HDRenderPipeline: Clean some code in Tessellation

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

             // DYNAMICLIGHTMAP_ON is used when we have an "enlighten lightmap" ie a lightmap updated at runtime by enlighten.This lightmap contain indirect lighting from realtime lights and realtime emissive material.Offline baked lighting(from baked material / light, 
             // both direct and indirect lighting) will hand up in the "regular" lightmap->LIGHTMAP_ON.
 
+            // No tessellation for Meta pass
+            #undef TESSELLATION_ON
+
             #define SHADERPASS SHADERPASS_LIGHT_TRANSPORT
             #include "../../Material/Material.hlsl"            
             #include "../Lit/ShaderPass/LitMetaPass.hlsl"

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

-float4 TessellationEdge(float3 p0, float3 p1, float3 p2, float3 n0, float3 n1, float3 n2)
+float4 GetTessellationFactors(float3 p0, float3 p1, float3 p2, float3 n0, float3 n1, float3 n2)
 {
     float maxDisplacement = ADD_ZERO_IDX(_HeightAmplitude);
 #ifdef _LAYER_COUNT
         float2(0.0, 0.0),
 #endif
         input.positionWS, 
-#ifdef VARYINGS_DS_NEED_NORMAL
-#else
-        float3(0.0, 0.0, 1.0),
-#endif
         layerTexCoord);
 
     // TODO: For now just use Layer0, but we are suppose to apply the same heightmap blending than in the pixel shader
     float height = 0.0;
 #endif
 
-    float3 displ = float3(0.0, 0.0, 0.0);
-#ifdef VARYINGS_DS_NEED_NORMAL
-    displ = height * input.normalWS;
-#endif
+    float3 displ = height * input.normalWS;
+
         // Applying scaling of the object if requested
 #ifdef _TESSELLATION_OBJECT_SCALE
     displ *= input.objectScale;

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

             // both direct and indirect lighting) will hand up in the "regular" lightmap->LIGHTMAP_ON.
 
 			// No tessellation for Meta pass
+            #undef TESSELLATION_ON
 
             #define SHADERPASS SHADERPASS_LIGHT_TRANSPORT
             #include "../../Material/Material.hlsl"            
 
             ENDHLSL
         }
-
+        
         Pass
         {
             Name "ShadowCaster"
 
             ENDHLSL
         }
-
+        
         Pass
         {
             Name "Motion Vectors"
 
             ENDHLSL
         }
-
+   
         Pass
         {
             Name "Distortion" // Name is not used
 
             ENDHLSL
         }
+
     }
 
     CustomEditor "Experimental.Rendering.HDPipeline.LitGUI"

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/ShaderPass/LitVelocityPass.hlsl

 
 // Tesselation require normal
 #if defined(TESSELLATION_ON) || REQUIRE_TANGENT_TO_WORLD
-// #define ATTRIBUTES_NEED_NORMAL
+// #define ATTRIBUTES_NEED_NORMAL - When reenable, think to also enable code in VertMesh.hlsl
 #endif
 #if REQUIRE_TANGENT_TO_WORLD
 #define ATTRIBUTES_NEED_TANGENT

Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderPass/TessellationShare.hlsl

     float3 p1 = varying1.vmesh.positionWS;
     float3 p2 = varying2.vmesh.positionWS;
 
-#ifdef VARYINGS_DS_NEED_NORMAL
-#else
-    float3 n0 = float3(0.0, 0.0, 0.0);
-    float3 n1 = float3(0.0, 0.0, 0.0);
-    float3 n2 = float3(0.0, 0.0, 0.0);
-#endif    
-    float4 tf = TessellationEdge(p0, p1, p2, n0, n1, n2);
+    float4 tf = GetTessellationFactors(p0, p1, p2, n0, n1, n2);
     TessellationFactors output;
     output.edge[0] = tf.x;
     output.edge[1] = tf.y;
     float3 p1 = varying1.vmesh.positionWS;
     float3 p2 = varying2.vmesh.positionWS;
 
-#ifdef VARYINGS_DS_NEED_NORMAL
-#else
-    float3 n0 = float3(0.0, 0.0, 0.0);
-    float3 n1 = float3(0.0, 0.0, 0.0);
-    float3 n2 = float3(0.0, 0.0, 0.0);
-#endif
 
     varying.vmesh.positionWS = PhongTessellation(   varying.vmesh.positionWS,
                                                     p0, p1, p2, n0, n1, n2,

Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderPass/VaryingMesh.hlsl

 // We can deduce these defines from the other defines
 // We need to pass to DS any varying required by pixel shader
 // If we have required an attributes that is not present in varyings it mean we will be for DS
-#if defined(VARYINGS_NEED_TANGENT_TO_WORLD) || defined(ATTRIBUTES_NEED_NORMAL)
-#define VARYINGS_DS_NEED_NORMAL
-#endif
 #if defined(VARYINGS_NEED_TANGENT_TO_WORLD) || defined(ATTRIBUTES_NEED_TANGENT)
 #define VARYINGS_DS_NEED_TANGENT
 #endif
 struct VaryingsMeshToDS
 {
     float3 positionWS;
-#ifdef VARYINGS_DS_NEED_NORMAL
-#endif
 #ifdef VARYINGS_DS_NEED_TANGENT
     float4 tangentWS;
 #endif
 struct PackedVaryingsMeshToDS
 {
     float3 interpolators0 : INTERNALTESSPOS; // positionWS
+    float3 interpolators1 : NORMAL; // NormalWS
-#ifdef VARYINGS_DS_NEED_NORMAL
-    float3 interpolators1 : NORMAL;
-#endif
 #ifdef VARYINGS_DS_NEED_TANGENT
     float4 interpolators2 : TANGENT;
 #endif
     PackedVaryingsMeshToDS output;
 
     output.interpolators0 = input.positionWS;
-#ifdef VARYINGS_DS_NEED_NORMAL
-#endif
 #ifdef VARYINGS_DS_NEED_TANGENT
     output.interpolators2 = input.tangentWS;
 #endif
     VaryingsMeshToDS output;
 
     output.positionWS = input.interpolators0;
-#ifdef VARYINGS_DS_NEED_NORMAL
-#endif
 #ifdef VARYINGS_DS_NEED_TANGENT
     output.tangentWS = input.interpolators2;
 #endif
     VaryingsMeshToDS ouput;
 
     TESSELLATION_INTERPOLATE_BARY(positionWS, baryCoords);
-#ifdef VARYINGS_DS_NEED_NORMAL
-#endif
 #ifdef VARYINGS_DS_NEED_TANGENT
     // This will interpolate the sign but should be ok in practice as we may expect a triangle to have same sign (? TO CHECK)
     TESSELLATION_INTERPOLATE_BARY(tangentWS, baryCoords);

Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderPass/VertMesh.hlsl

     output.objectScale.y = length(float3(worldTransform._m10, worldTransform._m11, worldTransform._m12));
     output.objectScale.z = length(float3(worldTransform._m20, worldTransform._m21, worldTransform._m22));
     #endif
-    // TODO deal with camera center rendering and instancing (This is the reason why we always perform tow steps transform to clip space + instancing matrix)  
-    #if defined(VARYINGS_NEED_TANGENT_TO_WORLD) || defined(VARYINGS_DS_NEED_NORMAL)
+    // TODO: deal with camera center rendering and instancing (This is the reason why we always perform tow steps transform to clip space + instancing matrix)  
+    // TODO: TEMP: Velocity has a flow as it doens't have normal. This need to be fix. In the mean time, generate fix normal so compiler doesn't complain - When fix, think to also enable ATTRIBUTES_NEED_NORMAL in LitVelocityPass.hlsl
+    #if SHADERPASS == SHADERPASS_VELOCITY
+    output.normalWS = float3(0.0, 0.0, 1.0);
+    #else
     output.normalWS = TransformObjectToWorldNormal(input.normalOS);
     #endif
     #if defined(VARYINGS_NEED_TANGENT_TO_WORLD) || defined(VARYINGS_DS_NEED_TANGENT)