Further optimize CullTriangleBackFace()

ScriptableRenderPipeline/Core/ShaderLibrary/GeometricTools.hlsl

 
 // Returns 'true' if a triangle defined by 3 vertices is back-facing.
 // 'epsilon' is the (negative) value of dot(N, V) below which we cull the triangle.
-bool CullTriangleBackFace(float3 p0, float3 p1, float3 p2, float epsilon, float3 viewPos)
+// 'winding' can be used to change the order: pass 1 for (p0 -> p1 -> p2), or -1 for (p0 -> p2 -> p1).
+bool CullTriangleBackFace(float3 p0, float3 p1, float3 p2, float epsilon, float3 viewPos,
+                          float winding)
 {
     float3 edge1 = p1 - p0;
     float3 edge2 = p2 - p0;
-    float  NdotV = dot(N, V);
+    float  NdotV = dot(N, V) * winding;
 
     // Optimize:
     // NdotV / (length(N) * length(V)) < Epsilon

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitDataMeshModification.hlsl

     if (_TessellationBackFaceCullEpsilon > -1) // Is backface culling enabled ?
     {
         // Handle transform mirroring (like negative scaling)
-        // Caution: don't change p1/p2 directly as it is use later
-        float3 backfaceP1 = unity_WorldTransformParams.w < 0.0 ? p2 : p1;
-        float3 backfaceP2 = unity_WorldTransformParams.w < 0.0 ? p1 : p2;
-
-        faceCull = CullTriangleBackFace(p0, backfaceP1, backfaceP2, _TessellationBackFaceCullEpsilon, GetCurrentViewPosition()); // Use shadow view
+        float winding = unity_WorldTransformParams.w;
+        faceCull = CullTriangleBackFace(p0, p1, p2, _TessellationBackFaceCullEpsilon, GetCurrentViewPosition(), winding); // Use shadow view
     }
 #endif