From 8b5f532e306a174ade34eae4c3edae258dc7d252 Mon Sep 17 00:00:00 2001
From: Chris Galvan <chgalvan@amazon.com>
Date: Tue, 25 Jan 2022 14:25:32 -0600
Subject: [PATCH 1/2] Disable render pipeline for EditorViewportWidget until a
 level has been loaded

Signed-off-by: Chris Galvan <chgalvan@amazon.com>
---
 Code/Editor/EditorViewportWidget.cpp | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/Code/Editor/EditorViewportWidget.cpp b/Code/Editor/EditorViewportWidget.cpp
index a8180bcace..6ba62604e8 100644
--- a/Code/Editor/EditorViewportWidget.cpp
+++ b/Code/Editor/EditorViewportWidget.cpp
@@ -89,6 +89,7 @@
 #include <LmbrCentral/Rendering/EditorCameraCorrectionBus.h>
 
 // Atom
+#include <Atom/RPI.Public/RenderPipeline.h>
 #include <Atom/RPI.Public/View.h>
 #include <Atom/RPI.Public/ViewportContextManager.h>
 #include <Atom/RPI.Public/ViewProviderBus.h>
@@ -584,7 +585,7 @@ void EditorViewportWidget::OnEditorNotifyEvent(EEditorNotifyEvent event)
         m_renderViewport->SetScene(nullptr);
         break;
 
-    case eNotify_OnEndSceneOpen:
+    case eNotify_OnEndLoad:
         UpdateScene();
         SetDefaultCamera();
         break;
@@ -2324,7 +2325,22 @@ void EditorViewportWidget::UpdateScene()
         {
             AZ::RPI::SceneNotificationBus::Handler::BusDisconnect();
             m_renderViewport->SetScene(mainScene);
-            AZ::RPI::SceneNotificationBus::Handler::BusConnect(m_renderViewport->GetViewportContext()->GetRenderScene()->GetId());
+            auto viewportContext = m_renderViewport->GetViewportContext();
+            AZ::RPI::SceneNotificationBus::Handler::BusConnect(viewportContext->GetRenderScene()->GetId());
+
+            // Don't enable the render pipeline until a level has been loaded
+            auto renderPipeline = viewportContext->GetCurrentPipeline();
+            if (renderPipeline)
+            {
+                if (GetIEditor()->IsLevelLoaded())
+                {
+                    renderPipeline->AddToRenderTick();
+                }
+                else
+                {
+                    renderPipeline->RemoveFromRenderTick();
+                }
+            }
         }
     }
 }

From 6e05ac678d475fc93925ba51be8df82aa96ff7a4 Mon Sep 17 00:00:00 2001
From: Chris Galvan <chgalvan@amazon.com>
Date: Tue, 25 Jan 2022 16:46:49 -0600
Subject: [PATCH 2/2] Hide the RenderViewportWidget when there is no level
 loaded so the gradient background is visible

Signed-off-by: Chris Galvan <chgalvan@amazon.com>
---
 Code/Editor/EditorViewportWidget.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Code/Editor/EditorViewportWidget.cpp b/Code/Editor/EditorViewportWidget.cpp
index 6ba62604e8..9a9e9f5ad3 100644
--- a/Code/Editor/EditorViewportWidget.cpp
+++ b/Code/Editor/EditorViewportWidget.cpp
@@ -2329,15 +2329,19 @@ void EditorViewportWidget::UpdateScene()
             AZ::RPI::SceneNotificationBus::Handler::BusConnect(viewportContext->GetRenderScene()->GetId());
 
             // Don't enable the render pipeline until a level has been loaded
+            // Also show/hide the RenderViewportWidget accordingly so that we get the
+            // expected gradient background when no level is loaded
             auto renderPipeline = viewportContext->GetCurrentPipeline();
             if (renderPipeline)
             {
                 if (GetIEditor()->IsLevelLoaded())
                 {
+                    m_renderViewport->show();
                     renderPipeline->AddToRenderTick();
                 }
                 else
                 {
+                    m_renderViewport->hide();
                     renderPipeline->RemoveFromRenderTick();
                 }
             }