Merge pull request #1587 from Unity-Technologies/Improve-camera-relative-rendering

HDRP: Improve camera relative rendering precision on object

com.unity.render-pipelines.core/CoreRP/ShaderLibrary/Common.hlsl

 
 // space at the end of the variable name
 // WS: world space
+// RWS: Camera-Relative world space. A space where the translation of the camera have already been substract in order to improve precision
 // VS: view space
 // OS: object space
 // CS: Homogenous clip spaces

com.unity.render-pipelines.core/CoreRP/ShaderLibrary/UnityInstancing.hlsl

         #endif
     UNITY_INSTANCING_BUFFER_END(unity_Builtins2)
 
+
-    #define UNITY_MATRIX_M     UNITY_ACCESS_INSTANCED_PROP(unity_Builtins0, unity_ObjectToWorldArray)
+    #ifdef MODIFY_MATRIX_FOR_CAMERA_RELATIVE_RENDERING
+    #define UNITY_MATRIX_M  ApplyCameraTranslationToMatrix(UNITY_ACCESS_INSTANCED_PROP(unity_Builtins0, unity_ObjectToWorldArray))
+    #else
+    #define UNITY_MATRIX_M  UNITY_ACCESS_INSTANCED_PROP(unity_Builtins0, unity_ObjectToWorldArray)
+    #endif
-    #define UNITY_MATRIX_I_M     UNITY_ACCESS_INSTANCED_PROP(MERGE_UNITY_BUILTINS_INDEX(UNITY_WORLDTOOBJECTARRAY_CB), unity_WorldToObjectArray)
+    #ifdef MODIFY_MATRIX_FOR_CAMERA_RELATIVE_RENDERING
+    #define UNITY_MATRIX_I_M    ApplyCameraTranslationToInverseMatrix(UNITY_ACCESS_INSTANCED_PROP(MERGE_UNITY_BUILTINS_INDEX(UNITY_WORLDTOOBJECTARRAY_CB), unity_WorldToObjectArray))
+    #else
+    #define UNITY_MATRIX_I_M    UNITY_ACCESS_INSTANCED_PROP(MERGE_UNITY_BUILTINS_INDEX(UNITY_WORLDTOOBJECTARRAY_CB), unity_WorldToObjectArray)
+    #endif
 
 #else // UNITY_INSTANCING_ENABLED
 

com.unity.render-pipelines.high-definition/CHANGELOG.md

 ### Changed
 - Re-enable shadow mask mode in debug view
 - SSS and Transmission code have been refactored to be able to share it between various material. Guidelines are in SubsurfaceScattering.hlsl
-- Change code in area light with LTC for Lit shader. Magnitude is now take from FGD texture instead of a separate texture.
+- Change code in area light with LTC for Lit shader. Magnitude is now take from FGD texture instead of a separate texture
+- Improve camera relative rendering: We now apply camera translation on the model matrix, so before the TransformObjectToWorld(). Note: unity_WorldToObject and unity_ObjectToWorld must never be used directly.
+- Rename positionWS to positionRWS (Camera relative world position) at a lot of places (mainly in interpolator and FragInputs). In case of custom shader user will be required to update their code. 
 
 ### Fixed
 - Fix contact shadows applied on transmission

com.unity.render-pipelines.high-definition/HDRP/Editor/ShaderGraph/HDPBRPass.template

         $AttributesMesh.uv2:                    #define ATTRIBUTES_NEED_TEXCOORD2
         $AttributesMesh.uv3:                    #define ATTRIBUTES_NEED_TEXCOORD3
         $AttributesMesh.color:                  #define ATTRIBUTES_NEED_COLOR
-        $VaryingsMeshToPS.positionWS:           #define VARYINGS_NEED_POSITION_WS
+        $VaryingsMeshToPS.positionRWS:          #define VARYINGS_NEED_POSITION_WS
         $VaryingsMeshToPS.normalWS:             #define VARYINGS_NEED_TANGENT_TO_WORLD
         $VaryingsMeshToPS.texCoord0:            #define VARYINGS_NEED_TEXCOORD0
         $VaryingsMeshToPS.texCoord1:            #define VARYINGS_NEED_TEXCOORD1
             $VertexDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          TransformWorldToViewDir(output.WorldSpaceBiTangent);
             $VertexDescriptionInputs.TangentSpaceBiTangent:     output.TangentSpaceBiTangent =       float3(0.0f, 1.0f, 0.0f);
             $VertexDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         input.positionOS;
-            $VertexDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          TransformObjectToWorld(input.positionOS);
+            $VertexDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          GetAbsolutePositionWS(TransformObjectToWorld(input.positionOS));
             $VertexDescriptionInputs.ViewSpacePosition:         output.ViewSpacePosition =           TransformWorldToView(output.WorldSpacePosition);
             $VertexDescriptionInputs.TangentSpacePosition:      output.TangentSpacePosition =        float3(0.0f, 0.0f, 0.0f);
             $VertexDescriptionInputs.WorldSpaceViewDirection:   output.WorldSpaceViewDirection =     GetWorldSpaceNormalizeViewDir(output.WorldSpacePosition);
             output.worldToTangent = k_identity3x3;
             output.positionSS = input.positionCS;       // input.positionCS is SV_Position
 
-            $FragInputs.positionWS:         output.positionWS = input.positionWS;
+            $FragInputs.positionRWS:        output.positionRWS = input.positionRWS;
             $FragInputs.worldToTangent:     output.worldToTangent = BuildWorldToTangent(input.tangentWS, input.normalWS);
             $FragInputs.texCoord0:          output.texCoord0 = input.texCoord0;
             $FragInputs.texCoord1:          output.texCoord1 = input.texCoord1;
             $SurfaceDescriptionInputs.ViewSpaceNormal:           output.ViewSpaceNormal =             mul(output.WorldSpaceNormal, (float3x3) UNITY_MATRIX_I_V);         // transposed multiplication by inverse matrix to handle normal scale
             $SurfaceDescriptionInputs.TangentSpaceNormal:        output.TangentSpaceNormal =          float3(0.0f, 0.0f, 1.0f);
             $SurfaceDescriptionInputs.WorldSpaceTangent:         output.WorldSpaceTangent =           input.worldToTangent[0].xyz;
-            $SurfaceDescriptionInputs.ObjectSpaceTangent:        output.ObjectSpaceTangent =          mul((float3x3) unity_WorldToObject, output.WorldSpaceTangent);
-            $SurfaceDescriptionInputs.ViewSpaceTangent:          output.ViewSpaceTangent =            mul((float3x3) UNITY_MATRIX_V, output.WorldSpaceTangent);
+            $SurfaceDescriptionInputs.ObjectSpaceTangent:        output.ObjectSpaceTangent =          TransformWorldToObjectDir(output.WorldSpaceTangent);
+            $SurfaceDescriptionInputs.ViewSpaceTangent:          output.ViewSpaceTangent =            TransformWorldToViewDir(output.WorldSpaceTangent);
-            $SurfaceDescriptionInputs.ObjectSpaceBiTangent:      output.ObjectSpaceBiTangent =        mul((float3x3) unity_WorldToObject, output.WorldSpaceBiTangent);
-            $SurfaceDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          mul((float3x3) UNITY_MATRIX_V, output.WorldSpaceBiTangent);
+            $SurfaceDescriptionInputs.ObjectSpaceBiTangent:      output.ObjectSpaceBiTangent =        TransformWorldToObjectDir(output.WorldSpaceBiTangent);
+            $SurfaceDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          TransformWorldToViewDir(output.WorldSpaceBiTangent);
-            $SurfaceDescriptionInputs.ObjectSpaceViewDirection:  output.ObjectSpaceViewDirection =    mul((float3x3) unity_WorldToObject, output.WorldSpaceViewDirection);
-            $SurfaceDescriptionInputs.ViewSpaceViewDirection:    output.ViewSpaceViewDirection =      mul((float3x3) UNITY_MATRIX_V, output.WorldSpaceViewDirection);
+            $SurfaceDescriptionInputs.ObjectSpaceViewDirection:  output.ObjectSpaceViewDirection =    TransformWorldToObjectDir(output.WorldSpaceViewDirection);
+            $SurfaceDescriptionInputs.ViewSpaceViewDirection:    output.ViewSpaceViewDirection =      TransformWorldToViewDir(output.WorldSpaceViewDirection);
-            $SurfaceDescriptionInputs.WorldSpacePosition:        // TODO: FragInputs.positionWS is badly named -- it's camera relative, not in world space
-            $SurfaceDescriptionInputs.WorldSpacePosition:        // we have to fix it up here to match graph input expectations
-            $SurfaceDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          input.positionWS + _WorldSpaceCameraPos;
-            $SurfaceDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         mul(unity_WorldToObject, float4(input.positionWS + _WorldSpaceCameraPos, 1.0f)).xyz;
-            $SurfaceDescriptionInputs.ViewSpacePosition:         float4 posViewSpace =                mul(UNITY_MATRIX_V, float4(input.positionWS, 1.0f));
+            $SurfaceDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          GetAbsolutePositionWS(input.positionRWS);
+            $SurfaceDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         TransformWorldToObject(input.positionRWS);
+            $SurfaceDescriptionInputs.ViewSpacePosition:         float4 posViewSpace =                TransformWorldToView(input.positionRWS);
-            $SurfaceDescriptionInputs.ScreenPosition:            output.ScreenPosition =              ComputeScreenPos(TransformWorldToHClip(input.positionWS), _ProjectionParams.x);
+            $SurfaceDescriptionInputs.ScreenPosition:            output.ScreenPosition =              ComputeScreenPos(TransformWorldToHClip(input.positionRWS), _ProjectionParams.x);
-            
+
             $SurfaceDescriptionInputs.VertexColor:               output.VertexColor =                 input.color;
 
             $SurfaceDescriptionInputs.FaceSign:                  output.FaceSign =    input.isFrontFace;
         float3 bentNormalWS =                   surfaceData.normalWS;           // TODO : make bent normals work
 
         builtinData.opacity =                   surfaceDescription.Alpha;
-        builtinData.bakeDiffuseLighting =       SampleBakedGI(fragInputs.positionWS, bentNormalWS, fragInputs.texCoord1, fragInputs.texCoord2);    // see GetBuiltinData()
+        builtinData.bakeDiffuseLighting =       SampleBakedGI(fragInputs.positionRWS, bentNormalWS, fragInputs.texCoord1, fragInputs.texCoord2);    // see GetBuiltinData()
 
         // It is safe to call this function here as surfaceData have been filled
         // We want to know if we must enable transmission on GI for SSS material, if the material have no SSS, this code will be remove by the compiler.
             // however it will not optimize the lightprobe case due to the proxy volume relying on dynamic if (we rely must get right of this dynamic if), not a problem for SH9, but a problem for proxy volume.
             // TODO: optimize more this code.
             // Add GI transmission contribution by resampling the GI for inverted vertex normal
-            builtinData.bakeDiffuseLighting += SampleBakedGI(fragInputs.positionWS, -fragInputs.worldToTangent[2], fragInputs.texCoord1, fragInputs.texCoord2) * bsdfData.transmittance;
+            builtinData.bakeDiffuseLighting += SampleBakedGI(fragInputs.positionRWS, -fragInputs.worldToTangent[2], fragInputs.texCoord1, fragInputs.texCoord2) * bsdfData.transmittance;
-        float4 shadowMask = SampleShadowMask(fragInputs.positionWS, fragInputs.texCoord1);
+        float4 shadowMask = SampleShadowMask(fragInputs.positionRWS, fragInputs.texCoord1);
         builtinData.shadowMask0 = shadowMask.x;
         builtinData.shadowMask1 = shadowMask.y;
         builtinData.shadowMask2 = shadowMask.z;

com.unity.render-pipelines.high-definition/HDRP/Editor/ShaderGraph/HDPBRSubShader.cs

             RequiredFields = new List<string>()
             {
                 "FragInputs.worldToTangent",
-                "FragInputs.positionWS",
+                "FragInputs.positionRWS",
                 "FragInputs.texCoord1",
                 "FragInputs.texCoord2"
             },
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             },
             RequiredFields = new List<string>()
             {
-                "FragInputs.positionWS",
+                "FragInputs.positionRWS",
             },
             StencilOverride = new List<string>()
             {
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             RequiredFields = new List<string>()
             {
                 "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {
             RequiredFields = new List<string>()
             {
 //                "FragInputs.worldToTangent",
-//                "FragInputs.positionWS",
+//                "FragInputs.positionRWS",
             },
             PixelShaderSlots = new List<int>()
             {

com.unity.render-pipelines.high-definition/HDRP/Editor/ShaderGraph/HDSubShaderUtilities.cs

         struct VaryingsMeshToPS
         {
             [Semantic("SV_Position")]           Vector4 positionCS;
-            [Optional]                          Vector3 positionWS;
+            [Optional]                          Vector3 positionRWS;
             [Optional]                          Vector3 normalWS;
             [Optional]                          Vector4 tangentWS;      // w contain mirror sign
             [Optional]                          Vector2 texCoord0;
 
             public static Dependency[] tessellationDependencies = new Dependency[]
             {
-                new Dependency("VaryingsMeshToPS.positionWS",       "VaryingsMeshToDS.positionWS"),
+                new Dependency("VaryingsMeshToPS.positionRWS",       "VaryingsMeshToDS.positionRWS"),
                 new Dependency("VaryingsMeshToPS.normalWS",         "VaryingsMeshToDS.normalWS"),
                 new Dependency("VaryingsMeshToPS.tangentWS",        "VaryingsMeshToDS.tangentWS"),
                 new Dependency("VaryingsMeshToPS.texCoord0",        "VaryingsMeshToDS.texCoord0"),
 
             public static Dependency[] standardDependencies = new Dependency[]
             {
-                new Dependency("VaryingsMeshToPS.positionWS",       "AttributesMesh.positionOS"),
+                new Dependency("VaryingsMeshToPS.positionRWS",       "AttributesMesh.positionOS"),
                 new Dependency("VaryingsMeshToPS.normalWS",         "AttributesMesh.normalOS"),
                 new Dependency("VaryingsMeshToPS.tangentWS",        "AttributesMesh.tangentOS"),
                 new Dependency("VaryingsMeshToPS.texCoord0",        "AttributesMesh.uv0"),
 
         struct VaryingsMeshToDS
         {
-            Vector3 positionWS;
+            Vector3 positionRWS;
             Vector3 normalWS;
             [Optional]      Vector4 tangentWS;
             [Optional]      Vector2 texCoord0;
         {
             public static Dependency[] dependencies = new Dependency[]
             {
-                new Dependency("FragInputs.positionWS",         "VaryingsMeshToPS.positionWS"),
+                new Dependency("FragInputs.positionRWS",        "VaryingsMeshToPS.positionRWS"),
                 new Dependency("FragInputs.worldToTangent",     "VaryingsMeshToPS.tangentWS"),
                 new Dependency("FragInputs.worldToTangent",     "VaryingsMeshToPS.normalWS"),
                 new Dependency("FragInputs.texCoord0",          "VaryingsMeshToPS.texCoord0"),
                 new Dependency("SurfaceDescriptionInputs.ObjectSpaceBiTangent",      "SurfaceDescriptionInputs.WorldSpaceBiTangent"),
                 new Dependency("SurfaceDescriptionInputs.ViewSpaceBiTangent",        "SurfaceDescriptionInputs.WorldSpaceBiTangent"),
 
-                new Dependency("SurfaceDescriptionInputs.WorldSpacePosition",        "FragInputs.positionWS"),
-                new Dependency("SurfaceDescriptionInputs.ObjectSpacePosition",       "FragInputs.positionWS"),
-                new Dependency("SurfaceDescriptionInputs.ViewSpacePosition",         "FragInputs.positionWS"),
+                new Dependency("SurfaceDescriptionInputs.WorldSpacePosition",        "FragInputs.positionRWS"),
+                new Dependency("SurfaceDescriptionInputs.ObjectSpacePosition",       "FragInputs.positionRWS"),
+                new Dependency("SurfaceDescriptionInputs.ViewSpacePosition",         "FragInputs.positionRWS"),
-                new Dependency("SurfaceDescriptionInputs.WorldSpaceViewDirection",   "FragInputs.positionWS"),                   // we build WorldSpaceViewDirection using FragInputs.positionWS in GetWorldSpaceNormalizeViewDir()
+                new Dependency("SurfaceDescriptionInputs.WorldSpaceViewDirection",   "FragInputs.positionRWS"),                   // we build WorldSpaceViewDirection using FragInputs.positionRWS in GetWorldSpaceNormalizeViewDir()
                 new Dependency("SurfaceDescriptionInputs.ObjectSpaceViewDirection",  "SurfaceDescriptionInputs.WorldSpaceViewDirection"),
                 new Dependency("SurfaceDescriptionInputs.ViewSpaceViewDirection",    "SurfaceDescriptionInputs.WorldSpaceViewDirection"),
                 new Dependency("SurfaceDescriptionInputs.TangentSpaceViewDirection", "SurfaceDescriptionInputs.WorldSpaceViewDirection"),

com.unity.render-pipelines.high-definition/HDRP/Editor/ShaderGraph/HDUnlitPassForward.template

         $AttributesMesh.uv2:                    #define ATTRIBUTES_NEED_TEXCOORD2
         $AttributesMesh.uv3:                    #define ATTRIBUTES_NEED_TEXCOORD3
         $AttributesMesh.color:                  #define ATTRIBUTES_NEED_COLOR
-        $VaryingsMeshToPS.positionWS:           #define VARYINGS_NEED_POSITION_WS
+        $VaryingsMeshToPS.positionRWS:          #define VARYINGS_NEED_POSITION_WS
         $VaryingsMeshToPS.normalWS:             #define VARYINGS_NEED_TANGENT_TO_WORLD
         $VaryingsMeshToPS.texCoord0:            #define VARYINGS_NEED_TEXCOORD0
         $VaryingsMeshToPS.texCoord1:            #define VARYINGS_NEED_TEXCOORD1
             $VertexDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          TransformWorldToViewDir(output.WorldSpaceBiTangent);
             $VertexDescriptionInputs.TangentSpaceBiTangent:     output.TangentSpaceBiTangent =       float3(0.0f, 1.0f, 0.0f);
             $VertexDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         input.positionOS;
-            $VertexDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          TransformObjectToWorld(input.positionOS);
+            $VertexDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          GetAbsolutePositionWS(TransformObjectToWorld(input.positionOS));
             $VertexDescriptionInputs.ViewSpacePosition:         output.ViewSpacePosition =           TransformWorldToView(output.WorldSpacePosition);
             $VertexDescriptionInputs.TangentSpacePosition:      output.TangentSpacePosition =        float3(0.0f, 0.0f, 0.0f);
             $VertexDescriptionInputs.WorldSpaceViewDirection:   output.WorldSpaceViewDirection =     GetWorldSpaceNormalizeViewDir(output.WorldSpacePosition);
             output.worldToTangent = k_identity3x3;
             output.positionSS = input.positionCS;       // input.positionCS is SV_Position
 
-            $FragInputs.positionWS:         output.positionWS = input.positionWS;
+            $FragInputs.positionRWS:        output.positionRWS = input.positionRWS;
             $FragInputs.worldToTangent:     output.worldToTangent = BuildWorldToTangent(input.tangentWS, input.normalWS);
             $FragInputs.texCoord0:          output.texCoord0 = input.texCoord0;
             $FragInputs.texCoord1:          output.texCoord1 = input.texCoord1;
             $SurfaceDescriptionInputs.ViewSpaceNormal:           output.ViewSpaceNormal =             mul(output.WorldSpaceNormal, (float3x3) UNITY_MATRIX_I_V);         // transposed multiplication by inverse matrix to handle normal scale
             $SurfaceDescriptionInputs.TangentSpaceNormal:        output.TangentSpaceNormal =          float3(0.0f, 0.0f, 1.0f);
             $SurfaceDescriptionInputs.WorldSpaceTangent:         output.WorldSpaceTangent =           input.worldToTangent[0].xyz;
-            $SurfaceDescriptionInputs.ObjectSpaceTangent:        output.ObjectSpaceTangent =          mul((float3x3) unity_WorldToObject, output.WorldSpaceTangent);
-            $SurfaceDescriptionInputs.ViewSpaceTangent:          output.ViewSpaceTangent =            mul((float3x3) UNITY_MATRIX_V, output.WorldSpaceTangent);
+            $SurfaceDescriptionInputs.ObjectSpaceTangent:        output.ObjectSpaceTangent =          TransformWorldToObjectDir(output.WorldSpaceTangent);
+            $SurfaceDescriptionInputs.ViewSpaceTangent:          output.ViewSpaceTangent =            TransformWorldToViewDir(output.WorldSpaceTangent);
-            $SurfaceDescriptionInputs.ObjectSpaceBiTangent:      output.ObjectSpaceBiTangent =        mul((float3x3) unity_WorldToObject, output.WorldSpaceBiTangent);
-            $SurfaceDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          mul((float3x3) UNITY_MATRIX_V, output.WorldSpaceBiTangent);
+            $SurfaceDescriptionInputs.ObjectSpaceBiTangent:      output.ObjectSpaceBiTangent =        TransformWorldToObjectDir(output.WorldSpaceBiTangent);
+            $SurfaceDescriptionInputs.ViewSpaceBiTangent:        output.ViewSpaceBiTangent =          TransformWorldToViewDir(output.WorldSpaceBiTangent);
-            $SurfaceDescriptionInputs.ObjectSpaceViewDirection:  output.ObjectSpaceViewDirection =    mul((float3x3) unity_WorldToObject, output.WorldSpaceViewDirection);
-            $SurfaceDescriptionInputs.ViewSpaceViewDirection:    output.ViewSpaceViewDirection =      mul((float3x3) UNITY_MATRIX_V, output.WorldSpaceViewDirection);
+            $SurfaceDescriptionInputs.ObjectSpaceViewDirection:  output.ObjectSpaceViewDirection =    TransformWorldToObjectDir(output.WorldSpaceViewDirection);
+            $SurfaceDescriptionInputs.ViewSpaceViewDirection:    output.ViewSpaceViewDirection =      TransformWorldToViewDir(output.WorldSpaceViewDirection);
-            $SurfaceDescriptionInputs.WorldSpacePosition:        // TODO: FragInputs.positionWS is badly named -- it's camera relative, not in world space
-            $SurfaceDescriptionInputs.WorldSpacePosition:        // we have to fix it up here to match graph input expectations
-            $SurfaceDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          input.positionWS + _WorldSpaceCameraPos;
-            $SurfaceDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         mul(unity_WorldToObject, float4(input.positionWS + _WorldSpaceCameraPos, 1.0f)).xyz;
-            $SurfaceDescriptionInputs.ViewSpacePosition:         float4 posViewSpace =                mul(UNITY_MATRIX_V, float4(input.positionWS, 1.0f));
+            $SurfaceDescriptionInputs.WorldSpacePosition:        output.WorldSpacePosition =          GetAbsolutePositionWS(input.positionRWS);
+            $SurfaceDescriptionInputs.ObjectSpacePosition:       output.ObjectSpacePosition =         TransformWorldToObject(input.positionRWS);
+            $SurfaceDescriptionInputs.ViewSpacePosition:         float4 posViewSpace =                TransformWorldToView(input.positionRWS);
-            $SurfaceDescriptionInputs.ScreenPosition:            output.ScreenPosition =              ComputeScreenPos(TransformWorldToHClip(input.positionWS), _ProjectionParams.x);
-            
+            $SurfaceDescriptionInputs.ScreenPosition:            output.ScreenPosition =              ComputeScreenPos(TransformWorldToHClip(input.positionRWS), _ProjectionParams.x);
+
-            
+
             $SurfaceDescriptionInputs.VertexColor:               output.VertexColor =                 input.color;
 
             $SurfaceDescriptionInputs.FaceSign:                  output.FaceSign =    input.isFrontFace;

com.unity.render-pipelines.high-definition/HDRP/Material/LayeredLit/LayeredLitData.hlsl

 #endif
 
     GetLayerTexCoord(   input.texCoord0, input.texCoord1, input.texCoord2, input.texCoord3,
-                        input.positionWS, input.worldToTangent[2].xyz, layerTexCoord);
+                        input.positionRWS, input.worldToTangent[2].xyz, layerTexCoord);
 }
 
 void ApplyDisplacementTileScale(inout float height0, inout float height1, inout float height2, inout float height3)

com.unity.render-pipelines.high-definition/HDRP/Material/Lit/LitBuiltinData.hlsl

 
     // TODO: Sample lightmap/lightprobe/volume proxy
     // This should also handle projective lightmap
-    builtinData.bakeDiffuseLighting = SampleBakedGI(input.positionWS, bentNormalWS, input.texCoord1, input.texCoord2);
+    builtinData.bakeDiffuseLighting = SampleBakedGI(input.positionRWS, bentNormalWS, input.texCoord1, input.texCoord2);
 
     // It is safe to call this function here as surfaceData have been filled
     // We want to know if we must enable transmission on GI for SSS material, if the material have no SSS, this code will be remove by the compiler.
         // however it will not optimize the lightprobe case due to the proxy volume relying on dynamic if (we rely must get right of this dynamic if), not a problem for SH9, but a problem for proxy volume.
         // TODO: optimize more this code.
         // Add GI transmission contribution by resampling the GI for inverted vertex normal
-        builtinData.bakeDiffuseLighting += SampleBakedGI(input.positionWS, -input.worldToTangent[2], input.texCoord1, input.texCoord2) * bsdfData.transmittance;
+        builtinData.bakeDiffuseLighting += SampleBakedGI(input.positionRWS, -input.worldToTangent[2], input.texCoord1, input.texCoord2) * bsdfData.transmittance;
-    float4 shadowMask = SampleShadowMask(input.positionWS, input.texCoord1);
+    float4 shadowMask = SampleShadowMask(input.positionRWS, input.texCoord1);
     builtinData.shadowMask0 = shadowMask.x;
     builtinData.shadowMask1 = shadowMask.y;
     builtinData.shadowMask2 = shadowMask.z;
     #endif
                             input.texCoord0, input.texCoord1, input.texCoord2, input.texCoord3, _UVMappingMaskEmissive, _UVMappingMaskEmissive,
                             _EmissiveColorMap_ST.xy, _EmissiveColorMap_ST.zw, float2(0.0, 0.0), float2(0.0, 0.0), 1.0, false,
-                            input.positionWS, _TexWorldScaleEmissive,
+                            input.positionRWS, _TexWorldScaleEmissive,
                             mappingType, layerTexCoord);
 
     #ifndef LAYERED_LIT_SHADER

com.unity.render-pipelines.high-definition/HDRP/Material/Lit/LitData.hlsl

     layerTexCoord.vertexTangentWS0 = input.worldToTangent[0];
     layerTexCoord.vertexBitangentWS0 = input.worldToTangent[1];
 
-    // TODO: We should use relative camera position here - This will be automatic when we will move to camera relative space.
-    float3 dPdx = ddx_fine(input.positionWS);
-    float3 dPdy = ddy_fine(input.positionWS);
+    float3 dPdx = ddx_fine(input.positionRWS);
+    float3 dPdy = ddy_fine(input.positionRWS);
 
     float3 sigmaX = dPdx - dot(dPdx, vertexNormalWS) * vertexNormalWS;
     float3 sigmaY = dPdy - dot(dPdy, vertexNormalWS) * vertexNormalWS;
 // in function with FragInputs input as parameters
 // layerTexCoord must have been initialize to 0 outside of this function
 void GetLayerTexCoord(float2 texCoord0, float2 texCoord1, float2 texCoord2, float2 texCoord3,
-                      float3 positionWS, float3 vertexNormalWS, inout LayerTexCoord layerTexCoord)
+                      float3 positionRWS, float3 vertexNormalWS, inout LayerTexCoord layerTexCoord)
 {
     layerTexCoord.vertexNormalWS = vertexNormalWS;
     layerTexCoord.triplanarWeights = ComputeTriplanarWeights(vertexNormalWS);
     // Be sure that the compiler is aware that we don't use UV1 to UV3 for main layer so it can optimize code
     ComputeLayerTexCoord(   texCoord0, texCoord1, texCoord2, texCoord3, _UVMappingMask, _UVDetailsMappingMask,
                             _BaseColorMap_ST.xy, _BaseColorMap_ST.zw, _DetailMap_ST.xy, _DetailMap_ST.zw, 1.0, _LinkDetailsWithBase,
-                            positionWS, _TexWorldScale,
+                            positionRWS, _TexWorldScale,
                             mappingType, layerTexCoord);
 }
 
 #endif
 
     GetLayerTexCoord(   input.texCoord0, input.texCoord1, input.texCoord2, input.texCoord3,
-                        input.positionWS, input.worldToTangent[2].xyz, layerTexCoord);
+                        input.positionRWS, input.worldToTangent[2].xyz, layerTexCoord);
 }
 
 #include "LitDataDisplacement.hlsl"

com.unity.render-pipelines.high-definition/HDRP/Material/Lit/LitDataIndividualLayer.hlsl

                                     // scale and bias for base and detail + global tiling factor (for layered lit only)
                                     float2 texScale, float2 texBias, float2 texScaleDetails, float2 texBiasDetails, float additionalTiling, float linkDetailsWithBase,
                                     // parameter for planar/triplanar
-                                    float3 positionWS, float worldScale,
+                                    float3 positionRWS, float worldScale,
                                     // mapping type and output
                                     int mappingType, inout LayerTexCoord layerTexCoord)
 {
     float2 uvXY;
     float2 uvZY;
 
-    GetTriplanarCoordinate(GetAbsolutePositionWS(positionWS) * worldScale, uvXZ, uvXY, uvZY);
+    GetTriplanarCoordinate(GetAbsolutePositionWS(positionRWS) * worldScale, uvXZ, uvXY, uvZY);
 
     // Planar is just XZ of triplanar
     if (mappingType == UV_MAPPING_PLANAR)

com.unity.render-pipelines.high-definition/HDRP/Material/Lit/LitDataMeshModification.hlsl

-float3 GetVertexDisplacement(float3 positionWS, float3 normalWS, float2 texCoord0, float2 texCoord1, float2 texCoord2, float2 texCoord3, float4 vertexColor)
+// Note: positionWS can be either in camera relative space or not
+float3 GetVertexDisplacement(float3 positionRWS, float3 normalWS, float2 texCoord0, float2 texCoord1, float2 texCoord2, float2 texCoord3, float4 vertexColor)
-    GetLayerTexCoord(texCoord0, texCoord1, texCoord2, texCoord3, positionWS, normalWS, layerTexCoord);
+    GetLayerTexCoord(texCoord0, texCoord1, texCoord2, texCoord3, positionRWS, normalWS, layerTexCoord);
 
     // TODO: do this algorithm for lod fetching as lod not available in vertex/domain shader
     // http://www.sebastiansylvan.com/post/the-problem-with-tessellation-in-directx-11/
 
-void ApplyVertexModification(AttributesMesh input, float3 normalWS, inout float3 positionWS, float4 time)
+// Note: positionWS can be either in camera relative space or not
+void ApplyVertexModification(AttributesMesh input, float3 normalWS, inout float3 positionRWS, float4 time)
-    positionWS += GetVertexDisplacement(positionWS, normalWS,
+    positionRWS += GetVertexDisplacement(positionRWS, normalWS,
     #ifdef ATTRIBUTES_NEED_TEXCOORD0
         input.uv0,
     #else
 #endif
 
 #ifdef _VERTEX_WIND
-    float3 rootWP = mul(GetObjectToWorldMatrix(), float4(0, 0, 0, 1)).xyz;
-    ApplyWindDisplacement(positionWS, normalWS, rootWP, _Stiffness, _Drag, _ShiverDrag, _ShiverDirectionality, _InitialBend, input.color.a, time);
+    // current wind implementation is in absolute world space
+    float3 rootWP = GetObjectAbsolutePositionWS();
+    float3 absolutePositionWS = GetAbsolutePositionWS(positionRWS);
+    ApplyWindDisplacement(absolutePositionWS, normalWS, rootWP, _Stiffness, _Drag, _ShiverDrag, _ShiverDirectionality, _InitialBend, input.color.a, time);
+    positionRWS = GetCameraRelativePositionWS(absolutePositionWS);
 #endif
 }
 
 // y - 2->0 edge
 // z - 0->1 edge
 // w - inside tessellation factor
-void ApplyTessellationModification(VaryingsMeshToDS input, float3 normalWS, inout float3 positionWS)
+void ApplyTessellationModification(VaryingsMeshToDS input, float3 normalWS, inout float3 positionRWS)
-    positionWS += GetVertexDisplacement(positionWS, normalWS,
+    positionRWS += GetVertexDisplacement(positionRWS, normalWS,
     #ifdef VARYINGS_DS_NEED_TEXCOORD0
         input.texCoord0,
     #else

com.unity.render-pipelines.high-definition/HDRP/Material/MaterialUtilities.hlsl

 // In unity we can have a mix of fully baked lightmap (static lightmap) + enlighten realtime lightmap (dynamic lightmap)
 // for each case we can have directional lightmap or not.
 // Else we have lightprobe for dynamic/moving entity. Either SH9 per object lightprobe or SH4 per pixel per object volume probe
-float3 SampleBakedGI(float3 positionWS, float3 normalWS, float2 uvStaticLightmap, float2 uvDynamicLightmap)
+float3 SampleBakedGI(float3 positionRWS, float3 normalWS, float2 uvStaticLightmap, float2 uvDynamicLightmap)
 {
     // If there is no lightmap, it assume lightprobe
 #if !defined(LIGHTMAP_ON) && !defined(DYNAMICLIGHTMAP_ON)
     }
     else
     {
-        // TODO: We use GetAbsolutePositionWS(positionWS) to handle the camera relative case here but this should be part of the unity_ProbeVolumeWorldToObject matrix on C++ side (sadly we can't modify it for HDRenderPipeline...)
-        return SampleProbeVolumeSH4(TEXTURE3D_PARAM(unity_ProbeVolumeSH, samplerunity_ProbeVolumeSH), GetAbsolutePositionWS(positionWS), normalWS, unity_ProbeVolumeWorldToObject,
+        // TODO: We use GetAbsolutePositionWS(positionRWS) to handle the camera relative case here but this should be part of the unity_ProbeVolumeWorldToObject matrix on C++ side (sadly we can't modify it for HDRenderPipeline...)
+        return SampleProbeVolumeSH4(TEXTURE3D_PARAM(unity_ProbeVolumeSH, samplerunity_ProbeVolumeSH), GetAbsolutePositionWS(positionRWS), normalWS, unity_ProbeVolumeWorldToObject,
                                     unity_ProbeVolumeParams.y, unity_ProbeVolumeParams.z, unity_ProbeVolumeMin, unity_ProbeVolumeSizeInv);
     }
 
 #endif
 }
 
-float4 SampleShadowMask(float3 positionWS, float2 uvStaticLightmap) // normalWS not use for now
+float4 SampleShadowMask(float3 positionRWS, float2 uvStaticLightmap) // normalWS not use for now
 {
 #if defined(LIGHTMAP_ON)
     float2 uv = uvStaticLightmap * unity_LightmapST.xy + unity_LightmapST.zw;
     if (unity_ProbeVolumeParams.x == 1.0)
     {
-        // TODO: We use GetAbsolutePositionWS(positionWS) to handle the camera relative case here but this should be part of the unity_ProbeVolumeWorldToObject matrix on C++ side (sadly we can't modify it for HDRenderPipeline...)
-        rawOcclusionMask = SampleProbeOcclusion(TEXTURE3D_PARAM(unity_ProbeVolumeSH, samplerunity_ProbeVolumeSH), GetAbsolutePositionWS(positionWS), unity_ProbeVolumeWorldToObject,
+        // TODO: We use GetAbsolutePositionWS(positionRWS) to handle the camera relative case here but this should be part of the unity_ProbeVolumeWorldToObject matrix on C++ side (sadly we can't modify it for HDRenderPipeline...)
+        rawOcclusionMask = SampleProbeOcclusion(TEXTURE3D_PARAM(unity_ProbeVolumeSH, samplerunity_ProbeVolumeSH), GetAbsolutePositionWS(positionRWS), unity_ProbeVolumeWorldToObject,
                                                 unity_ProbeVolumeParams.y, unity_ProbeVolumeParams.z, unity_ProbeVolumeMin, unity_ProbeVolumeSizeInv);
     }
     else

com.unity.render-pipelines.high-definition/HDRP/Material/StackLit/StackLitData.hlsl

 
 void InitializeMappingData(FragInputs input, out TextureUVMapping uvMapping)
 {
-    float3 position = GetAbsolutePositionWS(input.positionWS);
+    float3 position = GetAbsolutePositionWS(input.positionRWS);
     float2 uvXZ;
     float2 uvXY;
     float2 uvZY;
     uvMapping.vertexTangentWS[0] = input.worldToTangent[0];
     uvMapping.vertexBitangentWS[0] = input.worldToTangent[1];
 
-    float3 dPdx = ddx_fine(input.positionWS);
-    float3 dPdy = ddy_fine(input.positionWS);
+    float3 dPdx = ddx_fine(input.positionRWS);
+    float3 dPdy = ddy_fine(input.positionRWS);
 
     float3 sigmaX = dPdx - dot(dPdx, vertexNormalWS) * vertexNormalWS;
     float3 sigmaY = dPdy - dot(dPdy, vertexNormalWS) * vertexNormalWS;
 
     builtinData.opacity = alpha;
 
-    builtinData.bakeDiffuseLighting = SampleBakedGI(input.positionWS, surfaceData.normalWS, input.texCoord1, input.texCoord2);
+    builtinData.bakeDiffuseLighting = SampleBakedGI(input.positionRWS, surfaceData.normalWS, input.texCoord1, input.texCoord2);
 
     // It is safe to call this function here as surfaceData have been filled
     // We want to know if we must enable transmission on GI for SSS material, if the material have no SSS, this code will be remove by the compiler.
         // however it will not optimize the lightprobe case due to the proxy volume relying on dynamic if (we rely must get right of this dynamic if), not a problem for SH9, but a problem for proxy volume.
         // TODO: optimize more this code.
         // Add GI transmission contribution by resampling the GI for inverted vertex normal
-        builtinData.bakeDiffuseLighting += SampleBakedGI(input.positionWS, -input.worldToTangent[2], input.texCoord1, input.texCoord2) * bsdfData.transmittance;
+        builtinData.bakeDiffuseLighting += SampleBakedGI(input.positionRWS, -input.worldToTangent[2], input.texCoord1, input.texCoord2) * bsdfData.transmittance;
     }
 
     builtinData.emissiveColor = _EmissiveColor * lerp(float3(1.0, 1.0, 1.0), surfaceData.baseColor.rgb, _AlbedoAffectEmissive);
     builtinData.velocity = float2(0.0, 0.0);
 
 #ifdef SHADOWS_SHADOWMASK
-    float4 shadowMask = SampleShadowMask(input.positionWS, input.texCoord1);
+    float4 shadowMask = SampleShadowMask(input.positionRWS, input.texCoord1);
     builtinData.shadowMask0 = shadowMask.x;
     builtinData.shadowMask1 = shadowMask.y;
     builtinData.shadowMask2 = shadowMask.z;

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/FragInputs.hlsl

     // Contain value return by SV_POSITION (That is name positionCS in PackedVarying).
     // xy: unormalized screen position (offset by 0.5), z: device depth, w: depth in view space
     // Note: SV_POSITION is the result of the clip space position provide to the vertex shaders that is transform by the viewport
-    float4 positionSS; // In case depth offset is use, positionWS.w is equal to depth offset
-    float3 positionWS;
+    float4 positionSS; // In case depth offset is use, positionRWS.w is equal to depth offset
+    float3 positionRWS; // Relative camera space position
     float2 texCoord0;
     float2 texCoord1;
     float2 texCoord2;

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassDBuffer.hlsl

 {
     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 	DecalSurfaceData surfaceData;
-  
+
-    // Transform from world space to decal space (DS) to clip the decal.
-    // For this we must use absolute position.
-    // There is no lose of precision here as it doesn't involve the camera matrix
-    float3 positionWS = GetAbsolutePositionWS(posInput.positionWS);
-    float3 positionDS = mul(UNITY_MATRIX_I_M, float4(positionWS, 1.0)).xyz;
+    // Transform from relative world space to decal space (DS) to clip the decal
+    float3 positionDS = TransformWorldToObject(posInput.positionWS);
-    
+
     float4x4 normalToWorld = UNITY_ACCESS_INSTANCED_PROP(matrix, _NormalToWorld);
     GetSurfaceData(positionDS.xz, normalToWorld, surfaceData);
 	// have to do explicit test since compiler behavior is not defined for RW resources and discard instructions

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassDepthOnly.hlsl

     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS);
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS);
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassDistortion.hlsl

     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS);
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS);
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassForward.hlsl

     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS.xyz, uint2(input.positionSS.xy) / GetTileSize());
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS.xyz, uint2(input.positionSS.xy) / GetTileSize());
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassForwardUnlit.hlsl

     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS);
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS);
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassGBuffer.hlsl

     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS);
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS);
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassLightTransport.hlsl

     output.vmesh.positionCS = float4(uv * 2.0 - 1.0, inputMesh.positionOS.z > 0 ? 1.0e-4 : 0.0, 1.0);
 
 #ifdef VARYINGS_NEED_POSITION_WS
-    float3 positionWS = GetCameraRelativePositionWS(TransformObjectToWorld(inputMesh.positionOS));
-    output.vmesh.positionWS = positionWS;
+    output.vmesh.positionRWS = TransformObjectToWorld(inputMesh.positionOS);
 #endif
 
 #ifdef VARYINGS_NEED_TANGENT_TO_WORLD
     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS);
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS);
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/ShaderPassVelocity.hlsl

 #endif
 }
 
+// Transforms local position to camera relative world space
+float3 TransformPreviousObjectToWorld(float3 positionOS)
+{
+    float4x4 previousModelMatrix = ApplyCameraTranslationToMatrix(unity_MatrixPreviousM);
+    return mul(previousModelMatrix, float4(positionOS, 1.0)).xyz;
+}
+
 void VelocityPositionZBias(VaryingsToPS input)
 {
 #if defined(UNITY_REVERSED_Z)
     // It is not possible to correctly generate the motion vector for tesselated geometry as tessellation parameters can change
     // from one frame to another (adaptative, lod) + in Unity we only receive information for one non tesselated vertex.
     // So motion vetor will be based on interpolate previous position at vertex level instead.
-    varyingsType.vpass.positionCS = mul(_NonJitteredViewProjMatrix, float4(varyingsType.vmesh.positionWS, 1.0));
+    varyingsType.vpass.positionCS = mul(_NonJitteredViewProjMatrix, float4(varyingsType.vmesh.positionRWS, 1.0));
 
     // Note: unity_MotionVectorsParams.y is 0 is forceNoMotion is enabled
     bool forceNoMotion = unity_MotionVectorsParams.y == 0.0;
         if (hasDeformation)
             previousMesh.positionOS = inputPass.previousPositionOS;
         previousMesh = ApplyMeshModification(previousMesh);
-        float3 previousPositionWS = mul(unity_MatrixPreviousM, float4(previousMesh.positionOS, 1.0)).xyz;
+        float3 previousPositionRWS = TransformPreviousObjectToWorld(previousMesh.positionOS);
-        float3 previousPositionWS = mul(unity_MatrixPreviousM, hasDeformation ? float4(inputPass.previousPositionOS, 1.0) : float4(inputMesh.positionOS, 1.0)).xyz;
+        float3 previousPositionRWS = TransformPreviousObjectToWorld(hasDeformation ? inputPass.previousPositionOS : inputMesh.positionOS);
 #endif
 
 #ifdef ATTRIBUTES_NEED_NORMAL
 #endif
 
  #if defined(HAVE_VERTEX_MODIFICATION)
-        ApplyVertexModification(inputMesh, normalWS, previousPositionWS, _LastTime);
+        ApplyVertexModification(inputMesh, normalWS, previousPositionRWS, _LastTime);
-        //Need this since we are using the current position from VertMesh()
-        previousPositionWS = GetCameraRelativePositionWS(previousPositionWS);
-
-        varyingsType.vpass.previousPositionCS = mul(_PrevViewProjMatrix, float4(previousPositionWS, 1.0));
+        varyingsType.vpass.previousPositionCS = mul(_PrevViewProjMatrix, float4(previousPositionRWS, 1.0));
     }
 
     return PackVaryingsType(varyingsType);
     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 
     // input.positionSS is SV_Position
-    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionWS);
+    PositionInputs posInput = GetPositionInput(input.positionSS.xy, _ScreenSize.zw, input.positionSS.z, input.positionSS.w, input.positionRWS);
-    float3 V = GetWorldSpaceNormalizeViewDir(input.positionWS);
+    float3 V = GetWorldSpaceNormalizeViewDir(input.positionRWS);
 #else
     float3 V = 0; // Avoid the division by 0
 #endif

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/TessellationShare.hlsl

     VaryingsToDS varying1 = UnpackVaryingsToDS(input[1]);
     VaryingsToDS varying2 = UnpackVaryingsToDS(input[2]);
 
-    float3 p0 = varying0.vmesh.positionWS;
-    float3 p1 = varying1.vmesh.positionWS;
-    float3 p2 = varying2.vmesh.positionWS;
+    float3 p0 = varying0.vmesh.positionRWS;
+    float3 p1 = varying1.vmesh.positionRWS;
+    float3 p2 = varying2.vmesh.positionRWS;
 
     float3 n0 = varying0.vmesh.normalWS;
     float3 n1 = varying1.vmesh.normalWS;
     // We have Phong tessellation in all case where we don't have displacement only
 #ifdef _TESSELLATION_PHONG
 
-    float3 p0 = varying0.vmesh.positionWS;
-    float3 p1 = varying1.vmesh.positionWS;
-    float3 p2 = varying2.vmesh.positionWS;
+    float3 p0 = varying0.vmesh.positionRWS;
+    float3 p1 = varying1.vmesh.positionRWS;
+    float3 p2 = varying2.vmesh.positionRWS;
-    varying.vmesh.positionWS = PhongTessellation(   varying.vmesh.positionWS,
+    varying.vmesh.positionRWS = PhongTessellation(  varying.vmesh.positionRWS,
-    ApplyTessellationModification(varying.vmesh, varying.vmesh.normalWS, varying.vmesh.positionWS);
+    ApplyTessellationModification(varying.vmesh, varying.vmesh.normalWS, varying.vmesh.positionRWS);
 #endif
 
     return VertTesselation(varying);

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/VaryingMesh.hlsl

 {
     float4 positionCS;
 #ifdef VARYINGS_NEED_POSITION_WS
-    float3 positionWS;
+    float3 positionRWS;
 #endif
 #ifdef VARYINGS_NEED_TANGENT_TO_WORLD
     float3 normalWS;
     output.positionCS = input.positionCS;
 
 #ifdef VARYINGS_NEED_POSITION_WS
-    output.interpolators0 = input.positionWS;
+    output.interpolators0 = input.positionRWS;
 #endif
 
 #ifdef VARYINGS_NEED_TANGENT_TO_WORLD
     output.positionSS = input.positionCS; // input.positionCS is SV_Position
 
 #ifdef VARYINGS_NEED_POSITION_WS
-    output.positionWS.xyz = input.interpolators0.xyz;
+    output.positionRWS.xyz = input.interpolators0.xyz;
 #endif
 
 #ifdef VARYINGS_NEED_TANGENT_TO_WORLD
 // Position and normal are always present (for tessellation) and in world space
 struct VaryingsMeshToDS
 {
-    float3 positionWS;
+    float3 positionRWS;
     float3 normalWS;
 #ifdef VARYINGS_DS_NEED_TANGENT
     float4 tangentWS;
 
 struct PackedVaryingsMeshToDS
 {
-    float3 interpolators0 : INTERNALTESSPOS; // positionWS
+    float3 interpolators0 : INTERNALTESSPOS; // positionRWS
     float3 interpolators1 : NORMAL; // NormalWS
 
 #ifdef VARYINGS_DS_NEED_TANGENT
 
     UNITY_TRANSFER_INSTANCE_ID(input, output);
 
-    output.interpolators0 = input.positionWS;
+    output.interpolators0 = input.positionRWS;
     output.interpolators1 = input.normalWS;
 #ifdef VARYINGS_DS_NEED_TANGENT
     output.interpolators2 = input.tangentWS;
 
     UNITY_TRANSFER_INSTANCE_ID(input, output);
 
-    output.positionWS = input.interpolators0;
+    output.positionRWS = input.interpolators0;
     output.normalWS = input.interpolators1;
 #ifdef VARYINGS_DS_NEED_TANGENT
     output.tangentWS = input.interpolators2;
 
     UNITY_TRANSFER_INSTANCE_ID(input0, output);
 
-    TESSELLATION_INTERPOLATE_BARY(positionWS, baryCoords);
+    TESSELLATION_INTERPOLATE_BARY(positionRWS, baryCoords);
     TESSELLATION_INTERPOLATE_BARY(normalWS, baryCoords);
 #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)

com.unity.render-pipelines.high-definition/HDRP/ShaderPass/VertMesh.hlsl

     UNITY_SETUP_INSTANCE_ID(input);
     UNITY_TRANSFER_INSTANCE_ID(input, output);
 
-    float3 positionWS = TransformObjectToWorld(input.positionOS);
+    // This return the camera relative position (if enable)
+    float3 positionRWS = TransformObjectToWorld(input.positionOS);
 #ifdef ATTRIBUTES_NEED_NORMAL
     float3 normalWS = TransformObjectToWorldNormal(input.normalOS);
 #else
      float4 tangentWS = float4(TransformObjectToWorldDir(input.tangentOS.xyz), input.tangentOS.w);
 #endif
 
-    // TODO: deal with camera center rendering and instancing (This is the reason why we always perform two  steps transform to clip space + instancing matrix)
-
+     // Do vertex modification in camera relative space (if enable)
-    ApplyVertexModification(input, normalWS, positionWS, _Time);
+    ApplyVertexModification(input, normalWS, positionRWS, _Time);
-    positionWS = GetCameraRelativePositionWS(positionWS);
-
-    output.positionWS = positionWS;
+    output.positionRWS = positionRWS;
     output.normalWS = normalWS;
     #if defined(VARYINGS_NEED_TANGENT_TO_WORLD) || defined(VARYINGS_DS_NEED_TANGENT)
     output.tangentWS = tangentWS;
-    output.positionWS = positionWS;
+    output.positionRWS = positionRWS;
-    output.positionCS = TransformWorldToHClip(positionWS);
+    output.positionCS = TransformWorldToHClip(positionRWS);
     #ifdef VARYINGS_NEED_TANGENT_TO_WORLD
     output.normalWS = normalWS;
     output.tangentWS = tangentWS;
     UNITY_SETUP_INSTANCE_ID(input);
     UNITY_TRANSFER_INSTANCE_ID(input, output);
 
-    output.positionCS = TransformWorldToHClip(input.positionWS);
+    output.positionCS = TransformWorldToHClip(input.positionRWS);
-    output.positionWS = input.positionWS;
+    output.positionRWS = input.positionRWS;
 #endif
 
 #ifdef VARYINGS_NEED_TANGENT_TO_WORLD

com.unity.render-pipelines.high-definition/HDRP/ShaderVariables.hlsl

     return M;
 }
 
+// Helper to handle camera relative space
+
+float4x4 ApplyCameraTranslationToMatrix(float4x4 modelMatrix)
+{
+    // To handle camera relative rendering we substract the camera position in the model matrix
+    // User must not use UNITY_MATRIX_M directly, unless they understand what they do
+#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
+    modelMatrix._m03_m13_m23 -= _WorldSpaceCameraPos;
+#endif
+    return modelMatrix;
+}
+
+float4x4 ApplyCameraTranslationToInverseMatrix(float4x4 inverseModelMatrix)
+{
+#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
+    // To handle camera relative rendering we need to apply translation before converting to object space
+    float4x4 translationMatrix = { { 1.0, 0.0, 0.0, _WorldSpaceCameraPos.x },{ 0.0, 1.0, 0.0, _WorldSpaceCameraPos.y },{ 0.0, 0.0, 1.0, _WorldSpaceCameraPos.z },{ 0.0, 0.0, 0.0, 1.0 } };
+    return mul(inverseModelMatrix, translationMatrix);
+#else
+    return inverseModelMatrix;
+#endif
+}
+
 #ifdef USE_LEGACY_UNITY_MATRIX_VARIABLES
     #include "ShaderVariablesMatrixDefsLegacyUnity.hlsl"
 #else
+
+// This define allow to tell to unity instancing that we will use our camera relative functions (ApplyCameraTranslationToMatrix and  ApplyCameraTranslationToInverseMatrix) for the model view matrix
+#define MODIFY_MATRIX_FOR_CAMERA_RELATIVE_RENDERING
 #include "CoreRP/ShaderLibrary/UnityInstancing.hlsl"
 #include "ShaderVariablesFunctions.hlsl"
 

com.unity.render-pipelines.high-definition/HDRP/ShaderVariablesFunctions.hlsl

 #ifndef UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
 #define UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
 
+// This function always return the absolute position in WS
+float3 GetAbsolutePositionWS(float3 positionRWS)
+{
+#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
+    positionRWS += _WorldSpaceCameraPos;
+#endif
+    return positionRWS;
+}
+
+// This function return the camera relative position in WS
+float3 GetCameraRelativePositionWS(float3 positionWS)
+{
+#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
+    positionWS -= _WorldSpaceCameraPos;
+#endif
+    return positionWS;
+}
+
+// Return absolute world position of current object
+float3 GetObjectAbsolutePositionWS()
+{
+    float4x4 modelMatrix = UNITY_MATRIX_M;
+    return GetAbsolutePositionWS(modelMatrix._m03_m13_m23); // Translation object to world
+}
+
+// Return the PreTranslated ObjectToWorld Matrix (i.e matrix with _WorldSpaceCameraPos apply to it if we use camera relative rendering)
 float4x4 GetObjectToWorldMatrix()
 {
     return UNITY_MATRIX_M;
     return unity_WorldTransformParams.w;
 }
 
-float3 TransformWorldToView(float3 positionWS)
+float3 TransformWorldToView(float3 positionRWS)
-    return mul(GetWorldToViewMatrix(), float4(positionWS, 1.0)).xyz;
+    return mul(GetWorldToViewMatrix(), float4(positionRWS, 1.0)).xyz;
 }
 
 float3 TransformObjectToWorld(float3 positionOS)
 
-float3 TransformWorldToObject(float3 positionWS)
+float3 TransformWorldToObject(float3 positionRWS)
-    return mul(GetWorldToObjectMatrix(), float4(positionWS, 1.0)).xyz;
+    return mul(GetWorldToObjectMatrix(), float4(positionRWS, 1.0)).xyz;
 }
 
 float3 TransformObjectToWorldDir(float3 dirOS)
 }
 
 // Tranforms position from world space to homogenous space
-float4 TransformWorldToHClip(float3 positionWS)
+float4 TransformWorldToHClip(float3 positionRWS)
-    return mul(GetWorldToHClipMatrix(), float4(positionWS, 1.0));
+    return mul(GetWorldToHClipMatrix(), float4(positionRWS, 1.0));
 }
 
 // Tranforms vector from world space to homogenous space
     return mul((float3x3)GetViewToHClipMatrix(), directionVS);
 }
 
-// This function always return the absolute position in WS either the CameraRelative mode is enabled or not
-float3 GetAbsolutePositionWS(float3 positionWS)
-{
-#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
-    positionWS += _WorldSpaceCameraPos;
-#endif
-    return positionWS;
-}
-
-// This function always return the camera relative position in WS either the CameraRelative mode is enabled or not
-float3 GetCameraRelativePositionWS(float3 positionWS)
-{
-#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
-    positionWS -= _WorldSpaceCameraPos;
-#endif
-    return positionWS;
-}
-
 float3 GetPrimaryCameraPosition()
 {
 #if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
 }
 
 // Computes the world space view direction (pointing towards the viewer).
-float3 GetWorldSpaceViewDir(float3 positionWS)
+float3 GetWorldSpaceViewDir(float3 positionRWS)
-        return GetCurrentViewPosition() - positionWS;
+        return GetCurrentViewPosition() - positionRWS;
     }
     else
     {
 }
 
-float3 GetWorldSpaceNormalizeViewDir(float3 positionWS)
+float3 GetWorldSpaceNormalizeViewDir(float3 positionRWS)
-    return normalize(GetWorldSpaceViewDir(positionWS));
+    return normalize(GetWorldSpaceViewDir(positionRWS));
 }
 
 float3x3 CreateWorldToTangent(float3 normal, float3 tangent, float flipSign)

com.unity.render-pipelines.high-definition/HDRP/ShaderVariablesMatrixDefsHDCamera.hlsl

 #ifndef UNITY_SHADER_VARIABLES_MATRIX_DEFS_HDCAMERA_INCLUDED
 #define UNITY_SHADER_VARIABLES_MATRIX_DEFS_HDCAMERA_INCLUDED
 
+#define UNITY_MATRIX_M     ApplyCameraTranslationToMatrix(unity_ObjectToWorld)
+#define UNITY_MATRIX_I_M   ApplyCameraTranslationToInverseMatrix(unity_WorldToObject)
+
-#define UNITY_MATRIX_M     unity_ObjectToWorld
-#define UNITY_MATRIX_I_M   unity_WorldToObject
 #define UNITY_MATRIX_V     _ViewMatrixStereo[unity_StereoEyeIndex]
 #define UNITY_MATRIX_I_V   _InvViewMatrixStereo[unity_StereoEyeIndex]
 #define UNITY_MATRIX_P     OptimizeProjectionMatrix(unity_StereoMatrixP[unity_StereoEyeIndex])
 
 #else
 
-#define UNITY_MATRIX_M     unity_ObjectToWorld
-#define UNITY_MATRIX_I_M   unity_WorldToObject
 #define UNITY_MATRIX_V     _ViewMatrix
 #define UNITY_MATRIX_I_V   _InvViewMatrix
 #define UNITY_MATRIX_P     OptimizeProjectionMatrix(_ProjMatrix)

com.unity.render-pipelines.high-definition/HDRP/ShaderVariablesMatrixDefsLegacyUnity.hlsl

 #ifndef UNITY_SHADER_VARIABLES_MATRIX_DEFS_LEGACY_UNITY_INCLUDED
 #define UNITY_SHADER_VARIABLES_MATRIX_DEFS_LEGACY_UNITY_INCLUDED
 
-#define UNITY_MATRIX_M     unity_ObjectToWorld
-#define UNITY_MATRIX_I_M   unity_WorldToObject
+#define UNITY_MATRIX_M     ApplyCameraTranslationToMatrix(unity_ObjectToWorld)
+#define UNITY_MATRIX_I_M   ApplyCameraTranslationToInverseMatrix(unity_WorldToObject)
 #define UNITY_MATRIX_V     unity_MatrixV
 #define UNITY_MATRIX_I_V   unity_MatrixInvV
 #define UNITY_MATRIX_P     OptimizeProjectionMatrix(glstate_matrix_projection)