BREAKING CHANGE: Added IHierarchObject with Hierarchy Enter & Exit

Engine.Core/GameManager.cs

@@ -13,9 +13,11 @@ public class GameManager : BaseEntity, IGameManager
 {
     public event IGameManager.OnGameObjectRegisteredDelegate? OnGameObjectRegistered = null;
     public event IGameManager.OnGameObjectUnRegisteredDelegate? OnGameObjectUnRegistered = null;
-
+    public event IGameManager.OnHierarchyObjectRegisteredDelegate? OnHierarchyObjectRegistered = null;
+    public event IGameManager.OnHierarchyObjectUnRegisteredDelegate? OnHierarchyObjectUnRegistered = null;
 
     private readonly List<IGameObject> _gameObjects = new(Constants.GAME_OBJECTS_SIZE_INITIAL);
+    private readonly List<IHierarchyObject> _hierarchyObjects = new(Constants.GAME_OBJECTS_SIZE_INITIAL);
 
     private GameObjectFactory _gameObjectFactory = null!;
 
@@ -30,6 +32,7 @@ public class GameManager : BaseEntity, IGameManager
     }
 
     public IReadOnlyList<IGameObject> GameObjects => _gameObjects;
+    public IReadOnlyList<IHierarchyObject> HierarchyObjects => _hierarchyObjects;
 
     public override IStateEnable StateEnable
     {
@@ -101,21 +104,55 @@ public class GameManager : BaseEntity, IGameManager
 
     /////////////////////////////////////////////////////////////////
 
+    private void Register(IHierarchyObject hierarchyObject)
+    {
+        if (hierarchyObject is IGameObject gameObject)
+            Register(gameObject);
+        else
+        {
+            _hierarchyObjects.Add(hierarchyObject);
+            OnHierarchyObjectRegistered?.Invoke(this, hierarchyObject);
+        }
+    }
+
     private void Register(IGameObject gameObject)
     {
-        gameObject.Assign(this);
-
         gameObject.OnFinalized += OnGameObjectFinalize;
+        gameObject.OnExitedHierarchy += OnGameObjectExitedHierarchy;
 
         _gameObjects.Add(gameObject);
+        _hierarchyObjects.Add(gameObject);
+
+        if (!gameObject.EnterHierarchy(this))
+            throw new Exception($"{nameof(gameObject)} can't enter the hierarchy");
+
+        OnHierarchyObjectRegistered?.Invoke(this, gameObject);
         OnGameObjectRegistered?.Invoke(this, gameObject);
     }
 
+    private void Unregister(IHierarchyObject hierarchyObject)
+    {
+        if (hierarchyObject is IGameObject gameObject)
+            Unregister(gameObject);
+        else
+        {
+            _hierarchyObjects.Remove(hierarchyObject);
+            OnHierarchyObjectUnRegistered?.Invoke(this, hierarchyObject);
+        }
+    }
+
     private void Unregister(IGameObject gameObject)
     {
         gameObject.OnFinalized -= OnGameObjectFinalize;
+        gameObject.OnExitedHierarchy -= OnGameObjectExitedHierarchy;
 
         _gameObjects.Remove(gameObject);
+        _hierarchyObjects.Remove(gameObject);
+
+        if (!gameObject.ExitHierarchy())
+            throw new Exception($"{nameof(gameObject)} can't exit the hierarchy");
+
+        OnHierarchyObjectUnRegistered?.Invoke(this, gameObject);
         OnGameObjectUnRegistered?.Invoke(this, gameObject);
     }
 
@@ -125,6 +162,12 @@ public class GameManager : BaseEntity, IGameManager
             Unregister(gameObject);
     }
 
+    private void OnGameObjectExitedHierarchy(IHierarchyObject sender)
+    {
+        if (sender is IGameObject gameObject)
+            Unregister(gameObject);
+    }
+
     /////////////////////////////////////////////////////////////////
 
     public IEnumerator<IGameObject> GetEnumerator() => _gameObjects.GetEnumerator();