Graphics/SRP/RPF - [UUM-72067] Fix nullptr exception with missing renderFunc hash

This PR fixes the nullptr exception thrown when a Render Graph pass was missing a renderFunc but tried to compute its hash value. We will now return a hash value of 0 if no render function, the Render Graph compiler will return later an explicit error if the renderFunc is missing anyway. At least, now users have a clear message so they can address the issue by implementing their missing renderFunc.

Author: axoloto

Packages/com.unity.render-pipelines.core/Runtime/RenderGraph/RenderGraphPass.cs

@@ -557,7 +557,7 @@ public override bool HasRenderFunc()
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override int GetRenderFuncHash()
         {
-            return renderFunc.GetHashCode();
+            return (renderFunc != null) ? renderFunc.GetHashCode() : 0;
         }
     }
 
@@ -595,7 +595,7 @@ public override bool HasRenderFunc()
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override int GetRenderFuncHash()
         {
-            return renderFunc.GetHashCode();
+            return (renderFunc != null) ? renderFunc.GetHashCode() : 0;
         }
     }
 
@@ -633,7 +633,7 @@ public override bool HasRenderFunc()
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override int GetRenderFuncHash()
         {
-            return renderFunc.GetHashCode();
+            return (renderFunc != null) ? renderFunc.GetHashCode() : 0;
         }
     }
 
@@ -671,7 +671,7 @@ public override bool HasRenderFunc()
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override int GetRenderFuncHash()
         {
-            return renderFunc.GetHashCode();
+            return (renderFunc != null) ? renderFunc.GetHashCode() : 0;
         }
     }
 }

Packages/com.unity.render-pipelines.core/Tests/Editor/RenderGraphTests.cs

@@ -4,6 +4,7 @@
 using UnityEngine.Experimental.Rendering;
 using UnityEngine.Rendering.RenderGraphModule;
 using System.Collections.Generic;
+using UnityEngine.TestTools;
 
 #if UNITY_EDITOR
 using UnityEditor.Rendering;
@@ -13,10 +14,12 @@ namespace UnityEngine.Rendering.Tests
     class RenderGraphTests
     {
         // For RG Record/Hash/Compile testing, use m_RenderGraph
-        RenderGraph m_RenderGraph; 
+        RenderGraph m_RenderGraph;
+
         RenderPipelineAsset m_OldDefaultRenderPipeline;
+        RenderPipelineAsset m_OldQualityRenderPipeline;
 
-        // For RG Execute/Submit testing with rendering, use m_RenderGraphTestPipeline and its recordRenderGraphBody
+        // For RG Execute/Submit testing with rendering, use m_RenderGraphTestPipeline and m_RenderGraph in its recordRenderGraphBody
         RenderGraphTestPipelineAsset m_RenderGraphTestPipeline;
         RenderGraphTestGlobalSettings m_RenderGraphTestGlobalSettings;
 
@@ -96,12 +99,14 @@ public void Setup()
 #if UNITY_EDITOR
             EditorGraphicsSettings.SetRenderPipelineGlobalSettingsAsset<RenderGraphTestPipelineInstance>(m_RenderGraphTestGlobalSettings);
 #endif
-            // Saving old render pipeline to set it back after testing
+            // Saving old render pipelines to set them back after testing
             m_OldDefaultRenderPipeline = GraphicsSettings.defaultRenderPipeline;
+            m_OldQualityRenderPipeline = QualitySettings.renderPipeline;
 
             // Setting the custom RG render pipeline
             m_RenderGraphTestPipeline = ScriptableObject.CreateInstance<RenderGraphTestPipelineAsset>();
             GraphicsSettings.defaultRenderPipeline = m_RenderGraphTestPipeline;
+            QualitySettings.renderPipeline = m_RenderGraphTestPipeline;
 
             // Getting the RG from the custom asset pipeline
             m_RenderGraph = m_RenderGraphTestPipeline.renderGraph;
@@ -113,6 +118,9 @@ public void Cleanup()
             GraphicsSettings.defaultRenderPipeline = m_OldDefaultRenderPipeline;
             m_OldDefaultRenderPipeline = null;
 
+            QualitySettings.renderPipeline = m_OldQualityRenderPipeline;
+            m_OldQualityRenderPipeline = null;
+
             m_RenderGraph.Cleanup();    
 
             Object.DestroyImmediate(m_RenderGraphTestPipeline);
@@ -969,6 +977,35 @@ public void CreateLegacyRendererLists()
             GameObject.DestroyImmediate(gameObject);
         }
 
+        [Test]
+        public void RenderPassWithNoRenderFuncThrows()
+        {
+            // We need a real ScriptableRenderContext and a camera to execute the render graph
+            // add the default camera
+            var gameObject = new GameObject("testGameObject")
+            {
+                hideFlags = HideFlags.HideAndDontSave
+            };
+            gameObject.tag = "MainCamera";
+            var camera = gameObject.AddComponent<Camera>();
+
+            // record and execute render graph calls
+            m_RenderGraphTestPipeline.recordRenderGraphBody = (context, camera, cmd) =>
+            {
+                using (var builder = m_RenderGraph.AddRenderPass<RenderGraphTestPassData>("TestPassWithNoRenderFunc", out var passData))
+                {
+                    builder.AllowPassCulling(false);
+
+                    // no render func                    
+                }
+            };
+            LogAssert.Expect(LogType.Error, "Render Graph Execution error");
+            LogAssert.Expect(LogType.Exception, "InvalidOperationException: RenderPass TestPassWithNoRenderFunc was not provided with an execute function.");
+            camera.Render();
+
+            GameObject.DestroyImmediate(gameObject);
+        }
+
         /*
         // Disabled for now as version management is not exposed to user code
         [Test]