[HDRP] nullref fullscreen passthrough when the customRender callback …

…is used (Unity-Technologies#4902)

* Fix nullref when enabling fullscreen passthrough in HDRP Cameras

* Updated changelog

* Fix hdcamera null in callback

* Fix nullref again

* Correctly fix the error with fullscreen passthrough + add a warning message

* Cleanup code

* Added a test for begin/end camera rendering

Co-authored-by: sebastienlagarde <sebastien@unity3d.com>

TestProjects/HDRP_Tests/Assets/GraphicTests/HDRP_PlayModeTests/HDRP_PlayModeTests.asmdef

@@ -0,0 +1,21 @@
+{
+    "name": "HDRP_PlayModeTests",
+    "rootNamespace": "",
+    "references": [
+        "UnityEngine.TestRunner",
+        "Unity.RenderPipelines.HighDefinition.Runtime"
+    ],
+    "includePlatforms": [],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": true,
+    "precompiledReferences": [
+        "nunit.framework.dll"
+    ],
+    "autoReferenced": false,
+    "defineConstraints": [
+        "UNITY_INCLUDE_TESTS"
+    ],
+    "versionDefines": [],
+    "noEngineReferences": false
+}

TestProjects/HDRP_Tests/Assets/GraphicTests/HDRP_PlayModeTests/RenderPipelineManagerCallbackTests.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Linq;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.Rendering;
+using UnityEngine.TestTools;
+using System.Collections.Generic;
+using UnityEngine.Rendering.HighDefinition;
+
+public class RenderPipelineManagerCallbackTests
+{
+    const int k_RenderCount = 10;
+
+    int begin = 0;
+    int end = 0;
+
+    public Camera SetupTest()
+    {
+        begin = 0;
+        end = 0;
+
+        GameObject go = new GameObject();
+        var camera = go.AddComponent<Camera>();
+
+        RenderPipelineManager.beginCameraRendering += CountBeginCameraRender;
+        RenderPipelineManager.endCameraRendering += CountEndCameraRender;
+
+        return camera;
+    }
+
+    void CountBeginCameraRender(ScriptableRenderContext context, Camera camera) => begin++;
+
+    void CountEndCameraRender(ScriptableRenderContext context, Camera camera) => end++;
+
+    public bool CheckResult(int expectedValue)
+    {
+        RenderPipelineManager.beginCameraRendering -= CountBeginCameraRender;
+        RenderPipelineManager.endCameraRendering -= CountEndCameraRender;
+
+        return begin == end && begin == expectedValue;
+    }
+
+    [UnityTest]
+    public bool BeginAndEndCameraRenderingCallbackMatch_Camera()
+    {
+        var camera = SetupTest();
+        for (int i = 0; i < k_RenderCount; i++)
+            camera.Render();
+        return CheckResult(k_RenderCount);
+    }
+
+    [UnityTest]
+    public bool BeginAndEndCameraRenderingCallbackMatch_RenderToTexture()
+    {
+        var camera = SetupTest();
+        camera.targetTexture = new RenderTexture(1, 1, 32, RenderTextureFormat.ARGB32);
+        camera.targetTexture.Create();
+        for (int i = 0; i < k_RenderCount; i++)
+            camera.Render();
+        return CheckResult(k_RenderCount);
+    }
+
+    [UnityTest]
+    public bool BeginAndEndCameraRenderingCallbackMatch_CustomRender()
+    {
+        var camera = SetupTest();
+        var additionalData = camera.gameObject.AddComponent<HDAdditionalCameraData>();
+        additionalData.customRender += (_, _) => {};
+        for (int i = 0; i < k_RenderCount; i++)
+            camera.Render();
+        return CheckResult(k_RenderCount);
+    }
+
+    [UnityTest]
+    public bool BeginAndEndCameraRenderingCallbackMatch_FullscreenPassthrough()
+    {
+        var camera = SetupTest();
+        var additionalData = camera.gameObject.AddComponent<HDAdditionalCameraData>();
+        additionalData.fullscreenPassthrough = true;
+        for (int i = 0; i < k_RenderCount; i++)
+            camera.Render();
+        // Fullscreen passthrough don't trigger begin/end camera rendering
+        return CheckResult(0);
+    }
+}

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

@@ -262,6 +262,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed sceneview debug mode rendering (case 1211436)
 - Fixed Pixel Displacement that could be set on tessellation shader while it's not supported.
 - Fixed an issue where disabled reflection probes were still sent into the the ray tracing light cluster.
+- Fixed nullref when enabling fullscreen passthrough in HDRP Camera.
 
 ### Changed
 - Changed Window/Render Pipeline/HD Render Pipeline Wizard to Window/Rendering/HDRP Wizard

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/HDRenderPipeline.cs

@@ -1187,16 +1187,16 @@ protected override void Render(ScriptableRenderContext renderContext, Camera[] c
                         out var hdCamera,
                         out var cullingParameters);
 
-                    VFXCameraXRSettings cameraXRSettings;
-                    cameraXRSettings.viewTotal = hdCamera.xr.enabled ? 2U : 1U;
-                    cameraXRSettings.viewCount = (uint)hdCamera.viewCount;
-                    cameraXRSettings.viewOffset = (uint)hdCamera.xr.multipassId;
-
-                    VFXManager.PrepareCamera(camera, cameraXRSettings);
-
                     // Note: In case of a custom render, we have false here and 'TryCull' is not executed
                     if (!skipRequest)
                     {
+                        VFXCameraXRSettings cameraXRSettings;
+                        cameraXRSettings.viewTotal = hdCamera.xr.enabled ? 2U : 1U;
+                        cameraXRSettings.viewCount = (uint)hdCamera.viewCount;
+                        cameraXRSettings.viewOffset = (uint)hdCamera.xr.multipassId;
+
+                        VFXManager.PrepareCamera(camera, cameraXRSettings);
+
                         var needCulling = true;
 
                         // In XR multipass, culling results can be shared if the pass has the same culling id
@@ -1219,6 +1219,12 @@ protected override void Render(ScriptableRenderContext renderContext, Camera[] c
                             skipRequest = !TryCull(camera, hdCamera, renderContext, m_SkyManager, cullingParameters, m_Asset, ref cullingResults);
                     }
 
+                    if (additionalCameraData.hasCustomRender && additionalCameraData.fullscreenPassthrough)
+                    {
+                        Debug.LogWarning("HDRP Camera custom render is not supported when Fullscreen Passthrough is enabled. Please either disable Fullscreen Passthrough in the camera settings or remove all customRender callbacks attached to this camera.");
+                        continue;
+                    }
+
                     if (additionalCameraData != null && additionalCameraData.hasCustomRender)
                     {
                         skipRequest = true;