From bf361c2c13c9b8ec77dd855375ee79e76a04ff22 Mon Sep 17 00:00:00 2001
From: Yuriy Toporovskyy <toporovskyy.y@gmail.com>
Date: Wed, 4 Aug 2021 17:20:45 -0400
Subject: [PATCH] Handle the case where a camera deactivates and the previous
 camera on the stack should become the active view

Signed-off-by: Yuriy Toporovskyy <toporovskyy.y@gmail.com>
---
 .../Code/Source/CameraComponentController.cpp | 24 ++++++++++---------
 .../Code/Source/CameraComponentController.h   |  1 +
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/Gems/Camera/Code/Source/CameraComponentController.cpp b/Gems/Camera/Code/Source/CameraComponentController.cpp
index a81ef1c9ae..a8b5b8992e 100644
--- a/Gems/Camera/Code/Source/CameraComponentController.cpp
+++ b/Gems/Camera/Code/Source/CameraComponentController.cpp
@@ -115,6 +115,13 @@ namespace Camera
             AZ_Assert(m_atomCamera, "Attempted to activate Atom camera before component activation");
 
             const AZ::Name contextName = atomViewportRequests->GetDefaultViewportContextName();
+
+            // Connect to the bus the first time we activate the view
+            if (!AZ::RPI::ViewportContextNotificationBus::Handler::BusIsConnectedId(contextName))
+            {
+                AZ::RPI::ViewportContextNotificationBus::Handler::BusConnect(contextName);
+            }
+
             // Ensure the Atom camera is updated with our current transform state
             AZ::Transform localTransform;
             AZ::TransformBus::EventResult(localTransform, m_entityId, &AZ::TransformBus::Events::GetLocalTM);
@@ -125,7 +132,6 @@ namespace Camera
             // Push the Atom camera after we make sure we're up-to-date with our component's transform to ensure the viewport reads the correct state
             UpdateCamera();
             atomViewportRequests->PushView(contextName, m_atomCamera);
-            AZ::RPI::ViewportContextNotificationBus::Handler::BusConnect(contextName);
         }
     }
 
@@ -140,7 +146,6 @@ namespace Camera
         if (atomViewportRequests)
         {
             const AZ::Name contextName = atomViewportRequests->GetDefaultViewportContextName();
-            AZ::RPI::ViewportContextNotificationBus::Handler::BusDisconnect(contextName);
             atomViewportRequests->PopView(contextName, m_atomCamera);
         }
     }
@@ -446,7 +451,7 @@ namespace Camera
 
     bool CameraComponentController::IsActiveView()
     {
-        return AZ::RPI::ViewportContextNotificationBus::Handler::BusIsConnected();
+        return m_isActiveView;
     }
 
     void CameraComponentController::OnTransformChanged([[maybe_unused]] const AZ::Transform& local, const AZ::Transform& world)
@@ -472,18 +477,15 @@ namespace Camera
 
     void CameraComponentController::OnViewportSizeChanged([[maybe_unused]] AzFramework::WindowSize size)
     {
-        UpdateCamera();
+        if (IsActiveView())
+        {
+            UpdateCamera();
+        }
     }
 
     void CameraComponentController::OnViewportDefaultViewChanged(AZ::RPI::ViewPtr view)
     {
-        if (m_atomCamera != view)
-        {
-            // Note that when disconnected from this bus, this signals that we are not the active view
-            // There is nothing else to do here: leave our view on the viewport context stack, don't need
-            // to update properties. The viewport context system should handle it all!
-            AZ::RPI::ViewportContextNotificationBus::Handler::BusDisconnect();
-        }
+        m_isActiveView = m_atomCamera == view;
     }
 
     AZ::RPI::ViewPtr CameraComponentController::GetView() const
diff --git a/Gems/Camera/Code/Source/CameraComponentController.h b/Gems/Camera/Code/Source/CameraComponentController.h
index 3d7844e6ac..923da65618 100644
--- a/Gems/Camera/Code/Source/CameraComponentController.h
+++ b/Gems/Camera/Code/Source/CameraComponentController.h
@@ -132,6 +132,7 @@ namespace Camera
         AZ::RPI::AuxGeomDrawPtr m_atomAuxGeom;
         AZ::Event<const AZ::Matrix4x4&>::Handler m_onViewMatrixChanged;
         bool m_updatingTransformFromEntity = false;
+        bool m_isActiveView = false;
 
         // Cry view integration
         IView* m_view = nullptr;