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03-UnrealEngine/Rendering/Material/Vertex Interpolator材质节点.md

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+---
+title: Vertex Interpolator材质节点
+date: 2022-11-04 10:01:35
+excerpt: 
+tags: 
+rating: ⭐
+---
+推荐查看视频：https://www.youtube.com/watch?v=KyjlrKwbXCw
+
+本质上是一种将VS数据进行插值最后传递到PS中的节点。需要与CustomUV、VertexColor配合使用。

03-UnrealEngine/Rendering/Material/自定义材质输出节点.md

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+---
+title: 自定义材质输出节点
+date: 2022-09-02 11:30:37
+excerpt: 
+tags: 
+rating: ⭐
+---
+## 前言
+参考文章：https://zhuanlan.zhihu.com/p/163121357
+
+## 自定义材质输出节点
+继承`UMaterialExpressionCustomOutput`类并实现对应函数即可。
+
+具体可以参考`BentNormal`材质输出节点。Shader代码位于BasePassPixelShader.usf的ApplyBentNormal()，CPP代码位于UMaterialExpressionBentNormalCustomOutput类中（UE4.27）。这种节点会生成`NUM_MATERIAL_OUTPUTS_节点名`的宏。
+
+之后就可以在BasePassPixelShader.usf中通过宏与函数获取到对应的节点计算结果。比如：
+```c++
+void ApplyBentNormal( in FMaterialPixelParameters MaterialParameters, in float Roughness, inout float3 BentNormal, inout float DiffOcclusion, inout float SpecOcclusion )  
+{  
+#if NUM_MATERIAL_OUTPUTS_GETBENTNORMAL > 0  
+   #if MATERIAL_TANGENTSPACENORMAL  
+      BentNormal = normalize( TransformTangentVectorToWorld( MaterialParameters.TangentToWorld, GetBentNormal0(MaterialParameters) ) );  
+   #else  
+      BentNormal = GetBentNormal0(MaterialParameters);  
+   #endif  
+  
+   FSphericalGaussian HemisphereSG = Hemisphere_ToSphericalGaussian( MaterialParameters.WorldNormal );  
+   FSphericalGaussian NormalSG = ClampedCosine_ToSphericalGaussian( MaterialParameters.WorldNormal );  
+   FSphericalGaussian VisibleSG = BentNormalAO_ToSphericalGaussian( BentNormal, DiffOcclusion );  
+   FSphericalGaussian DiffuseSG = Mul( NormalSG, VisibleSG );  
+   float VisibleCosAngle = sqrt( 1 - DiffOcclusion );  
+  
+#if 1  // Mix full resolution normal with low res bent normal  
+   BentNormal = DiffuseSG.Axis;  
+   //DiffOcclusion = saturate( Integral( DiffuseSG ) / Dot( NormalSG, HemisphereSG ) );  
+   DiffOcclusion = saturate( Integral( DiffuseSG ) * 0.42276995 );  
+#endif  
+  
+   float3 N = MaterialParameters.WorldNormal;  
+   float3 V = MaterialParameters.CameraVector;  
+  
+   SpecOcclusion  = DotSpecularSG( Roughness, N, V, VisibleSG );  
+   SpecOcclusion /= DotSpecularSG( Roughness, N, V, HemisphereSG );  
+  
+   SpecOcclusion = saturate( SpecOcclusion );  
+#endif  
+}
+```