Support depth offset with the triplanar POM

SampleScenes/HDTest/GraphicTest/Parallax Occlusion Mapping/Material/POM - Wood triplanar.mat

   m_PrefabInternal: {fileID: 0}
   m_Name: POM - Wood triplanar
   m_Shader: {fileID: 4800000, guid: 6e4ae4064600d784cac1e41a9e6f2e59, type: 3}
-  m_ShaderKeywords: _HEIGHTMAP _MAPPING_TRIPLANAR _NORMALMAP _NORMALMAP_TANGENT_SPACE
+  m_ShaderKeywords: _DEPTHOFFSET_ON _HEIGHTMAP _MAPPING_TRIPLANAR _NORMALMAP _NORMALMAP_TANGENT_SPACE
+    _PER_PIXEL_DISPLACEMENT _PER_PIXEL_DISPLACEMENT_OBJECT_SCALE _PER_PIXEL_DISPLACEMENT_TILING_SCALE
   m_LightmapFlags: 4
   m_EnableInstancingVariants: 0
   m_DoubleSidedGI: 0
         m_Offset: {x: 0, y: 0}
     - _BaseColorMap:
         m_Texture: {fileID: 2800000, guid: 927434958f610214aa6a4179f134f5fd, type: 3}
-        m_Scale: {x: 2, y: 2}
+        m_Scale: {x: 1, y: 1}
         m_Offset: {x: 0, y: 0}
     - _BentNormalMap:
         m_Texture: {fileID: 0}
         m_Scale: {x: 1, y: 1}
         m_Offset: {x: 0, y: 0}
     m_Floats:
+    - _ATDistance: 1
     - _AlbedoAffectEmissive: 0
     - _AlphaCutoff: 0.5
     - _AlphaCutoffEnable: 0
     - _CoatIOR: 0.5
     - _CullMode: 2
     - _Cutoff: 0.5
-    - _DepthOffsetEnable: 0
+    - _DepthOffsetEnable: 1
     - _DetailAOScale: 1
     - _DetailAlbedoScale: 1
     - _DetailHeightScale: 1
     - _DstBlend: 0
     - _EmissiveColorMode: 1
     - _EmissiveIntensity: 0
-    - _EnablePerPixelDisplacement: 0
+    - _EnablePerPixelDisplacement: 1
     - _EnableSpecularOcclusion: 0
     - _EnableVertexDisplacement: 0
     - _EnableWind: 0
-    - _HeightAmplitude: 0.02
+    - _HeightAmplitude: 0.5
-    - _HeightMax: 1
-    - _HeightMin: -1
+    - _HeightMax: 50
+    - _HeightMin: 0
+    - _IOR: 1
+    - _InvTilingScale: 1
     - _MaterialID: 1
     - _Metallic: 0
     - _Mode: 0
     - _PPDLodThreshold: 5
-    - _PPDMaxSamples: 15
+    - _PPDMaxSamples: 64
+    - _PPDPrimitiveLength: 1
+    - _PPDPrimitiveWidth: 1
+    - _PerPixelDisplacementTilingScale: 1
+    - _RefractionMode: 0
     - _ShiverDirectionality: 0.5
     - _ShiverDrag: 0.2
     - _Smoothness: 0.5
     - _SubsurfaceProfile: 0
     - _SubsurfaceRadius: 1
     - _SurfaceType: 0
-    - _TexWorldScale: 0.1
+    - _TexWorldScale: 0.2
+    - _ThicknessMultiplier: 1
     - _UVBase: 5
     - _UVDetail: 0
     - _UVMappingPlanar: 0
     - _DoubleSidedConstants: {r: 1, g: 1, b: -1, a: 0}
     - _EmissionColor: {r: 0, g: 0, b: 0, a: 1}
     - _EmissiveColor: {r: 0, g: 0, b: 0, a: 1}
+    - _InvPrimScale: {r: 1, g: 1, b: 0, a: 0}
+    - _TransmittanceColor: {r: 1, g: 1, b: 1, a: 1}
     - _UVDetailsMappingMask: {r: 1, g: 0, b: 0, a: 0}
     - _UVMappingMask: {r: 0, g: 0, b: 0, a: 0}

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitData.hlsl

         // Perform a POM in each direction and modify appropriate texture coordinate
         ppdParam.uv = layerTexCoord.base.uvZY;
         viewDirTS   = float3(V.x > 0.0 ? uvZY : -uvZY, V.x);
-        viewDirTS  *= GetInverseObjectScale().xzy; // Switch from Y-up to Z-up
-        unitAngle   = saturate(FastACosPos(viewDirUV.z) * INV_HALF_PI);            // TODO: optimize
+        unitAngle   = saturate(FastACosPos(abs(viewDirUV.z)) * INV_HALF_PI);       // TODO: optimize
         numSteps    = (int)lerp(_PPDMinSamples, _PPDMaxSamples, unitAngle);
         float2 offsetZY = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirUV, 1, ppdParam, planeHeight);
 
         height = layerTexCoord.triplanarWeights.x * planeHeight;
+        NdotV  = layerTexCoord.triplanarWeights.x * abs(viewDirTS.z);
-        viewDirTS  *= GetInverseObjectScale().xzy; // Switch from Y-up to Z-up
-        unitAngle   = saturate(FastACosPos(viewDirUV.z) * INV_HALF_PI);            // TODO: optimize
+        unitAngle   = saturate(FastACosPos(abs(viewDirUV.z)) * INV_HALF_PI);       // TODO: optimize
         numSteps    = (int)lerp(_PPDMinSamples, _PPDMaxSamples, unitAngle);
         float2 offsetXZ = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirUV, 1, ppdParam, planeHeight);
 
+        NdotV  += layerTexCoord.triplanarWeights.y * abs(viewDirTS.z);
-        viewDirTS  *= GetInverseObjectScale().xzy; // Switch from Y-up to Z-up
-        unitAngle   = saturate(FastACosPos(viewDirUV.z) * INV_HALF_PI);            // TODO: optimize
+        unitAngle   = saturate(FastACosPos(abs(viewDirUV.z)) * INV_HALF_PI);       // TODO: optimize
         numSteps    = (int)lerp(_PPDMinSamples, _PPDMaxSamples, unitAngle);
         float2 offsetXY = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirUV, 1, ppdParam, planeHeight);
 
-
-        NdotV = 1; // TODO.
+        NdotV  += layerTexCoord.triplanarWeights.z * abs(viewDirTS.z);
     }
     else
     {
         float3 viewDirTS = isPlanar ? float3(uvXZ, V.y) : TransformWorldToTangent(V, input.worldToTangent);
         viewDirTS *= GetInverseObjectScale().xzy; // Switch from Y-up to Z-up
 
-        NdotV = viewDirTS.z;
+        NdotV = abs(viewDirTS.z);
-        float  unitAngle = saturate(FastACosPos(viewDirUV.z) * INV_HALF_PI);            // TODO: optimize
+        float  unitAngle = saturate(FastACosPos(abs(viewDirUV.z)) * INV_HALF_PI);       // TODO: optimize
-        // POM uses a normalized view vector in the UV space to intersect the heightmap within a 1x1x1 box.
         float2 offset = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirUV, 1, ppdParam, height);
 
         // Apply offset to all UVSet0 / planar