Fix various DX12 + Vulkan issue for null geometry input (draw procedural)

Author: johnpars

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

@@ -330,5 +330,12 @@ Pass
 
     $splice(PostGraphIncludes)
 
+    // --------------------------------------------------
+    // Visual Effect Vertex Invocations
+
+	#ifdef HAVE_VFX_MODIFICATION
+	#include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/VisualEffectVertex.hlsl"
+	#endif
+
     ENDHLSL
 }

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/Templates/VFX/Config.template.hlsl

@@ -2,6 +2,8 @@ $splice(VFXDefineSpace)
 
 $splice(VFXDefines)
 
+#define NULL_GEOMETRY_INPUT defined(HAVE_VFX_PLANAR_PRIMITIVE)
+
 // Explicitly defined here for now (similar to how it was done in the previous VFX code-gen)
 #define HAS_ATTRIBUTES 1
 
@@ -183,20 +185,20 @@ bool GetInterpolatorAndElementData(inout VaryingsMeshType output, inout Attribut
 void BuildWorldToElement(VaryingsMeshType input)
 {
 #ifdef VARYINGS_NEED_WORLD_TO_ELEMENT
-    UNITY_MATRIX_I_M[0] = input.worldToElement0;
-    UNITY_MATRIX_I_M[1] = input.worldToElement1;
-    UNITY_MATRIX_I_M[2] = input.worldToElement2;
-    UNITY_MATRIX_I_M[3] = float4(0,0,0,1);
+    worldToElement[0] = input.worldToElement0;
+    worldToElement[1] = input.worldToElement1;
+    worldToElement[2] = input.worldToElement2;
+    worldToElement[3] = float4(0,0,0,1);
 #endif
 }
 
 void BuildElementToWorld(VaryingsMeshType input)
 {
 #ifdef VARYINGS_NEED_ELEMENT_TO_WORLD
-    UNITY_MATRIX_M[0] = input.elementToWorld0;
-    UNITY_MATRIX_M[1] = input.elementToWorld1;
-    UNITY_MATRIX_M[2] = input.elementToWorld2;
-    UNITY_MATRIX_M[3] = float4(0,0,0,1);
+    elementToWorld[0] = input.elementToWorld0;
+    elementToWorld[1] = input.elementToWorld1;
+    elementToWorld[2] = input.elementToWorld2;
+    elementToWorld[3] = float4(0,0,0,1);
 #endif
 }
 

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/Templates/VFX/ConfigPlanarPrimitive.template.hlsl

@@ -6,6 +6,8 @@
 
 #define VFX_NON_UNIFORM_SCALE VFX_LOCAL_SPACE
 
+#define HAVE_VFX_PLANAR_PRIMITIVE
+
 bool GetMeshAndElementIndex(inout AttributesMesh input, inout AttributesElement element)
 {
     uint id = input.vertexID;

com.unity.render-pipelines.high-definition/Editor/VFXGraph/VFXHDRPSubTarget.cs

@@ -6,6 +6,7 @@
 using UnityEditor.ShaderGraph;
 using UnityEditor.ShaderGraph.Internal;
 using UnityEditor.VFX;
+using UnityEngine.Rendering;
 
 namespace UnityEditor.Rendering.HighDefinition.ShaderGraph
 {
@@ -98,7 +99,7 @@ out var vertexPropertiesAssignDescriptor
 
                 passDescriptor.pragmas = new PragmaCollection
                 {
-                    passDescriptor.pragmas,
+                    ModifyVertexEntry(passDescriptor.pragmas),
                     Pragma.MultiCompileInstancing
                 };
 
@@ -129,6 +130,36 @@ out var vertexPropertiesAssignDescriptor
             return subShaderDescriptor;
         }
 
+        private static readonly GraphicsDeviceType[] s_RequiresModifiedVertexEntry = new GraphicsDeviceType[]
+        {
+            GraphicsDeviceType.Direct3D12,
+            GraphicsDeviceType.Vulkan
+        };
+
+        static PragmaCollection ModifyVertexEntry(PragmaCollection pragmas)
+        {
+            // Only modify the entry for the required APIs.
+            var graphicsAPI = PlayerSettings.GetGraphicsAPIs(EditorUserBuildSettings.activeBuildTarget)[0];
+            if (s_RequiresModifiedVertexEntry.All(o => o != graphicsAPI))
+                return pragmas;
+
+            // Replace the default vertex shader entry with one defined by VFX.
+            // NOTE: Assumes they are named "Vert" for all shader passes, which they are.
+            const string k_CoreBasicVertex = "#pragma vertex Vert";
+
+            var pragmaVFX = new PragmaCollection();
+
+            foreach (var pragma in pragmas)
+            {
+                if (pragma.value != k_CoreBasicVertex)
+                    pragmaVFX.Add(pragma.descriptor);
+                else
+                    pragmaVFX.Add(Pragma.Vertex("VertVFX"));
+            }
+
+            return pragmaVFX;
+        }
+
         static StructDescriptor AttributesMeshVFX = new StructDescriptor()
         {
             name = "AttributesMesh",

com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/VisualEffectVertex.hlsl

@@ -0,0 +1,42 @@
+// Wrapper vertex invocations for VFX. Necesarry to work around various null input geometry issues for vertex input layout on DX12 and Vulkan.
+// These entrypoints will only be called in the case of DX12/Vulkan.
+#if NULL_GEOMETRY_INPUT
+    #ifdef MOTION_VEC_VERTEX_COMMON_INCLUDED
+        PackedVaryingsType VertVFX(uint vertexID : VERTEXID_SEMANTIC, uint instanceID : INSTANCEID_SEMANTIC)
+        {
+            AttributesMesh inputMesh;
+            ZERO_INITIALIZE(AttributesMesh, inputMesh);
+
+            AttributesPass inputPass;
+            ZERO_INITIALIZE(AttributesPass, inputPass);
+
+            inputMesh.vertexID = vertexID;
+            inputMesh.instanceID = instanceID;
+
+            return Vert(inputMesh, inputPass);
+        }
+    #else
+        PackedVaryingsType VertVFX(uint vertexID : VERTEXID_SEMANTIC, uint instanceID : INSTANCEID_SEMANTIC)
+        {
+            AttributesMesh inputMesh;
+            ZERO_INITIALIZE(AttributesMesh, inputMesh);
+
+            inputMesh.vertexID = vertexID;
+            inputMesh.instanceID = instanceID;
+
+            return Vert(inputMesh);
+        }
+    #endif
+#else
+    #ifdef MOTION_VEC_VERTEX_COMMON_INCLUDED
+        PackedVaryingsType VertVFX(AttributesMesh inputMesh, AttributesPass inputPass)
+        {
+            return Vert(inputMesh, inputPass);
+        }
+    #else
+        PackedVaryingsType VertVFX(AttributesMesh inputMesh)
+        {
+            return Vert(inputMesh);
+        }
+    #endif
+#endif