Merge pull request #172 from Unity-Technologies/Tessellatoin-tile-scale

HDRenderPipeline: Add tessellation tile scale

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/Editor/LayeredLitUI.cs

         static public void SetupLayersMappingKeywords(Material material)
         {
             // object scale affect tile
-            SetKeyword(material, "_LAYER_TILING_UNIFORM_SCALE", material.GetFloat(kObjectScaleAffectTile) > 0.0f);
+            SetKeyword(material, "_LAYER_TILING_COUPLED_WITH_UNIFORM_OBJECT_SCALE", material.GetFloat(kObjectScaleAffectTile) > 0.0f);
 
             // Blend mask
             LayerUVBaseMapping UVBlendMaskMapping = (LayerUVBaseMapping)material.GetFloat(kUVBlendMask);

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/LayeredLit.shader

     #pragma shader_feature _DOUBLESIDED_ON
     #pragma shader_feature _PER_PIXEL_DISPLACEMENT
 
-    #pragma shader_feature _LAYER_TILING_UNIFORM_SCALE
+    #pragma shader_feature _LAYER_TILING_COUPLED_WITH_UNIFORM_OBJECT_SCALE
     #pragma shader_feature _ _LAYER_MAPPING_PLANAR_BLENDMASK _LAYER_MAPPING_TRIPLANAR_BLENDMASK
     #pragma shader_feature _ _LAYER_MAPPING_PLANAR0 _LAYER_MAPPING_TRIPLANAR0
     #pragma shader_feature _ _LAYER_MAPPING_PLANAR1 _LAYER_MAPPING_TRIPLANAR1

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/LayeredLitTessellation.shader

         _TessellationShapeFactor("Tessellation shape factor", Range(0.0, 1.0)) = 0.75 // Only use with Phong
         _TessellationBackFaceCullEpsilon("Tessellation back face epsilon", Range(-1.0, 0.0)) = -0.25
         [ToggleOff] _TessellationObjectScale("Tessellation object scale", Float) = 0.0
+        [ToggleOff] _TessellationTilingScale("Tessellation tiling scale", Float) = 1.0
         // TODO: Handle culling mode for backface culling
     }
 
     // Default is _TESSELLATION_PHONG
     #pragma shader_feature _ _TESSELLATION_DISPLACEMENT _TESSELLATION_DISPLACEMENT_PHONG
     #pragma shader_feature _TESSELLATION_OBJECT_SCALE
+    #pragma shader_feature _TESSELLATION_TILING_SCALE
-    #pragma shader_feature _LAYER_TILING_UNIFORM_SCALE
+    #pragma shader_feature _LAYER_TILING_COUPLED_WITH_UNIFORM_OBJECT_SCALE
     #pragma shader_feature _ _LAYER_MAPPING_PLANAR_BLENDMASK _LAYER_MAPPING_TRIPLANAR_BLENDMASK
     #pragma shader_feature _ _LAYER_MAPPING_PLANAR0 _LAYER_MAPPING_TRIPLANAR0
     #pragma shader_feature _ _LAYER_MAPPING_PLANAR1 _LAYER_MAPPING_TRIPLANAR1

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Editor/BaseLitUI.cs

             public static GUIContent tessellationShapeFactorText = new GUIContent("Shape factor", "Strength of Phong tessellation shape (lerp factor)");
             public static GUIContent tessellationBackFaceCullEpsilonText = new GUIContent("Triangle culling Epsilon", "If -1.0 back face culling is enabled for tessellation, higher number mean more aggressive culling and better performance");
             public static GUIContent tessellationObjectScaleText = new GUIContent("Enable object scale", "Tessellation displacement will take into account the object scale - Only work with uniform positive scale");
+            public static GUIContent tessellationTilingScaleText = new GUIContent("Enable tiling scale", "Tessellation displacement will take into account the tiling scale - Only work with uniform positive scale");
         }
 
         public enum TessellationMode
         protected const string kTessellationBackFaceCullEpsilon = "_TessellationBackFaceCullEpsilon";
         protected MaterialProperty tessellationObjectScale = null;
         protected const string kTessellationObjectScale = "_TessellationObjectScale";
+        protected MaterialProperty tessellationTilingScale = null;
+        protected const string kTessellationTilingScale = "_TessellationTilingScale";
 
         protected override void FindBaseMaterialProperties(MaterialProperty[] props)
         {
             tessellationShapeFactor = FindProperty(kTessellationShapeFactor, props, false);
             tessellationBackFaceCullEpsilon = FindProperty(kTessellationBackFaceCullEpsilon, props, false);
             tessellationObjectScale = FindProperty(kTessellationObjectScale, props, false);
+            tessellationTilingScale = FindProperty(kTessellationTilingScale, props, false);
         }
 
         void TessellationModePopup()
                     m_MaterialEditor.ShaderProperty(tessellationBackFaceCullEpsilon, StylesBaseLit.tessellationBackFaceCullEpsilonText);
                 }
                 m_MaterialEditor.ShaderProperty(tessellationObjectScale, StylesBaseLit.tessellationObjectScaleText);
+                m_MaterialEditor.ShaderProperty(tessellationTilingScale, StylesBaseLit.tessellationTilingScaleText);
                 EditorGUI.indentLevel--;
             }
         }
                     material.EnableKeyword("_TESSELLATION_DISPLACEMENT_PHONG");
                 }
 
-                bool tessellationObjectScaleEnable = material.GetFloat(kTessellationObjectScale) == 1.0;
+                bool tessellationObjectScaleEnable = material.GetFloat(kTessellationObjectScale) > 0.0;
+
+                bool tessellationTilingScaleEnable = material.GetFloat(kTessellationTilingScale) > 0.0;
+                SetKeyword(material, "_TESSELLATION_TILING_SCALE", tessellationTilingScaleEnable);
             }
         }
 

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

                         input.positionWS, input.worldToTangent[2].xyz, layerTexCoord);
 }
 
+// Note: This function is call by both Per vertex and Per pixel displacement
 float GetMaxDisplacement()
 {
     float maxDisplacement = 0.0;
 // Calculate displacement for per vertex displacement mapping
 float ComputePerVertexDisplacement(LayerTexCoord layerTexCoord, float4 vertexColor, float lod)
 {
-    return (SAMPLE_UVMAPPING_TEXTURE2D_LOD(_HeightMap, sampler_HeightMap, layerTexCoord.base, lod).r - _HeightCenter) * _HeightAmplitude;
+    float height = (SAMPLE_UVMAPPING_TEXTURE2D_LOD(_HeightMap, sampler_HeightMap, layerTexCoord.base, lod).r - _HeightCenter) * _HeightAmplitude;
+    #ifdef _TESSELLATION_TILING_SCALE
+    // When we change the tiling, we have want to conserve the ratio with the displacement (and this is consistent with per pixel displacement)
+    height /= max(_BaseColorMap_ST.x, _BaseColorMap_ST.y);
+    #endif
+    return height;
 }
 
 void GetSurfaceAndBuiltinData(FragInputs input, float3 V, inout PositionInputs posInput, out SurfaceData surfaceData, out BuiltinData builtinData)
     // On all layers (but not on blend mask) we can scale the tiling with object scale (only uniform supported)
     // Note: the object scale doesn't affect planar/triplanar mapping as they already handle the object scale.
     float tileObjectScale = 1.0;
-#ifdef _LAYER_TILING_UNIFORM_SCALE
+#ifdef _LAYER_TILING_COUPLED_WITH_UNIFORM_OBJECT_SCALE
     // Extract scaling from world transform
     float4x4 worldTransform = GetObjectToWorldMatrix();
     // assuming uniform scaling, take only the first column
                         input.positionWS, input.worldToTangent[2].xyz, layerTexCoord);
 }
 
+void ApplyTessellationTileScale(inout float height0, inout float height1, inout float height2, inout float height3)
+{
+    // When we change the tiling, we have want to conserve the ratio with the displacement (and this is consistent with per pixel displacement)
+#ifdef _TESSELLATION_TILING_SCALE
+    float tileObjectScale = 1.0;
+    #ifdef _LAYER_TILING_COUPLED_WITH_UNIFORM_OBJECT_SCALE
+    // Extract scaling from world transform
+    float4x4 worldTransform = GetObjectToWorldMatrix();
+    // assuming uniform scaling, take only the first column
+    tileObjectScale = length(float3(worldTransform._m00, worldTransform._m01, worldTransform._m02));
+    #endif  
+
+    height0 /= _LayerTiling0 * max(_BaseColorMap0_ST.x, _BaseColorMap0_ST.y);
+    #if !defined(_MAIN_LAYER_INFLUENCE_MODE)
+    height0 *= tileObjectScale;  // We only affect layer0 in case we are not in influence mode (i.e we should not change the base object)
+    #endif
+    height1 /= tileObjectScale * _LayerTiling1 * max(_BaseColorMap1_ST.x, _BaseColorMap1_ST.y);
+    height2 /= tileObjectScale * _LayerTiling2 * max(_BaseColorMap2_ST.x, _BaseColorMap2_ST.y);
+    height3 /= tileObjectScale * _LayerTiling3 * max(_BaseColorMap3_ST.x, _BaseColorMap3_ST.y);
+#endif
+}
+
 // This function is just syntaxic sugar to nullify height not used based on heightmap avaibility and layer
 void SetEnabledHeightByLayer(inout float height0, inout float height1, inout float height2, inout float height3)
 {
 
 // Return the maximun amplitude use by all enabled heightmap
 // use for tessellation culling and per pixel displacement
+// TODO: For vertex displacement this should take into account the modification in ApplyTessellationTileScale but it should be conservative here (as long as tiling is not negative)
 float GetMaxDisplacement()
 {
     float maxDisplacement = 0.0;
     float height1 = (SAMPLE_UVMAPPING_TEXTURE2D_LOD(_HeightMap1, SAMPLER_HEIGHTMAP_IDX, layerTexCoord.base1, lod).r - _LayerCenterOffset1) * _LayerHeightAmplitude1;
     float height2 = (SAMPLE_UVMAPPING_TEXTURE2D_LOD(_HeightMap2, SAMPLER_HEIGHTMAP_IDX, layerTexCoord.base2, lod).r - _LayerCenterOffset2) * _LayerHeightAmplitude2;
     float height3 = (SAMPLE_UVMAPPING_TEXTURE2D_LOD(_HeightMap3, SAMPLER_HEIGHTMAP_IDX, layerTexCoord.base3, lod).r - _LayerCenterOffset3) * _LayerHeightAmplitude3;
+    ApplyTessellationTileScale(height0, height1, height2, height3); // Only apply with per vertex displacement
     SetEnabledHeightByLayer(height0, height1, height2, height3);
     float heightResult = BlendLayeredScalar(height0, height1, height2, height3, weights);
 

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

 float _TessellationShapeFactor;
 float _TessellationBackFaceCullEpsilon;
 float _TessellationObjectScale;
+float _TessellationTilingScale;
 #endif

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitTessellation.shader

         _TessellationShapeFactor("Tessellation shape factor", Range(0.0, 1.0)) = 0.75 // Only use with Phong
         _TessellationBackFaceCullEpsilon("Tessellation back face epsilon", Range(-1.0, 0.0)) = -0.25
         [ToggleOff] _TessellationObjectScale("Tessellation object scale", Float) = 0.0
+        [ToggleOff] _TessellationTilingScale("Tessellation tiling height scale", Float) = 1.0
          // TODO: Handle culling mode for backface culling
     }
 
     // Default is _TESSELLATION_PHONG
     #pragma shader_feature _ _TESSELLATION_DISPLACEMENT _TESSELLATION_DISPLACEMENT_PHONG
     #pragma shader_feature _TESSELLATION_OBJECT_SCALE
+    #pragma shader_feature _TESSELLATION_TILING_SCALE
 
     #pragma shader_feature _ _MAPPING_PLANAR _MAPPING_TRIPLANAR
     #pragma shader_feature _NORMALMAP_TANGENT_SPACE