ATOM-16747 RPISystemInterface::GetDefaultScene returns the scene crea… (#5153) (#5389)

* ATOM-16747 RPISystemInterface::GetDefaultScene returns the scene created by PreviewRenderer but not the Main Scene
Deprecate GetDefaultScene() function.
Update all the places which use GetDefaultScene to use Scene::GetFeatureProcessorFromEntityId or GetMainScene.
Tested with Editor, UI Editor, Material Editor, game launcher.

Signed-off-by: Qing Tao <55564570+VickyAtAZ@users.noreply.github.com>
(cherry picked from commit 8da6bea073)

Gems/Atom/RPI/Code/Source/RPI.Public/Culling.cpp

@@ -699,9 +699,7 @@ namespace AZ
             m_parentScene = parentScene;
 
             AZ_Assert(m_visScene == nullptr, "IVisibilityScene already created for this RPI::Scene");
-            char sceneIdBuf[40] = "";
-            m_parentScene->GetId().ToString(sceneIdBuf);
-            AZ::Name visSceneName(AZStd::string::format("RenderCullScene[%s]", sceneIdBuf));
+            AZ::Name visSceneName(AZStd::string::format("RenderCullScene[%s]", m_parentScene->GetName().GetCStr()));
             m_visScene = AZ::Interface<AzFramework::IVisibilitySystem>::Get()->CreateVisibilityScene(visSceneName);
 
 #ifdef AZ_CULL_DEBUG_ENABLED

Gems/Atom/RPI/Code/Source/RPI.Public/RPISystem.cpp

@@ -159,6 +159,11 @@ namespace AZ
                     AZ_Assert(false, "Scene was already registered");
                     return;
                 }
+                else if (!scene->GetName().IsEmpty() && scene->GetName() == sceneItem->GetName())
+                {
+                    // only report a warning if there is a scene with duplicated name
+                    AZ_Warning("RPISystem", false, "There is a registered scene with same name [%s]", scene->GetName().GetCStr());
+                }
             }
 
             m_scenes.push_back(scene);
@@ -177,11 +182,35 @@ namespace AZ
             AZ_Assert(false, "Can't unregister scene which wasn't registered");
         }
 
-        ScenePtr RPISystem::GetScene(const SceneId& sceneId) const
+        Scene* RPISystem::GetScene(const SceneId& sceneId) const
         {
             for (const auto& scene : m_scenes)
             {
                 if (scene->GetId() == sceneId)
+                {
+                    return scene.get();
+                }
+            }
+            return nullptr;
+        }
+
+        Scene* RPISystem::GetSceneByName(const AZ::Name& name) const
+        {
+            for (const auto& scene : m_scenes)
+            {
+                if (scene->GetName() == name)
+                {
+                    return scene.get();
+                }
+            }
+            return nullptr;
+        }
+        
+        ScenePtr RPISystem::GetDefaultScene() const
+        {
+            for (const auto& scene : m_scenes)
+            {
+                if (scene->GetName() == AZ::Name("Main"))
                 {
                     return scene;
                 }
@@ -189,16 +218,6 @@ namespace AZ
             return nullptr;
         }
 
-        ScenePtr RPISystem::GetDefaultScene() const
-        {
-            if (m_scenes.size() > 0)
-            {
-                return m_scenes[0];
-            }
-            return nullptr;
-        }
-
-
         RenderPipelinePtr RPISystem::GetRenderPipelineForWindow(AzFramework::NativeWindowHandle windowHandle)
         {
             RenderPipelinePtr renderPipeline;

Gems/Atom/RPI/Code/Source/RPI.Public/Scene.cpp

@@ -45,7 +45,9 @@ namespace AZ
                 auto shaderAsset = RPISystemInterface::Get()->GetCommonShaderAssetForSrgs();
                 scene->m_srg = ShaderResourceGroup::Create(shaderAsset, sceneSrgLayout->GetName());
             }
-            
+
+            scene->m_name = sceneDescriptor.m_nameId;
+
             return ScenePtr(scene);
         }
 
@@ -83,10 +85,23 @@ namespace AZ
             return nullptr;
         }
 
+        Scene* Scene::GetSceneForEntityId(AZ::EntityId entityId)
+        {
+            // Find the entity context for the entity ID.
+            AzFramework::EntityContextId entityContextId = AzFramework::EntityContextId::CreateNull();
+            AzFramework::EntityIdContextQueryBus::EventResult(entityContextId, entityId, &AzFramework::EntityIdContextQueryBus::Events::GetOwningContextId);
+
+            if (!entityContextId.IsNull())
+            {
+                return GetSceneForEntityContextId(entityContextId);
+            }
+            return nullptr;
+        }
+
 
         Scene::Scene()
         {
-            m_id = Uuid::CreateRandom();
+            m_id = AZ::Uuid::CreateRandom();
             m_cullingScene = aznew CullingScene();
             SceneRequestBus::Handler::BusConnect(m_id);
             m_drawFilterTagRegistry = RHI::DrawFilterTagRegistry::Create();
@@ -299,7 +314,6 @@ namespace AZ
             // Force to update the lookup table since adding render pipeline would effect any pipeline states created before pass system tick
             RebuildPipelineStatesLookup();
 
-            AZ_Assert(!m_id.IsNull(), "RPI::Scene needs to have a valid uuid.");
             SceneNotificationBus::Event(m_id, &SceneNotification::OnRenderPipelineAdded, pipeline);
         }
         
@@ -785,6 +799,11 @@ namespace AZ
         {
             return m_id;
         }
+
+        AZ::Name Scene::GetName() const
+        {
+            return m_name;
+        }
                 
         bool Scene::SetDefaultRenderPipeline(const RenderPipelineId& pipelineId)
         {