Compute the height for the triplanar POM

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitData.hlsl

         if (isTriplanar)
         {
             float3 viewDirTS;
+            float planeHeight;
             int numSteps;
 
             // Perform a POM in each direction and modify appropriate texture coordinate
-            float2 offsetZY = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirTS, maxHeight, ppdParam, height);
+            float2 offsetZY = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirTS, maxHeight, ppdParam, planeHeight);
+            height = layerTexCoord.triplanarWeights.x * planeHeight;
-            float2 offsetXZ = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirTS, maxHeight, ppdParam, height);
+            float2 offsetXZ = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirTS, maxHeight, ppdParam, planeHeight);
+            height += layerTexCoord.triplanarWeights.y * planeHeight;
-            float2 offsetXY = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirTS, maxHeight, ppdParam, height);
+            float2 offsetXY = ParallaxOcclusionMapping(lod, _PPDLodThreshold, numSteps, viewDirTS, maxHeight, ppdParam, planeHeight);
-
-            height = 0.0; // TODO
+            height += layerTexCoord.triplanarWeights.z * planeHeight;
         }
         else
         {