLOD(texCoords) */))) * 0.5f + 0.5f;
 	src.w = blend;
 	dst.xyz = src.xyz * src.w + dst.xyz * (1.0f - src.w);
 	dst.w = dst.w * (1.0f - src.w);
 void ApplyBlendDiffuse(inout float4 dst, inout int matMask, float2 texCoords, int sliceIndex, int mapMask, float blend)
 {
-	float4 src = SAMPLE_TEXTURE2D_ARRAY_LOD(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex, ComputeTextureLOD(texCoords));
+	float4 src = SAMPLE_TEXTURE2D_ARRAY_LOD(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex, 0 /* ComputeTextureLOD(texCoords) */);
 	src.w *= blend;
 	dst.xyz = src.xyz * src.w + dst.xyz * (1.0f - src.w);
 	dst.w = dst.w * (1.0f - src.w);
 void ApplyBlendMask(inout float4 dst, inout int matMask, float2 texCoords, int sliceIndex, int mapMask, float blend)
 {
-	float4 src = SAMPLE_TEXTURE2D_ARRAY_LOD(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex, ComputeTextureLOD(texCoords));
+	float4 src = SAMPLE_TEXTURE2D_ARRAY_LOD(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex, 0 /* ComputeTextureLOD(texCoords) */);
 	src.z = src.w;
 	src.w = blend;
 	dst.xyz = src.xyz * src.w + dst.xyz * (1.0f - src.w);