Fix backface and displacement picking for HDRP

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

@@ -692,6 +692,46 @@ real Pow4(real x)
 
 TEMPLATE_3_FLT(RangeRemap, min, max, t, return saturate((t - min) / (max - min)))
 
+float4x4 Inverse(float4x4 m)
+{
+    float n11 = m[0][0], n12 = m[1][0], n13 = m[2][0], n14 = m[3][0];
+    float n21 = m[0][1], n22 = m[1][1], n23 = m[2][1], n24 = m[3][1];
+    float n31 = m[0][2], n32 = m[1][2], n33 = m[2][2], n34 = m[3][2];
+    float n41 = m[0][3], n42 = m[1][3], n43 = m[2][3], n44 = m[3][3];
+
+    float t11 = n23 * n34 * n42 - n24 * n33 * n42 + n24 * n32 * n43 - n22 * n34 * n43 - n23 * n32 * n44 + n22 * n33 * n44;
+    float t12 = n14 * n33 * n42 - n13 * n34 * n42 - n14 * n32 * n43 + n12 * n34 * n43 + n13 * n32 * n44 - n12 * n33 * n44;
+    float t13 = n13 * n24 * n42 - n14 * n23 * n42 + n14 * n22 * n43 - n12 * n24 * n43 - n13 * n22 * n44 + n12 * n23 * n44;
+    float t14 = n14 * n23 * n32 - n13 * n24 * n32 - n14 * n22 * n33 + n12 * n24 * n33 + n13 * n22 * n34 - n12 * n23 * n34;
+
+    float det = n11 * t11 + n21 * t12 + n31 * t13 + n41 * t14;
+    float idet = 1.0f / det;
+
+    float4x4 ret;
+
+    ret[0][0] = t11 * idet;
+    ret[0][1] = (n24 * n33 * n41 - n23 * n34 * n41 - n24 * n31 * n43 + n21 * n34 * n43 + n23 * n31 * n44 - n21 * n33 * n44) * idet;
+    ret[0][2] = (n22 * n34 * n41 - n24 * n32 * n41 + n24 * n31 * n42 - n21 * n34 * n42 - n22 * n31 * n44 + n21 * n32 * n44) * idet;
+    ret[0][3] = (n23 * n32 * n41 - n22 * n33 * n41 - n23 * n31 * n42 + n21 * n33 * n42 + n22 * n31 * n43 - n21 * n32 * n43) * idet;
+
+    ret[1][0] = t12 * idet;
+    ret[1][1] = (n13 * n34 * n41 - n14 * n33 * n41 + n14 * n31 * n43 - n11 * n34 * n43 - n13 * n31 * n44 + n11 * n33 * n44) * idet;
+    ret[1][2] = (n14 * n32 * n41 - n12 * n34 * n41 - n14 * n31 * n42 + n11 * n34 * n42 + n12 * n31 * n44 - n11 * n32 * n44) * idet;
+    ret[1][3] = (n12 * n33 * n41 - n13 * n32 * n41 + n13 * n31 * n42 - n11 * n33 * n42 - n12 * n31 * n43 + n11 * n32 * n43) * idet;
+
+    ret[2][0] = t13 * idet;
+    ret[2][1] = (n14 * n23 * n41 - n13 * n24 * n41 - n14 * n21 * n43 + n11 * n24 * n43 + n13 * n21 * n44 - n11 * n23 * n44) * idet;
+    ret[2][2] = (n12 * n24 * n41 - n14 * n22 * n41 + n14 * n21 * n42 - n11 * n24 * n42 - n12 * n21 * n44 + n11 * n22 * n44) * idet;
+    ret[2][3] = (n13 * n22 * n41 - n12 * n23 * n41 - n13 * n21 * n42 + n11 * n23 * n42 + n12 * n21 * n43 - n11 * n22 * n43) * idet;
+
+    ret[3][0] = t14 * idet;
+    ret[3][1] = (n13 * n24 * n31 - n14 * n23 * n31 + n14 * n21 * n33 - n11 * n24 * n33 - n13 * n21 * n34 + n11 * n23 * n34) * idet;
+    ret[3][2] = (n14 * n22 * n31 - n12 * n24 * n31 - n14 * n21 * n32 + n11 * n24 * n32 + n12 * n21 * n34 - n11 * n22 * n34) * idet;
+    ret[3][3] = (n12 * n23 * n31 - n13 * n22 * n31 + n13 * n21 * n32 - n11 * n23 * n32 - n12 * n21 * n33 + n11 * n22 * n33) * idet;
+
+    return ret;
+}
+
 // ----------------------------------------------------------------------------
 // Texture utilities
 // ----------------------------------------------------------------------------

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

@@ -52,6 +52,7 @@ The version number for this package has increased due to a version update of a r
 - Fixed issue when null parameters in a volume component would spam null reference errors. Produce a warning instead.
 - Fix volument component creation via script.
 - Fixed GC allocs in render graph.
+- Fixed scene picking passes.
 
 ### Changed
 - Combined occlusion meshes into one to reduce draw calls and state changes with XR single-pass.

com.unity.render-pipelines.high-definition/Documentation~/Upgrading-from-2020.1-to-2020.2.md

@@ -192,6 +192,8 @@ From 10.x, HDRP uses range remapping for the metallic property when using a mask
 In the Lit, LitTessellation, LayeredLit and LayeredLitTesselation shaders, two new properties have been added: `_MetallicRemapMin` and `_MetallicRemapMax`.
 In the Decal shader, the property `_MetallicRemapMin` have been added, and `_MetallicScale` has been renamed as `_MetallicRemapMax`.
 
+From 10.x, a new pass ScenePickingPass have been added to all the shader and master node to allow the editor to correctly handle the picking with tesselated objects and backfaced objects.
+
 ## Raytracing
 
 From Unity 2020.2, the Raytracing Node in shader graph now apply the raytraced path (previously low path) to all raytraced effects but path tracing.

com.unity.render-pipelines.high-definition/Editor/BuildProcessors/HDRPPreprocessShaders.cs

@@ -24,7 +24,8 @@ protected override bool DoShadersStripper(HDRenderPipelineAsset hdrpAsset, Shade
 
             // Remove editor only pass
             bool isSceneSelectionPass = snippet.passName == "SceneSelectionPass";
-            if (isSceneSelectionPass)
+            bool isScenePickingPass = snippet.passName == "ScenePickingPass";
+            if (isSceneSelectionPass || isScenePickingPass)
                 return true;
 
             // CAUTION: We can't identify transparent material in the stripped in a general way.

com.unity.render-pipelines.high-definition/Editor/Material/Decal/ShaderGraph/DecalPass.template

@@ -48,6 +48,11 @@ Pass
 
     $splice(HybridV1InjectedBuiltinProperties)
 
+    // -- Properties used by ScenePickingPass
+    #ifdef SCENEPICKINGPASS
+    float4 _SelectionID;
+    #endif
+
     // Includes
     $splice(PreGraphIncludes)
 

com.unity.render-pipelines.high-definition/Editor/Material/Decal/ShaderGraph/DecalSubTarget.cs

@@ -197,6 +197,7 @@ void AddColorMaskProperty(string referenceName)
 #region SubShaders
         static class SubShaders
         {
+            // Relies on the order shader passes are declared in DecalSystem.cs
             public static SubShaderDescriptor Decal = new SubShaderDescriptor()
             {
                 generatesPreview = true,
@@ -206,6 +207,7 @@ static class SubShaders
                     { DecalPasses.DecalProjectorForwardEmissive, new FieldCondition(AffectsEmission, true) },
                     { DecalPasses.DBufferMesh, new FieldCondition(DecalDefault, true) },
                     { DecalPasses.DecalMeshForwardEmissive, new FieldCondition(AffectsEmission, true) },
+                    { DecalPasses.ScenePicking, new FieldCondition(DecalDefault, true) },
                     { DecalPasses.Preview, new FieldCondition(Fields.IsPreview, true) },
                 },
             };
@@ -215,8 +217,23 @@ static class SubShaders
         #region Passes
         public static class DecalPasses
         {
-            // CAUTION: c# code relies on the order in which the passes are declared, any change will need to be reflected in Decalsystem.cs - s_MaterialDecalNames array
-            // and DecalSet.InitializeMaterialValues()
+            // CAUTION: c# code relies on the order in which the passes are declared, any change will need to be reflected in Decalsystem.cs - enum MaterialDecalPass
+
+            public static PassDescriptor ScenePicking = new PassDescriptor()
+            {
+                // Definition
+                displayName = "ScenePickingPass",
+                referenceName = "SHADERPASS_DEPTH_ONLY",
+                lightMode = "Picking",
+                useInPreview = false,
+
+                // Collections
+                renderStates = DecalRenderStates.ScenePicking,
+                pragmas = DecalPragmas.Instanced,
+                defines = CoreDefines.ScenePicking,
+                includes = DecalIncludes.ScenePicking,
+            };
+
             public static PassDescriptor DBufferProjector = new PassDescriptor()
             {
                 // Definition
@@ -385,6 +402,11 @@ static class DecalRenderStates
             readonly static string s_DecalColorMask = "ColorMask [_DecalColorMask0]\n\tColorMask [_DecalColorMask1] 1\n\tColorMask [_DecalColorMask2] 2\n\tColorMask [_DecalColorMask3] 3";
             readonly static string s_DecalBlend = "Blend 0 SrcAlpha OneMinusSrcAlpha, Zero OneMinusSrcAlpha \n\tBlend 1 SrcAlpha OneMinusSrcAlpha, Zero OneMinusSrcAlpha \n\tBlend 2 SrcAlpha OneMinusSrcAlpha, Zero OneMinusSrcAlpha \n\tBlend 3 Zero OneMinusSrcColor";
 
+            public static RenderStateCollection ScenePicking = new RenderStateCollection
+            {
+                { RenderState.Cull(Cull.Back) },
+            };
+
             public static RenderStateCollection DBufferProjector = new RenderStateCollection
             {
                 { RenderState.Blend(s_DecalBlend) },
@@ -536,6 +558,17 @@ static class DecalIncludes
                 { kDecal, IncludeLocation.Pregraph },
                 { kPassDecal, IncludeLocation.Postgraph },
             };
+
+            public static IncludeCollection ScenePicking = new IncludeCollection
+            {
+                { kPacking, IncludeLocation.Pregraph },
+                { kColor, IncludeLocation.Pregraph },
+                { kFunctions, IncludeLocation.Pregraph },
+                { CoreIncludes.MinimalCorePregraph },
+                { kDecal, IncludeLocation.Pregraph },
+                { CoreIncludes.kPickingSpaceTransforms, IncludeLocation.Pregraph },
+                { kPassDecal, IncludeLocation.Postgraph },
+            };
         }
 #endregion
     }

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/HDShaderPasses.cs

@@ -74,6 +74,42 @@ IncludeCollection GenerateIncludes()
 
 #endregion
 
+#region Scene Picking Pass
+
+        public static PassDescriptor GenerateScenePicking()
+        {
+            return new PassDescriptor
+            {
+                // Definition
+                displayName = "ScenePickingPass",
+                referenceName = "SHADERPASS_DEPTH_ONLY",
+                lightMode = "Picking",
+                useInPreview = false,
+
+                // Collections
+                renderStates = CoreRenderStates.ScenePicking,
+                pragmas = CorePragmas.DotsInstancedInV1AndV2EditorSync,
+                defines = CoreDefines.ScenePicking,
+                includes = GenerateIncludes(),
+            };
+
+            IncludeCollection GenerateIncludes()
+            {
+                var includes = new IncludeCollection();
+
+                includes.Add(CoreIncludes.CorePregraph);
+                includes.Add(CoreIncludes.kPassPlaceholder, IncludeLocation.Pregraph);
+                includes.Add(CoreIncludes.CoreUtility);
+                includes.Add(CoreIncludes.kShaderGraphFunctions, IncludeLocation.Pregraph);
+                includes.Add(CoreIncludes.kPickingSpaceTransforms, IncludeLocation.Pregraph);
+                includes.Add(CoreIncludes.kPassDepthOnly, IncludeLocation.Postgraph);
+
+                return includes;
+            }
+        }
+
+#endregion
+
 #region Scene Selection Pass
 
         public static PassDescriptor GenerateSceneSelection(bool supportLighting)

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/HDTarget.cs

@@ -594,6 +594,11 @@ public static class Uniforms
             { RenderState.ColorMask("ColorMask 0") },
         };
 
+        public static RenderStateCollection ScenePicking = new RenderStateCollection
+        {
+            { RenderState.Cull(Uniforms.cullMode) },
+        };
+
         public static RenderStateCollection SceneSelection = new RenderStateCollection
         {
             { RenderState.Cull(Cull.Off) },
@@ -800,6 +805,11 @@ static class CoreKeywords
 #region Defines
     static class CoreDefines
     {
+        public static DefineCollection ScenePicking = new DefineCollection
+        {
+            { CoreKeywordDescriptors.ScenePickingPass, 1 },
+        };
+
         public static DefineCollection SceneSelection = new DefineCollection
         {
             { RayTracingQualityNode.GetRayTracingQualityKeyword(), 0 },
@@ -860,6 +870,7 @@ static class CoreIncludes
         public const string kFragInputs = "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/ShaderPass/FragInputs.hlsl";
         public const string kMaterial = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Material.hlsl";
         public const string kDebugDisplay = "Packages/com.unity.render-pipelines.high-definition/Runtime/Debug/DebugDisplay.hlsl";
+        public const string kPickingSpaceTransforms = "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/PickingSpaceTransforms.hlsl";
 
         // CoreUtility
         public const string kBuiltInUtilities = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/BuiltinUtilities.hlsl";
@@ -1160,6 +1171,15 @@ static class CoreKeywordDescriptors
             scope = KeywordScope.Local,
         };
 
+        public static KeywordDescriptor ScenePickingPass = new KeywordDescriptor()
+        {
+            displayName = "Scene Picking Pass",
+            referenceName = "SCENEPICKINGPASS",
+            type = KeywordType.Boolean,
+            definition = KeywordDefinition.ShaderFeature,
+            scope = KeywordScope.Local,
+        };
+
         public static KeywordDescriptor SceneSelectionPass = new KeywordDescriptor()
         {
             displayName = "Scene Selection Pass",

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/SurfaceSubTarget.cs

@@ -79,6 +79,7 @@ PassCollection GetPasses()
                     // Common "surface" passes
                     HDShaderPasses.GenerateShadowCaster(supportLighting),
                     HDShaderPasses.GenerateMETA(supportLighting),
+                    HDShaderPasses.GenerateScenePicking(),
                     HDShaderPasses.GenerateSceneSelection(supportLighting),
                     HDShaderPasses.GenerateMotionVectors(supportLighting, supportForward),
                     { HDShaderPasses.GenerateBackThenFront(supportLighting), new FieldCondition(HDFields.TransparentBackFace, true)},

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/Templates/ShaderPass.template

@@ -119,6 +119,11 @@ Pass
     // -- Graph Properties
     $splice(GraphProperties)
 
+    // -- Property used by ScenePickingPass
+    #ifdef SCENEPICKINGPASS
+    float4 _SelectionID;
+    #endif
+
     // -- Properties used by SceneSelectionPass
     #ifdef SCENESELECTIONPASS
     int _ObjectId;

com.unity.render-pipelines.high-definition/Runtime/Material/AxF/AxF.shader

@@ -216,6 +216,35 @@ Shader "HDRP/AxF"
         // This tags allow to use the shader replacement features
         Tags{ "RenderPipeline" = "HDRenderPipeline" "RenderType" = "HDLitShader" }
 
+        Pass
+        {
+            Name "ScenePickingPass"
+            Tags { "LightMode" = "Picking" }
+
+            Cull [_CullMode]
+
+            HLSLPROGRAM
+
+            // Note: Require _SelectionID variable
+
+            // We reuse depth prepass for the scene selection, allow to handle alpha correctly as well as tessellation and vertex animation
+            #define SHADERPASS SHADERPASS_DEPTH_ONLY
+            #define SCENEPICKINGPASS
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Material.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/AxF/AxF.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/AxF/ShaderPass/AxFDepthPass.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/AxF/AxFData.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/PickingSpaceTransforms.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/ShaderPass/ShaderPassDepthOnly.hlsl"
+
+            #pragma vertex Vert
+            #pragma fragment Frag
+
+            #pragma editor_sync_compilation
+
+            ENDHLSL
+        }
+
         Pass
         {
             Name "SceneSelectionPass"

com.unity.render-pipelines.high-definition/Runtime/Material/AxF/AxFProperties.hlsl

@@ -133,8 +133,9 @@ float _SpecularAAThreshold;
 // TODO: Fix the code in legacy unity so we can customize the behavior for GI
 float3 _EmissionColor;
 
-// Following two variables are feeded by the C++ Editor for Scene selection
+// Following three variables are feeded by the C++ Editor for Scene selection
 int _ObjectId;
 int _PassValue;
+float4 _SelectionID;
 
 CBUFFER_END

com.unity.render-pipelines.high-definition/Runtime/Material/Decal/Decal.shader

@@ -98,8 +98,10 @@ Shader "HDRP/Decal"
     {
         Tags{ "RenderPipeline" = "HDRenderPipeline"}
 
-		// c# code relies on the order in which the passes are declared, any change will need to be reflected in Decalsystem.cs - s_MaterialDecalNames and s_MaterialDecalSGNames array
-        // and DecalSet.InitializeMaterialValues()
+        // c# code relies on the order in which the passes are declared, any change will need to be reflected in
+        // DecalSystem.cs - enum MaterialDecalPass
+        // DecalSubTarget.cs  - class SubShaders
+        // Caution: passes stripped in builds (like the scene picking pass) need to be put last to have consistent indices
 
 		Pass // 0
 		{
@@ -257,6 +259,40 @@ Shader "HDRP/Decal"
             ENDHLSL
         }
 
+        Pass // 4
+        {
+            Name "ScenePickingPass"
+            Tags { "LightMode" = "Picking" }
+
+            Cull Back
+
+            HLSLPROGRAM
+
+            #pragma only_renderers d3d11 playstation xboxone vulkan metal switch
+
+            //enable GPU instancing support
+            #pragma instancing_options renderinglayer
+            #pragma multi_compile _ DOTS_INSTANCING_ON
+            // enable dithering LOD crossfade
+            #pragma multi_compile _ LOD_FADE_CROSSFADE
+
+            // Note: Require _SelectionID variable
+
+            // We reuse depth prepass for the scene selection, allow to handle alpha correctly as well as tessellation and vertex animation
+            #define SHADERPASS SHADERPASS_DEPTH_ONLY
+            #define SCENEPICKINGPASS
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Decal/DecalProperties.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Decal/Decal.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Decal/ShaderPass/DecalSharePass.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/PickingSpaceTransforms.hlsl"
+            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/ShaderPass/ShaderPassDecal.hlsl"
+
+            #pragma editor_sync_compilation
+
+            ENDHLSL
+        }
+
 	}
     CustomEditor "Rendering.HighDefinition.DecalUI"
 }

com.unity.render-pipelines.high-definition/Runtime/Material/Decal/DecalProperties.hlsl

@@ -29,4 +29,8 @@ float _Smoothness;
 float _AO;
 float _Metallic;
 
+#ifdef SCENEPICKINGPASS
+    float4 _SelectionID;
+#endif
+
 #endif