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/Include/Atom/RPI.Public/RPISystem.h

@@ -70,7 +70,8 @@ namespace AZ
             void InitializeSystemAssets() override;
             void RegisterScene(ScenePtr scene) override;
             void UnregisterScene(ScenePtr scene) override;
-            ScenePtr GetScene(const SceneId& sceneId) const override;
+            Scene* GetScene(const SceneId& sceneId) const override;
+            Scene* GetSceneByName(const AZ::Name& name) const override;
             ScenePtr GetDefaultScene() const override;
             RenderPipelinePtr GetRenderPipelineForWindow(AzFramework::NativeWindowHandle windowHandle) override;
             Data::Asset<ShaderAsset> GetCommonShaderAssetForSrgs() const override;

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/RPISystemInterface.h

@@ -13,6 +13,7 @@
 
 #include <Atom/RPI.Public/Base.h>
 
+#include <AzCore/Name/Name.h>
 #include <AzFramework/Windowing/WindowBus.h>
 
 namespace AZ
@@ -46,11 +47,14 @@ namespace AZ
             //! Unregister a scene from RPISystem. The scene won't be simulated or rendered.
             virtual void UnregisterScene(ScenePtr scene) = 0;
 
-            // [GFX TODO] to be removed when we have scene setup in AZ Core
-            virtual ScenePtr GetDefaultScene() const = 0;
-
+            //! Deprecated. Use GetSceneByName(name), GetSceneForEntityContextId(entityContextId) or Scene::GetSceneForEntityId(AZ::EntityId entityId) instead
+            AZ_DEPRECATED(virtual ScenePtr GetDefaultScene() const = 0;, "This method has been deprecated. Please use GetSceneByName(name), GetSceneForEntityContextId(entityContextId) or Scene::GetSceneForEntityId(AZ::EntityId entityId) instead.");
+            
             //! Get scene by using scene id.
-            virtual ScenePtr GetScene(const SceneId& sceneId) const = 0;
+            virtual Scene* GetScene(const SceneId& sceneId) const = 0;
+
+            //! Get scene by using scene name.
+            virtual Scene* GetSceneByName(const AZ::Name& name) const = 0;
 
             //! Get the render pipeline created for a window
             virtual RenderPipelinePtr GetRenderPipelineForWindow(AzFramework::NativeWindowHandle windowHandle) = 0;

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/Scene.h

@@ -80,6 +80,9 @@ namespace AZ
             //! Gets the RPI::Scene for a given entityContextId.
             //! May return nullptr if there is no RPI::Scene created for that entityContext.
             static Scene* GetSceneForEntityContextId(AzFramework::EntityContextId entityContextId);
+            
+            //! Gets the RPI::Scene for a given entityId.
+            static Scene* GetSceneForEntityId(AZ::EntityId entityId);
 
             ~Scene();
 
@@ -135,6 +138,8 @@ namespace AZ
 
             const SceneId& GetId() const;
 
+            AZ::Name GetName() const;
+
             //! Set default pipeline by render pipeline ID.
             //! It returns true if the default render pipeline was set from the input ID.
             //! If the specified render pipeline doesn't exist in this scene then it won't do anything and returns false.
@@ -245,6 +250,9 @@ namespace AZ
             // The uuid to identify this scene.
             SceneId m_id;
 
+            // Scene's name which is set at initialization. Can be empty
+            AZ::Name m_name;
+
             bool m_activated = false;
             bool m_taskGraphActive = false; // update during tick, to ensure it only changes on frame boundaries
 
@@ -286,13 +294,10 @@ namespace AZ
         template<typename FeatureProcessorType>
         FeatureProcessorType* Scene::GetFeatureProcessorForEntity(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())
+            RPI::Scene* renderScene = GetSceneForEntityId(entityId);            
+            if (renderScene)
             {
-                return GetFeatureProcessorForEntityContextId<FeatureProcessorType>(entityContextId);
+                return renderScene->GetFeatureProcessor<FeatureProcessorType>();
             }
             return nullptr;
         };

Gems/Atom/RPI/Code/Include/Atom/RPI.Reflect/System/SceneDescriptor.h

@@ -9,6 +9,7 @@
 #pragma once
 
 #include <AzCore/Asset/AssetCommon.h>
+#include <AzCore/Name/Name.h>
 #include <AzCore/std/containers/vector.h>
 #include <AzCore/std/string/string.h>
 
@@ -25,6 +26,9 @@ namespace AZ
 
             //! List of feature processors which the scene will initially enable.
             AZStd::vector<AZStd::string> m_featureProcessorNames;
+
+            //! A name used as scene id. It can be used to search a registered scene via RPISystemInterface::GetScene()
+            AZ::Name m_nameId;
         };
     } // namespace RPI
 } // namespace AZ