refactor: switched from universe objects to behaviours on all managers like update, draw & physics etc.

Engine.Core/CoroutineManager.cs

@@ -3,7 +3,7 @@ using System.Collections.Generic;
 
 namespace Syntriax.Engine.Core;
 
-public class CoroutineManager : UniverseObject
+public class CoroutineManager : Behaviour
 {
     private readonly List<IEnumerator> enumerators = [];
 
@@ -18,12 +18,12 @@ public class CoroutineManager : UniverseObject
         enumerators.Remove(enumerator);
     }
 
-    protected override void OnEnteringUniverse(IUniverse universe)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
         universe.OnUpdate.AddListener(OnUpdate);
     }
 
-    protected override void OnExitingUniverse(IUniverse universe)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         universe.OnUpdate.RemoveListener(OnUpdate);
     }

Engine.Core/Helpers/Event.cs

@@ -5,11 +5,14 @@ namespace Syntriax.Engine.Core;
 
 public class Event
 {
-    private readonly List<EventHandler> listeners = new(8);
+    private readonly List<EventHandler> listeners = new(4);
+    private readonly List<EventHandler> onceListeners = new(2);
 
     public void AddListener(EventHandler listener) => listeners.Add(listener);
+    public void AddOnceListener(EventHandler listener) => onceListeners.Add(listener);
     public void RemoveListener(EventHandler listener) => listeners.Remove(listener);
-    public void Clear() => listeners.Clear();
+    public void RemoveOnceListener(EventHandler listener) => onceListeners.Remove(listener);
+    public void Clear() { listeners.Clear(); onceListeners.Clear(); }
     public void Invoke()
     {
         for (int i = 0; i < listeners.Count; i++)
@@ -19,6 +22,17 @@ public class Event
                 string methodCallRepresentation = $"{listeners[i].Method.DeclaringType?.FullName}.{listeners[i].Method.Name}()";
                 Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
             }
+
+        for (int i = onceListeners.Count - 1; i >= 0; i--)
+        {
+            try { onceListeners[i].Invoke(); }
+            catch (Exception exception)
+            {
+                string methodCallRepresentation = $"{onceListeners[i].Method.DeclaringType?.FullName}.{onceListeners[i].Method.Name}()";
+                Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
+            }
+            onceListeners.RemoveAt(i);
+        }
     }
 
     public delegate void EventHandler();
@@ -26,20 +40,34 @@ public class Event
 
 public class Event<TSender>
 {
-    private readonly List<EventHandler> listeners = new(8);
+    private readonly List<EventHandler> listeners = new(4);
+    private readonly List<EventHandler> onceListeners = new(2);
 
     public void AddListener(EventHandler listener) => listeners.Add(listener);
+    public void AddOnceListener(EventHandler listener) => onceListeners.Add(listener);
     public void RemoveListener(EventHandler listener) => listeners.Remove(listener);
-    public void Clear() => listeners.Clear();
+    public void RemoveOnceListener(EventHandler listener) => onceListeners.Remove(listener);
-    public void Invoke(TSender argument)
+    public void Clear() { listeners.Clear(); onceListeners.Clear(); }
+    public void Invoke(TSender sender)
     {
         for (int i = 0; i < listeners.Count; i++)
-            try { listeners[i].Invoke(argument); }
+            try { listeners[i].Invoke(sender); }
             catch (Exception exception)
             {
-                string methodCallRepresentation = $"{listeners[i].Method.DeclaringType?.FullName}.{listeners[i].Method.Name}({argument})";
+                string methodCallRepresentation = $"{listeners[i].Method.DeclaringType?.FullName}.{listeners[i].Method.Name}({sender})";
                 Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
             }
+
+        for (int i = onceListeners.Count - 1; i >= 0; i--)
+        {
+            try { onceListeners[i].Invoke(sender); }
+            catch (Exception exception)
+            {
+                string methodCallRepresentation = $"{onceListeners[i].Method.DeclaringType?.FullName}.{onceListeners[i].Method.Name}({sender})";
+                Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
+            }
+            onceListeners.RemoveAt(i);
+        }
     }
 
     public delegate void EventHandler(TSender sender);
@@ -47,11 +75,14 @@ public class Event<TSender>
 
 public class Event<TSender, TArguments>
 {
-    private readonly List<EventHandler> listeners = new(8);
+    private readonly List<EventHandler> listeners = new(4);
+    private readonly List<EventHandler> onceListeners = new(2);
 
     public void AddListener(EventHandler listener) => listeners.Add(listener);
+    public void AddOnceListener(EventHandler listener) => onceListeners.Add(listener);
     public void RemoveListener(EventHandler listener) => listeners.Remove(listener);
-    public void Clear() => listeners.Clear();
+    public void RemoveOnceListener(EventHandler listener) => onceListeners.Remove(listener);
+    public void Clear() { listeners.Clear(); onceListeners.Clear(); }
     public void Invoke(TSender sender, TArguments args)
     {
         for (int i = 0; i < listeners.Count; i++)
@@ -61,6 +92,17 @@ public class Event<TSender, TArguments>
                 string methodCallRepresentation = $"{listeners[i].Method.DeclaringType?.FullName}.{listeners[i].Method.Name}({string.Join(", ", sender, args)})";
                 Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
             }
+
+        for (int i = onceListeners.Count - 1; i >= 0; i--)
+        {
+            try { onceListeners[i].Invoke(sender, args); }
+            catch (Exception exception)
+            {
+                string methodCallRepresentation = $"{onceListeners[i].Method.DeclaringType?.FullName}.{onceListeners[i].Method.Name}({string.Join(", ", sender, args)})";
+                Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
+            }
+            onceListeners.RemoveAt(i);
+        }
     }
 
     public delegate void EventHandler(TSender sender, TArguments args);

Engine.Core/Systems/DrawManager.cs

@@ -2,7 +2,7 @@ using System.Collections.Generic;
 
 namespace Syntriax.Engine.Core;
 
-public class DrawManager : UniverseObject
+public class DrawManager : Behaviour
 {
     // We use Descending order because draw calls are running from last to first
     private static Comparer<IBehaviour> SortByDescendingPriority() => Comparer<IBehaviour>.Create((x, y) => y.Priority.CompareTo(x.Priority));
@@ -29,7 +29,7 @@ public class DrawManager : UniverseObject
             postDrawEntities[i].PostDraw();
     }
 
-    protected override void OnEnteringUniverse(IUniverse universe)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
         preDrawEntities.Assign(universe);
         drawEntities.Assign(universe);
@@ -40,7 +40,7 @@ public class DrawManager : UniverseObject
         universe.OnPostDraw.AddListener(OnPostDraw);
     }
 
-    protected override void OnExitingUniverse(IUniverse universe)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         preDrawEntities.Unassign();
         drawEntities.Unassign();

Engine.Core/Systems/UpdateManager.cs

@@ -2,7 +2,7 @@ using System.Collections.Generic;
 
 namespace Syntriax.Engine.Core;
 
-public class UpdateManager : UniverseObject
+public class UpdateManager : Behaviour
 {
     // We use Ascending order because draw calls are running from last to first
     private static Comparer<IBehaviour> SortByAscendingPriority() => Comparer<IBehaviour>.Create((x, y) => x.Priority.CompareTo(y.Priority));
@@ -14,7 +14,7 @@ public class UpdateManager : UniverseObject
 
     private readonly List<IFirstFrameUpdate> toCallFirstFrameUpdates = new(32);
 
-    protected override void OnEnteringUniverse(IUniverse universe)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
         firstFrameUpdates.Assign(universe);
         preUpdateEntities.Assign(universe);
@@ -26,7 +26,7 @@ public class UpdateManager : UniverseObject
         universe.OnPostUpdate.AddListener(OnPostUpdate);
     }
 
-    protected override void OnExitingUniverse(IUniverse universe)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         firstFrameUpdates.Unassign();
         preUpdateEntities.Unassign();

Engine.Integration/Engine.Integration.MonoGame/Abstract/IDrawableSprite.cs

@@ -1,10 +1,8 @@
-using Microsoft.Xna.Framework.Graphics;
-
 using Syntriax.Engine.Core;
 
 namespace Syntriax.Engine.Integration.MonoGame;
 
 public interface IDrawableSprite : IBehaviour
 {
-    void Draw(SpriteBatch spriteBatch);
+    void Draw(ISpriteBatch spriteBatch);
 }

Engine.Integration/Engine.Integration.MonoGame/Abstract/ISpriteBatch.cs

@@ -0,0 +1,29 @@
+using System.Text;
+
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+using Syntriax.Engine.Core;
+
+namespace Syntriax.Engine.Integration.MonoGame;
+
+public interface ISpriteBatch
+{
+    void Begin(SpriteSortMode sortMode = SpriteSortMode.Deferred, BlendState? blendState = null, SamplerState? samplerState = null, DepthStencilState? depthStencilState = null, RasterizerState? rasterizerState = null, Effect? effect = null, Matrix? transformMatrix = null);
+    void Draw(Texture2D texture, Vector2D position, AABB? sourceAABB, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth);
+    void Draw(Texture2D texture, Vector2D position, AABB? sourceAABB, Color color, float rotation, Vector2D origin, float scale, SpriteEffects effects, float layerDepth);
+    void Draw(Texture2D texture, AABB destinationAABB, AABB? sourceAABB, Color color, float rotation, Vector2D origin, SpriteEffects effects, float layerDepth);
+    void Draw(Texture2D texture, Vector2D position, AABB? sourceAABB, Color color);
+    void Draw(Texture2D texture, AABB destinationAABB, AABB? sourceAABB, Color color);
+    void Draw(Texture2D texture, Vector2D position, Color color);
+    void Draw(Texture2D texture, AABB destinationAABB, Color color);
+    void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color);
+    void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color, float rotation, Vector2D origin, float scale, SpriteEffects effects, float layerDepth);
+    void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth);
+    void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth, bool rtl);
+    void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color);
+    void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color, float rotation, Vector2D origin, float scale, SpriteEffects effects, float layerDepth);
+    void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth);
+    void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth, bool rtl);
+    void End();
+}

Engine.Integration/Engine.Integration.MonoGame/Behaviours/SpriteBatchWrapper.cs

@@ -0,0 +1,64 @@
+using System.Text;
+
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+using Syntriax.Engine.Core;
+
+namespace Syntriax.Engine.Integration.MonoGame;
+
+public class SpriteBatchWrapper(GraphicsDevice graphicsDevice) : ISpriteBatch
+{
+    private readonly SpriteBatch spriteBatch = new(graphicsDevice);
+
+    public void Begin(SpriteSortMode sortMode = SpriteSortMode.Deferred, BlendState? blendState = null, SamplerState? samplerState = null, DepthStencilState? depthStencilState = null, RasterizerState? rasterizerState = null, Effect? effect = null, Matrix? transformMatrix = null)
+        => spriteBatch.Begin(sortMode, blendState, samplerState, depthStencilState, rasterizerState, effect, transformMatrix);
+
+    public void Draw(Texture2D texture, Vector2D position, AABB? sourceAABB, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth)
+        => spriteBatch.Draw(texture, position.ToDisplayVector2(), sourceAABB?.ToRectangle(), color, rotation, origin.ToDisplayVector2(), scale.ToDisplayVector2(), effects, layerDepth);
+
+    public void Draw(Texture2D texture, Vector2D position, AABB? sourceAABB, Color color, float rotation, Vector2D origin, float scale, SpriteEffects effects, float layerDepth)
+        => spriteBatch.Draw(texture, position.ToDisplayVector2(), sourceAABB?.ToRectangle(), color, rotation, origin.ToDisplayVector2(), scale, effects, layerDepth);
+
+    public void Draw(Texture2D texture, AABB destinationAABB, AABB? sourceAABB, Color color, float rotation, Vector2D origin, SpriteEffects effects, float layerDepth)
+        => spriteBatch.Draw(texture, destinationAABB.ToRectangle(), sourceAABB?.ToRectangle(), color, rotation, origin.ToDisplayVector2(), effects, layerDepth);
+
+    public void Draw(Texture2D texture, Vector2D position, AABB? sourceAABB, Color color)
+        => spriteBatch.Draw(texture, position.ToDisplayVector2(), sourceAABB?.ToRectangle(), color);
+
+    public void Draw(Texture2D texture, AABB destinationAABB, AABB? sourceAABB, Color color)
+        => spriteBatch.Draw(texture, destinationAABB.ToRectangle(), sourceAABB?.ToRectangle(), color);
+
+    public void Draw(Texture2D texture, Vector2D position, Color color)
+        => spriteBatch.Draw(texture, position.ToDisplayVector2(), color);
+
+    public void Draw(Texture2D texture, AABB destinationAABB, Color color)
+        => spriteBatch.Draw(texture, destinationAABB.ToRectangle(), color);
+
+    public void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color);
+
+    public void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color, float rotation, Vector2D origin, float scale, SpriteEffects effects, float layerDepth)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color, rotation, origin.ToDisplayVector2(), scale, effects, layerDepth);
+
+    public void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color, rotation, origin.ToDisplayVector2(), scale.ToDisplayVector2(), effects, layerDepth);
+
+    public void DrawString(SpriteFont spriteFont, string text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth, bool rtl)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color, rotation, origin.ToDisplayVector2(), scale.ToDisplayVector2(), effects, layerDepth, rtl);
+
+    public void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color);
+
+    public void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color, float rotation, Vector2D origin, float scale, SpriteEffects effects, float layerDepth)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color, rotation, origin.ToDisplayVector2(), scale, effects, layerDepth);
+
+    public void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color, rotation, origin.ToDisplayVector2(), scale.ToDisplayVector2(), effects, layerDepth);
+
+    public void DrawString(SpriteFont spriteFont, StringBuilder text, Vector2D position, Color color, float rotation, Vector2D origin, Vector2D scale, SpriteEffects effects, float layerDepth, bool rtl)
+        => spriteBatch.DrawString(spriteFont, text, position.ToDisplayVector2(), color, rotation, origin.ToDisplayVector2(), scale.ToDisplayVector2(), effects, layerDepth, rtl);
+
+    public void End()
+        => spriteBatch.End();
+}

Engine.Integration/Engine.Integration.MonoGame/Behaviours/SpriteBatcher.cs

@@ -1,7 +1,5 @@
 using System.Collections.Generic;
 
-using Microsoft.Xna.Framework.Graphics;
-
 using Syntriax.Engine.Core;
 
 namespace Syntriax.Engine.Integration.MonoGame;
@@ -9,8 +7,10 @@ namespace Syntriax.Engine.Integration.MonoGame;
 public class SpriteBatcher : BehaviourBase, IFirstFrameUpdate, IDraw
 {
     private static Comparer<IBehaviour> SortByPriority() => Comparer<IBehaviour>.Create((x, y) => y.Priority.CompareTo(x.Priority));
-    private SpriteBatch spriteBatch = null!;
+
+    private ISpriteBatch spriteBatch = null!;
     private MonoGameCamera2DBehaviour camera2D = null!;
+
     private readonly ActiveBehaviourCollectorSorted<IDrawableSprite> drawableSprites = new() { SortBy = SortByPriority() };
 
     public void FirstActiveFrame()
@@ -18,7 +18,7 @@ public class SpriteBatcher : BehaviourBase, IFirstFrameUpdate, IDraw
         MonoGameWindowContainer windowContainer = Universe.FindRequiredBehaviour<MonoGameWindowContainer>();
         camera2D = Universe.FindRequiredBehaviour<MonoGameCamera2DBehaviour>();
 
-        spriteBatch = new(windowContainer.Window.GraphicsDevice);
+        spriteBatch = new SpriteBatchWrapper(windowContainer.Window.GraphicsDevice);
         drawableSprites.Unassign();
         drawableSprites.Assign(Universe);
     }

Engine.Integration/Engine.Integration.MonoGame/EngineConverter.cs

@@ -13,18 +13,25 @@ public static class EngineConverterExtensions
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static UniverseTime ToEngineTime(this GameTime gameTime) => new(gameTime.TotalGameTime, gameTime.ElapsedGameTime);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Vector2D ToVector2D(this Vector2 vector) => new(vector.X, vector.Y);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Color ToColor(this ColorRGBA rgba) => new(rgba.R, rgba.G, rgba.B, rgba.A);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Vector2D ToVector2D(this Point point) => new(point.X, point.Y);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Vector2 ToVector2(this Vector2D vector) => new(vector.X, vector.Y);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Vector2 ToDisplayVector2(this Vector2D vector) => vector.Scale(screenScale).ToVector2();
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Vector2D ApplyDisplayScale(this Vector2D vector) => vector.Scale(screenScale);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Rectangle ToDisplayRectangle(this Rectangle rectangle, DisplayMode displayMode) => new()
     {
@@ -33,4 +40,13 @@ public static class EngineConverterExtensions
         Width = rectangle.Width,
         Height = rectangle.Height
     };
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static Rectangle ToRectangle(this AABB aabb) => new()
+    {
+        X = (int)(aabb.LowerBoundary.X * screenScale.X),
+        Y = (int)(aabb.LowerBoundary.Y * screenScale.Y),
+        Width = (int)(aabb.UpperBoundary.X - aabb.LowerBoundary.X),
+        Height = (int)(aabb.UpperBoundary.Y - aabb.LowerBoundary.Y)
+    };
 }

Engine.Physics2D/PhysicsCoroutineManager.cs

@@ -5,7 +5,7 @@ using Syntriax.Engine.Core;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class PhysicsCoroutineManager : UniverseObject
+public class PhysicsCoroutineManager : Behaviour
 {
     private readonly Event<IUniverse, IUniverse.UpdateArguments>.EventHandler delegateOnUpdate = null!;
 
@@ -23,9 +23,9 @@ public class PhysicsCoroutineManager : UniverseObject
         enumerators.Remove(enumerator);
     }
 
-    protected override void OnEnteringUniverse(IUniverse universe)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
-        physicsEngine = universe.GetUniverseObject<IPhysicsEngine2D>();
+        physicsEngine = universe.FindRequiredBehaviour<IPhysicsEngine2D>();
         if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
             foundPhysicsEngine.OnPhysicsStep.RemoveListener(OnPhysicsStep);
         else
@@ -44,11 +44,11 @@ public class PhysicsCoroutineManager : UniverseObject
         }
     }
 
-    protected override void OnExitingUniverse(IUniverse universe)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         if (physicsEngine is IPhysicsEngine2D existingPhysicsEngine)
             existingPhysicsEngine.OnPhysicsStep.RemoveListener(OnPhysicsStep);
-        universe.OnUpdate.RemoveListener(OnUpdate);
+        universe.OnUpdate.RemoveListener(delegateOnUpdate);
     }
 
     private void OnUpdate(IUniverse sender, IUniverse.UpdateArguments args)
@@ -56,11 +56,11 @@ public class PhysicsCoroutineManager : UniverseObject
         if (Universe is not IUniverse universe)
             return;
 
-        physicsEngine = universe.GetUniverseObject<IPhysicsEngine2D>();
+        physicsEngine = universe.FindRequiredBehaviour<IPhysicsEngine2D>();
         if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
         {
             foundPhysicsEngine.OnPhysicsStep.AddListener(OnPhysicsStep);
-            universe.OnUpdate.RemoveListener(OnUpdate);
+            universe.OnUpdate.RemoveListener(delegateOnUpdate);
         }
     }
 

Engine.Physics2D/PhysicsEngine2D.cs

@@ -4,7 +4,7 @@ using Syntriax.Engine.Core;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class PhysicsEngine2D : UniverseObject, IPhysicsEngine2D
+public class PhysicsEngine2D : Behaviour, IPhysicsEngine2D
 {
     public Event<IPhysicsEngine2D, float> OnPhysicsIteration { get; } = new();
     public Event<IPhysicsEngine2D, float> OnPhysicsStep { get; } = new();
@@ -174,7 +174,7 @@ public class PhysicsEngine2D : UniverseObject, IPhysicsEngine2D
         rigidBody.Transform.Rotation += rigidBody.AngularVelocity * intervalDeltaTime;
     }
 
-    protected override void OnEnteringUniverse(IUniverse universe)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
         physicsPreUpdateCollector.Assign(universe);
         physicsUpdateCollector.Assign(universe);
@@ -185,7 +185,7 @@ public class PhysicsEngine2D : UniverseObject, IPhysicsEngine2D
         universe.OnPreUpdate.AddListener(OnEnginePreUpdate);
     }
 
-    protected override void OnExitingUniverse(IUniverse universe)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         physicsPreUpdateCollector.Unassign();
         physicsUpdateCollector.Unassign();

Engine.Systems/Tween/TweenManager.cs

@@ -5,7 +5,7 @@ using Syntriax.Engine.Core;
 
 namespace Syntriax.Engine.Systems.Tween;
 
-public class TweenManager : UniverseObject, ITweenManager
+public class TweenManager : Behaviour, ITweenManager
 {
     private CoroutineManager coroutineManager = null!;
 
@@ -73,12 +73,12 @@ public class TweenManager : UniverseObject, ITweenManager
         Return((Tween)tween);
     }
 
-    protected override void OnEnteringUniverse(IUniverse universe)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
-        coroutineManager = universe.GetRequiredUniverseObject<CoroutineManager>();
+        coroutineManager = universe.FindRequiredBehaviour<CoroutineManager>();
     }
 
-    protected override void OnExitingUniverse(IUniverse universe)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         coroutineManager = null!;
     }