[HDRP][Compositor] Fix edge cases when cameras are missing or deleted

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

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixes some labels being clipped in the Render Graph Viewer
 - Fixed issue when decal projector material is none.
 - Fixed the sampling of the normal buffer in the the forward transparent pass.
+- Fixed issues with camera management in the graphics compositor (cases 1292548, 1292549).
 
 ## [10.2.0] - 2020-10-19
 

com.unity.render-pipelines.high-definition/Runtime/Compositor/CompositionLayer.cs

@@ -123,9 +123,10 @@ public float aspectRatio
         {
             get
             {
-                if (m_Camera != null)
+                var compositor = CompositionManager.GetInstance();
+                if (compositor != null && compositor.outputCamera != null)
                 {
-                    return (float)m_Camera.pixelWidth / m_Camera.pixelHeight;
+                    return (float)compositor.outputCamera.pixelWidth / compositor.outputCamera.pixelHeight;
                 }
                 return 1.0f;
             }
@@ -158,6 +159,9 @@ public static CompositorLayer CreateStackLayer(LayerType type = CompositorLayer.
 
             if (newLayer.m_Type == LayerType.Image || newLayer.m_Type == LayerType.Video)
             {
+                if (newLayer.m_Camera == null)
+                    newLayer.m_Camera = CompositionManager.CreateCamera(layerName);
+
                 // Image and movie layers do not render any 3D objects
                 newLayer.m_OverrideCullingMask = true;
                 newLayer.m_CullingMask = 0;
@@ -200,10 +204,11 @@ public int pixelWidth
         {
             get
             {
-                if (m_Camera)
+                var compositor = CompositionManager.GetInstance();
+                if (compositor && compositor.outputCamera)
                 {
                     float resScale = EnumToScale(m_ResolutionScale);
-                    return (int)(resScale * m_Camera.pixelWidth);
+                    return (int)(resScale * compositor.outputCamera.pixelWidth);
                 }
                 return 0;
             }
@@ -212,10 +217,11 @@ public int pixelHeight
         {
             get
             {
-                if (m_Camera)
+                var compositor = CompositionManager.GetInstance();
+                if (compositor && compositor.outputCamera)
                 {
                     float resScale = EnumToScale(m_ResolutionScale);
-                    return (int)(resScale * m_Camera.pixelHeight);
+                    return (int)(resScale * compositor.outputCamera.pixelHeight);
                 }
                 return 0;
             }
@@ -227,13 +233,6 @@ public void Init(string layerID = "")
                 m_LayerName = layerID;
             }
 
-            // Compositor output layers (that allocate the render targets) also need a reference camera, just to get the reference pixel width/height
-            // Note: Movie & image layers are rendered at the output resolution (and not the movie/image resolution). This is required to have post-processing effects like film grain at full res.
-            if (m_Camera == null)
-            {
-                m_Camera = CompositionManager.GetSceneCamera();
-            }
-
             var compositor = CompositionManager.GetInstance();
 
             // Create a new camera if necessary or use the one specified by the user
@@ -244,7 +243,7 @@ public void Init(string layerID = "")
                 // - is not shared between layers
                 // - is not used in an mage/video layer (in this case the camera is not exposed at all, so it makes sense to let the compositor manage it)
                 // - it does not force-clear the RT (the first layer of a stack, even if disabled by the user), still clears the RT
-                bool shouldClear = !enabled && m_LayerPositionInStack == 0;
+                bool shouldClear = !enabled && m_LayerPositionInStack == 0 && m_Camera;
                 bool isImageOrVideo = (m_Type == LayerType.Image || m_Type == LayerType.Video);
                 if (!isImageOrVideo && !hasLayerOverrides && !shouldClear && !compositor.IsThisCameraShared(m_Camera))
                 {
@@ -527,14 +526,17 @@ internal void CopyInternalCameraData()
 
             // Copy/update the camera data (but preserve the camera depth/draw-order [case 1264552])
             var drawOrder = m_LayerCamera.depth;
-            m_LayerCamera.CopyFrom(m_Camera);
-            m_LayerCamera.depth = drawOrder;
-
-            var cameraDataOrig = m_Camera.GetComponent<HDAdditionalCameraData>();
-            var cameraData = m_LayerCamera.GetComponent<HDAdditionalCameraData>();
-            if (cameraDataOrig)
+            if (m_Camera)
             {
-                cameraDataOrig.CopyTo(cameraData);
+                m_LayerCamera.CopyFrom(m_Camera);
+                m_LayerCamera.depth = drawOrder;
+
+                var cameraDataOrig = m_Camera.GetComponent<HDAdditionalCameraData>();
+                var cameraData = m_LayerCamera.GetComponent<HDAdditionalCameraData>();
+                if (cameraDataOrig)
+                {
+                    cameraDataOrig.CopyTo(cameraData);
+                }
             }
         }
 
@@ -606,15 +608,18 @@ public bool ValidateRTSize(int referenceWidth, int referenceHeight)
 
         public void SetupClearColor()
         {
-            m_LayerCamera.enabled = true;
-            m_LayerCamera.cullingMask = 0;
-            var cameraData = m_LayerCamera.GetComponent<HDAdditionalCameraData>();
-            var cameraDataOrig = m_Camera.GetComponent<HDAdditionalCameraData>();
+            if (m_LayerCamera && m_Camera)
+            {
+                m_LayerCamera.enabled = true;
+                m_LayerCamera.cullingMask = 0;
+                var cameraData = m_LayerCamera.GetComponent<HDAdditionalCameraData>();
+                var cameraDataOrig = m_Camera.GetComponent<HDAdditionalCameraData>();
 
-            cameraData.clearColorMode = cameraDataOrig.clearColorMode;
-            cameraData.clearDepth = true;
+                cameraData.clearColorMode = cameraDataOrig.clearColorMode;
+                cameraData.clearDepth = true;
 
-            m_ClearsBackGround = true;
+                m_ClearsBackGround = true;
+            }
         }
 
         public void AddInputFilter(CompositionFilter filter)

com.unity.render-pipelines.high-definition/Runtime/Compositor/CompositionManager.cs

@@ -70,6 +70,12 @@ public bool enableOutput
                         {
                             layer.camera.enabled = value;
                         }
+                        else
+                        {
+                            // The target texture was managed by the compositor, reset it so the user can se the camera output
+                            if (layer.camera && value == false)
+                                layer.camera.targetTexture = null;
+                        }
                     }
                 }
             }
@@ -107,9 +113,9 @@ public float aspectRatio
         {
             get
             {
-                if (m_InputLayers.Count > 0)
+                if (m_OutputCamera)
                 {
-                    return m_InputLayers[0].aspectRatio;
+                    return (float)m_OutputCamera.pixelWidth / m_OutputCamera.pixelHeight;
                 }
                 return 1.0f;
             }
@@ -257,7 +263,6 @@ bool ValidateAndFixRuntime()
         {
             if (m_OutputCamera == null)
             {
-                Debug.Log("No camera was found");
                 return false;
             }
 
@@ -434,10 +439,13 @@ public void SetupLayerPriorities()
         public void OnAfterAssemblyReload()
         {
             // Bug? : After assembly reload, the customRender callback is dropped, so set it again
-            var cameraData = m_OutputCamera.GetComponent<HDAdditionalCameraData>();
-            if (cameraData && !cameraData.hasCustomRender)
+            if (m_OutputCamera)
             {
-                cameraData.customRender += CustomRender;
+                var cameraData = m_OutputCamera.GetComponent<HDAdditionalCameraData>();
+                if (cameraData && !cameraData.hasCustomRender)
+                {
+                    cameraData.customRender += CustomRender;
+                }
             }
         }
 
@@ -837,10 +845,22 @@ static public Camera GetSceneCamera()
                     return camera;
                 }
             }
-            Debug.LogWarning("Camera not found");
+
             return null;
         }
 
+        static public Camera CreateCamera(string cameraName)
+        {
+            var newCameraGameObject = new GameObject(cameraName)
+            {
+                hideFlags = HideFlags.HideInInspector | HideFlags.HideInHierarchy | HideFlags.HideAndDontSave
+            };
+            var newCamera = newCameraGameObject.AddComponent<Camera>();
+            newCameraGameObject.AddComponent<HDAdditionalCameraData>();
+
+            return newCamera;
+        }
+
         static public CompositionManager GetInstance() =>
             s_CompositorInstance ?? (s_CompositorInstance = GameObject.FindObjectOfType(typeof(CompositionManager), true) as CompositionManager);