HDRenderPipeline: Small fix that cause POM to be tiled

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/LitDataInternal.hlsl

     float lod = CALCULATE_TEXTURE2D_LOD(ADD_IDX(_HeightMap), ADD_ZERO_IDX(sampler_HeightMap), uv);
 
     // Do a first step before the loop to init all value correctly
-    float2 texOffsetCurrent = uv;
+    float2 texOffsetCurrent = 0;
     float prevHeight = SAMPLE_TEXTURE2D_LOD(ADD_IDX(_HeightMap), ADD_ZERO_IDX(sampler_HeightMap), uv + texOffsetCurrent, lod).r;
     texOffsetCurrent += texOffsetPerStep;
     float currHeight = SAMPLE_TEXTURE2D_LOD(ADD_IDX(_HeightMap), ADD_ZERO_IDX(sampler_HeightMap), uv + texOffsetCurrent, lod).r;
 
     // Found below and above points, now perform line interesection (ray) with piecewise linear heightfield approximation
 
+    // Refine the search by adding few extra intersection
+#define POM_REFINE 1
+#if POM_REFINE
-#define POM_REFINE 0
-#if POM_REFINE
+    float pt0 = rayHeight + stepSize;
+    float pt1 = rayHeight;
+    float delta0 = pt0 - prevHeight;
+    float delta1 = pt1 - currHeight;
+
+    float2 offset = float2(0.0, 0.0);
+
+    float threshold = 1.0;
+
+    for (int i = 0; i < 5; ++i)
+    {
+        float t = (pt0 * delta1 - pt1 * delta0) / (delta1 - delta0);
+        offset = (1 - t) * texOffsetPerStep * numSteps;
+
+        currHeight = SAMPLE_TEXTURE2D_LOD(ADD_IDX(_HeightMap), ADD_ZERO_IDX(sampler_HeightMap), uv + offset, lod).r;
+
+        threshold = t - currHeight;
+
+        if (abs(threshold) <= 0.01)
+            break;
+
+        if (threshold < 0.0)
+        {
+            delta1 = threshold;
+            pt1 = t;
+        }
+        else
+        {
+            delta0 = threshold;
+            pt0 = t;
+        }
+    }
-    /*
-    float t0 = rayHeight + stepSize;
-    float t1 = rayHeight; 
-    float delta0 = t0 - prevHeight;
-    float delta1 = t1 - currHeight;
-    float t = (t0 * delta1 - t1 * delta0) / (delta1 - delta0);
-    float2 offset = uv + (1 - t) * texOffsetPerStep * numSteps;
-    */
-        
+    
+    //float pt0 = rayHeight + stepSize;
+    //float pt1 = rayHeight; 
+    //float delta0 = pt0 - prevHeight;
+    //float delta1 = pt1 - currHeight;
+    //float t = (pt0 * delta1 - pt1 * delta0) / (delta1 - delta0);
+    //float2 offset = (1 - t) * texOffsetPerStep * numSteps;
+
+    // A bit more optimize
-    float2 offset = (ratio) * (texOffsetCurrent - texOffsetPerStep) + (1.0 - ratio) * texOffsetCurrent; 
+    float2 offset = texOffsetCurrent - ratio * texOffsetPerStep;
 
 #endif
 

Assets/TestScenes/HDTest/GraphicTest/Parallax Occlusion Mapping/Material/POM - Wood.mat

         m_Offset: {x: 0, y: 0}
     - _BaseColorMap:
         m_Texture: {fileID: 2800000, guid: 0353c00d9bc99f14780836a6a51a6d97, type: 3}
-        m_Scale: {x: 1, y: 1}
+        m_Scale: {x: 2, y: 2}
         m_Offset: {x: 0, y: 0}
     - _BumpMap:
         m_Texture: {fileID: 0}
     - _GlossMapScale: 1
     - _Glossiness: 0.5
     - _GlossyReflections: 1
-    - _HeightAmplitude: 0.09
+    - _HeightAmplitude: 0.17
     - _HeightCenter: 0.5
     - _MaterialId: 0
     - _Metallic: 0
     - _OcclusionStrength: 1
-    - _PPDMaxSamples: 64
+    - _PPDMaxSamples: 15
     - _PPDMinSamples: 1
     - _Parallax: 0.02
     - _Smoothness: 0.5

Assets/TestScenes/HDTest/GraphicTest/Tessellation/Material/Tessellation - Wood.mat

         m_Offset: {x: 0, y: 0}
     - _BaseColorMap:
         m_Texture: {fileID: 2800000, guid: 0353c00d9bc99f14780836a6a51a6d97, type: 3}
-        m_Scale: {x: 1, y: 1}
+        m_Scale: {x: 2, y: 2}
         m_Offset: {x: 0, y: 0}
     - _BumpMap:
         m_Texture: {fileID: 0}
     - _SubSurfaceRadius: 0
     - _SurfaceType: 0
     - _TessellationBackFaceCullEpsilon: -0.25
-    - _TessellationFactor: 10
+    - _TessellationFactor: 15
     - _TessellationFactorMaxDistance: 50
     - _TessellationFactorMinDistance: 20
     - _TessellationFactorTriangleSize: 100