From 5d9c99436a81cabeff5758a22f86522acfc63265 Mon Sep 17 00:00:00 2001
From: nvsickle <nvsickle@amazon.com>
Date: Wed, 5 May 2021 16:54:31 -0700
Subject: [PATCH] Ensure CameraComponentController entities get synced with
 Atom camera changes.

This ensures the camera entity's transform gets correctly set if the RPI::View (or ViewportContext) is directly used instead of adjusting the entity transform, for e.g. camera controllers.
---
 .../Code/Source/CameraComponentController.cpp  | 18 ++++++++++++++++++
 .../Code/Source/CameraComponentController.h    |  3 +++
 2 files changed, 21 insertions(+)

diff --git a/Gems/Camera/Code/Source/CameraComponentController.cpp b/Gems/Camera/Code/Source/CameraComponentController.cpp
index 2799d897d6..3dcee68169 100644
--- a/Gems/Camera/Code/Source/CameraComponentController.cpp
+++ b/Gems/Camera/Code/Source/CameraComponentController.cpp
@@ -160,6 +160,17 @@ namespace Camera
         incompatible.push_back(AZ_CRC("CameraService", 0x1dd1caa4));
     }
 
+    void CameraComponentController::Init()
+    {
+        m_onViewMatrixChanged = AZ::Event<const AZ::Matrix4x4&>::Handler([this](const AZ::Matrix4x4&)
+        {
+            if (!m_updatingTransformFromEntity)
+            {
+                AZ::TransformBus::Event(m_entityId, &AZ::TransformInterface::SetWorldTM, m_atomCamera->GetCameraTransform());
+            }
+        });
+    }
+
     void CameraComponentController::Activate(AZ::EntityId entityId)
     {
         m_entityId = entityId;
@@ -218,6 +229,8 @@ namespace Camera
                 }
             }
             AZ::RPI::ViewProviderBus::Handler::BusConnect(m_entityId);
+
+            m_atomCamera->ConnectWorldToViewMatrixChangedHandler(m_onViewMatrixChanged);
         }
 
         UpdateCamera();
@@ -258,6 +271,7 @@ namespace Camera
         if (atomViewportRequests)
         {
             AZ::RPI::ViewProviderBus::Handler::BusDisconnect(m_entityId);
+            m_onViewMatrixChanged.Disconnect();
         }
 
         DeactivateAtomView();
@@ -376,7 +390,9 @@ namespace Camera
 
         if (m_atomCamera)
         {
+            m_updatingTransformFromEntity = true;
             m_atomCamera->SetCameraTransform(AZ::Matrix3x4::CreateFromTransform(world.GetOrthogonalized()));
+            m_updatingTransformFromEntity = false;
         }
     }
 
@@ -425,7 +441,9 @@ namespace Camera
                 m_config.m_nearClipDistance,
                 m_config.m_farClipDistance,
                 true);
+            m_updatingTransformFromEntity = true;
             m_atomCamera->SetViewToClipMatrix(viewToClipMatrix);
+            m_updatingTransformFromEntity = false;
         }
     }
 
diff --git a/Gems/Camera/Code/Source/CameraComponentController.h b/Gems/Camera/Code/Source/CameraComponentController.h
index 92e1354f17..cae6ad4663 100644
--- a/Gems/Camera/Code/Source/CameraComponentController.h
+++ b/Gems/Camera/Code/Source/CameraComponentController.h
@@ -77,6 +77,7 @@ namespace Camera
         static void GetProvidedServices(AZ::ComponentDescriptor::DependencyArrayType& provided);
         static void GetIncompatibleServices(AZ::ComponentDescriptor::DependencyArrayType& incompatible);
 
+        void Init();
         void Activate(AZ::EntityId entityId);
         void Deactivate();
         void SetConfiguration(const CameraComponentConfig& config);
@@ -121,6 +122,8 @@ namespace Camera
         // Atom integration
         AZ::RPI::ViewPtr m_atomCamera;
         AZ::RPI::AuxGeomDrawPtr m_atomAuxGeom;
+        AZ::Event<const AZ::Matrix4x4&>::Handler m_onViewMatrixChanged;
+        bool m_updatingTransformFromEntity = false;
 
         // Cry view integration
         IView* m_view = nullptr;