chore: forgotten InvokeSafe usage in TweenExtensions

Engine.Core/Abstract/Assignable/IHasGameManager.cs

@@ -1,26 +0,0 @@
-namespace Syntriax.Engine.Core.Abstract;
-
-/// <summary>
-/// Indicates the object is an <see cref="IAssignable"/> with an assignable <see cref="ITransform2D"/> field.
-/// </summary>
-public interface IHasGameManager : IAssignable
-{
-    /// <summary>
-    /// Event triggered when the <see cref="IGameManager"/> value has has been assigned a new value.
-    /// </summary>
-    event GameManagerAssignedEventHandler? OnGameManagerAssigned;
-
-    /// <inheritdoc cref="IGameManager" />
-    IGameManager GameManager { get; }
-
-    /// <summary>
-    /// Assign a value to the <see cref="IGameManager"/> field of this object.
-    /// </summary>
-    /// <param name="gameManager">New <see cref="IGameManager"/> to assign.</param>
-    /// <returns> 
-    /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
-    /// </returns>
-    bool Assign(IGameManager gameManager);
-
-    delegate void GameManagerAssignedEventHandler(IHasGameManager sender);
-}

Engine.Core/Abstract/Assignable/IHasHierarchyObject.cs

@@ -1,26 +0,0 @@
-namespace Syntriax.Engine.Core.Abstract;
-
-/// <summary>
-/// Indicates the object is an <see cref="IAssignable"/> with an assignable <see cref="IHierarchyObject"/> field.
-/// </summary>
-public interface IHasHierarchyObject : IAssignable
-{
-    /// <summary>
-    /// Event triggered when the <see cref="IHierarchyObject"/> value has has been assigned a new value.
-    /// </summary>
-    event HierarchyObjectAssignedEventHandler? OnHierarchyObjectAssigned;
-
-    /// <inheritdoc cref="IHierarchyObject" />
-    IHierarchyObject HierarchyObject { get; }
-
-    /// <summary>
-    /// Assign a value to the <see cref="IHierarchyObject"/> field of this object.
-    /// </summary>
-    /// <param name="hierarchyObject">New <see cref="IHierarchyObject"/> to assign.</param>
-    /// <returns> 
-    /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
-    /// </returns>
-    bool Assign(IHierarchyObject hierarchyObject);
-
-    delegate void HierarchyObjectAssignedEventHandler(IHasHierarchyObject sender);
-}

Engine.Core/Abstract/Assignable/IHasUniverse.cs

@@ -0,0 +1,26 @@
+namespace Syntriax.Engine.Core.Abstract;
+
+/// <summary>
+/// Indicates the object is an <see cref="IAssignable"/> with an assignable <see cref="IUniverse"/> field.
+/// </summary>
+public interface IHasUniverse : IAssignable
+{
+    /// <summary>
+    /// Event triggered when the <see cref="IUniverse"/> value has has been assigned a new value.
+    /// </summary>
+    event UniverseAssignedEventHandler? OnUniverseAssigned;
+
+    /// <inheritdoc cref="IUniverse" />
+    IUniverse Universe { get; }
+
+    /// <summary>
+    /// Assign a value to the <see cref="IUniverse"/> field of this object.
+    /// </summary>
+    /// <param name="universe">New <see cref="IUniverse"/> to assign.</param>
+    /// <returns> 
+    /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
+    /// </returns>
+    bool Assign(IUniverse universe);
+
+    delegate void UniverseAssignedEventHandler(IHasUniverse sender);
+}

Engine.Core/Abstract/Assignable/IHasUniverseObject.cs

@@ -0,0 +1,26 @@
+namespace Syntriax.Engine.Core.Abstract;
+
+/// <summary>
+/// Indicates the object is an <see cref="IAssignable"/> with an assignable <see cref="IUniverseObject"/> field.
+/// </summary>
+public interface IHasUniverseObject : IAssignable
+{
+    /// <summary>
+    /// Event triggered when the <see cref="IUniverseObject"/> value has has been assigned a new value.
+    /// </summary>
+    event UniverseObjectAssignedEventHandler? OnUniverseObjectAssigned;
+
+    /// <inheritdoc cref="IUniverseObject" />
+    IUniverseObject UniverseObject { get; }
+
+    /// <summary>
+    /// Assign a value to the <see cref="IUniverseObject"/> field of this object.
+    /// </summary>
+    /// <param name="universeObject">New <see cref="IUniverseObject"/> to assign.</param>
+    /// <returns> 
+    /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
+    /// </returns>
+    bool Assign(IUniverseObject universeObject);
+
+    delegate void UniverseObjectAssignedEventHandler(IHasUniverseObject sender);
+}

Engine.Core/Abstract/IBehaviour.cs

@@ -1,7 +1,7 @@
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
-/// Represents a behaviour that any object in the game might use to interact with itself or other objects. 
+/// Represents a behaviour that any object in the engine that might use to interact with itself or other objects. 
 /// </summary>
 public interface IBehaviour : IEntity, IActive, IHasBehaviourController, IHasStateEnable
 {

Engine.Core/Abstract/IBehaviourCollector.cs

@@ -4,10 +4,10 @@ namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
 /// Represents a collector for the class type of <typeparamref name="T"/>.
-/// Provides mechanisms for tracking additions and removals, and notifies subscribers when such events occur on the assigned <see cref="IGameManager"/>.
+/// Provides mechanisms for tracking additions and removals, and notifies subscribers when such events occur on the assigned <see cref="IUniverse"/>.
 /// </summary>
 /// <typeparam name="T">The type of objects tracked by the collector.</typeparam>
-public interface IBehaviourCollector<T> : IHasGameManager, IEnumerable<T> where T : class
+public interface IBehaviourCollector<T> : IHasUniverse, IEnumerable<T> where T : class
 {
     /// <summary>
     /// Event triggered when an object of type <typeparamref name="T"/> is added to the collector.

Engine.Core/Abstract/IBehaviourController.cs

@@ -3,9 +3,9 @@ using System.Collections.Generic;
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
-/// Represents a controller for managing <see cref="IBehaviour"/>s and notify them accordingly about the engine's updates. Connected to an <see cref="IHierarchyObject"/>.
+/// Represents a controller for managing <see cref="IBehaviour"/>s and notify them accordingly about the engine's updates. Connected to an <see cref="IUniverseObject"/>.
 /// </summary>
-public interface IBehaviourController : IInitializable, IHasHierarchyObject, IEnumerable<IBehaviour>
+public interface IBehaviourController : IInitializable, IHasUniverseObject, IEnumerable<IBehaviour>
 {
     /// <summary>
     /// Event triggered before the update of <see cref="IBehaviour"/>s.
@@ -60,7 +60,7 @@ public interface IBehaviourController : IInitializable, IHasHierarchyObject, IEn
     /// </summary>
     /// <typeparam name="T">The type of <see cref="IBehaviour"/>s to get.</typeparam>
     /// <returns>A list of <see cref="IBehaviour"/>s of the specified type.</returns>
-    IList<T> GetBehaviours<T>();
+    IReadOnlyList<T> GetBehaviours<T>();
 
     /// <summary>
     /// Gets all <see cref="IBehaviour"/>s of the specified type and stores them in the provided list.

Engine.Core/Abstract/IGameManager.cs

@@ -1,76 +0,0 @@
-using System.Collections.Generic;
-
-namespace Syntriax.Engine.Core.Abstract;
-
-/// <summary>
-/// Represents a game world responsible for managing <see cref="IHierarchyObject"/>s.
-/// </summary>
-public interface IGameManager : IEntity, IEnumerable<IHierarchyObject>
-{
-    /// <summary>
-    /// Event triggered when <see cref="Update(double)"/> is called on the <see cref="IGameManager"/>.
-    /// </summary>
-    event UpdateEventHandler? OnUpdate;
-
-    /// <summary>
-    /// Event triggered when <see cref="PreDraw"/> is called on the <see cref="IGameManager"/>.
-    /// </summary>
-    event PreDawEventHandler? OnPreDraw;
-
-    /// <summary>
-    /// Event triggered when a <see cref="IHierarchyObject"/> is registered to the <see cref="IGameManager"/>.
-    /// </summary>
-    event HierarchyObjectRegisteredEventHandler? OnHierarchyObjectRegistered;
-
-    /// <summary>
-    /// Event triggered when a <see cref="IHierarchyObject"/> is unregistered from the <see cref="IGameManager"/>.
-    /// </summary>
-    event HierarchyObjectUnRegisteredEventHandler? OnHierarchyObjectUnRegistered;
-
-    /// <summary>
-    /// Contains time data related to this <see cref="IGameManager"/>.
-    /// </summary>
-    EngineTime Time { get; }
-
-    /// <summary>
-    /// Gets a read-only list of <see cref="IHierarchyObject"/>s managed by the <see cref="IGameManager"/>.
-    /// </summary>
-    IReadOnlyList<IHierarchyObject> HierarchyObjects { get; }
-
-    /// <summary>
-    /// Registers an <see cref="IHierarchyObject"/> to the <see cref="IGameManager"/>.
-    /// </summary>
-    /// <param name="hierarchyObject">The <see cref="IHierarchyObject"/> to register.</param>
-    void Register(IHierarchyObject hierarchyObject);
-
-    /// <summary>
-    /// Instantiates a <see cref="IHierarchyObject"/> of type T with the given arguments and registers it to the <see cref="IGameManager"/>.
-    /// </summary>
-    /// <typeparam name="T">The type of <see cref="IHierarchyObject"/> to instantiate.</typeparam>
-    /// <param name="args">Constructor parameters for the given type of <see cref="IHierarchyObject"/>.</param>
-    /// <returns>The instantiated <see cref="IHierarchyObject"/>.</returns>
-    T InstantiateHierarchyObject<T>(params object?[]? args) where T : class, IHierarchyObject;
-
-    /// <summary>
-    /// Removes an <see cref="IHierarchyObject"/> from the <see cref="IGameManager"/>.
-    /// </summary>
-    /// <param name="hierarchyObject">The <see cref="IHierarchyObject"/> to remove.</param>
-    void Remove(IHierarchyObject hierarchyObject);
-
-    /// <summary>
-    /// Updates the <see cref="IGameManager"/> with the given delta time.
-    /// </summary>
-    /// <param name="engineTime">Delta time.</param>
-    void Update(EngineTime engineTime);
-
-    /// <summary>
-    /// Performs operations that should be done before the draw calls.
-    /// </summary>
-    void PreDraw();
-
-    delegate void UpdateEventHandler(IGameManager sender, EngineTime engineTime);
-    delegate void PreDawEventHandler(IGameManager sender);
-
-    delegate void HierarchyObjectRegisteredEventHandler(IGameManager sender, IHierarchyObject hierarchyObjectRegistered);
-    delegate void HierarchyObjectUnRegisteredEventHandler(IGameManager sender, IHierarchyObject hierarchyObjectUnregistered);
-}

Engine.Core/Abstract/IHierarchyObject.cs

@@ -1,131 +0,0 @@
-using System.Collections.Generic;
-
-namespace Syntriax.Engine.Core.Abstract;
-
-/// <summary>
-/// Represents an <see cref="IEntity"/> that can enter and exit a hierarchy within the <see cref="IGameManager"/> system.
-/// This interface allows for tracking the object's presence in the hierarchy and provides events 
-/// for notifying when the see enters or exits the hierarchy.
-/// </summary>
-public interface IHierarchyObject : IEntity, IActive, INameable, IHasBehaviourController, IEnumerable<IHierarchyObject>
-{
-    /// <summary>
-    /// Event triggered when the <see cref="IHierarchyObject"/> enters the hierarchy.
-    /// </summary>
-    event EnteredHierarchyEventHandler? OnEnteredHierarchy;
-
-    /// <summary>
-    /// Event triggered when the <see cref="IHierarchyObject"/> exits the hierarchy.
-    /// </summary>
-    event ExitedHierarchyEventHandler? OnExitedHierarchy;
-
-    /// <summary>
-    /// Event triggered when the <see cref="Parent"/> of the <see cref="IHierarchyObject"/> changes. The second parameter is the old <see cref="IHierarchyObject"/>.
-    /// </summary>
-    event ParentChangedEventHandler? OnParentChanged;
-
-    /// <summary>
-    /// Event triggered when a new <see cref="IHierarchyObject"/> is added to the <see cref="Children"/>.
-    /// </summary>
-    event ChildrenAddedEventHandler? OnChildrenAdded;
-
-    /// <summary>
-    /// Event triggered when an <see cref="IHierarchyObject"/> is removed from the <see cref="Children"/>.
-    /// </summary>
-    event ChildrenRemovedEventHandler? OnChildrenRemoved;
-
-    /// <summary>
-    /// Gets the <see cref="IGameManager"/> this <see cref="IHierarchyObject"/> is connected to, if any.
-    /// </summary>
-    IGameManager GameManager { get; }
-
-    /// <summary>
-    /// Indicates whether the <see cref="IHierarchyObject"/> is currently in the hierarchy.
-    /// </summary>
-    bool IsInHierarchy { get; }
-
-    /// <summary>
-    /// The parent <see cref="IHierarchyObject"/> of the <see cref="IHierarchyObject"/>.
-    /// </summary>
-    IHierarchyObject? Parent { get; }
-
-    /// <summary>
-    /// The <see cref="IHierarchyObject"/>s that have this <see cref="IHierarchyObject"/> as their <see cref="Parent"/>.
-    /// </summary>
-    IReadOnlyList<IHierarchyObject> Children { get; }
-
-    /// <summary>
-    /// Internal method to handle entering the hierarchy.
-    /// This should be called by the system to properly manage hierarchy states.
-    /// </summary>
-    /// <param name="gameManager">The <see cref="IGameManager"/> that is managing this hierarchy.</param>
-    /// <returns>
-    /// <see cref="true"/> if the <see cref="IHierarchyObject"/> successfully entered the hierarchy; 
-    /// <see cref="false"/> if it failed to do so.
-    /// </returns>
-    internal bool EnterHierarchy(IGameManager gameManager);
-
-    /// <summary>
-    /// Internal method to handle exiting the hierarchy.
-    /// This should be called by the system to properly manage hierarchy states.
-    /// </summary>
-    /// <returns>
-    /// <see cref="true"/> if the <see cref="IHierarchyObject"/> successfully exited the hierarchy; 
-    /// <see cref="false"/> if it failed to do so.
-    /// </returns>
-    internal bool ExitHierarchy();
-
-    /// <summary>
-    /// Sets the parent <see cref="IHierarchyObject"/> of this <see cref="IHierarchyObject"/>.
-    /// </summary>
-    /// <param name="hierarchyObject">The parent <see cref="IHierarchyObject"/> to set.</param>
-    void SetParent(IHierarchyObject? hierarchyObject);
-
-    /// <summary>
-    /// Adds a child <see cref="IHierarchyObject"/> to this <see cref="IHierarchyObject"/>.
-    /// </summary>
-    /// <param name="hierarchyObject">The child <see cref="IHierarchyObject"/> to add.</param>
-    void AddChild(IHierarchyObject hierarchyObject);
-
-    /// <summary>
-    /// Removes a child <see cref="IHierarchyObject"/> from this <see cref="IHierarchyObject"/>.
-    /// </summary>
-    /// <param name="hierarchyObject">The child <see cref="IHierarchyObject"/> to remove.</param>
-    void RemoveChild(IHierarchyObject hierarchyObject);
-
-    /// <summary>
-    /// EventHandler delegate for the event triggered when the <see cref="IHierarchyObject"/> enters the hierarchy of a <see cref="IGameManager">.
-    /// </summary>
-    /// <param name="sender">The <see cref="IHierarchyObject"/> that entered the hierarchy.</param>
-    /// <param name="gameManager">The <see cref="IGameManager"/> that the <see cref="IHierarchyObject"/> has entered it's hierarchy.</param>
-    delegate void EnteredHierarchyEventHandler(IHierarchyObject sender, IGameManager gameManager);
-
-    /// <summary>
-    /// EventHandler delegate for the event triggered when the <see cref="IHierarchyObject"/> exits the hierarchy of a <see cref="IGameManager">.
-    /// </summary>
-    /// <param name="sender">The <see cref="IHierarchyObject"/> that exited the hierarchy.</param>
-    /// <param name="gameManager">The <see cref="IGameManager"/> that the <see cref="IHierarchyObject"/> has exited it's hierarchy.</param>
-    delegate void ExitedHierarchyEventHandler(IHierarchyObject sender, IGameManager gameManager);
-
-    /// <summary>
-    /// Delegate for the event triggered when the <see cref="IHierarchyObject"/>'s parent changes.
-    /// </summary>
-    /// <param name="sender">The <see cref="IHierarchyObject"/> that the parent has changed.</param>
-    /// <param name="previousParent">The previous <see cref="IHierarchyObject"/> the sender was a child of.</param>
-    /// <param name="newParent">The new and current <see cref="IHierarchyObject"/> the sender is a child of.</param>
-    delegate void ParentChangedEventHandler(IHierarchyObject sender, IHierarchyObject? previousParent, IHierarchyObject? newParent);
-
-    /// <summary>
-    /// Delegate for the event triggered when a new <see cref="IHierarchyObject"/> added as a child.
-    /// </summary>
-    /// <param name="sender">The parent <see cref="IHierarchyObject"/> this event is being called from.</param>
-    /// <param name="childrenAdded">The <see cref="IHierarchyObject"/> that got removed as a children of the sender <see cref="IHierarchyObject"/>.</param>
-    delegate void ChildrenAddedEventHandler(IHierarchyObject sender, IHierarchyObject childrenAdded);
-
-    /// <summary>
-    /// Delegate for the event triggered when a new <see cref="IHierarchyObject"/> removed from being a child.
-    /// </summary>
-    /// <param name="sender">The parent <see cref="IHierarchyObject"/> this event is being called from.</param>
-    /// <param name="childrenAdded">The <see cref="IHierarchyObject"/> that got removed as a children of the sender <see cref="IHierarchyObject"/>.</param>
-    delegate void ChildrenRemovedEventHandler(IHierarchyObject sender, IHierarchyObject childrenRemoved);
-}

Engine.Core/Abstract/IUniverse.cs

@@ -0,0 +1,91 @@
+using System.Collections.Generic;
+
+namespace Syntriax.Engine.Core.Abstract;
+
+/// <summary>
+/// Represents a universe responsible for managing <see cref="IUniverseObject"/>s.
+/// </summary>
+public interface IUniverse : IEntity, IEnumerable<IUniverseObject>
+{
+    /// <summary>
+    /// Event triggered when <see cref="Update(UniverseTime)"/> is about to be called called on the <see cref="IUniverse"/>.
+    /// </summary>
+    event UpdateEventHandler? OnPreUpdate;
+
+    /// <summary>
+    /// Event triggered when <see cref="Update(UniverseTime)"/> is called on the <see cref="IUniverse"/>.
+    /// </summary>
+    event UpdateEventHandler? OnUpdate;
+
+    /// <summary>
+    /// Event triggered when <see cref="PreDraw"/> is called on the <see cref="IUniverse"/>.
+    /// </summary>
+    event PreDrawEventHandler? OnPreDraw;
+
+    /// <summary>
+    /// Event triggered when a <see cref="IUniverseObject"/> is registered to the <see cref="IUniverse"/>.
+    /// </summary>
+    event UniverseObjectRegisteredEventHandler? OnUniverseObjectRegistered;
+
+    /// <summary>
+    /// Event triggered when a <see cref="IUniverseObject"/> is unregistered from the <see cref="IUniverse"/>.
+    /// </summary>
+    event UniverseObjectUnRegisteredEventHandler? OnUniverseObjectUnRegistered;
+
+    /// <summary>
+    /// Current time scale the <see cref="IUniverse"/> operates on.
+    /// </summary>
+    float TimeScale { get; set; }
+
+    /// <summary>
+    /// Contains time data related to this <see cref="IUniverse"/>.
+    /// </summary>
+    UniverseTime Time { get; }
+
+    /// <summary>
+    /// Contains unscaled time data related to this <see cref="IUniverse"/>.
+    /// </summary>
+    UniverseTime UnscaledTime { get; }
+
+    /// <summary>
+    /// Gets a read-only list of <see cref="IUniverseObject"/>s managed by the <see cref="IUniverse"/>.
+    /// </summary>
+    IReadOnlyList<IUniverseObject> UniverseObjects { get; }
+
+    /// <summary>
+    /// Registers an <see cref="IUniverseObject"/> to the <see cref="IUniverse"/>.
+    /// </summary>
+    /// <param name="universeObject">The <see cref="IUniverseObject"/> to register.</param>
+    void Register(IUniverseObject universeObject);
+
+    /// <summary>
+    /// Instantiates a <see cref="IUniverseObject"/> of type T with the given arguments and registers it to the <see cref="IUniverse"/>.
+    /// </summary>
+    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to instantiate.</typeparam>
+    /// <param name="args">Constructor parameters for the given type of <see cref="IUniverseObject"/>.</param>
+    /// <returns>The instantiated <see cref="IUniverseObject"/>.</returns>
+    T InstantiateUniverseObject<T>(params object?[]? args) where T : class, IUniverseObject;
+
+    /// <summary>
+    /// Removes an <see cref="IUniverseObject"/> from the <see cref="IUniverse"/>.
+    /// </summary>
+    /// <param name="universeObject">The <see cref="IUniverseObject"/> to remove.</param>
+    void Remove(IUniverseObject universeObject);
+
+    /// <summary>
+    /// Updates the <see cref="IUniverse"/> with the given delta time.
+    /// </summary>
+    /// <param name="universeTime">Delta time.</param>
+    void Update(UniverseTime universeTime);
+
+    /// <summary>
+    /// Performs operations that should be done before the draw calls.
+    /// </summary>
+    void PreDraw();
+
+    delegate void UpdateEventHandler(IUniverse sender, UniverseTime engineTime);
+    delegate void PreDrawEventHandler(IUniverse sender);
+
+    delegate void UniverseObjectRegisteredEventHandler(IUniverse sender, IUniverseObject universeObjectRegistered);
+    delegate void UniverseObjectUnRegisteredEventHandler(IUniverse sender, IUniverseObject universeObjectUnregistered);
+}

Engine.Core/Abstract/IUniverseObject.cs

@@ -0,0 +1,131 @@
+using System.Collections.Generic;
+
+namespace Syntriax.Engine.Core.Abstract;
+
+/// <summary>
+/// Represents an <see cref="IEntity"/> that can enter and exit a universe within the <see cref="IUniverse"/> system.
+/// This interface allows for tracking the object's presence in the universe and provides events 
+/// for notifying when the see enters or exits the universe.
+/// </summary>
+public interface IUniverseObject : IEntity, IActive, INameable, IHasBehaviourController, IEnumerable<IUniverseObject>
+{
+    /// <summary>
+    /// Event triggered when the <see cref="IUniverseObject"/> enters the universe.
+    /// </summary>
+    event EnteredUniverseEventHandler? OnEnteredUniverse;
+
+    /// <summary>
+    /// Event triggered when the <see cref="IUniverseObject"/> exits the universe.
+    /// </summary>
+    event ExitedUniverseEventHandler? OnExitedUniverse;
+
+    /// <summary>
+    /// Event triggered when the <see cref="Parent"/> of the <see cref="IUniverseObject"/> changes. The second parameter is the old <see cref="IUniverseObject"/>.
+    /// </summary>
+    event ParentChangedEventHandler? OnParentChanged;
+
+    /// <summary>
+    /// Event triggered when a new <see cref="IUniverseObject"/> is added to the <see cref="Children"/>.
+    /// </summary>
+    event ChildrenAddedEventHandler? OnChildrenAdded;
+
+    /// <summary>
+    /// Event triggered when an <see cref="IUniverseObject"/> is removed from the <see cref="Children"/>.
+    /// </summary>
+    event ChildrenRemovedEventHandler? OnChildrenRemoved;
+
+    /// <summary>
+    /// Gets the <see cref="IUniverse"/> this <see cref="IUniverseObject"/> is connected to, if any.
+    /// </summary>
+    IUniverse Universe { get; }
+
+    /// <summary>
+    /// Indicates whether the <see cref="IUniverseObject"/> is currently in the universe.
+    /// </summary>
+    bool IsInUniverse { get; }
+
+    /// <summary>
+    /// The parent <see cref="IUniverseObject"/> of the <see cref="IUniverseObject"/>.
+    /// </summary>
+    IUniverseObject? Parent { get; }
+
+    /// <summary>
+    /// The <see cref="IUniverseObject"/>s that have this <see cref="IUniverseObject"/> as their <see cref="Parent"/>.
+    /// </summary>
+    IReadOnlyList<IUniverseObject> Children { get; }
+
+    /// <summary>
+    /// Internal method to handle entering the universe.
+    /// This should be called by the system to properly manage universe states.
+    /// </summary>
+    /// <param name="universe">The <see cref="IUniverse"/> that is managing this universe.</param>
+    /// <returns>
+    /// <see cref="true"/> if the <see cref="IUniverseObject"/> successfully entered the universe; 
+    /// <see cref="false"/> if it failed to do so.
+    /// </returns>
+    internal bool EnterUniverse(IUniverse universe);
+
+    /// <summary>
+    /// Internal method to handle exiting the universe.
+    /// This should be called by the system to properly manage universe states.
+    /// </summary>
+    /// <returns>
+    /// <see cref="true"/> if the <see cref="IUniverseObject"/> successfully exited the universe; 
+    /// <see cref="false"/> if it failed to do so.
+    /// </returns>
+    internal bool ExitUniverse();
+
+    /// <summary>
+    /// Sets the parent <see cref="IUniverseObject"/> of this <see cref="IUniverseObject"/>.
+    /// </summary>
+    /// <param name="universeObject">The parent <see cref="IUniverseObject"/> to set.</param>
+    void SetParent(IUniverseObject? universeObject);
+
+    /// <summary>
+    /// Adds a child <see cref="IUniverseObject"/> to this <see cref="IUniverseObject"/>.
+    /// </summary>
+    /// <param name="universeObject">The child <see cref="IUniverseObject"/> to add.</param>
+    void AddChild(IUniverseObject universeObject);
+
+    /// <summary>
+    /// Removes a child <see cref="IUniverseObject"/> from this <see cref="IUniverseObject"/>.
+    /// </summary>
+    /// <param name="universeObject">The child <see cref="IUniverseObject"/> to remove.</param>
+    void RemoveChild(IUniverseObject universeObject);
+
+    /// <summary>
+    /// EventHandler delegate for the event triggered when the <see cref="IUniverseObject"/> enters the universe of a <see cref="IUniverse">.
+    /// </summary>
+    /// <param name="sender">The <see cref="IUniverseObject"/> that entered the universe.</param>
+    /// <param name="universe">The <see cref="IUniverse"/> that the <see cref="IUniverseObject"/> has entered it's universe.</param>
+    delegate void EnteredUniverseEventHandler(IUniverseObject sender, IUniverse universe);
+
+    /// <summary>
+    /// EventHandler delegate for the event triggered when the <see cref="IUniverseObject"/> exits the universe of a <see cref="IUniverse">.
+    /// </summary>
+    /// <param name="sender">The <see cref="IUniverseObject"/> that exited the universe.</param>
+    /// <param name="universe">The <see cref="IUniverse"/> that the <see cref="IUniverseObject"/> has exited it's universe.</param>
+    delegate void ExitedUniverseEventHandler(IUniverseObject sender, IUniverse universe);
+
+    /// <summary>
+    /// Delegate for the event triggered when the <see cref="IUniverseObject"/>'s parent changes.
+    /// </summary>
+    /// <param name="sender">The <see cref="IUniverseObject"/> that the parent has changed.</param>
+    /// <param name="previousParent">The previous <see cref="IUniverseObject"/> the sender was a child of.</param>
+    /// <param name="newParent">The new and current <see cref="IUniverseObject"/> the sender is a child of.</param>
+    delegate void ParentChangedEventHandler(IUniverseObject sender, IUniverseObject? previousParent, IUniverseObject? newParent);
+
+    /// <summary>
+    /// Delegate for the event triggered when a new <see cref="IUniverseObject"/> added as a child.
+    /// </summary>
+    /// <param name="sender">The parent <see cref="IUniverseObject"/> this event is being called from.</param>
+    /// <param name="childrenAdded">The <see cref="IUniverseObject"/> that got removed as a children of the sender <see cref="IUniverseObject"/>.</param>
+    delegate void ChildrenAddedEventHandler(IUniverseObject sender, IUniverseObject childrenAdded);
+
+    /// <summary>
+    /// Delegate for the event triggered when a new <see cref="IUniverseObject"/> removed from being a child.
+    /// </summary>
+    /// <param name="sender">The parent <see cref="IUniverseObject"/> this event is being called from.</param>
+    /// <param name="childrenAdded">The <see cref="IUniverseObject"/> that got removed as a children of the sender <see cref="IUniverseObject"/>.</param>
+    delegate void ChildrenRemovedEventHandler(IUniverseObject sender, IUniverseObject childrenRemoved);
+}

Engine.Core/ActiveBehaviourCollector.cs

@@ -9,7 +9,7 @@ namespace Syntriax.Engine.Core;
 public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : class, IBehaviour
 {
     public event IAssignable.UnassignEventHandler? OnUnassigned = null;
-    public event IHasGameManager.GameManagerAssignedEventHandler? OnGameManagerAssigned = null;
+    public event IHasUniverse.UniverseAssignedEventHandler? OnUniverseAssigned = null;
 
     public event IBehaviourCollector<T>.CollectedEventHandler? OnCollected = null;
     public event IBehaviourCollector<T>.RemovedEventHandler? OnRemoved = null;
@@ -19,29 +19,29 @@ public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : clas
     protected readonly Dictionary<IActive, T> monitoringActiveToBehaviour = new(32);
 
     public IReadOnlyList<T> Behaviours => activeBehaviours;
-    public IGameManager GameManager { get; private set; } = null!;
+    public IUniverse Universe { get; private set; } = null!;
 
     public T this[Index index] => activeBehaviours[index];
 
     public ActiveBehaviourCollector() { }
-    public ActiveBehaviourCollector(IGameManager gameManager) => Assign(gameManager);
+    public ActiveBehaviourCollector(IUniverse universe) => Assign(universe);
 
-    private void OnHierarchyObjectRegistered(IGameManager manager, IHierarchyObject hierarchyObject)
+    private void OnUniverseObjectRegistered(IUniverse manager, IUniverseObject universeObject)
     {
-        hierarchyObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
+        universeObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
-        hierarchyObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
+        universeObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
 
-        foreach (IBehaviour item in hierarchyObject.BehaviourController)
+        foreach (IBehaviour item in universeObject.BehaviourController)
-            OnBehaviourAdded(hierarchyObject.BehaviourController, item);
+            OnBehaviourAdded(universeObject.BehaviourController, item);
     }
 
-    private void OnHierarchyObjectUnregistered(IGameManager manager, IHierarchyObject hierarchyObject)
+    private void OnUniverseObjectUnregistered(IUniverse manager, IUniverseObject universeObject)
     {
-        hierarchyObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
+        universeObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
-        hierarchyObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
+        universeObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
 
-        foreach (IBehaviour item in hierarchyObject.BehaviourController)
+        foreach (IBehaviour item in universeObject.BehaviourController)
-            OnBehaviourRemoved(hierarchyObject.BehaviourController, item);
+            OnBehaviourRemoved(universeObject.BehaviourController, item);
     }
 
     protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
@@ -63,12 +63,12 @@ public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : clas
         {
             activeBehaviours.Add(behaviour);
             OnBehaviourAdd(behaviour);
-            OnCollected?.Invoke(this, behaviour);
+            OnCollected?.InvokeSafe(this, behaviour);
         }
         else if (activeBehaviours.Remove(behaviour))
         {
             OnBehaviourRemove(behaviour);
-            OnRemoved?.Invoke(this, behaviour);
+            OnRemoved?.InvokeSafe(this, behaviour);
         }
     }
 
@@ -85,40 +85,40 @@ public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : clas
         if (activeBehaviours.Remove(tBehaviour))
         {
             OnBehaviourRemove(tBehaviour);
-            OnRemoved?.Invoke(this, tBehaviour);
+            OnRemoved?.InvokeSafe(this, tBehaviour);
         }
     }
 
-    public bool Assign(IGameManager gameManager)
+    public bool Assign(IUniverse universe)
     {
-        if (GameManager is not null)
+        if (Universe is not null)
             return false;
 
-        foreach (IHierarchyObject hierarchyObject in gameManager.HierarchyObjects)
+        foreach (IUniverseObject universeObject in universe.UniverseObjects)
-            OnHierarchyObjectRegistered(gameManager, hierarchyObject);
+            OnUniverseObjectRegistered(universe, universeObject);
 
-        gameManager.OnHierarchyObjectRegistered += OnHierarchyObjectRegistered;
+        universe.OnUniverseObjectRegistered += OnUniverseObjectRegistered;
-        gameManager.OnHierarchyObjectUnRegistered += OnHierarchyObjectUnregistered;
+        universe.OnUniverseObjectUnRegistered += OnUniverseObjectUnregistered;
 
-        GameManager = gameManager;
+        Universe = universe;
-        OnGameManagerAssigned?.Invoke(this);
+        OnUniverseAssigned?.InvokeSafe(this);
 
         return true;
     }
 
     public bool Unassign()
     {
-        if (GameManager is null)
+        if (Universe is null)
             return false;
 
-        foreach (IHierarchyObject hierarchyObject in GameManager.HierarchyObjects)
+        foreach (IUniverseObject universeObject in Universe.UniverseObjects)
-            OnHierarchyObjectUnregistered(GameManager, hierarchyObject);
+            OnUniverseObjectUnregistered(Universe, universeObject);
 
-        GameManager.OnHierarchyObjectRegistered -= OnHierarchyObjectRegistered;
+        Universe.OnUniverseObjectRegistered -= OnUniverseObjectRegistered;
-        GameManager.OnHierarchyObjectUnRegistered -= OnHierarchyObjectUnregistered;
+        Universe.OnUniverseObjectUnRegistered -= OnUniverseObjectUnregistered;
 
-        GameManager = null!;
+        Universe = null!;
-        OnUnassigned?.Invoke(this);
+        OnUnassigned?.InvokeSafe(this);
         return true;
     }
 

Engine.Core/ActiveBehaviourCollectorSorted.cs

@@ -6,7 +6,18 @@ namespace Syntriax.Engine.Core;
 
 public class ActiveBehaviourCollectorSorted<T> : ActiveBehaviourCollector<T> where T : class, IBehaviour
 {
-    public Comparison<T>? SortBy { get; set; } = null;
+    private Comparison<T>? _sortBy = null;
+    public Comparison<T>? SortBy
+    {
+        get => _sortBy;
+        set
+        {
+            _sortBy = value;
+
+            if (value is not null)
+                activeBehaviours.Sort(value);
+        }
+    }
 
     protected override void OnBehaviourAdd(IBehaviour behaviour)
     {
@@ -15,5 +26,5 @@ public class ActiveBehaviourCollectorSorted<T> : ActiveBehaviourCollector<T> whe
     }
 
     public ActiveBehaviourCollectorSorted() { }
-    public ActiveBehaviourCollectorSorted(IGameManager gameManager) : base(gameManager) { }
+    public ActiveBehaviourCollectorSorted(IUniverse universe, Comparison<T> sortBy) : base(universe) => SortBy = sortBy;
 }

Engine.Core/BaseEntity.cs

@@ -33,7 +33,7 @@ public abstract class BaseEntity : IEntity
             string previousId = _id;
 
             _id = value;
-            OnIdChanged?.Invoke(this, previousId);
+            OnIdChanged?.InvokeSafe(this, previousId);
         }
     }
 
@@ -47,9 +47,9 @@ public abstract class BaseEntity : IEntity
 
             _initialized = value;
             if (value)
-                OnInitialized?.Invoke(this);
+                OnInitialized?.InvokeSafe(this);
             else
-                OnFinalized?.Invoke(this);
+                OnFinalized?.InvokeSafe(this);
         }
     }
 
@@ -62,7 +62,7 @@ public abstract class BaseEntity : IEntity
         _stateEnable = stateEnable;
         _stateEnable.Assign(this);
         OnAssign(stateEnable);
-        OnStateEnableAssigned?.Invoke(this);
+        OnStateEnableAssigned?.InvokeSafe(this);
         return true;
     }
 
@@ -76,7 +76,7 @@ public abstract class BaseEntity : IEntity
 
         _stateEnable = null!;
         _stateEnable.Unassign();
-        OnUnassigned?.Invoke(this);
+        OnUnassigned?.InvokeSafe(this);
         return true;
     }
 

Engine.Core/Behaviour.cs

@@ -6,8 +6,8 @@ public abstract class Behaviour : BehaviourBase
 {
     private bool isInitializedThisFrame = false;
 
-    protected IGameManager GameManager => BehaviourController.HierarchyObject.GameManager;
+    protected IUniverse Universe => BehaviourController.UniverseObject.Universe;
-    protected IHierarchyObject HierarchyObject => BehaviourController.HierarchyObject;
+    protected IUniverseObject UniverseObject => BehaviourController.UniverseObject;
 
     public Behaviour()
     {
@@ -27,13 +27,13 @@ public abstract class Behaviour : BehaviourBase
         BehaviourController.OnPreUpdate += PreUpdate;
         BehaviourController.OnPreDraw += PreDraw;
         BehaviourController.OnUpdate += Update;
-        BehaviourController.HierarchyObject.OnEnteredHierarchy += EnteredHierarchy;
+        BehaviourController.UniverseObject.OnEnteredUniverse += EnteredUniverse;
-        BehaviourController.HierarchyObject.OnExitedHierarchy += ExitedHierarchy;
+        BehaviourController.UniverseObject.OnExitedUniverse += ExitedUniverse;
 
         OnInitialize();
 
-        if (HierarchyObject.IsInHierarchy)
+        if (UniverseObject.IsInUniverse)
-            EnteredHierarchy(HierarchyObject, GameManager);
+            EnteredUniverse(UniverseObject, Universe);
     }
 
     protected virtual void OnFinalize() { }
@@ -42,19 +42,21 @@ public abstract class Behaviour : BehaviourBase
         BehaviourController.OnPreUpdate -= PreUpdate;
         BehaviourController.OnPreDraw -= PreDraw;
         BehaviourController.OnUpdate -= Update;
-        BehaviourController.HierarchyObject.OnEnteredHierarchy -= EnteredHierarchy;
+        BehaviourController.UniverseObject.OnEnteredUniverse -= EnteredUniverse;
-        BehaviourController.HierarchyObject.OnExitedHierarchy -= ExitedHierarchy;
+        BehaviourController.UniverseObject.OnExitedUniverse -= ExitedUniverse;
 
         OnFinalize();
 
-        if (HierarchyObject.IsInHierarchy)
+        if (UniverseObject.IsInUniverse)
-            ExitedHierarchy(HierarchyObject, GameManager);
+            ExitedUniverse(UniverseObject, Universe);
     }
 
     protected virtual void OnPreUpdatePreActiveCheck() { }
     protected virtual void OnPreUpdate() { }
     protected virtual void PreUpdate(IBehaviourController _)
     {
+        Debug.AssertHelpers.AssertInitialized(this);
+
         OnPreUpdatePreActiveCheck();
 
         if (!IsActive)
@@ -77,6 +79,8 @@ public abstract class Behaviour : BehaviourBase
     protected virtual void OnUpdate() { }
     protected virtual void Update(IBehaviourController _)
     {
+        Debug.AssertHelpers.AssertInitialized(this);
+
         OnUpdatePreActiveCheck();
 
         if (!IsActive)
@@ -89,6 +93,8 @@ public abstract class Behaviour : BehaviourBase
     protected virtual void OnPreDraw() { }
     protected virtual void PreDraw(IBehaviourController _)
     {
+        Debug.AssertHelpers.AssertInitialized(this);
+
         OnPreDrawPreActiveCheck();
 
         if (!StateEnable.Enabled)
@@ -97,9 +103,9 @@ public abstract class Behaviour : BehaviourBase
         OnPreDraw();
     }
 
-    protected virtual void OnEnteredHierarchy(IGameManager gameManager) { }
+    protected virtual void OnEnteredUniverse(IUniverse universe) { }
-    protected virtual void EnteredHierarchy(IHierarchyObject sender, IGameManager gameManager) => OnEnteredHierarchy(gameManager);
+    protected virtual void EnteredUniverse(IUniverseObject sender, IUniverse universe) => OnEnteredUniverse(universe);
 
-    protected virtual void OnExitedHierarchy(IGameManager gameManager) { }
+    protected virtual void OnExitedUniverse(IUniverse universe) { }
-    protected virtual void ExitedHierarchy(IHierarchyObject sender, IGameManager gameManager) => OnExitedHierarchy(gameManager);
+    protected virtual void ExitedUniverse(IUniverseObject sender, IUniverse universe) => OnExitedUniverse(universe);
 }

Engine.Core/Behaviour2D.cs

@@ -8,7 +8,7 @@ public abstract class Behaviour2D : Behaviour, IBehaviour2D
 
     protected sealed override void OnInitialize(IInitializable _)
     {
-        Transform = BehaviourController.GetBehaviourInChildren<ITransform2D>() ?? throw new($"{HierarchyObject.Name} does not contain any {nameof(ITransform2D)}");
+        Transform = BehaviourController.GetRequiredBehaviour<ITransform2D>();
         base.OnInitialize(_);
     }
 
@@ -23,6 +23,6 @@ public abstract class Behaviour2D : Behaviour, IBehaviour2D
     protected sealed override void FirstActiveFrame() => base.FirstActiveFrame();
     protected sealed override void Update(IBehaviourController behaviourController) => base.Update(behaviourController);
     protected sealed override void PreDraw(IBehaviourController behaviourController) => base.PreDraw(behaviourController);
-    protected sealed override void EnteredHierarchy(IHierarchyObject sender, IGameManager gameManager) => base.EnteredHierarchy(sender, gameManager);
+    protected sealed override void EnteredUniverse(IUniverseObject sender, IUniverse universe) => base.EnteredUniverse(sender, universe);
-    protected sealed override void ExitedHierarchy(IHierarchyObject sender, IGameManager gameManager) => base.ExitedHierarchy(sender, gameManager);
+    protected sealed override void ExitedUniverse(IUniverseObject sender, IUniverse universe) => base.ExitedUniverse(sender, universe);
 }

Engine.Core/BehaviourBase.cs

@@ -1,5 +1,4 @@
 using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
 
 namespace Syntriax.Engine.Core;
 
@@ -24,7 +23,7 @@ public abstract class BehaviourBase : BaseEntity, IBehaviour
 
             int previousPriority = _priority;
             _priority = value;
-            OnPriorityChanged?.Invoke(this, previousPriority);
+            OnPriorityChanged?.InvokeSafe(this, previousPriority);
         }
     }
 
@@ -39,16 +38,16 @@ public abstract class BehaviourBase : BaseEntity, IBehaviour
 
         _behaviourController = behaviourController;
         OnAssign(behaviourController);
-        behaviourController.OnHierarchyObjectAssigned += OnHierarchyObjectAssigned;
+        behaviourController.OnUniverseObjectAssigned += OnUniverseObjectAssigned;
-        if (behaviourController.HierarchyObject is not null)
+        if (behaviourController.UniverseObject is not null)
-            OnHierarchyObjectAssigned(behaviourController);
+            OnUniverseObjectAssigned(behaviourController);
-        OnBehaviourControllerAssigned?.Invoke(this);
+        OnBehaviourControllerAssigned?.InvokeSafe(this);
         return true;
     }
 
-    private void OnHierarchyObjectAssigned(IHasHierarchyObject sender)
+    private void OnUniverseObjectAssigned(IHasUniverseObject sender)
     {
-        sender.HierarchyObject.OnActiveChanged += OnHierarchyObjectActiveChanged;
+        sender.UniverseObject.OnActiveChanged += OnUniverseObjectActiveChanged;
         UpdateActive();
     }
 
@@ -62,27 +61,26 @@ public abstract class BehaviourBase : BaseEntity, IBehaviour
     protected override void UnassignInternal()
     {
         StateEnable.OnEnabledChanged -= OnStateEnabledChanged;
-        BehaviourController.OnHierarchyObjectAssigned -= OnHierarchyObjectAssigned;
+        BehaviourController.OnUniverseObjectAssigned -= OnUniverseObjectAssigned;
         base.UnassignInternal();
         _behaviourController = null!;
     }
 
     protected override void InitializeInternal()
     {
-        base.InitializeInternal();
+        Debug.AssertHelpers.AssertBehaviourControllerAssigned(this);
-        NotAssignedException.Check(this, _behaviourController);
+        Debug.AssertHelpers.AssertStateEnableAssigned(this);
-        NotAssignedException.Check(this, StateEnable);
     }
 
     private void OnStateEnabledChanged(IStateEnable sender, bool previousState) => UpdateActive();
-    private void OnHierarchyObjectActiveChanged(IActive sender, bool previousState) => UpdateActive();
+    private void OnUniverseObjectActiveChanged(IActive sender, bool previousState) => UpdateActive();
 
     private void UpdateActive()
     {
         bool previousActive = IsActive;
-        _isActive = StateEnable.Enabled && _behaviourController.HierarchyObject.IsActive;
+        _isActive = StateEnable.Enabled && _behaviourController.UniverseObject.IsActive;
 
         if (previousActive != IsActive)
-            OnActiveChanged?.Invoke(this, previousActive);
+            OnActiveChanged?.InvokeSafe(this, previousActive);
     }
 }

Engine.Core/BehaviourCollector.cs

@@ -9,7 +9,7 @@ namespace Syntriax.Engine.Core;
 public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
 {
     public event IAssignable.UnassignEventHandler? OnUnassigned = null;
-    public event IHasGameManager.GameManagerAssignedEventHandler? OnGameManagerAssigned = null;
+    public event IHasUniverse.UniverseAssignedEventHandler? OnUniverseAssigned = null;
 
     public event IBehaviourCollector<T>.CollectedEventHandler? OnCollected = null;
     public event IBehaviourCollector<T>.RemovedEventHandler? OnRemoved = null;
@@ -17,29 +17,29 @@ public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
     protected readonly List<T> behaviours = new(32);
 
     public IReadOnlyList<T> Behaviours => behaviours;
-    public IGameManager GameManager { get; private set; } = null!;
+    public IUniverse Universe { get; private set; } = null!;
 
     public T this[Index index] => behaviours[index];
 
     public BehaviourCollector() { }
-    public BehaviourCollector(IGameManager gameManager) => Assign(gameManager);
+    public BehaviourCollector(IUniverse universe) => Assign(universe);
 
-    private void OnHierarchyObjectRegistered(IGameManager manager, IHierarchyObject hierarchyObject)
+    private void OnUniverseObjectRegistered(IUniverse manager, IUniverseObject universeObject)
     {
-        hierarchyObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
+        universeObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
-        hierarchyObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
+        universeObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
 
-        foreach (IBehaviour item in hierarchyObject.BehaviourController)
+        foreach (IBehaviour item in universeObject.BehaviourController)
-            OnBehaviourAdded(hierarchyObject.BehaviourController, item);
+            OnBehaviourAdded(universeObject.BehaviourController, item);
     }
 
-    private void OnHierarchyObjectUnregistered(IGameManager manager, IHierarchyObject hierarchyObject)
+    private void OnUniverseObjectUnregistered(IUniverse manager, IUniverseObject universeObject)
     {
-        hierarchyObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
+        universeObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
-        hierarchyObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
+        universeObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
 
-        foreach (IBehaviour item in hierarchyObject.BehaviourController)
+        foreach (IBehaviour item in universeObject.BehaviourController)
-            OnBehaviourRemoved(hierarchyObject.BehaviourController, item);
+            OnBehaviourRemoved(universeObject.BehaviourController, item);
     }
 
     protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
@@ -50,7 +50,7 @@ public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
 
         behaviours.Add(tBehaviour);
         OnBehaviourAdd(behaviour);
-        OnCollected?.Invoke(this, tBehaviour);
+        OnCollected?.InvokeSafe(this, tBehaviour);
     }
 
     protected virtual void OnBehaviourRemove(IBehaviour behaviour) { }
@@ -63,41 +63,41 @@ public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
             return;
 
         OnBehaviourRemove(behaviour);
-        OnRemoved?.Invoke(this, tBehaviour);
+        OnRemoved?.InvokeSafe(this, tBehaviour);
     }
 
-    protected virtual void OnAssign(IGameManager gameManager) { }
+    protected virtual void OnAssign(IUniverse universe) { }
-    public bool Assign(IGameManager gameManager)
+    public bool Assign(IUniverse universe)
     {
-        if (GameManager is not null)
+        if (Universe is not null)
             return false;
 
-        foreach (IHierarchyObject hierarchyObject in gameManager.HierarchyObjects)
+        foreach (IUniverseObject universeObject in universe.UniverseObjects)
-            OnHierarchyObjectRegistered(gameManager, hierarchyObject);
+            OnUniverseObjectRegistered(universe, universeObject);
 
-        gameManager.OnHierarchyObjectRegistered += OnHierarchyObjectRegistered;
+        universe.OnUniverseObjectRegistered += OnUniverseObjectRegistered;
-        gameManager.OnHierarchyObjectUnRegistered += OnHierarchyObjectUnregistered;
+        universe.OnUniverseObjectUnRegistered += OnUniverseObjectUnregistered;
 
-        GameManager = gameManager;
+        Universe = universe;
-        OnAssign(gameManager);
+        OnAssign(universe);
-        OnGameManagerAssigned?.Invoke(this);
+        OnUniverseAssigned?.InvokeSafe(this);
 
         return true;
     }
 
     public bool Unassign()
     {
-        if (GameManager is null)
+        if (Universe is null)
             return false;
 
-        foreach (IHierarchyObject hierarchyObject in GameManager.HierarchyObjects)
+        foreach (IUniverseObject universeObject in Universe.UniverseObjects)
-            OnHierarchyObjectUnregistered(GameManager, hierarchyObject);
+            OnUniverseObjectUnregistered(Universe, universeObject);
 
-        GameManager.OnHierarchyObjectRegistered -= OnHierarchyObjectRegistered;
+        Universe.OnUniverseObjectRegistered -= OnUniverseObjectRegistered;
-        GameManager.OnHierarchyObjectUnRegistered -= OnHierarchyObjectUnregistered;
+        Universe.OnUniverseObjectUnRegistered -= OnUniverseObjectUnregistered;
 
-        GameManager = null!;
+        Universe = null!;
-        OnUnassigned?.Invoke(this);
+        OnUnassigned?.InvokeSafe(this);
         return true;
     }
 

Engine.Core/BehaviourCollectorSorted.cs

@@ -6,7 +6,18 @@ namespace Syntriax.Engine.Core;
 
 public class BehaviourCollectorSorted<T> : BehaviourCollector<T> where T : class
 {
-    public Comparison<T>? SortBy { get; set; } = null;
+    private Comparison<T>? _sortBy = null;
+    public Comparison<T>? SortBy
+    {
+        get => _sortBy;
+        set
+        {
+            _sortBy = value;
+
+            if (value is not null)
+                behaviours.Sort(value);
+        }
+    }
 
     protected override void OnBehaviourAdd(IBehaviour behaviour)
     {
@@ -15,5 +26,5 @@ public class BehaviourCollectorSorted<T> : BehaviourCollector<T> where T : class
     }
 
     public BehaviourCollectorSorted() { }
-    public BehaviourCollectorSorted(IGameManager gameManager) : base(gameManager) { }
+    public BehaviourCollectorSorted(IUniverse universe, Comparison<T> sortBy) : base(universe) => SortBy = sortBy;
 }

Engine.Core/BehaviourController.cs

@@ -4,7 +4,6 @@ using System.Collections.Generic;
 using System.Linq;
 
 using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
 
 namespace Syntriax.Engine.Core;
 
@@ -17,7 +16,7 @@ public class BehaviourController : IBehaviourController
 
     public event IBehaviourController.BehaviourAddedEventHandler? OnBehaviourAdded = null;
     public event IBehaviourController.BehaviourRemovedEventHandler? OnBehaviourRemoved = null;
-    public event IHasHierarchyObject.HierarchyObjectAssignedEventHandler? OnHierarchyObjectAssigned = null;
+    public event IHasUniverseObject.UniverseObjectAssignedEventHandler? OnUniverseObjectAssigned = null;
 
     public event IInitializable.InitializedEventHandler? OnInitialized = null;
     public event IInitializable.FinalizedEventHandler? OnFinalized = null;
@@ -26,10 +25,10 @@ public class BehaviourController : IBehaviourController
 
     private readonly IList<IBehaviour> behaviours = new List<IBehaviour>(Constants.BEHAVIOURS_SIZE_INITIAL);
 
-    private IHierarchyObject _hierarchyObject = null!;
+    private IUniverseObject _universeObject = null!;
     private bool _initialized = false;
 
-    public IHierarchyObject HierarchyObject => _hierarchyObject;
+    public IUniverseObject UniverseObject => _universeObject;
 
     public bool IsInitialized
     {
@@ -41,9 +40,9 @@ public class BehaviourController : IBehaviourController
 
             _initialized = value;
             if (value)
-                OnInitialized?.Invoke(this);
+                OnInitialized?.InvokeSafe(this);
             else
-                OnFinalized?.Invoke(this);
+                OnFinalized?.InvokeSafe(this);
         }
     }
 
@@ -56,12 +55,12 @@ public class BehaviourController : IBehaviourController
 
         behaviour.Initialize();
         behaviour.OnPriorityChanged += OnPriorityChange;
-        OnBehaviourAdded?.Invoke(this, behaviour);
+        OnBehaviourAdded?.InvokeSafe(this, behaviour);
         return behaviour;
     }
 
     public T AddBehaviour<T>(params object?[]? args) where T : class, IBehaviour
-        => AddBehaviour(Factory.BehaviourFactory.Instantiate<T>(_hierarchyObject, args));
+        => AddBehaviour(Factory.BehaviourFactory.Instantiate<T>(_universeObject, args));
 
     public T? GetBehaviour<T>()
     {
@@ -72,7 +71,7 @@ public class BehaviourController : IBehaviourController
         return default;
     }
 
-    public IList<T> GetBehaviours<T>()
+    public IReadOnlyList<T> GetBehaviours<T>()
     {
         List<T>? behaviours = null;
         foreach (IBehaviour behaviourItem in this.behaviours)
@@ -116,23 +115,23 @@ public class BehaviourController : IBehaviourController
     public void RemoveBehaviour<T>(T behaviour) where T : class, IBehaviour
     {
         if (!behaviours.Contains(behaviour))
-            throw new Exception($"{behaviour.GetType().Name} does not exist in {HierarchyObject.Name}'s {nameof(IBehaviourController)}.");
+            throw new Exception($"{behaviour.GetType().Name} does not exist in {UniverseObject.Name}'s {nameof(IBehaviourController)}.");
 
         behaviour.OnPriorityChanged -= OnPriorityChange;
         behaviour.Finalize();
         behaviours.Remove(behaviour);
-        OnBehaviourRemoved?.Invoke(this, behaviour);
+        OnBehaviourRemoved?.InvokeSafe(this, behaviour);
     }
 
-    protected virtual void OnAssign(IHierarchyObject hierarchyObject) { }
+    protected virtual void OnAssign(IUniverseObject universeObject) { }
-    public bool Assign(IHierarchyObject hierarchyObject)
+    public bool Assign(IUniverseObject universeObject)
     {
-        if (HierarchyObject is not null && HierarchyObject.IsInitialized)
+        if (UniverseObject is not null && UniverseObject.IsInitialized)
             return false;
 
-        _hierarchyObject = hierarchyObject;
+        _universeObject = universeObject;
-        OnAssign(hierarchyObject);
+        OnAssign(universeObject);
-        OnHierarchyObjectAssigned?.Invoke(this);
+        OnUniverseObjectAssigned?.InvokeSafe(this);
         return true;
     }
 
@@ -141,7 +140,7 @@ public class BehaviourController : IBehaviourController
         if (IsInitialized)
             return false;
 
-        NotAssignedException.Check(this, _hierarchyObject);
+        Debug.AssertHelpers.AssertUniverseObjectAssigned(this);
 
         foreach (IBehaviour behaviour in behaviours)
             behaviour.Initialize();
@@ -167,30 +166,30 @@ public class BehaviourController : IBehaviourController
         if (IsInitialized)
             return false;
 
-        _hierarchyObject = null!;
+        _universeObject = null!;
-        OnUnassigned?.Invoke(this);
+        OnUnassigned?.InvokeSafe(this);
         return true;
     }
 
     public void Update()
     {
-        if (!HierarchyObject.StateEnable.Enabled)
+        if (!UniverseObject.StateEnable.Enabled)
             return;
 
-        OnPreUpdate?.Invoke(this);
+        OnPreUpdate?.InvokeSafe(this);
-        OnUpdate?.Invoke(this);
+        OnUpdate?.InvokeSafe(this);
     }
 
     public void UpdatePreDraw()
     {
-        if (!HierarchyObject.StateEnable.Enabled)
+        if (!UniverseObject.StateEnable.Enabled)
             return;
 
-        OnPreDraw?.Invoke(this);
+        OnPreDraw?.InvokeSafe(this);
     }
 
     public BehaviourController() { }
-    public BehaviourController(IHierarchyObject hierarchyObject) => Assign(hierarchyObject);
+    public BehaviourController(IUniverseObject universeObject) => Assign(universeObject);
 
     private void InsertBehaviourByPriority<T>(T behaviour) where T : class, IBehaviour
     {

Engine.Core/CoroutineManager.cs

@@ -5,7 +5,7 @@ using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
 
-public class CoroutineManager : HierarchyObject
+public class CoroutineManager : UniverseObject
 {
     private readonly List<IEnumerator> enumerators = [];
 
@@ -20,17 +20,17 @@ public class CoroutineManager : HierarchyObject
         enumerators.Remove(enumerator);
     }
 
-    protected override void OnEnteringHierarchy(IGameManager gameManager)
+    protected override void OnEnteringUniverse(IUniverse universe)
     {
-        gameManager.OnUpdate += OnUpdate;
+        universe.OnUpdate += OnUpdate;
     }
 
-    protected override void OnExitingHierarchy(IGameManager gameManager)
+    protected override void OnExitingUniverse(IUniverse universe)
     {
-        gameManager.OnUpdate -= OnUpdate;
+        universe.OnUpdate -= OnUpdate;
     }
 
-    private void OnUpdate(IGameManager sender, EngineTime time)
+    private void OnUpdate(IUniverse sender, UniverseTime time)
     {
         for (int i = enumerators.Count - 1; i >= 0; i--)
         {

Engine.Core/Engine.Core.puml

@@ -7,11 +7,11 @@ skinparam nodesep 100
 title Core Engine Relations
 
 interface Engine.Core.Abstract.IEntity extends Engine.Core.Abstract.IInitializable {}
-interface Engine.Core.Abstract.IHierarchyObject extends Engine.Core.Abstract.IEntity, Engine.Core.Abstract.INameable {}
+interface Engine.Core.Abstract.IUniverseObject extends Engine.Core.Abstract.IEntity, Engine.Core.Abstract.INameable {}
 
 interface Engine.Core.Abstract.INameable {}
 
-Engine.Core.Abstract.IHierarchyObject --> Engine.Core.Abstract.IBehaviourController: has
+Engine.Core.Abstract.IUniverseObject --> Engine.Core.Abstract.IBehaviourController: has
 Engine.Core.Abstract.IBehaviourController "1" --> "0..*" Engine.Core.Abstract.IBehaviour: has
 
 interface Engine.Core.Abstract.IBehaviourController {}
@@ -19,18 +19,18 @@ interface Engine.Core.Abstract.IBehaviour {}
 interface Engine.Core.Abstract.IBehaviour2D extends Engine.Core.Abstract.IBehaviour {}
 interface Engine.Core.Abstract.IBehaviour3D extends Engine.Core.Abstract.IBehaviour {}
 
-interface Engine.Core.Abstract.IGameManager {}
+interface Engine.Core.Abstract.IUniverse {}
-Engine.Core.Abstract.IGameManager "1" -r-> "0..*" Engine.Core.Abstract.IHierarchyObject: has
+Engine.Core.Abstract.IUniverse "1" -r-> "0..*" Engine.Core.Abstract.IUniverseObject: has
 
 ' together {
 '     interface Engine.Core.Abstract.IAssignable {}
 '     interface Engine.Core.Abstract.IHasStateEnable extends Engine.Core.Abstract.IAssignable {}
-'     interface Engine.Core.Abstract.IHasGameManager extends Engine.Core.Abstract.IAssignable {}
+'     interface Engine.Core.Abstract.IHasUniverse extends Engine.Core.Abstract.IAssignable {}
-'     interface Engine.Core.Abstract.IHasHierarchyObject extends Engine.Core.Abstract.IAssignable {}
+'     interface Engine.Core.Abstract.IHasUniverseObject extends Engine.Core.Abstract.IAssignable {}
 '     interface Engine.Core.Abstract.IHasBehaviourController extends Engine.Core.Abstract.IAssignable {}
 '     ' Engine.Core.Abstract.IHasStateEnable --> Engine.Core.Abstract.IStateEnable: has
-'     ' Engine.Core.Abstract.IHasGameManager --> Engine.Core.Abstract.IGameManager: has
+'     ' Engine.Core.Abstract.IHasUniverse --> Engine.Core.Abstract.IUniverse: has
-'     ' Engine.Core.Abstract.IHasHierarchyObject --> Engine.Core.Abstract.IHierarchyObject: has
+'     ' Engine.Core.Abstract.IHasUniverseObject --> Engine.Core.Abstract.IUniverseObject: has
 '     ' Engine.Core.Abstract.IHasBehaviourController --> Engine.Core.Abstract.IBehaviourController: has
 ' }
 

Engine.Core/Exceptions/AssignException.cs

@@ -1,12 +0,0 @@
-using System;
-
-namespace Syntriax.Engine.Core.Exceptions;
-
-public class AssignException : Exception
-{
-    public AssignException() : base("Assign operation has failed.") { }
-    public AssignException(string? message) : base(message) { }
-
-    public static AssignException From<T, T2>(T to, T2? value)
-        => new($"Assign operation has failed on T: {to?.GetType().FullName ?? "\"null\""}, value: {value?.GetType().ToString() ?? "\"null\""}");
-}

Engine.Core/Exceptions/AssignFailedException.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Syntriax.Engine.Core.Exceptions;
+
+public class AssignFailedException(string? message) : Exception(message)
+{
+    public static AssignFailedException From<T, T2>(T to, T2? value)
+        => new($"Assign operation has failed on T: {to?.GetType().FullName ?? "\"null\""}, value: {value?.GetType().ToString() ?? "\"null\""}");
+}

Engine.Core/Exceptions/BehaviourNotFoundException.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Syntriax.Engine.Core.Exceptions;
+
+public class BehaviourNotFoundException(string? message) : Exception(message)
+{
+    public static NotAssignedException FromType<TBehaviour>()
+        => new($"{typeof(TBehaviour).FullName} was not found");
+}

Engine.Core/Exceptions/NotAssignedException.cs

@@ -1,21 +1,9 @@
 using System;
-using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core.Exceptions;
 
-public class NotAssignedException : Exception
+public class NotAssignedException(string? message) : Exception(message)
 {
-    public NotAssignedException() : base("The object has not been assigned.") { }
-    public NotAssignedException(string? message) : base(message) { }
-
     public static NotAssignedException From<T1, T2>(T1 to, T2? value)
         => new($"{value?.GetType().FullName ?? "\"null\""} has not been assigned to {to?.GetType().FullName ?? "\"null\""}");
-
-    public static void Check<T1, T2>(T1 to, T2? value)
-    {
-        if (value is not null)
-            return;
-
-        throw From(to, value);
-    }
 }

Engine.Core/Exceptions/UniverseObjectNotFoundException.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Syntriax.Engine.Core.Exceptions;
+
+public class UniverseObjectNotFoundException(string? message) : Exception(message)
+{
+    public static NotAssignedException FromType<TUniverseObject>()
+        => new($"{typeof(TUniverseObject).FullName} was not found");
+}

Engine.Core/Extensions/Abstract/TransformExtensions.cs

@@ -1,9 +0,0 @@
-namespace Syntriax.Engine.Core.Abstract;
-
-public static class TransformExtensions
-{
-    public static Vector2D TransformVector2D(this ITransform2D transform, Vector2D vector)
-        => vector.Scale(transform.Scale)
-                 .Rotate(transform.Rotation * Math.DegreeToRadian)
-                 .Add(transform.Position);
-}

Engine.Core/Extensions/BehaviourControllerExtensions.cs

@@ -1,6 +1,7 @@
 using System.Diagnostics.CodeAnalysis;
 
 using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Exceptions;
 
 namespace Syntriax.Engine.Core;
 
@@ -19,6 +20,15 @@ public static class BehaviourControllerExtensions
         return behaviour is not null;
     }
 
+    /// <summary>
+    /// Gets a <see cref="IBehaviour"/> of the specified type in the provided <see cref="IBehaviourController"/>. Throws an error if not found.
+    /// </summary>
+    /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
+    /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
+    /// <returns>The <see cref="IBehaviour"/> of the specified type if found; otherwise, throws <see cref="BehaviourNotFoundException"/>.</returns>
+    public static T GetRequiredBehaviour<T>(this IBehaviourController behaviourController) where T : class
+        => behaviourController.GetBehaviour<T>() ?? throw new BehaviourNotFoundException($"{behaviourController.UniverseObject.Name}'s {nameof(IBehaviourController)} does not contain any {typeof(T).FullName}");
+
     /// <summary>
     /// Gets an existing <see cref="IBehaviour"/> of the specified type, or adds and returns a new one if it doesn't exist.
     /// </summary>
@@ -30,12 +40,12 @@ public static class BehaviourControllerExtensions
         => behaviourController.GetBehaviour<T>() ?? behaviourController.AddBehaviour<T>(args);
 
     /// <summary>
-    /// Tries to get a <see cref="IBehaviour"/> of the specified type in the parent hierarchy.
+    /// Tries to get a <see cref="IBehaviour"/> of the specified type in it's <see cref="IUniverseObject"/>'s parents recursively.
     /// </summary>
     /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
     /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
     /// <param name="behaviour">When this method returns, contains the <see cref="IBehaviour"/> of the specified type, if found; otherwise, null.</param>
-    /// <returns><see cref="true"/> if a <see cref="IBehaviour"/> of the specified type was found in the parent hierarchy; otherwise, <see cref="false"/>.</returns>
+    /// <returns><see cref="true"/> if a <see cref="IBehaviour"/> of the specified type was found in the parent universe; otherwise, <see cref="false"/>.</returns>
     public static bool TryGetBehaviourInParent<T>(this IBehaviourController behaviourController, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
     {
         behaviour = GetBehaviourInParent<T>(behaviourController);
@@ -43,7 +53,7 @@ public static class BehaviourControllerExtensions
     }
 
     /// <summary>
-    /// Gets a <see cref="IBehaviour"/> of the specified type in the parent hierarchy.
+    /// Gets a <see cref="IBehaviour"/> of the specified type in it's <see cref="IUniverseObject"/>'s parents recursively.
     /// </summary>
     /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
     /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
@@ -54,22 +64,31 @@ public static class BehaviourControllerExtensions
 
         while (controller is not null)
         {
-            if (behaviourController.GetBehaviour<T>() is T behaviour)
+            if (controller.GetBehaviour<T>() is T behaviour)
                 return behaviour;
 
-            controller = controller.HierarchyObject.Parent?.BehaviourController;
+            controller = controller.UniverseObject.Parent?.BehaviourController;
         }
 
         return default;
     }
 
     /// <summary>
-    /// Tries to get a <see cref="IBehaviour"/> of the specified type in the child hierarchy.
+    /// Gets a <see cref="IBehaviour"/> of the specified type in it's <see cref="IUniverseObject"/>'s parents recursively. Throws an error if not found.
+    /// </summary>
+    /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
+    /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
+    /// <returns>The <see cref="IBehaviour"/> of the specified type if found; otherwise, throws <see cref="BehaviourNotFoundException"/>.</returns>
+    public static T GetRequiredBehaviourInParent<T>(this IBehaviourController behaviourController) where T : class
+        => behaviourController.GetBehaviourInParent<T>() ?? throw new BehaviourNotFoundException($"{behaviourController.UniverseObject.Name}'s {nameof(IBehaviourController)} does not contain any {typeof(T).FullName} on any parent");
+
+    /// <summary>
+    /// Tries to get a <see cref="IBehaviour"/> of the specified type in it's <see cref="IUniverseObject"/>'s children recursively.
     /// </summary>
     /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
     /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
     /// <param name="behaviour">When this method returns, contains the <see cref="IBehaviour"/> of the specified type, if found; otherwise, null.</param>
-    /// <returns><see cref="true"/> if a <see cref="IBehaviour"/> of the specified type was found in the child hierarchy; otherwise, <see cref="false"/>.</returns>
+    /// <returns><see cref="true"/> if a <see cref="IBehaviour"/> of the specified type was found in the child universe; otherwise, <see cref="false"/>.</returns>
     public static bool TryGetBehaviourInChildren<T>(this IBehaviourController behaviourController, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
     {
         behaviour = GetBehaviourInChildren<T>(behaviourController);
@@ -77,7 +96,7 @@ public static class BehaviourControllerExtensions
     }
 
     /// <summary>
-    /// Gets a <see cref="IBehaviour"/> of the specified type in the child hierarchy.
+    /// Gets a <see cref="IBehaviour"/> of the specified type in it's <see cref="IUniverseObject"/>'s children recursively.
     /// </summary>
     /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
     /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
@@ -87,10 +106,19 @@ public static class BehaviourControllerExtensions
         if (behaviourController.GetBehaviour<T>() is T localBehaviour)
             return localBehaviour;
 
-        foreach (IHierarchyObject child in behaviourController.HierarchyObject)
+        foreach (IUniverseObject child in behaviourController.UniverseObject)
             if (GetBehaviourInChildren<T>(child.BehaviourController) is T behaviour)
                 return behaviour;
 
         return default;
     }
+
+    /// <summary>
+    /// Gets a <see cref="IBehaviour"/> of the specified type in the children recursively. Throws an error if not found.
+    /// </summary>
+    /// <typeparam name="T">The type of <see cref="IBehaviour"/> to get.</typeparam>
+    /// <param name="behaviourController">The <see cref="IBehaviourController"/> to start searching from.</param>
+    /// <returns>The <see cref="IBehaviour"/> of the specified type if found; otherwise, throws <see cref="BehaviourNotFoundException"/>.</returns>
+    public static T GetRequiredBehaviourInChildren<T>(this IBehaviourController behaviourController) where T : class
+        => behaviourController.GetBehaviourInChildren<T>() ?? throw new BehaviourNotFoundException($"{behaviourController.UniverseObject.Name}'s {nameof(IBehaviourController)} does not contain any {typeof(T).FullName} on any children ");
 }

Engine.Core/Extensions/BehaviourExtensions.cs

@@ -7,29 +7,29 @@ namespace Syntriax.Engine.Core;
 
 public static class BehaviourExtensions
 {
-    public static T? FindBehaviour<T>(this IEnumerable<IHierarchyObject> hierarchyObjects) where T : class
+    public static T? FindBehaviour<T>(this IEnumerable<IUniverseObject> universeObjects) where T : class
     {
-        foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
+        foreach (IUniverseObject universeObject in universeObjects)
-            if (hierarchyObject.BehaviourController.GetBehaviour<T>() is T behaviour)
+            if (universeObject.BehaviourController.GetBehaviour<T>() is T behaviour)
                 return behaviour;
 
         return default;
     }
 
-    public static bool TryFindBehaviour<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    public static bool TryFindBehaviour<T>(this IEnumerable<IUniverseObject> universeObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
     {
-        behaviour = FindBehaviour<T>(hierarchyObjects);
+        behaviour = FindBehaviour<T>(universeObjects);
         return behaviour is not null;
     }
 
-    public static void FindBehaviours<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, List<T> behaviours) where T : class
+    public static void FindBehaviours<T>(this IEnumerable<IUniverseObject> universeObjects, List<T> behaviours) where T : class
     {
         behaviours.Clear();
         List<T> cache = [];
 
-        foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
+        foreach (IUniverseObject universeObject in universeObjects)
         {
-            hierarchyObject.BehaviourController.GetBehaviours(cache);
+            universeObject.BehaviourController.GetBehaviours(cache);
             behaviours.AddRange(cache);
         }
     }

Engine.Core/Extensions/GameManagerExtensions.cs

@@ -1,9 +0,0 @@
-using Syntriax.Engine.Core.Abstract;
-
-namespace Syntriax.Engine.Core;
-
-public static class GameManagerExtensions
-{
-    public static IHierarchyObject InstantiateHierarchyObject(this IGameManager gameManager, params object?[]? args)
-        => gameManager.InstantiateHierarchyObject<HierarchyObject>(args);
-}

Engine.Core/Extensions/HierarchyObjectExtensions.cs

@@ -1,38 +0,0 @@
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
-
-using Syntriax.Engine.Core.Abstract;
-
-namespace Syntriax.Engine.Core;
-
-public static class HierarchyObjectExtensions
-{
-    public static IHierarchyObject SetHierarchyObject(this IHierarchyObject hierarchyObject, string name)
-    {
-        hierarchyObject.Name = name;
-        return hierarchyObject;
-    }
-
-    public static T? FindHierarchyObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects) where T : class
-    {
-        foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
-            if (hierarchyObject is T @object)
-                return @object;
-
-        return default;
-    }
-
-    public static bool TryFindHierarchyObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
-    {
-        behaviour = FindHierarchyObject<T>(hierarchyObjects);
-        return behaviour is not null;
-    }
-
-    public static void FindHierarchyObjects<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, List<T> behaviours) where T : class
-    {
-        behaviours.Clear();
-        foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
-            if (hierarchyObject is T @object)
-                behaviours.Add(@object);
-    }
-}

Engine.Core/Extensions/UniverseExtensions.cs

@@ -0,0 +1,16 @@
+using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Exceptions;
+
+namespace Syntriax.Engine.Core;
+
+public static class UniverseExtensions
+{
+    public static IUniverseObject InstantiateUniverseObject(this IUniverse universe, params object?[]? args)
+        => universe.InstantiateUniverseObject<UniverseObject>(args);
+
+    public static T GetRequiredUniverseObject<T>(this IUniverse universe) where T : class
+        => universe.GetUniverseObject<T>() ?? throw new UniverseObjectNotFoundException($"{universe.GetType().FullName}({universe.Id}) does not contain any {nameof(IUniverseObject)} object of type {typeof(T).FullName}");
+
+    public static T FindRequiredBehaviour<T>(this IUniverse universe) where T : class
+        => universe.FindBehaviour<T>() ?? throw new BehaviourNotFoundException($"{universe.GetType().FullName}({universe.Id}) does not contain any {nameof(IUniverseObject)} with {nameof(IBehaviour)} of type {typeof(T).FullName}");
+}

Engine.Core/Extensions/UniverseObjectExtensions.cs

@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public static class UniverseObjectExtensions
+{
+    public static T SetUniverseObject<T>(this T universeObject, string? name = "", IUniverseObject? parent = null) where T : IUniverseObject
+    {
+        if (!string.IsNullOrWhiteSpace(name))
+            universeObject.Name = name;
+        if (parent is not null)
+            universeObject.SetParent(parent);
+        return universeObject;
+    }
+
+    public static T? GetUniverseObject<T>(this IEnumerable<IUniverseObject> universeObjects) where T : class
+    {
+        foreach (IUniverseObject universeObject in universeObjects)
+            if (universeObject is T @object)
+                return @object;
+
+        return default;
+    }
+
+    public static bool TryGetUniverseObject<T>(this IEnumerable<IUniverseObject> universeObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    {
+        behaviour = GetUniverseObject<T>(universeObjects);
+        return behaviour is not null;
+    }
+
+    public static void GetUniverseObjects<T>(this IEnumerable<IUniverseObject> universeObjects, List<T> behaviours) where T : class
+    {
+        behaviours.Clear();
+        foreach (IUniverseObject universeObject in universeObjects)
+            if (universeObject is T @object)
+                behaviours.Add(@object);
+    }
+}

Engine.Core/Factory/BehaviourControllerFactory.cs

@@ -5,19 +5,19 @@ namespace Syntriax.Engine.Core.Factory;
 
 public class BehaviourControllerFactory
 {
-    public static IBehaviourController Instantiate(IHierarchyObject hierarchyObject)
+    public static IBehaviourController Instantiate(IUniverseObject universeObject)
-        => Instantiate<BehaviourController>(hierarchyObject);
+        => Instantiate<BehaviourController>(universeObject);
 
-    public static T Instantiate<T>(IHierarchyObject hierarchyObject, params object?[]? args)
+    public static T Instantiate<T>(IUniverseObject universeObject, params object?[]? args)
         where T : class, IBehaviourController
     {
         T behaviourController = TypeFactory.Get<T>(args);
 
-        if (!hierarchyObject.Assign(behaviourController))
+        if (!universeObject.Assign(behaviourController))
-            throw AssignException.From(hierarchyObject, behaviourController);
+            throw AssignFailedException.From(universeObject, behaviourController);
 
-        if (!behaviourController.Assign(hierarchyObject))
+        if (!behaviourController.Assign(universeObject))
-            throw AssignException.From(behaviourController, hierarchyObject);
+            throw AssignFailedException.From(behaviourController, universeObject);
 
         return behaviourController;
     }

Engine.Core/Factory/BehaviourFactory.cs

@@ -5,22 +5,22 @@ namespace Syntriax.Engine.Core.Factory;
 
 public class BehaviourFactory
 {
-    public static T Instantiate<T>(IHierarchyObject hierarchyObject, params object?[]? args) where T : class, IBehaviour
+    public static T Instantiate<T>(IUniverseObject universeObject, params object?[]? args) where T : class, IBehaviour
-        => Instantiate<T>(hierarchyObject, stateEnable: null, args);
+        => Instantiate<T>(universeObject, stateEnable: null, args);
 
-    public static T Instantiate<T>(IHierarchyObject hierarchyObject, IStateEnable? stateEnable, params object?[]? args)
+    public static T Instantiate<T>(IUniverseObject universeObject, IStateEnable? stateEnable, params object?[]? args)
         where T : class, IBehaviour
     {
         T behaviour = TypeFactory.Get<T>(args);
 
         stateEnable ??= TypeFactory.Get<StateEnable>();
         if (!stateEnable.Assign(behaviour))
-            throw AssignException.From(stateEnable, behaviour);
+            throw AssignFailedException.From(stateEnable, behaviour);
 
         if (!behaviour.Assign(stateEnable))
-            throw AssignException.From(behaviour, stateEnable);
+            throw AssignFailedException.From(behaviour, stateEnable);
-        if (!behaviour.Assign(hierarchyObject.BehaviourController))
+        if (!behaviour.Assign(universeObject.BehaviourController))
-            throw AssignException.From(behaviour, hierarchyObject.BehaviourController);
+            throw AssignFailedException.From(behaviour, universeObject.BehaviourController);
 
         return behaviour;
     }

Engine.Core/Factory/HierarchyObjectFactory.cs

@@ -1,35 +0,0 @@
-using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
-
-namespace Syntriax.Engine.Core.Factory;
-
-public class HierarchyObjectFactory
-{
-    public static T Instantiate<T>(params object?[]? args) where T : class, IHierarchyObject
-        => Instantiate<T>(behaviourController: null, stateEnable: null, args);
-
-    public static T Instantiate<T>(
-        IBehaviourController? behaviourController = null,
-        IStateEnable? stateEnable = null,
-        params object?[]? args
-    )
-        where T : class, IHierarchyObject
-    {
-        T hierarchyObject = TypeFactory.Get<T>(args);
-
-        behaviourController ??= TypeFactory.Get<BehaviourController>();
-        stateEnable ??= TypeFactory.Get<StateEnable>();
-
-        if (!behaviourController.Assign(hierarchyObject))
-            throw AssignException.From(behaviourController, hierarchyObject);
-        if (!stateEnable.Assign(hierarchyObject))
-            throw AssignException.From(stateEnable, hierarchyObject);
-
-        if (!hierarchyObject.Assign(behaviourController))
-            throw AssignException.From(hierarchyObject, behaviourController);
-        if (!hierarchyObject.Assign(stateEnable))
-            throw AssignException.From(hierarchyObject, stateEnable);
-
-        return hierarchyObject;
-    }
-}

Engine.Core/Factory/StateEnableFactory.cs

@@ -12,10 +12,10 @@ public class StateEnableFactory
         T stateEnable = TypeFactory.Get<T>(args);
 
         if (!entity.Assign(stateEnable))
-            throw AssignException.From(entity, stateEnable);
+            throw AssignFailedException.From(entity, stateEnable);
 
         if (!stateEnable.Assign(entity))
-            throw AssignException.From(stateEnable, entity);
+            throw AssignFailedException.From(stateEnable, entity);
 
         return stateEnable;
     }

Engine.Core/Factory/UniverseObjectFactory.cs

@@ -0,0 +1,37 @@
+using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Exceptions;
+
+namespace Syntriax.Engine.Core.Factory;
+
+public class UniverseObjectFactory
+{
+    public static IUniverseObject Instantiate() => Instantiate<UniverseObject>();
+    public static T Instantiate<T>(params object?[]? args) where T : class, IUniverseObject
+        => Instantiate<T>(behaviourController: null, stateEnable: null, args);
+
+    public static IUniverseObject Instantiate(IBehaviourController? behaviourController = null, IStateEnable? stateEnable = null) => Instantiate<UniverseObject>(behaviourController, stateEnable);
+    public static T Instantiate<T>(
+        IBehaviourController? behaviourController = null,
+        IStateEnable? stateEnable = null,
+        params object?[]? args
+    )
+        where T : class, IUniverseObject
+    {
+        T universeObject = TypeFactory.Get<T>(args);
+
+        behaviourController ??= TypeFactory.Get<BehaviourController>();
+        stateEnable ??= TypeFactory.Get<StateEnable>();
+
+        if (!behaviourController.Assign(universeObject))
+            throw AssignFailedException.From(behaviourController, universeObject);
+        if (!stateEnable.Assign(universeObject))
+            throw AssignFailedException.From(stateEnable, universeObject);
+
+        if (!universeObject.Assign(behaviourController))
+            throw AssignFailedException.From(universeObject, behaviourController);
+        if (!universeObject.Assign(stateEnable))
+            throw AssignFailedException.From(universeObject, stateEnable);
+
+        return universeObject;
+    }
+}

Engine.Core/GameManager.cs

@@ -1,139 +0,0 @@
-using System;
-using System.Collections;
-using System.Collections.Generic;
-
-using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
-
-namespace Syntriax.Engine.Core;
-
-[System.Diagnostics.DebuggerDisplay("HierarchyObject Count: {_hierarchyObjects.Count}")]
-public class GameManager : BaseEntity, IGameManager
-{
-    public event IGameManager.UpdateEventHandler? OnUpdate = null;
-    public event IGameManager.PreDawEventHandler? OnPreDraw = null;
-
-    public event IGameManager.HierarchyObjectRegisteredEventHandler? OnHierarchyObjectRegistered = null;
-    public event IGameManager.HierarchyObjectUnRegisteredEventHandler? OnHierarchyObjectUnRegistered = null;
-
-    private readonly List<IHierarchyObject> _hierarchyObjects = new(Constants.GAME_OBJECTS_SIZE_INITIAL);
-
-    public IReadOnlyList<IHierarchyObject> HierarchyObjects => _hierarchyObjects;
-
-    public override IStateEnable StateEnable
-    {
-        get
-        {
-            if (base.StateEnable is null)
-            {
-                Assign(Factory.StateEnableFactory.Instantiate(this));
-                if (base.StateEnable is null)
-                    throw NotAssignedException.From(this, base.StateEnable);
-            }
-
-            return base.StateEnable;
-        }
-    }
-
-    public EngineTime Time { get; private set; } = new();
-
-    public void Register(IHierarchyObject hierarchyObject)
-    {
-        if (_hierarchyObjects.Contains(hierarchyObject))
-            throw new Exception($"{nameof(IHierarchyObject)} named {hierarchyObject.Name} is already registered to the {nameof(GameManager)}.");
-
-        hierarchyObject.OnFinalized += OnHierarchyObjectFinalize;
-        hierarchyObject.OnExitedHierarchy += OnHierarchyObjectExitedHierarchy;
-
-        if (!hierarchyObject.Initialize())
-            throw new Exception($"{hierarchyObject.Name} can't be initialized");
-
-        foreach (IHierarchyObject child in hierarchyObject.Children)
-            Register(child);
-
-        _hierarchyObjects.Add(hierarchyObject);
-
-        if (!hierarchyObject.EnterHierarchy(this))
-            throw new Exception($"{hierarchyObject.Name} can't enter the hierarchy");
-
-        OnHierarchyObjectRegistered?.Invoke(this, hierarchyObject);
-    }
-
-    public T InstantiateHierarchyObject<T>(params object?[]? args) where T : class, IHierarchyObject
-    {
-        T hierarchyObject = Factory.HierarchyObjectFactory.Instantiate<T>(args);
-        Register(hierarchyObject);
-        return hierarchyObject;
-    }
-
-    public void Remove(IHierarchyObject hierarchyObject)
-    {
-        if (!_hierarchyObjects.Contains(hierarchyObject))
-            throw new Exception($"{nameof(IHierarchyObject)} named {hierarchyObject.Name} is not registered to the {nameof(GameManager)}.");
-
-        hierarchyObject.OnFinalized -= OnHierarchyObjectFinalize;
-        hierarchyObject.OnExitedHierarchy -= OnHierarchyObjectExitedHierarchy;
-
-        foreach (IHierarchyObject child in hierarchyObject.Children)
-            Remove(child);
-
-        _hierarchyObjects.Remove(hierarchyObject);
-
-        if (!hierarchyObject.ExitHierarchy())
-            throw new Exception($"{hierarchyObject.Name} can't exit the hierarchy");
-
-        if (!hierarchyObject.Finalize())
-            throw new Exception($"{hierarchyObject.Name} can't be finalized");
-
-        OnHierarchyObjectUnRegistered?.Invoke(this, hierarchyObject);
-    }
-
-    protected override void InitializeInternal()
-    {
-        base.InitializeInternal();
-        NotAssignedException.Check(this, StateEnable);
-
-        foreach (IHierarchyObject hierarchyObject in HierarchyObjects)
-            hierarchyObject.Initialize();
-    }
-
-    protected override void FinalizeInternal()
-    {
-        base.FinalizeInternal();
-        for (int i = HierarchyObjects.Count; i >= 0; i--)
-            HierarchyObjects[i].Finalize();
-    }
-
-    public void Update(EngineTime engineTime)
-    {
-        Time = engineTime;
-
-        for (int i = 0; i < HierarchyObjects.Count; i++)
-            HierarchyObjects[i].BehaviourController.Update();
-
-        OnUpdate?.Invoke(this, engineTime);
-    }
-
-    public void PreDraw()
-    {
-        for (int i = 0; i < HierarchyObjects.Count; i++)
-            HierarchyObjects[i].BehaviourController.UpdatePreDraw();
-
-        OnPreDraw?.Invoke(this);
-    }
-
-    private void OnHierarchyObjectFinalize(IInitializable initializable)
-    {
-        if (initializable is IHierarchyObject hierarchyObject)
-            Remove(hierarchyObject);
-    }
-
-    private void OnHierarchyObjectExitedHierarchy(IHierarchyObject sender, IGameManager gameManager)
-    {
-        if (sender is IHierarchyObject hierarchyObject)
-            Remove(hierarchyObject);
-    }
-
-    public IEnumerator<IHierarchyObject> GetEnumerator() => _hierarchyObjects.GetEnumerator();
-    IEnumerator IEnumerable.GetEnumerator() => _hierarchyObjects.GetEnumerator();
-}

Engine.Core/Helpers/AssertHelpers.cs

@@ -0,0 +1,32 @@
+using System.Runtime.CompilerServices;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core.Debug;
+
+public class AssertHelpers
+{
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertInitialized(IInitializable initializable)
+        => System.Diagnostics.Debug.Assert(initializable.IsInitialized, $"{initializable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertBehaviourControllerAssigned(IHasBehaviourController assignable)
+        => System.Diagnostics.Debug.Assert(assignable.BehaviourController is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertEntityAssigned(IHasEntity assignable)
+        => System.Diagnostics.Debug.Assert(assignable.Entity is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertUniverseAssigned(IHasUniverse assignable)
+        => System.Diagnostics.Debug.Assert(assignable.Universe is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertUniverseObjectAssigned(IHasUniverseObject assignable)
+        => System.Diagnostics.Debug.Assert(assignable.UniverseObject is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertStateEnableAssigned(IHasStateEnable assignable)
+        => System.Diagnostics.Debug.Assert(assignable.StateEnable is not null, $"{assignable.GetType().Name} must be initialized");
+}

Engine.Core/Helpers/DelegateHelpers.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace Syntriax.Engine.Core;
+
+public static class DelegateHelpers
+{
+    public static void InvokeSafe(this Delegate @delegate, params object?[] args)
+    {
+        foreach (Delegate invocation in @delegate.GetInvocationList())
+            try { invocation.DynamicInvoke(args); }
+            catch (Exception exception)
+            {
+                string methodCallRepresentation = $"{invocation.Method.DeclaringType?.FullName}.{invocation.Method.Name}({string.Join(", ", args)})";
+                Console.WriteLine($"Unexpected exception on invocation of method {methodCallRepresentation}:{Environment.NewLine}{exception.InnerException}");
+            }
+    }
+}

Engine.Core/Primitives/Circle.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+
 using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
@@ -66,8 +67,8 @@ public readonly struct Circle(Vector2D center, float radius)
     /// <summary>
     /// Transforms the <see cref="Circle"/> by the specified <see cref="ITransform2D"/>.
     /// </summary>
-    public static Circle TransformCircle(ITransform2D transform, Circle circle)
+    public static Circle Transform(ITransform2D transform, Circle circle)
-        => new(transform.TransformVector2D(circle.Center), circle.Radius * (transform.Scale.Magnitude / Vector2D.One.Magnitude));
+        => new(transform.Transform(circle.Center), circle.Radius * (transform.Scale.Magnitude / Vector2D.One.Magnitude));
 
     /// <summary>
     /// Checks if two <see cref="Circle"/>s are approximately equal.
@@ -97,8 +98,11 @@ public static class CircleExtensions
     /// <inheritdoc cref="Circle.Project(Circle, Vector2D)" />
     public static Projection1D ToProjection(this Circle circle, Vector2D projectionVector) => Circle.Project(circle, projectionVector);
 
-    /// <inheritdoc cref="Circle.TransformCircle(ITransform2D, Circle)" />
+    /// <inheritdoc cref="Circle.Transform(ITransform2D, Circle)" />
-    public static Circle TransformCircle(this ITransform2D transform, Circle circle) => Circle.TransformCircle(transform, circle);
+    public static Circle Transform(this ITransform2D transform, Circle circle) => Circle.Transform(transform, circle);
+
+    /// <inheritdoc cref="Circle.Transform(ITransform2D, Circle)" />
+    public static Circle Transform(this Circle circle, ITransform2D transform) => Circle.Transform(transform, circle);
 
     /// <inheritdoc cref="Circle.ApproximatelyEquals(Circle, Circle, float)" />
     public static bool ApproximatelyEquals(this Circle left, Circle right, float epsilon = float.Epsilon) => Circle.ApproximatelyEquals(left, right, epsilon);

Engine.Core/Primitives/Shape2D.cs

@@ -1,5 +1,6 @@
 using System.Collections;
 using System.Collections.Generic;
+
 using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
@@ -9,20 +10,20 @@ namespace Syntriax.Engine.Core;
 /// </summary>
 /// <param name="vertices">The vertices of the shape.</param>
 /// <remarks>
-/// Initializes a new instance of the <see cref="Shape2D"/> struct with the specified vertices.
+/// Initializes a new instance of a <see cref="Shape2D"/> struct with the specified vertices.
 /// </remarks>
 [System.Diagnostics.DebuggerDisplay("Vertices Count: {Vertices.Count}")]
 public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
 {
     public static readonly Shape2D Triangle = CreateNgon(3, Vector2D.Up);
-    public static readonly Shape2D Box = CreateNgon(4, Vector2D.One);
+    public static readonly Shape2D Square = CreateNgon(4, Vector2D.One);
     public static readonly Shape2D Pentagon = CreateNgon(5, Vector2D.Up);
     public static readonly Shape2D Hexagon = CreateNgon(6, Vector2D.Right);
 
     private readonly List<Vector2D> _verticesList = vertices;
 
     /// <summary>
-    /// Gets the vertices of the shape.
+    /// Gets the vertices of the <see cref="Shape2D"/>.
     /// </summary>
     public IReadOnlyList<Vector2D> Vertices => _verticesList;
 
@@ -34,10 +35,10 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     public Vector2D this[System.Index index] => Vertices[index];
 
     /// <summary>
-    /// Returns a copy of the current shape.
+    /// Returns a copy of the current <see cref="Shape2D"/>.
     /// </summary>
-    /// <param name="shape">The shape to copy.</param>
+    /// <param name="shape">The <see cref="Shape2D"/> to copy.</param>
-    /// <returns>A copy of the input shape.</returns>
+    /// <returns>A copy of the input <see cref="Shape2D"/>.</returns>
     public static Shape2D CreateCopy(Shape2D shape) => new(new List<Vector2D>(shape.Vertices));
 
     /// <summary>
@@ -69,10 +70,10 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     }
 
     /// <summary>
-    /// Gets the super triangle that encloses the given shape.
+    /// Gets the super triangle that encloses the given <see cref="Shape2D"/>.
     /// </summary>
-    /// <param name="shape">The shape to enclose.</param>
+    /// <param name="shape">The <see cref="Shape2D"/> to enclose.</param>
-    /// <returns>The super triangle that encloses the given shape.</returns>
+    /// <returns>The super triangle that encloses the given <see cref="Shape2D"/>.</returns>
     public static Triangle GetSuperTriangle(Shape2D shape)
     {
         float minX = float.MaxValue, minY = float.MaxValue;
@@ -100,10 +101,35 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     }
 
     /// <summary>
-    /// Gets the lines that form the edges of the shape.
+    /// Triangulates the given convex <see cref="Shape2D"/>.
     /// </summary>
-    /// <param name="shape">The shape to get lines from.</param>
+    /// <param name="shape">The <see cref="Shape2D"/> to triangulate.</param>
-    /// <param name="lines">The list to populate with lines.</param>
+    /// <param name="triangles">The list to populate with triangles.</param>
+    public static void TriangulateConvex(Shape2D shape, IList<Triangle> triangles)
+    {
+        triangles.Clear();
+
+        for (int i = 2; i < shape.Vertices.Count; i++)
+            triangles.Add(new Triangle(shape[0], shape[i - 1], shape[i]));
+    }
+
+    /// <summary>
+    /// Triangulates the given convex <see cref="Shape2D"/>.
+    /// </summary>
+    /// <param name="shape">The <see cref="Shape2D"/> to triangulate.</param>
+    /// <returns>A list of <see cref="Triangle"/>s that makes up the given convex <see cref="Shape2D"/>.</returns>
+    public static List<Triangle> TriangulateConvex(Shape2D shape)
+    {
+        List<Triangle> triangles = new(shape.Vertices.Count - 2);
+        TriangulateConvex(shape, triangles);
+        return triangles;
+    }
+
+    /// <summary>
+    /// Gets the <see cref="Line2D"/>s that form the edges of the <see cref="Shape2D"/>.
+    /// </summary>
+    /// <param name="shape">The <see cref="Shape2D"/> to get <see cref="Line2D"/>s from.</param>
+    /// <param name="lines">The list to populate with <see cref="Line2D"/>.</sparam>
     public static void GetLines(Shape2D shape, IList<Line2D> lines)
     {
         lines.Clear();
@@ -113,10 +139,10 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     }
 
     /// <summary>
-    /// Gets a list of lines that form the edges of the shape.
+    /// Gets a list of <see cref="Line2D"/>s that form the edges of the <see cref="Shape2D"/>.
     /// </summary>
-    /// <param name="shape">The shape to get lines from.</param>
+    /// <param name="shape">The shape to get <see cref="Line2D"/>s from.</param>
-    /// <returns>A list of lines that form the edges of the shape.</returns>
+    /// <returns>A list of <see cref="Line2D"/>s that form the edges of the <see cref="Shape2D"/>.</returns>
     public static List<Line2D> GetLines(Shape2D shape)
     {
         List<Line2D> lines = new(shape.Vertices.Count - 1);
@@ -125,7 +151,7 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     }
 
     /// <summary>
-    /// Projects the shape onto a vector.
+    /// Projects the <see cref="Shape2D"/> onto a 1D plane.
     /// </summary>
     /// <param name="shape">The shape to project.</param>
     /// <param name="projectionVector">The vector to project onto.</param>
@@ -140,11 +166,11 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     }
 
     /// <summary>
-    /// Projects the shape onto a vector.
+    /// Projects the <see cref="Shape2D"/> onto a vector.
     /// </summary>
-    /// <param name="shape">The shape to project.</param>
+    /// <param name="shape">The <see cref="Shape2D"/> to project.</param>
     /// <param name="projectionVector">The vector to project onto.</param>
-    /// <returns>The projection of the shape onto the vector.</returns>
+    /// <returns>The projection of the <see cref="Shape2D"/> onto the vector.</returns>
     public static Projection1D Project(Shape2D shape, Vector2D projectionVector)
     {
         float min = float.MaxValue;
@@ -161,44 +187,44 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
     }
 
     /// <summary>
-    /// Transforms the shape using the specified transform.
+    /// Transforms the <see cref="Shape2D"/> using the specified <see cref="ITransform2D"/>.
     /// </summary>
-    /// <param name="shape">The shape to transform.</param>
+    /// <param name="shape">The <see cref="Shape2D"/> to transform.</param>
-    /// <param name="transform">The transform to apply.</param>
+    /// <param name="transform">The <see cref="ITransform2D"/> to apply.</param>
-    /// <returns>The transformed shape.</returns>
+    /// <returns>The transformed <see cref="Shape2D"/>.</returns>
-    public static Shape2D TransformShape(Shape2D shape, ITransform2D transform)
+    public static Shape2D Transform(Shape2D shape, ITransform2D transform)
     {
         List<Vector2D> vertices = new(shape.Vertices.Count);
 
         int count = shape.Vertices.Count;
         for (int i = 0; i < count; i++)
-            vertices.Add(transform.TransformVector2D(shape[i]));
+            vertices.Add(transform.Transform(shape[i]));
 
         return new Shape2D(vertices);
     }
 
     /// <summary>
-    /// Transforms the shape using the specified transform.
+    /// Transforms the <see cref="Shape2D"/> using the specified <see cref="ITransform2D"/>.
     /// </summary>
-    /// <param name="from">The shape to transform.</param>
+    /// <param name="from">The <see cref="Shape2D"/> to transform.</param>
-    /// <param name="transform">The transform to apply.</param>
+    /// <param name="transform">The <see cref="ITransform2D"/> to apply.</param>
-    /// <param name="to">The transformed shape.</param>
+    /// <param name="to">The transformed <see cref="Shape2D"/>.</param>
-    public static void TransformShape(Shape2D from, ITransform2D transform, ref Shape2D to)
+    public static void Transform(Shape2D from, ITransform2D transform, ref Shape2D to)
     {
         to._verticesList.Clear();
 
         int count = from._verticesList.Count;
         for (int i = 0; i < count; i++)
-            to._verticesList.Add(transform.TransformVector2D(from[i]));
+            to._verticesList.Add(transform.Transform(from[i]));
     }
 
     /// <summary>
-    /// Determines whether two shapes are approximately equal.
+    /// Determines whether two <see cref="Shape2D"/>s are approximately equal.
     /// </summary>
-    /// <param name="left">The first shape to compare.</param>
+    /// <param name="left">The first <see cref="Shape2D"/> to compare.</param>
-    /// <param name="right">The second shape to compare.</param>
+    /// <param name="right">The second <see cref="Shape2D"/> to compare.</param>
     /// <param name="epsilon">The epsilon range.</param>
-    /// <returns><c>true</c> if the shapes are approximately equal; otherwise, <c>false</c>.</returns>
+    /// <returns><c>true</c> if the <see cref="Shape2D"/>s are approximately equal; otherwise, <c>false</c>.</returns>
     public static bool ApproximatelyEquals(Shape2D left, Shape2D right, float epsilon = float.Epsilon)
     {
         if (left.Vertices.Count != right.Vertices.Count)
@@ -229,6 +255,12 @@ public static class Shape2DExtensions
     /// <inheritdoc cref="Shape2D.GetSuperTriangle(Shape2D)" />
     public static Triangle ToSuperTriangle(this Shape2D shape) => Shape2D.GetSuperTriangle(shape);
 
+    /// <inheritdoc cref="Shape2D.TriangulateConvex(Shape2D, IList{Triangle})" />
+    public static void ToTrianglesConvex(this Shape2D shape, IList<Triangle> lines) => Shape2D.TriangulateConvex(shape, lines);
+
+    /// <inheritdoc cref="Shape2D.TriangulateConvex(Shape2D)" />
+    public static List<Triangle> ToTrianglesConvex(this Shape2D shape) => Shape2D.TriangulateConvex(shape);
+
     /// <inheritdoc cref="Shape2D.GetLines(Shape2D, IList{Line2D})" />
     public static void ToLines(this Shape2D shape, IList<Line2D> lines) => Shape2D.GetLines(shape, lines);
 
@@ -241,11 +273,17 @@ public static class Shape2DExtensions
     /// <inheritdoc cref="Shape2D.Project(Shape2D, Vector2D)" />
     public static Projection1D ToProjection(this Shape2D shape, Vector2D projectionVector) => Shape2D.Project(shape, projectionVector);
 
-    /// <inheritdoc cref="Shape2D.TransformShape(Shape2D, ITransform2D)" />
+    /// <inheritdoc cref="Shape2D.Transform(Shape2D, ITransform2D)" />
-    public static Shape2D TransformShape(this ITransform2D transform, Shape2D shape) => Shape2D.TransformShape(shape, transform);
+    public static Shape2D Transform(this ITransform2D transform, Shape2D shape) => Shape2D.Transform(shape, transform);
 
-    /// <inheritdoc cref="Shape2D.TransformShape(Shape2D, ITransform2D, Shape2D)" />
+    /// <inheritdoc cref="Shape2D.Transform(Shape2D, ITransform2D, Shape2D)" />
-    public static void TransformShape(this ITransform2D transform, Shape2D from, ref Shape2D to) => Shape2D.TransformShape(from, transform, ref to);
+    public static void Transform(this ITransform2D transform, Shape2D from, ref Shape2D to) => Shape2D.Transform(from, transform, ref to);
+
+    /// <inheritdoc cref="Shape2D.Transform(Shape2D, ITransform2D)" />
+    public static Shape2D Transform(this Shape2D shape, ITransform2D transform) => Shape2D.Transform(shape, transform);
+
+    /// <inheritdoc cref="Shape2D.Transform(Shape2D, ITransform2D, ref Shape2D)" />
+    public static void Transform(this Shape2D from, ITransform2D transform, ref Shape2D to) => Shape2D.Transform(from, transform, ref to);
 
     /// <inheritdoc cref="Shape2D.ApproximatelyEquals(Shape2D, Shape2D, float)" />
     public static bool ApproximatelyEquals(this Shape2D left, Shape2D right, float epsilon = float.Epsilon) => Shape2D.ApproximatelyEquals(left, right, epsilon);

Engine.Core/Primitives/Vector2D.cs

@@ -1,4 +1,5 @@
 using System;
+using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
 
@@ -278,6 +279,17 @@ public readonly struct Vector2D(float x, float y)
         return 0;
     }
 
+    /// <summary>
+    /// Transforms the <see cref="Vector2D"/> using the specified <see cref="ITransform2D"/>.
+    /// </summary>
+    /// <param name="vector">The <see cref="Vector2D"/> to transform.</param>
+    /// <param name="transform">The <see cref="ITransform2D"/> to apply.</param>
+    /// <returns>The transformed <see cref="Vector2D"/>.</returns>
+    public static Vector2D Transform(Vector2D vector, ITransform2D transform)
+        => vector.Scale(transform.Scale)
+                 .Rotate(transform.Rotation * Math.DegreeToRadian)
+                 .Add(transform.Position);
+
     /// <summary>
     /// Checks if two <see cref="Vector2D"/>s are approximately equal within a specified epsilon range.
     /// </summary>
@@ -379,6 +391,12 @@ public static class Vector2DExtensions
     /// <inheritdoc cref="Vector2D.Dot(Vector2D, Vector2D)" />
     public static float Dot(this Vector2D left, Vector2D right) => Vector2D.Dot(left, right);
 
+    /// <inheritdoc cref="Vector2D.Transform(Vector2D, ITransform2D)" />
+    public static Vector2D Transform(this Vector2D vector, ITransform2D transform) => Vector2D.Transform(vector, transform);
+
+    /// <inheritdoc cref="Vector2D.Transform(Vector2D, ITransform2D)" />
+    public static Vector2D Transform(this ITransform2D transform, Vector2D vector) => Vector2D.Transform(vector, transform);
+
     /// <inheritdoc cref="Vector2D.ApproximatelyEquals(Vector2D, Vector2D, float) " />
     public static bool ApproximatelyEquals(this Vector2D left, Vector2D right, float epsilon = float.Epsilon) => Vector2D.ApproximatelyEquals(left, right, epsilon);
 }

Engine.Core/StateEnable.cs

@@ -23,7 +23,7 @@ public class StateEnable : IStateEnable
 
             bool previousState = _enabled;
             _enabled = value;
-            OnEnabledChanged?.Invoke(this, previousState);
+            OnEnabledChanged?.InvokeSafe(this, previousState);
         }
     }
 
@@ -35,7 +35,7 @@ public class StateEnable : IStateEnable
 
         _entity = entity;
         OnAssign(entity);
-        OnEntityAssigned?.Invoke(this);
+        OnEntityAssigned?.InvokeSafe(this);
         return true;
     }
 
@@ -45,7 +45,7 @@ public class StateEnable : IStateEnable
             return false;
 
         _entity = null!;
-        OnUnassigned?.Invoke(this);
+        OnUnassigned?.InvokeSafe(this);
         return true;
     }
 }

Engine.Core/Static/Internal/Constants.cs

@@ -3,6 +3,5 @@ namespace Syntriax.Engine.Core;
 internal static class Constants
 {
     internal static int BEHAVIOURS_SIZE_INITIAL = 16;
-    internal static int GAME_OBJECTS_SIZE_INITIAL = 256;
+    internal static int UNIVERSE_OBJECTS_SIZE_INITIAL = 256;
-    internal static int DRAWABLE_OBJECTS_SIZE_INITIAL = 256;
 }

Engine.Core/Transform2D.cs

@@ -2,7 +2,7 @@ using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
 
-[System.Diagnostics.DebuggerDisplay("Name: {HierarchyObject.Name, nq} Position: {Position.ToString(), nq}, Scale: {Scale.ToString(), nq}, Rotation: {Rotation}")]
+[System.Diagnostics.DebuggerDisplay("Name: {UniverseObject.Name, nq} Position: {Position.ToString(), nq}, Scale: {Scale.ToString(), nq}, Rotation: {Rotation}")]
 public class Transform2D : Behaviour, ITransform2D
 {
     public event ITransform2D.PositionChangedEventHandler? OnPositionChanged = null;
@@ -31,7 +31,7 @@ public class Transform2D : Behaviour, ITransform2D
             _position = value;
 
             UpdateLocalPosition();
-            OnPositionChanged?.Invoke(this, _position);
+            OnPositionChanged?.InvokeSafe(this, _position);
         }
     }
 
@@ -47,7 +47,7 @@ public class Transform2D : Behaviour, ITransform2D
             _scale = value;
 
             UpdateLocalScale();
-            OnScaleChanged?.Invoke(this, previousScale);
+            OnScaleChanged?.InvokeSafe(this, previousScale);
         }
     }
 
@@ -63,7 +63,7 @@ public class Transform2D : Behaviour, ITransform2D
             _rotation = value;
 
             UpdateLocalRotation();
-            OnRotationChanged?.Invoke(this, previousRotation);
+            OnRotationChanged?.InvokeSafe(this, previousRotation);
         }
     }
 
@@ -79,7 +79,7 @@ public class Transform2D : Behaviour, ITransform2D
             _localPosition = value;
 
             UpdatePosition();
-            OnPositionChanged?.Invoke(this, previousPosition);
+            OnPositionChanged?.InvokeSafe(this, previousPosition);
         }
     }
 
@@ -92,10 +92,13 @@ public class Transform2D : Behaviour, ITransform2D
                 return;
 
             Vector2D previousScale = _scale;
+            Vector2D previousPosition = _position;
             _localScale = value;
 
             UpdateScale();
-            OnScaleChanged?.Invoke(this, previousScale);
+            UpdatePosition();
+            OnScaleChanged?.InvokeSafe(this, previousScale);
+            OnPositionChanged?.InvokeSafe(this, previousPosition);
         }
     }
 
@@ -111,7 +114,7 @@ public class Transform2D : Behaviour, ITransform2D
             _localRotation = value;
 
             UpdateRotation();
-            OnRotationChanged?.Invoke(this, previousRotation);
+            OnRotationChanged?.InvokeSafe(this, previousRotation);
         }
     }
 
@@ -120,13 +123,9 @@ public class Transform2D : Behaviour, ITransform2D
         if (parentTransform is null)
             return;
 
-        float previousRotation = Rotation;
-
         UpdatePosition();
-        UpdateRotation();
 
-        OnPositionChanged?.Invoke(this, previousPosition);
+        OnPositionChanged?.InvokeSafe(this, previousPosition);
-        OnRotationChanged?.Invoke(this, previousRotation);
     }
 
     private void RecalculateScale(ITransform2D _, Vector2D previousScale)
@@ -134,9 +133,13 @@ public class Transform2D : Behaviour, ITransform2D
         if (parentTransform is null)
             return;
 
-        UpdateScale();
+        Vector2D previousPosition = _position;
 
-        OnScaleChanged?.Invoke(this, previousScale);
+        UpdateScale();
+        UpdatePosition();
+
+        OnScaleChanged?.InvokeSafe(this, previousScale);
+        OnPositionChanged?.InvokeSafe(this, previousPosition);
     }
 
     private void RecalculateRotation(ITransform2D _, float previousRotation)
@@ -146,11 +149,11 @@ public class Transform2D : Behaviour, ITransform2D
 
         Vector2D previousPosition = Position;
 
-        UpdatePosition();
         UpdateRotation();
+        UpdatePosition();
 
-        OnPositionChanged?.Invoke(this, previousPosition);
+        OnRotationChanged?.InvokeSafe(this, previousRotation);
-        OnRotationChanged?.Invoke(this, previousRotation);
+        OnPositionChanged?.InvokeSafe(this, previousPosition);
     }
 
     private void UpdateLocalPosition()
@@ -203,53 +206,62 @@ public class Transform2D : Behaviour, ITransform2D
 
     protected override void InitializeInternal()
     {
-        UpdateParent(BehaviourController.HierarchyObject.Parent);
+        UpdateReferences(UniverseObject.Parent);
-        BehaviourController.HierarchyObject.OnParentChanged += OnParentChanged;
+        UniverseObject.OnParentChanged += OnParentChanged;
     }
 
     protected override void FinalizeInternal()
     {
-        BehaviourController.HierarchyObject.OnParentChanged -= OnParentChanged;
+        UniverseObject.OnParentChanged -= OnParentChanged;
     }
 
-    private void UpdateParent(IHierarchyObject? parent)
+    private void UpdateReferences(IUniverseObject? parent)
     {
         ITransform2D? previousParent = parentTransform;
         if (previousParent is not null)
         {
-            previousParent.BehaviourController.HierarchyObject.RemoveChild(HierarchyObject);
             previousParent.OnPositionChanged -= RecalculatePosition;
             previousParent.OnScaleChanged -= RecalculateScale;
             previousParent.OnRotationChanged -= RecalculateRotation;
-            previousParent.BehaviourController.HierarchyObject.OnParentChanged -= OnParentChanged;
+            previousParent.BehaviourController.UniverseObject.OnParentChanged -= OnParentChanged;
+            previousParent.BehaviourController.OnBehaviourAdded -= LookForTransform2D;
         }
 
         parentTransform = parent?.BehaviourController.GetBehaviour<ITransform2D>();
 
         if (parentTransform is not null)
         {
-            parentTransform.BehaviourController.HierarchyObject.AddChild(HierarchyObject);
             parentTransform.OnPositionChanged += RecalculatePosition;
             parentTransform.OnScaleChanged += RecalculateScale;
             parentTransform.OnRotationChanged += RecalculateRotation;
-            parentTransform.BehaviourController.HierarchyObject.OnParentChanged += OnParentChanged;
+            parentTransform.BehaviourController.UniverseObject.OnParentChanged += OnParentChanged;
 
             UpdatePosition();
             UpdateScale();
             UpdateRotation();
         }
+        else if (UniverseObject.Parent is not null)
+            UniverseObject.Parent.BehaviourController.OnBehaviourAdded += LookForTransform2D;
 
         UpdateLocalPosition();
         UpdateLocalScale();
         UpdateLocalRotation();
 
-        OnPositionChanged?.Invoke(this, Position);
+        OnPositionChanged?.InvokeSafe(this, Position);
-        OnScaleChanged?.Invoke(this, Scale);
+        OnScaleChanged?.InvokeSafe(this, Scale);
-        OnRotationChanged?.Invoke(this, Rotation);
+        OnRotationChanged?.InvokeSafe(this, Rotation);
     }
 
-    private void OnParentChanged(IHierarchyObject sender, IHierarchyObject? previousParent, IHierarchyObject? newParent)
+    private void LookForTransform2D(IBehaviourController sender, IBehaviour behaviourAdded)
     {
-        UpdateParent(newParent);
+        if (behaviourAdded is not ITransform2D transform2D)
+            return;
+
+        UpdateReferences(UniverseObject.Parent);
+    }
+
+    private void OnParentChanged(IUniverseObject sender, IUniverseObject? previousParent, IUniverseObject? newParent)
+    {
+        UpdateReferences(newParent);
     }
 }

Engine.Core/Universe.cs

@@ -0,0 +1,141 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+[System.Diagnostics.DebuggerDisplay("UniverseObject Count: {_universeObjects.Count}")]
+public class Universe : BaseEntity, IUniverse
+{
+    public event IUniverse.UpdateEventHandler? OnPreUpdate = null;
+    public event IUniverse.UpdateEventHandler? OnUpdate = null;
+    public event IUniverse.PreDrawEventHandler? OnPreDraw = null;
+
+    public event IUniverse.UniverseObjectRegisteredEventHandler? OnUniverseObjectRegistered = null;
+    public event IUniverse.UniverseObjectUnRegisteredEventHandler? OnUniverseObjectUnRegistered = null;
+
+    private readonly List<IUniverseObject> _universeObjects = new(Constants.UNIVERSE_OBJECTS_SIZE_INITIAL);
+    private float _timeScale = 1f;
+
+    public IReadOnlyList<IUniverseObject> UniverseObjects => _universeObjects;
+
+    public UniverseTime Time { get; private set; } = new();
+    public UniverseTime UnscaledTime { get; private set; } = new();
+    public float TimeScale
+    {
+        get => _timeScale;
+        set => _timeScale = value.Max(0f);
+    }
+
+    public void Register(IUniverseObject universeObject)
+    {
+        if (_universeObjects.Contains(universeObject))
+            throw new Exception($"{nameof(IUniverseObject)} named {universeObject.Name} is already registered to the {nameof(Universe)}.");
+
+        universeObject.OnFinalized += OnUniverseObjectFinalize;
+        universeObject.OnExitedUniverse += OnUniverseObjectExitedUniverse;
+
+        if (!universeObject.Initialize())
+            throw new Exception($"{universeObject.Name} can't be initialized");
+
+        for (int i = 0; i < universeObject.Children.Count; i++)
+            Register(universeObject.Children[i]);
+
+        _universeObjects.Add(universeObject);
+
+        if (!universeObject.EnterUniverse(this))
+            throw new Exception($"{universeObject.Name} can't enter the universe");
+
+        OnUniverseObjectRegistered?.InvokeSafe(this, universeObject);
+    }
+
+    public T InstantiateUniverseObject<T>(params object?[]? args) where T : class, IUniverseObject
+    {
+        T universeObject = Factory.UniverseObjectFactory.Instantiate<T>(args);
+        Register(universeObject);
+        return universeObject;
+    }
+
+    public void Remove(IUniverseObject universeObject)
+    {
+        universeObject.SetParent(null);
+        RemoveIncursive(universeObject);
+    }
+
+    private void RemoveIncursive(IUniverseObject universeObject)
+    {
+        if (!_universeObjects.Contains(universeObject))
+            throw new Exception($"{nameof(IUniverseObject)} named {universeObject.Name} is not registered to the {nameof(Universe)}.");
+
+        universeObject.OnFinalized -= OnUniverseObjectFinalize;
+        universeObject.OnExitedUniverse -= OnUniverseObjectExitedUniverse;
+
+        for (int i = universeObject.Children.Count - 1; i >= 0; i--)
+            Remove(universeObject.Children[i]);
+
+        _universeObjects.Remove(universeObject);
+
+        if (!universeObject.ExitUniverse())
+            throw new Exception($"{universeObject.Name} can't exit the universe");
+
+        if (!universeObject.Finalize())
+            throw new Exception($"{universeObject.Name} can't be finalized");
+
+        OnUniverseObjectUnRegistered?.InvokeSafe(this, universeObject);
+    }
+
+    protected override void InitializeInternal()
+    {
+        foreach (IUniverseObject universeObject in UniverseObjects)
+            universeObject.Initialize();
+    }
+
+    protected override void FinalizeInternal()
+    {
+        base.FinalizeInternal();
+        for (int i = UniverseObjects.Count; i >= 0; i--)
+            UniverseObjects[i].Finalize();
+    }
+
+    public void Update(UniverseTime engineTime)
+    {
+        Debug.AssertHelpers.AssertInitialized(this);
+
+        UnscaledTime = engineTime;
+        Time = new(TimeSpan.FromTicks((long)(Time.TimeSinceStart.Ticks + engineTime.DeltaSpan.Ticks * TimeScale)), TimeSpan.FromTicks((long)(engineTime.DeltaSpan.Ticks * TimeScale)));
+
+        OnPreUpdate?.InvokeSafe(this, Time);
+
+        for (int i = 0; i < UniverseObjects.Count; i++)
+            UniverseObjects[i].BehaviourController.Update();
+
+        OnUpdate?.InvokeSafe(this, Time);
+    }
+
+    public void PreDraw()
+    {
+        Debug.AssertHelpers.AssertInitialized(this);
+
+        for (int i = 0; i < UniverseObjects.Count; i++)
+            UniverseObjects[i].BehaviourController.UpdatePreDraw();
+
+        OnPreDraw?.InvokeSafe(this);
+    }
+
+    private void OnUniverseObjectFinalize(IInitializable initializable)
+    {
+        if (initializable is IUniverseObject universeObject)
+            Remove(universeObject);
+    }
+
+    private void OnUniverseObjectExitedUniverse(IUniverseObject sender, IUniverse universe)
+    {
+        if (sender is IUniverseObject universeObject)
+            Remove(universeObject);
+    }
+
+    public IEnumerator<IUniverseObject> GetEnumerator() => _universeObjects.GetEnumerator();
+    IEnumerator IEnumerable.GetEnumerator() => _universeObjects.GetEnumerator();
+}

Engine.Core/UniverseObject.cs

@@ -6,28 +6,28 @@ using Syntriax.Engine.Core.Abstract;
 namespace Syntriax.Engine.Core;
 
 [System.Diagnostics.DebuggerDisplay("Name: {Name}, Initialized: {Initialized}")]
-public class HierarchyObject : BaseEntity, IHierarchyObject
+public class UniverseObject : BaseEntity, IUniverseObject
 {
-    public event IHierarchyObject.EnteredHierarchyEventHandler? OnEnteredHierarchy = null;
+    public event IUniverseObject.EnteredUniverseEventHandler? OnEnteredUniverse = null;
-    public event IHierarchyObject.ExitedHierarchyEventHandler? OnExitedHierarchy = null;
+    public event IUniverseObject.ExitedUniverseEventHandler? OnExitedUniverse = null;
-    public event IHierarchyObject.ParentChangedEventHandler? OnParentChanged = null;
+    public event IUniverseObject.ParentChangedEventHandler? OnParentChanged = null;
-    public event IHierarchyObject.ChildrenAddedEventHandler? OnChildrenAdded = null;
+    public event IUniverseObject.ChildrenAddedEventHandler? OnChildrenAdded = null;
-    public event IHierarchyObject.ChildrenRemovedEventHandler? OnChildrenRemoved = null;
+    public event IUniverseObject.ChildrenRemovedEventHandler? OnChildrenRemoved = null;
     public event IHasBehaviourController.BehaviourControllerAssignedEventHandler? OnBehaviourControllerAssigned = null;
     public event INameable.NameChangedEventHandler? OnNameChanged = null;
     public event IActive.ActiveChangedEventHandler? OnActiveChanged = null;
 
-    private string _name = nameof(HierarchyObject);
+    private string _name = nameof(UniverseObject);
-    private IGameManager _gameManager = null!;
+    private IUniverse _universe = null!;
     private IBehaviourController _behaviourController = null!;
     private bool _isActive = false;
-    private readonly List<IHierarchyObject> _children = [];
+    private readonly List<IUniverseObject> _children = [];
 
-    public IHierarchyObject? Parent { get; private set; } = null;
+    public IUniverseObject? Parent { get; private set; } = null;
-    public IReadOnlyList<IHierarchyObject> Children => _children;
+    public IReadOnlyList<IUniverseObject> Children => _children;
     public IBehaviourController BehaviourController => _behaviourController;
-    public IGameManager GameManager => _gameManager;
+    public IUniverse Universe => _universe;
-    public bool IsInHierarchy => _gameManager is not null;
+    public bool IsInUniverse => _universe is not null;
     public bool IsActive => _isActive;
 
     public string Name
@@ -39,41 +39,44 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
 
             string previousName = _name;
             _name = value;
-            OnNameChanged?.Invoke(this, previousName);
+            OnNameChanged?.InvokeSafe(this, previousName);
         }
     }
 
-    protected virtual void OnEnteringHierarchy(IGameManager gameManager) { }
+    protected virtual void OnEnteringUniverse(IUniverse universe) { }
-    bool IHierarchyObject.EnterHierarchy(IGameManager gameManager)
+    bool IUniverseObject.EnterUniverse(IUniverse universe)
     {
-        if (IsInHierarchy)
+        if (IsInUniverse)
             return false;
 
-        _gameManager = gameManager;
+        _universe = universe;
         UpdateActive();
-        OnEnteringHierarchy(gameManager);
+        OnEnteringUniverse(universe);
-        OnEnteredHierarchy?.Invoke(this, gameManager);
+        OnEnteredUniverse?.InvokeSafe(this, universe);
         return true;
     }
 
-    protected virtual void OnExitingHierarchy(IGameManager gameManager) { }
+    protected virtual void OnExitingUniverse(IUniverse universe) { }
-    bool IHierarchyObject.ExitHierarchy()
+    bool IUniverseObject.ExitUniverse()
     {
-        if (!IsInHierarchy || _gameManager is not IGameManager gameManager)
+        if (!IsInUniverse || _universe is not IUniverse universe)
             return false;
 
-        _gameManager = null!;
+        OnExitingUniverse(universe);
-        OnExitingHierarchy(gameManager);
+        _universe = null!;
-        OnExitedHierarchy?.Invoke(this, gameManager);
+        OnExitedUniverse?.InvokeSafe(this, universe);
         return true;
     }
 
-    public void SetParent(IHierarchyObject? parent)
+    public void SetParent(IUniverseObject? parent)
     {
-        if (parent == this || Parent == parent)
+        if (parent == this)
+            throw new Exceptions.AssignFailedException($"{Name} can not parent itself");
+
+        if (Parent == parent)
             return;
 
-        IHierarchyObject? previousParent = Parent;
+        IUniverseObject? previousParent = Parent;
         if (previousParent is not null)
         {
             previousParent.RemoveChild(this);
@@ -84,31 +87,34 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
 
         if (parent is not null)
         {
+            if (parent.IsInUniverse && !IsInUniverse)
+                parent.Universe.Register(this);
+
             parent.AddChild(this);
             parent.OnActiveChanged += OnParentActiveChanged;
         }
 
         UpdateActive();
-        OnParentChanged?.Invoke(this, previousParent, parent);
+        OnParentChanged?.InvokeSafe(this, previousParent, parent);
     }
 
-    public void AddChild(IHierarchyObject parent)
+    public void AddChild(IUniverseObject parent)
     {
         if (_children.Contains(parent))
             return;
 
         _children.Add(parent);
         parent.SetParent(this);
-        OnChildrenAdded?.Invoke(this, parent);
+        OnChildrenAdded?.InvokeSafe(this, parent);
     }
 
-    public void RemoveChild(IHierarchyObject parent)
+    public void RemoveChild(IUniverseObject child)
     {
-        if (!_children.Remove(parent))
+        if (!_children.Remove(child))
             return;
 
-        parent.SetParent(null);
+        child.SetParent(null);
-        OnChildrenRemoved?.Invoke(this, parent);
+        OnChildrenRemoved?.InvokeSafe(this, child);
     }
 
     protected virtual void OnAssign(IBehaviourController behaviourController) { }
@@ -119,7 +125,7 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
 
         _behaviourController = behaviourController;
         OnAssign(behaviourController);
-        OnBehaviourControllerAssigned?.Invoke(this);
+        OnBehaviourControllerAssigned?.InvokeSafe(this);
         return true;
     }
 
@@ -139,7 +145,7 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
         _isActive = StateEnable.Enabled && (Parent?.IsActive ?? true);
 
         if (previousActive != IsActive)
-            OnActiveChanged?.Invoke(this, previousActive);
+            OnActiveChanged?.InvokeSafe(this, previousActive);
     }
 
     protected override void UnassignInternal()
@@ -154,6 +160,11 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
         _behaviourController ??= Factory.BehaviourControllerFactory.Instantiate(this);
     }
 
-    public IEnumerator<IHierarchyObject> GetEnumerator() => _children.GetEnumerator();
+    public UniverseObject()
+    {
+        _name = GetType().Name;
+    }
+
+    public IEnumerator<IUniverseObject> GetEnumerator() => _children.GetEnumerator();
     IEnumerator IEnumerable.GetEnumerator() => _children.GetEnumerator();
 }

Engine.Core/UniverseTime.cs

@@ -2,7 +2,7 @@ using System;
 
 namespace Syntriax.Engine.Core;
 
-public readonly struct EngineTime(TimeSpan TimeSinceStart, TimeSpan TimeDelta)
+public readonly struct UniverseTime(TimeSpan TimeSinceStart, TimeSpan TimeDelta)
 {
     public readonly TimeSpan TimeSinceStart = TimeSinceStart;
     public readonly TimeSpan DeltaSpan = TimeDelta;

Engine.Physics2D/Collider2DBehaviourBase.cs

@@ -10,7 +10,7 @@ public abstract class Collider2DBehaviourBase : Behaviour2D, ICollider2D
     public event ICollider2D.CollisionResolvedEventHandler? OnCollisionResolved = null;
     public event ICollider2D.TriggeredEventHandler? OnTriggered = null;
 
-    protected bool NeedsRecalculation { get; private set; } = true;
+    protected bool NeedsRecalculation { get; set; } = true;
     protected IRigidBody2D? _rigidBody2D = null;
 
     public IRigidBody2D? RigidBody2D => _rigidBody2D;
@@ -37,10 +37,10 @@ public abstract class Collider2DBehaviourBase : Behaviour2D, ICollider2D
         Transform.OnPositionChanged += SetNeedsRecalculationFromPosition;
         Transform.OnRotationChanged += SetNeedsRecalculationFromRotation;
         Transform.OnScaleChanged += SetNeedsRecalculationFromScale;
-        HierarchyObject.OnParentChanged += UpdateRigidBody2D;
+        UniverseObject.OnParentChanged += UpdateRigidBody2D;
     }
 
-    private void UpdateRigidBody2D(IHierarchyObject sender, IHierarchyObject? previousParent, IHierarchyObject? newParent)
+    private void UpdateRigidBody2D(IUniverseObject sender, IUniverseObject? previousParent, IUniverseObject? newParent)
     {
         BehaviourController.TryGetBehaviourInParent(out _rigidBody2D);
     }
@@ -71,7 +71,7 @@ public abstract class Collider2DBehaviourBase : Behaviour2D, ICollider2D
         Transform.OnRotationChanged -= SetNeedsRecalculationFromRotation;
     }
 
-    public void Detect(CollisionDetectionInformation collisionDetectionInformation) => OnCollisionDetected?.Invoke(this, collisionDetectionInformation);
+    public void Detect(CollisionDetectionInformation collisionDetectionInformation) => OnCollisionDetected?.InvokeSafe(this, collisionDetectionInformation);
-    public void Resolve(CollisionDetectionInformation collisionDetectionInformation) => OnCollisionResolved?.Invoke(this, collisionDetectionInformation);
+    public void Resolve(CollisionDetectionInformation collisionDetectionInformation) => OnCollisionResolved?.InvokeSafe(this, collisionDetectionInformation);
-    public void Trigger(ICollider2D initiator) => OnTriggered?.Invoke(this, initiator);
+    public void Trigger(ICollider2D initiator) => OnTriggered?.InvokeSafe(this, initiator);
 }

Engine.Physics2D/Collider2DCircleBehaviour.cs

@@ -5,10 +5,20 @@ namespace Syntriax.Engine.Physics2D;
 
 public class Collider2DCircleBehaviour : Collider2DBehaviourBase, ICircleCollider2D
 {
-    public Circle CircleWorld { get; protected set; } = Circle.UnitCircle;
+    private Circle _circleLocal = Circle.UnitCircle;
-    public Circle CircleLocal { get; set; } = Circle.UnitCircle;
 
-    public override void CalculateCollider() => CircleWorld = Transform.TransformCircle(CircleLocal);
+    public Circle CircleWorld { get; protected set; } = Circle.UnitCircle;
+    public Circle CircleLocal
+    {
+        get => _circleLocal;
+        set
+        {
+            _circleLocal = value;
+            NeedsRecalculation = true;
+        }
+    }
+
+    public override void CalculateCollider() => CircleWorld = Transform.Transform(_circleLocal);
 
     public Collider2DCircleBehaviour() { }
     public Collider2DCircleBehaviour(Circle circle) => CircleLocal = circle;

Engine.Physics2D/Collider2DShapeBehaviour.cs

@@ -6,12 +6,24 @@ namespace Syntriax.Engine.Physics2D;
 public class Collider2DShapeBehaviour : Collider2DBehaviourBase, IShapeCollider2D
 {
     public Shape2D ShapeWorld { get => _shapeWorld; protected set => _shapeWorld = value; }
-    public Shape2D ShapeLocal { get; set; } = Shape2D.Box;
+    public Shape2D ShapeLocal
+    {
+        get => _shapeLocal;
+        set
+        {
+            _shapeLocal = value;
+            NeedsRecalculation = true;
+        }
+    }
 
-    private Shape2D _shapeWorld = Shape2D.Box.CreateCopy();
+    private Shape2D _shapeWorld = Shape2D.Square.CreateCopy();
+    private Shape2D _shapeLocal = Shape2D.Square;
 
-    public override void CalculateCollider() => Transform.TransformShape(ShapeLocal, ref _shapeWorld);
+    public override void CalculateCollider() => Transform.Transform(ShapeLocal, ref _shapeWorld);
 
     public Collider2DShapeBehaviour() { }
-    public Collider2DShapeBehaviour(Shape2D shape) => ShapeLocal = shape;
+    public Collider2DShapeBehaviour(Shape2D shape)
+    {
+        ShapeLocal = shape;
+    }
 }

Engine.Physics2D/PhysicsCoroutineManager.cs

@@ -7,7 +7,7 @@ using Syntriax.Engine.Physics2D.Abstract;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class PhysicsCoroutineManager : HierarchyObject
+public class PhysicsCoroutineManager : UniverseObject
 {
     private readonly List<IEnumerator> enumerators = [];
     private IPhysicsEngine2D? physicsEngine = null;
@@ -23,13 +23,13 @@ public class PhysicsCoroutineManager : HierarchyObject
         enumerators.Remove(enumerator);
     }
 
-    protected override void OnEnteringHierarchy(IGameManager gameManager)
+    protected override void OnEnteringUniverse(IUniverse universe)
     {
-        physicsEngine = gameManager.FindHierarchyObject<IPhysicsEngine2D>();
+        physicsEngine = universe.GetUniverseObject<IPhysicsEngine2D>();
         if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
             foundPhysicsEngine.OnPhysicsStep += OnPhysicsStep;
         else
-            gameManager.OnUpdate += OnUpdate;
+            universe.OnUpdate += OnUpdate;
     }
 
     private void OnPhysicsStep(IPhysicsEngine2D sender, float stepDeltaTime)
@@ -44,23 +44,23 @@ public class PhysicsCoroutineManager : HierarchyObject
         }
     }
 
-    protected override void OnExitingHierarchy(IGameManager gameManager)
+    protected override void OnExitingUniverse(IUniverse universe)
     {
         if (physicsEngine is IPhysicsEngine2D existingPhysicsEngine)
             existingPhysicsEngine.OnPhysicsStep -= OnPhysicsStep;
-        gameManager.OnUpdate -= OnUpdate;
+        universe.OnUpdate -= OnUpdate;
     }
 
-    private void OnUpdate(IGameManager sender, EngineTime engineTime)
+    private void OnUpdate(IUniverse sender, UniverseTime engineTime)
     {
-        if (GameManager is not IGameManager gameManager)
+        if (Universe is not IUniverse universe)
             return;
 
-        physicsEngine = gameManager.FindHierarchyObject<IPhysicsEngine2D>();
+        physicsEngine = universe.GetUniverseObject<IPhysicsEngine2D>();
         if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
         {
             foundPhysicsEngine.OnPhysicsStep += OnPhysicsStep;
-            gameManager.OnUpdate -= OnUpdate;
+            universe.OnUpdate -= OnUpdate;
         }
     }
 }

Engine.Physics2D/PhysicsEngine2D.cs

@@ -1,43 +1,27 @@
-using System.Collections.Generic;
+using Syntriax.Engine.Core;
-
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Physics2D.Abstract;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class PhysicsEngine2D : IPhysicsEngine2D
+public class PhysicsEngine2D : UniverseObject, IPhysicsEngine2D
 {
     public event IPhysicsEngine2D.PhysicsIterationEventHandler? OnPhysicsIteration = null;
     public event IPhysicsEngine2D.PhysicsStepEventHandler? OnPhysicsStep = null;
 
-    private readonly List<IRigidBody2D> rigidBodies = new(32);
+    private float physicsTicker = 0f;
-    private readonly List<ICollider2D> colliders = new(64);
+    private int _iterationPerStep = 1;
+    private float _iterationPeriod = 1f / 60f;
 
-    private int _iterationCount = 1;
+    protected readonly ICollisionDetector2D collisionDetector = null!;
+    protected readonly ICollisionResolver2D collisionResolver = null!;
 
-    private readonly ICollisionDetector2D collisionDetector = null!;
+    protected BehaviourCollector<IRigidBody2D> rigidBodyCollector = new();
-    private readonly ICollisionResolver2D collisionResolver = null!;
+    protected BehaviourCollector<ICollider2D> colliderCollector = new();
+    protected BehaviourCollector<IPhysicsUpdate> physicsUpdateCollector = new();
 
-    public int IterationPerStep { get => _iterationCount; set => _iterationCount = value < 1 ? 1 : value; }
+    public int IterationPerStep { get => _iterationPerStep; set => _iterationPerStep = value < 1 ? 1 : value; }
-
+    public float IterationPeriod { get => _iterationPeriod; set => _iterationPeriod = value.Max(0.0001f); }
-    public void AddRigidBody(IRigidBody2D rigidBody)
-    {
-        if (rigidBodies.Contains(rigidBody))
-            return;
-
-        rigidBodies.Add(rigidBody);
-
-        foreach (ICollider2D collider2D in rigidBody.BehaviourController.GetBehaviours<ICollider2D>())
-            colliders.Add(collider2D);
-
-        rigidBody.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
-        rigidBody.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
-    }
-
-    public void RemoveRigidBody(IRigidBody2D rigidBody)
-    {
-        rigidBodies.Remove(rigidBody);
-    }
 
     public void Step(float deltaTime)
     {
@@ -46,23 +30,23 @@ public class PhysicsEngine2D : IPhysicsEngine2D
         for (int iterationIndex = 0; iterationIndex < IterationPerStep; iterationIndex++)
         {
             // Can Parallel
-            for (int i = 0; i < rigidBodies.Count; i++)
+            foreach (IRigidBody2D rigidBody in rigidBodyCollector)
-                StepRigidBody(rigidBodies[i], intervalDeltaTime);
+                StepRigidBody(rigidBody, intervalDeltaTime);
 
             // Can Parallel
-            foreach (ICollider2D collider in colliders)
+            foreach (ICollider2D collider in colliderCollector)
                 collider.Recalculate();
 
             // Can Parallel
-            for (int x = 0; x < colliders.Count; x++)
+            for (int x = 0; x < colliderCollector.Behaviours.Count; x++)
             {
-                ICollider2D? colliderX = colliders[x];
+                ICollider2D? colliderX = colliderCollector.Behaviours[x];
                 if (!colliderX.IsActive)
                     return;
 
-                for (int y = x + 1; y < colliders.Count; y++)
+                for (int y = x + 1; y < colliderCollector.Behaviours.Count; y++)
                 {
-                    ICollider2D? colliderY = colliders[y];
+                    ICollider2D? colliderY = colliderCollector.Behaviours[y];
 
                     if (!colliderY.IsActive)
                         return;
@@ -87,7 +71,7 @@ public class PhysicsEngine2D : IPhysicsEngine2D
                         }
                         else if (colliderY.IsTrigger)
                         {
-                            colliderY.Trigger(colliderY);
+                            colliderY.Trigger(colliderX);
                             continue;
                         }
 
@@ -106,9 +90,14 @@ public class PhysicsEngine2D : IPhysicsEngine2D
                     }
                 }
             }
-            OnPhysicsIteration?.Invoke(this, intervalDeltaTime);
+
+            OnPhysicsIteration?.InvokeSafe(this, intervalDeltaTime);
         }
-        OnPhysicsStep?.Invoke(this, deltaTime);
+
+        foreach (IPhysicsUpdate physicsUpdate in physicsUpdateCollector)
+            physicsUpdate.PhysicsUpdate(deltaTime);
+
+        OnPhysicsStep?.InvokeSafe(this, deltaTime);
     }
 
     private static void StepRigidBody(IRigidBody2D rigidBody, float intervalDeltaTime)
@@ -120,20 +109,33 @@ public class PhysicsEngine2D : IPhysicsEngine2D
         rigidBody.Transform.Rotation += rigidBody.AngularVelocity * intervalDeltaTime;
     }
 
-    private void OnBehaviourAdded(IBehaviourController controller, IBehaviour behaviour)
+    protected override void OnEnteringUniverse(IUniverse universe)
     {
-        if (behaviour is not ICollider2D collider2D)
+        physicsUpdateCollector.Assign(universe);
-            return;
+        colliderCollector.Assign(universe);
+        rigidBodyCollector.Assign(universe);
 
-        colliders.Add(collider2D);
+        universe.OnPreUpdate += OnEnginePreUpdate;
     }
 
-    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviour behaviour)
+    protected override void OnExitingUniverse(IUniverse universe)
     {
-        if (behaviour is not ICollider2D collider2D)
+        physicsUpdateCollector.Unassign();
-            return;
+        colliderCollector.Unassign();
+        rigidBodyCollector.Unassign();
 
-        colliders.Remove(collider2D);
+        universe.OnPreUpdate -= OnEnginePreUpdate;
+    }
+
+    private void OnEnginePreUpdate(IUniverse sender, UniverseTime engineTime)
+    {
+        physicsTicker += engineTime.DeltaTime;
+
+        while (physicsTicker >= IterationPeriod)
+        {
+            physicsTicker -= IterationPeriod;
+            Step(IterationPeriod);
+        }
     }
 
     public PhysicsEngine2D()

Engine.Physics2D/PhysicsEngine2DStandalone.cs

@@ -1,24 +1,44 @@
+using System.Collections.Generic;
+
 using Syntriax.Engine.Core;
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Physics2D.Abstract;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class PhysicsEngine2DCollector : HierarchyObject, IPhysicsEngine2D
+public class PhysicsEngine2DStandalone : IPhysicsEngine2D
 {
     public event IPhysicsEngine2D.PhysicsIterationEventHandler? OnPhysicsIteration = null;
     public event IPhysicsEngine2D.PhysicsStepEventHandler? OnPhysicsStep = null;
 
-    private int _iterationPerStep = 1;
+    private readonly List<IRigidBody2D> rigidBodies = new(32);
+    private readonly List<ICollider2D> colliders = new(64);
 
-    protected readonly ICollisionDetector2D collisionDetector = null!;
+    private int _iterationCount = 1;
-    protected readonly ICollisionResolver2D collisionResolver = null!;
 
-    protected BehaviourCollector<IRigidBody2D> rigidBodyCollector = new();
+    private readonly ICollisionDetector2D collisionDetector = null!;
-    protected BehaviourCollector<ICollider2D> colliderCollector = new();
+    private readonly ICollisionResolver2D collisionResolver = null!;
-    protected BehaviourCollector<IPhysicsUpdate> physicsUpdateCollector = new();
 
-    public int IterationPerStep { get => _iterationPerStep; set => _iterationPerStep = value < 1 ? 1 : value; }
+    public int IterationPerStep { get => _iterationCount; set => _iterationCount = value < 1 ? 1 : value; }
+
+    public void AddRigidBody(IRigidBody2D rigidBody)
+    {
+        if (rigidBodies.Contains(rigidBody))
+            return;
+
+        rigidBodies.Add(rigidBody);
+
+        foreach (ICollider2D collider2D in rigidBody.BehaviourController.GetBehaviours<ICollider2D>())
+            colliders.Add(collider2D);
+
+        rigidBody.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
+        rigidBody.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
+    }
+
+    public void RemoveRigidBody(IRigidBody2D rigidBody)
+    {
+        rigidBodies.Remove(rigidBody);
+    }
 
     public void Step(float deltaTime)
     {
@@ -27,23 +47,23 @@ public class PhysicsEngine2DCollector : HierarchyObject, IPhysicsEngine2D
         for (int iterationIndex = 0; iterationIndex < IterationPerStep; iterationIndex++)
         {
             // Can Parallel
-            foreach (IRigidBody2D rigidBody in rigidBodyCollector)
+            for (int i = 0; i < rigidBodies.Count; i++)
-                StepRigidBody(rigidBody, intervalDeltaTime);
+                StepRigidBody(rigidBodies[i], intervalDeltaTime);
 
             // Can Parallel
-            foreach (ICollider2D collider in colliderCollector)
+            foreach (ICollider2D collider in colliders)
                 collider.Recalculate();
 
             // Can Parallel
-            for (int x = 0; x < colliderCollector.Behaviours.Count; x++)
+            for (int x = 0; x < colliders.Count; x++)
             {
-                ICollider2D? colliderX = colliderCollector.Behaviours[x];
+                ICollider2D? colliderX = colliders[x];
                 if (!colliderX.IsActive)
                     return;
 
-                for (int y = x + 1; y < colliderCollector.Behaviours.Count; y++)
+                for (int y = x + 1; y < colliders.Count; y++)
                 {
-                    ICollider2D? colliderY = colliderCollector.Behaviours[y];
+                    ICollider2D? colliderY = colliders[y];
 
                     if (!colliderY.IsActive)
                         return;
@@ -68,7 +88,7 @@ public class PhysicsEngine2DCollector : HierarchyObject, IPhysicsEngine2D
                         }
                         else if (colliderY.IsTrigger)
                         {
-                            colliderY.Trigger(colliderY);
+                            colliderY.Trigger(colliderX);
                             continue;
                         }
 
@@ -87,14 +107,9 @@ public class PhysicsEngine2DCollector : HierarchyObject, IPhysicsEngine2D
                     }
                 }
             }
-
+            OnPhysicsIteration?.InvokeSafe(this, intervalDeltaTime);
-            OnPhysicsIteration?.Invoke(this, intervalDeltaTime);
         }
-
+        OnPhysicsStep?.InvokeSafe(this, deltaTime);
-        foreach (IPhysicsUpdate physicsUpdate in physicsUpdateCollector)
-            physicsUpdate.PhysicsUpdate(deltaTime);
-
-        OnPhysicsStep?.Invoke(this, deltaTime);
     }
 
     private static void StepRigidBody(IRigidBody2D rigidBody, float intervalDeltaTime)
@@ -105,27 +120,30 @@ public class PhysicsEngine2DCollector : HierarchyObject, IPhysicsEngine2D
         rigidBody.Transform.Position += rigidBody.Velocity * intervalDeltaTime;
         rigidBody.Transform.Rotation += rigidBody.AngularVelocity * intervalDeltaTime;
     }
-    protected override void OnEnteringHierarchy(IGameManager gameManager)
+
+    private void OnBehaviourAdded(IBehaviourController controller, IBehaviour behaviour)
     {
-        physicsUpdateCollector.Assign(gameManager);
+        if (behaviour is not ICollider2D collider2D)
-        colliderCollector.Assign(gameManager);
+            return;
-        rigidBodyCollector.Assign(gameManager);
+
+        colliders.Add(collider2D);
     }
 
-    protected override void OnExitingHierarchy(IGameManager gameManager)
+    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviour behaviour)
     {
-        physicsUpdateCollector.Unassign();
+        if (behaviour is not ICollider2D collider2D)
-        colliderCollector.Unassign();
+            return;
-        rigidBodyCollector.Unassign();
+
+        colliders.Remove(collider2D);
     }
 
-    public PhysicsEngine2DCollector()
+    public PhysicsEngine2DStandalone()
     {
         collisionDetector = new CollisionDetector2D();
         collisionResolver = new CollisionResolver2D();
     }
 
-    public PhysicsEngine2DCollector(ICollisionDetector2D collisionDetector, ICollisionResolver2D collisionResolver)
+    public PhysicsEngine2DStandalone(ICollisionDetector2D collisionDetector, ICollisionResolver2D collisionResolver)
     {
         this.collisionDetector = collisionDetector;
         this.collisionResolver = collisionResolver;

Engine.Systems/StateMachine/State.cs

@@ -1,3 +1,5 @@
+using Syntriax.Engine.Core;
+
 namespace Syntriax.Engine.StateMachine;
 
 public class State : IState
@@ -35,12 +37,12 @@ public class State : IState
     public void Update()
     {
         if (GetNextState() is IState transitionState)
-            OnStateTransitionReady?.Invoke(this, transitionState);
+            OnStateTransitionReady?.InvokeSafe(this, transitionState);
-        OnStateUpdate?.Invoke(this);
+        OnStateUpdate?.InvokeSafe(this);
     }
 
-    public void TransitionTo(IState from) => OnStateTransitionedTo?.Invoke(this, from);
+    public void TransitionTo(IState from) => OnStateTransitionedTo?.InvokeSafe(this, from);
-    public void TransitionFrom(IState to) => OnStateTransitionedFrom?.Invoke(this, to);
+    public void TransitionFrom(IState to) => OnStateTransitionedFrom?.InvokeSafe(this, to);
 
     public IState? GetNextState()
     {

Engine.Systems/StateMachine/StateBehaviourBase.cs

@@ -16,21 +16,21 @@ public abstract class StateBehaviourBase : Behaviour, IState
     public void Update()
     {
         OnUpdateState();
-        OnStateUpdate?.Invoke(this);
+        OnStateUpdate?.InvokeSafe(this);
     }
 
     protected virtual void OnTransitionedToState(IState from) { }
     public void TransitionTo(IState from)
     {
         OnTransitionedToState(from);
-        OnStateTransitionedTo?.Invoke(this, from);
+        OnStateTransitionedTo?.InvokeSafe(this, from);
     }
 
     protected virtual void OnTransitionedFromState(IState to) { }
     public void TransitionFrom(IState to)
     {
         OnTransitionedFromState(to);
-        OnStateTransitionedFrom?.Invoke(this, to);
+        OnStateTransitionedFrom?.InvokeSafe(this, to);
     }
 
     public abstract IState? GetNextState();

Engine.Systems/StateMachine/StateMachine.cs

@@ -21,7 +21,7 @@ public class StateMachine : Behaviour
             _state = value;
             previousState.TransitionFrom(value);
             value.TransitionTo(_state);
-            OnStateChanged?.Invoke(this, previousState, value);
+            OnStateChanged?.InvokeSafe(this, previousState, value);
 
             value.OnStateTransitionReady += OnStateTransitionReady;
         }

Engine.Systems/Time/IStopwatch.cs

@@ -2,9 +2,9 @@ namespace Syntriax.Engine.Systems.Time;
 
 public interface IStopwatch : IReadOnlyStopwatch
 {
-    void StopwatchStart();
+    void Start();
-    void StopwatchStop();
+    void Stop();
 
-    void StopwatchPause();
+    void Pause();
-    void StopwatchResume();
+    void Resume();
 }

Engine.Systems/Time/ITicker.cs

@@ -5,7 +5,7 @@ public interface ITicker : IStopwatch
     event TickerTickEventHandler? OnTick;
 
     int TickCounter { get; }
-    double TickPeriod { get; set; }
+    double Period { get; set; }
 
     delegate void TickerTickEventHandler(ITicker sender);
 }

Engine.Systems/Time/ITimer.cs

@@ -2,9 +2,9 @@ namespace Syntriax.Engine.Systems.Time;
 
 public interface ITimer : IReadOnlyTimer
 {
-    void TimerStart(double time);
+    void Start(double time);
-    void TimerStop();
+    void Stop();
 
-    void TimerPause();
+    void Pause();
-    void TimerResume();
+    void Resume();
 }

Engine.Systems/Time/StopwatchBehaviour.cs

@@ -17,7 +17,7 @@ public class StopwatchBehaviour : Behaviour, IStopwatch
     private bool shouldBeTicking = false;
     private bool hasStartedTickingBefore = false;
 
-    public virtual void StopwatchStart()
+    public virtual void Start()
     {
         Time = 0f;
 
@@ -28,7 +28,7 @@ public class StopwatchBehaviour : Behaviour, IStopwatch
             StartStopwatch();
     }
 
-    public virtual void StopwatchStop()
+    public virtual void Stop()
     {
         if (!shouldBeTicking)
             return;
@@ -36,7 +36,7 @@ public class StopwatchBehaviour : Behaviour, IStopwatch
         shouldBeTicking = false;
 
         State = TimerState.Stopped;
-        OnStopped?.Invoke(this);
+        OnStopped?.InvokeSafe(this);
     }
 
     protected override void OnUpdate()
@@ -44,41 +44,41 @@ public class StopwatchBehaviour : Behaviour, IStopwatch
         if (State is not TimerState.Ticking)
             return;
 
-        double delta = GameManager.Time.DeltaSpan.TotalSeconds;
+        double delta = Universe.Time.DeltaSpan.TotalSeconds;
 
         Time += delta;
-        OnDelta?.Invoke(this, delta);
+        OnDelta?.InvokeSafe(this, delta);
     }
 
-    protected override void OnEnteredHierarchy(IGameManager gameManager)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
         if (!shouldBeTicking || State is TimerState.Ticking)
             return;
 
         if (hasStartedTickingBefore)
-            StopwatchResume();
+            Resume();
         else
             StartStopwatch();
     }
 
-    protected override void OnExitedHierarchy(IGameManager gameManager)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         if (!shouldBeTicking || State is not TimerState.Ticking)
             return;
 
-        StopwatchPause();
+        Pause();
     }
 
-    public virtual void StopwatchPause()
+    public virtual void Pause()
     {
         State = TimerState.Paused;
-        OnPaused?.Invoke(this);
+        OnPaused?.InvokeSafe(this);
     }
 
-    public virtual void StopwatchResume()
+    public virtual void Resume()
     {
         State = TimerState.Ticking;
-        OnResumed?.Invoke(this);
+        OnResumed?.InvokeSafe(this);
     }
 
     private void StartStopwatch()
@@ -86,7 +86,7 @@ public class StopwatchBehaviour : Behaviour, IStopwatch
         hasStartedTickingBefore = true;
 
         State = TimerState.Ticking;
-        OnStarted?.Invoke(this);
+        OnStarted?.InvokeSafe(this);
     }
 
     protected override void OnFinalize()

Engine.Systems/Time/TickerBehaviour.cs

@@ -1,31 +1,33 @@
+using Syntriax.Engine.Core;
+
 namespace Syntriax.Engine.Systems.Time;
 
 public class TickerBehaviour : StopwatchBehaviour, ITicker
 {
     public event ITicker.TickerTickEventHandler? OnTick = null;
 
-    public double TickPeriod { get; set; } = 1f;
+    public double Period { get; set; } = 1f;
     public int TickCounter { get; private set; } = 0;
 
     private double nextTick = 0f;
 
-    public override void StopwatchStart()
+    public override void Start()
     {
         TickCounter = 0;
-        base.StopwatchStart();
+        base.Start();
-        nextTick = Time + TickPeriod;
+        nextTick = Time + Period;
     }
 
     protected override void OnUpdate()
     {
         base.OnUpdate();
 
-        if (Time < nextTick)
+        while (Time > nextTick)
-            return;
+        {
-
+            nextTick += Period;
-        nextTick += TickPeriod;
+            TickCounter++;
-        TickCounter++;
+            OnTick?.InvokeSafe(this);
-        OnTick?.Invoke(this);
+        }
     }
 
     protected override void OnFinalize()

Engine.Systems/Time/TimerBehaviour.cs

@@ -31,7 +31,7 @@ public class TimerBehaviour : Behaviour, ITimer
     private bool shouldBeTicking = false;
     private bool hasStartedTickingBefore = false;
 
-    public virtual void TimerStart(double time)
+    public virtual void Start(double time)
     {
         StartTime = time;
         Remaining = time;
@@ -43,7 +43,7 @@ public class TimerBehaviour : Behaviour, ITimer
             StartTimer();
     }
 
-    public virtual void TimerStop()
+    public virtual void Stop()
     {
         if (!shouldBeTicking)
             return;
@@ -51,7 +51,7 @@ public class TimerBehaviour : Behaviour, ITimer
         shouldBeTicking = false;
 
         State = TimerState.Stopped;
-        OnStopped?.Invoke(this);
+        OnStopped?.InvokeSafe(this);
     }
 
     protected override void OnUpdate()
@@ -59,44 +59,44 @@ public class TimerBehaviour : Behaviour, ITimer
         if (State is not TimerState.Ticking)
             return;
 
-        double delta = GameManager.Time.DeltaSpan.TotalSeconds;
+        double delta = Universe.Time.DeltaSpan.TotalSeconds;
 
         Remaining -= delta;
-        OnDelta?.Invoke(this, delta);
+        OnDelta?.InvokeSafe(this, delta);
 
         if (Remaining <= .0f)
-            TimerStop();
+            Stop();
     }
 
-    protected override void OnEnteredHierarchy(IGameManager gameManager)
+    protected override void OnEnteredUniverse(IUniverse universe)
     {
         if (!shouldBeTicking || State is TimerState.Ticking)
             return;
 
         if (hasStartedTickingBefore)
-            TimerResume();
+            Resume();
         else
             StartTimer();
     }
 
-    protected override void OnExitedHierarchy(IGameManager gameManager)
+    protected override void OnExitedUniverse(IUniverse universe)
     {
         if (!shouldBeTicking || State is not TimerState.Ticking)
             return;
 
-        TimerPause();
+        Pause();
     }
 
-    public virtual void TimerPause()
+    public virtual void Pause()
     {
         State = TimerState.Paused;
-        OnPaused?.Invoke(this);
+        OnPaused?.InvokeSafe(this);
     }
 
-    public virtual void TimerResume()
+    public virtual void Resume()
     {
         State = TimerState.Ticking;
-        OnResumed?.Invoke(this);
+        OnResumed?.InvokeSafe(this);
     }
 
     private void StartTimer()
@@ -104,7 +104,7 @@ public class TimerBehaviour : Behaviour, ITimer
         hasStartedTickingBefore = true;
 
         State = TimerState.Ticking;
-        OnStarted?.Invoke(this);
+        OnStarted?.InvokeSafe(this);
     }
 
     protected override void OnFinalize()

Engine.Systems/Tween/Easings.cs

@@ -7,66 +7,66 @@ internal static class EaseConstants
     internal const float c1 = 1.70158f;
     internal const float c2 = c1 * 1.525f;
     internal const float c3 = c1 + 1f;
-    internal const float c4 = 2f * Core.Math.PI / 3;
+    internal const float c4 = 2f * Core.Math.PI / 3f;
     internal const float c5 = 2f * Core.Math.PI / 4.5f;
 }
 
-public readonly struct EaseLinear : IEasing { public readonly float Evaluate(float value) => value; }
+public readonly struct EaseLinear : IEasing { public readonly float Evaluate(float x) => x; }
 
-public readonly struct EaseInQuad : IEasing { public readonly float Evaluate(float value) => value * value; }
+public readonly struct EaseInQuad : IEasing { public readonly float Evaluate(float x) => x * x; }
-public readonly struct EaseOutQuad : IEasing { public readonly float Evaluate(float value) => 1f - (1f - value) * (1f - value); }
+public readonly struct EaseOutQuad : IEasing { public readonly float Evaluate(float x) => 1f - (1f - x) * (1f - x); }
-public readonly struct EaseInOutQuad : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? 2f * value * value : 1f - Core.Math.Pow(-2f * value + 2f, 2f) * .5f; }
+public readonly struct EaseInOutQuad : IEasing { public readonly float Evaluate(float x) => x < .5f ? 2f * x * x : 1f - Core.Math.Pow(-2f * x + 2f, 2f) * .5f; }
 
-public readonly struct EaseInCubic : IEasing { public readonly float Evaluate(float value) => value * value * value; }
+public readonly struct EaseInCubic : IEasing { public readonly float Evaluate(float x) => x * x * x; }
-public readonly struct EaseOutCubic : IEasing { public readonly float Evaluate(float value) => 1f - Core.Math.Pow(1f - value, 3); }
+public readonly struct EaseOutCubic : IEasing { public readonly float Evaluate(float x) => 1f - Core.Math.Pow(1f - x, 3f); }
-public readonly struct EaseInOutCubic : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? 4f * value * value * value : 1f - Core.Math.Pow(-2f * value + 2f, 3) * .5f; }
+public readonly struct EaseInOutCubic : IEasing { public readonly float Evaluate(float x) => x < .5f ? 4f * x * x * x : 1f - Core.Math.Pow(-2f * x + 2f, 3f) * .5f; }
 
-public readonly struct EaseInQuart : IEasing { public readonly float Evaluate(float value) => value * value * value * value; }
+public readonly struct EaseInQuart : IEasing { public readonly float Evaluate(float x) => x * x * x * x; }
-public readonly struct EaseOutQuart : IEasing { public readonly float Evaluate(float value) => 1f - Core.Math.Pow(1f - value, 4f); }
+public readonly struct EaseOutQuart : IEasing { public readonly float Evaluate(float x) => 1f - Core.Math.Pow(1f - x, 4f); }
-public readonly struct EaseInOutQuart : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? 8 * value * value * value * value : 1f - Core.Math.Pow(-2f * value + 2f, 4f) * .5f; }
+public readonly struct EaseInOutQuart : IEasing { public readonly float Evaluate(float x) => x < .5f ? 8f * x * x * x * x : 1f - Core.Math.Pow(-2f * x + 2f, 4f) * .5f; }
 
-public readonly struct EaseInQuint : IEasing { public readonly float Evaluate(float value) => value * value * value * value * value; }
+public readonly struct EaseInQuint : IEasing { public readonly float Evaluate(float x) => x * x * x * x * x; }
-public readonly struct EaseOutQuint : IEasing { public readonly float Evaluate(float value) => 1f - Core.Math.Pow(1f - value, 5); }
+public readonly struct EaseOutQuint : IEasing { public readonly float Evaluate(float x) => 1f - Core.Math.Pow(1f - x, 5f); }
-public readonly struct EaseInOutQuint : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? 16 * value * value * value * value * value : 1f - Core.Math.Pow(-2f * value + 2f, 5) * .5f; }
+public readonly struct EaseInOutQuint : IEasing { public readonly float Evaluate(float x) => x < .5f ? 16f * x * x * x * x * x : 1f - Core.Math.Pow(-2f * x + 2f, 5f) * .5f; }
 
-public readonly struct EaseInSine : IEasing { public readonly float Evaluate(float value) => 1f - Core.Math.Cos(value * Core.Math.PI * .5f); }
+public readonly struct EaseInSine : IEasing { public readonly float Evaluate(float x) => 1f - Core.Math.Cos(x * Core.Math.PI * .5f); }
-public readonly struct EaseOutSine : IEasing { public readonly float Evaluate(float value) => Core.Math.Sin(value * Core.Math.PI * .5f); }
+public readonly struct EaseOutSine : IEasing { public readonly float Evaluate(float x) => Core.Math.Sin(x * Core.Math.PI * .5f); }
-public readonly struct EaseInOutSine : IEasing { public readonly float Evaluate(float value) => -(Core.Math.Cos(Core.Math.PI * value) - 1f) * .5f; }
+public readonly struct EaseInOutSine : IEasing { public readonly float Evaluate(float x) => -(Core.Math.Cos(Core.Math.PI * x) - 1f) * .5f; }
 
-public readonly struct EaseInExpo : IEasing { public readonly float Evaluate(float value) => value == 0 ? 0 : Core.Math.Pow(2f, 10f * value - 10f); }
+public readonly struct EaseInExpo : IEasing { public readonly float Evaluate(float x) => x == 0f ? 0f : Core.Math.Pow(2f, 10f * x - 10f); }
-public readonly struct EaseOutExpo : IEasing { public readonly float Evaluate(float value) => value == 1f ? 1f : 1f - Core.Math.Pow(2f, -10f * value); }
+public readonly struct EaseOutExpo : IEasing { public readonly float Evaluate(float x) => x == 1f ? 1f : 1f - Core.Math.Pow(2f, -10f * x); }
-public readonly struct EaseInOutExpo : IEasing { public readonly float Evaluate(float value) => value == 0 ? 0 : value == 1f ? 1f : value < 0.5f ? Core.Math.Pow(2f, 20 * value - 10f) * .5f : (2f - Core.Math.Pow(2f, -20 * value + 10f)) * .5f; }
+public readonly struct EaseInOutExpo : IEasing { public readonly float Evaluate(float x) => x == 0f ? 0f : x == 1f ? 1f : x < .5f ? Core.Math.Pow(2f, 20f * x - 10f) * .5f : (2f - Core.Math.Pow(2f, -20f * x + 10f)) * .5f; }
 
-public readonly struct EaseInCirc : IEasing { public readonly float Evaluate(float value) => 1f - Core.Math.Sqrt(1f - Core.Math.Pow(value, 2f)); }
+public readonly struct EaseInCirc : IEasing { public readonly float Evaluate(float x) => 1f - Core.Math.Sqrt(1f - Core.Math.Pow(x, 2f)); }
-public readonly struct EaseOutCirc : IEasing { public readonly float Evaluate(float value) => Core.Math.Sqrt(1f - Core.Math.Pow(value - 1f, 2f)); }
+public readonly struct EaseOutCirc : IEasing { public readonly float Evaluate(float x) => Core.Math.Sqrt(1f - Core.Math.Pow(x - 1f, 2f)); }
-public readonly struct EaseInOutCirc : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? (1f - Core.Math.Sqrt(1f - Core.Math.Pow(2f * value, 2f))) * .5f : (Core.Math.Sqrt(1f - Core.Math.Pow(-2f * value + 2f, 2f)) + 1f) * .5f; }
+public readonly struct EaseInOutCirc : IEasing { public readonly float Evaluate(float x) => x < .5f ? (1f - Core.Math.Sqrt(1f - Core.Math.Pow(2f * x, 2f))) * .5f : (Core.Math.Sqrt(1f - Core.Math.Pow(-2f * x + 2f, 2f)) + 1f) * .5f; }
 
-public readonly struct EaseInBack : IEasing { public readonly float Evaluate(float value) => EaseConstants.c3 * value * value * value - EaseConstants.c1 * value * value; }
+public readonly struct EaseInBack : IEasing { public readonly float Evaluate(float x) => EaseConstants.c3 * x * x * x - EaseConstants.c1 * x * x; }
-public readonly struct EaseOutBack : IEasing { public readonly float Evaluate(float value) => 1f + EaseConstants.c3 * Core.Math.Pow(value - 1f, 3) + EaseConstants.c1 * Core.Math.Pow(value - 1f, 2f); }
+public readonly struct EaseOutBack : IEasing { public readonly float Evaluate(float x) => 1f + EaseConstants.c3 * Core.Math.Pow(x - 1f, 3f) + EaseConstants.c1 * Core.Math.Pow(x - 1f, 2f); }
-public readonly struct EaseInOutBack : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? Core.Math.Pow(2f * value, 2f) * ((EaseConstants.c2 + 1f) * 2f * value - EaseConstants.c2) * .5f : (Core.Math.Pow(2f * value - 2f, 2f) * ((EaseConstants.c2 + 1f) * (value * 2f - 2f) + EaseConstants.c2) + 2f) * .5f; }
+public readonly struct EaseInOutBack : IEasing { public readonly float Evaluate(float x) => x < .5f ? Core.Math.Pow(2f * x, 2f) * ((EaseConstants.c2 + 1f) * 2f * x - EaseConstants.c2) * .5f : (Core.Math.Pow(2f * x - 2f, 2f) * ((EaseConstants.c2 + 1f) * (x * 2f - 2f) + EaseConstants.c2) + 2f) * .5f; }
 
-public readonly struct EaseInElastic : IEasing { public readonly float Evaluate(float value) => value == 0 ? 0 : value == 1f ? 1f : -Core.Math.Pow(2f, 10f * value - 10f) * Core.Math.Sin((value * 10f - 10.75f) * EaseConstants.c4); }
+public readonly struct EaseInElastic : IEasing { public readonly float Evaluate(float x) => x == 0 ? 0 : x == 1f ? 1f : -Core.Math.Pow(2f, 10f * x - 10f) * Core.Math.Sin((x * 10f - 10.75f) * EaseConstants.c4); }
-public readonly struct EaseOutElastic : IEasing { public readonly float Evaluate(float value) => value == 0 ? 0 : value == 1f ? 1f : Core.Math.Pow(2f, -10f * value) * Core.Math.Sin((value * 10f - 0.75f) * EaseConstants.c4) + 1f; }
+public readonly struct EaseOutElastic : IEasing { public readonly float Evaluate(float x) => x == 0 ? 0 : x == 1f ? 1f : Core.Math.Pow(2f, -10f * x) * Core.Math.Sin((x * 10f - .75f) * EaseConstants.c4) + 1f; }
-public readonly struct EaseInOutElastic : IEasing { public readonly float Evaluate(float value) => value == 0 ? 0 : value == 1f ? 1f : value < 0.5f ? -(Core.Math.Pow(2f, 20 * value - 10f) * Core.Math.Sin((20 * value - 11.125f) * EaseConstants.c5)) * .5f : Core.Math.Pow(2f, -20 * value + 10f) * Core.Math.Sin((20 * value - 11.125f) * EaseConstants.c5) * .5f + 1f; }
+public readonly struct EaseInOutElastic : IEasing { public readonly float Evaluate(float x) => x == 0 ? 0 : x == 1f ? 1f : x < .5f ? -(Core.Math.Pow(2f, 20f * x - 10f) * Core.Math.Sin((20f * x - 11.125f) * EaseConstants.c5)) * .5f : Core.Math.Pow(2f, -20f * x + 10f) * Core.Math.Sin((20f * x - 11.125f) * EaseConstants.c5) * .5f + 1f; }
 
-public readonly struct EaseInBounce : IEasing { public readonly float Evaluate(float value) => 1f - new EaseOutBounce().Evaluate(1f - value); }
+public readonly struct EaseInBounce : IEasing { public readonly float Evaluate(float x) => 1f - new EaseOutBounce().Evaluate(1f - x); }
 public readonly struct EaseOutBounce : IEasing
 {
-    public readonly float Evaluate(float value)
+    public readonly float Evaluate(float x)
     {
         const float n1 = 7.5625f;
         const float d1 = 2.75f;
 
-        if (value < 1 / d1)
+        if (x < 1f / d1)
-            return n1 * value * value;
+            return n1 * x * x;
 
-        if (value < 2 / d1)
+        if (x < 2f / d1)
-            return n1 * (value -= 1.5f / d1) * value + 0.75f;
+            return n1 * (x -= 1.5f / d1) * x + .75f;
 
-        if (value < 2.5 / d1)
+        if (x < 2.5f / d1)
-            return n1 * (value -= 2.25f / d1) * value + 0.9375f;
+            return n1 * (x -= 2.25f / d1) * x + .9375f;
 
-        return n1 * (value -= 2.625f / d1) * value + 0.984375f;
+        return n1 * (x -= 2.625f / d1) * x + .984375f;
     }
 }
-public readonly struct EaseInOutBounce : IEasing { public readonly float Evaluate(float value) => value < 0.5f ? (1f - new EaseOutBounce().Evaluate(1f - 2f * value)) * .5f : (1f + new EaseOutBounce().Evaluate(2f * value - 1f)) * .5f; }
+public readonly struct EaseInOutBounce : IEasing { public readonly float Evaluate(float x) => x < .5f ? (1f - new EaseOutBounce().Evaluate(1f - 2f * x)) * .5f : (1f + new EaseOutBounce().Evaluate(2f * x - 1f)) * .5f; }

Engine.Systems/Tween/IEasing.cs

@@ -2,6 +2,6 @@ namespace Syntriax.Engine.Systems.Tween;
 
 public interface IEasing
 {
-    float Evaluate(float value);
+    float Evaluate(float x);
 }
 

Engine.Systems/Tween/Tween.cs

@@ -26,14 +26,14 @@ internal class Tween : ITween
             _state = value;
             switch (value)
             {
-                case TweenState.Completed: OnCompleted?.Invoke(this); OnEnded?.Invoke(this); break;
+                case TweenState.Completed: OnCompleted?.InvokeSafe(this); OnEnded?.InvokeSafe(this); break;
-                case TweenState.Cancelled: OnCancelled?.Invoke(this); OnEnded?.Invoke(this); break;
+                case TweenState.Cancelled: OnCancelled?.InvokeSafe(this); OnEnded?.InvokeSafe(this); break;
-                case TweenState.Paused: OnPaused?.Invoke(this); break;
+                case TweenState.Paused: OnPaused?.InvokeSafe(this); break;
                 case TweenState.Playing:
                     if (previousState == TweenState.Idle)
-                        OnStarted?.Invoke(this);
+                        OnStarted?.InvokeSafe(this);
                     else
-                        OnResumed?.Invoke(this);
+                        OnResumed?.InvokeSafe(this);
                     break;
             }
         }
@@ -58,9 +58,9 @@ internal class Tween : ITween
 
             _counter = value.Min(Duration).Max(0f);
             Progress = Counter / Duration;
-            OnUpdated?.Invoke(this);
+            OnUpdated?.InvokeSafe(this);
 
-            OnDeltaUpdated?.Invoke(this, Easing.Evaluate(Progress) - Easing.Evaluate(previousProgress));
+            OnDeltaUpdated?.InvokeSafe(this, Easing.Evaluate(Progress) - Easing.Evaluate(previousProgress));
 
             if (_counter >= Duration)
                 State = TweenState.Completed;

Engine.Systems/Tween/TweenExtensions.cs

@@ -1,3 +1,5 @@
+using Syntriax.Engine.Core;
+
 namespace Syntriax.Engine.Systems.Tween;
 
 public static class TweenExtensions
@@ -42,49 +44,49 @@ public static class TweenExtensions
     public static ITween OnStart(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnStarted += _ => callback.Invoke();
+        tweenConcrete.OnStarted += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnPause(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnPaused += _ => callback.Invoke();
+        tweenConcrete.OnPaused += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnResume(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnResumed += _ => callback.Invoke();
+        tweenConcrete.OnResumed += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnCancel(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnCancelled += _ => callback.Invoke();
+        tweenConcrete.OnCancelled += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnComplete(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnCompleted += _ => callback.Invoke();
+        tweenConcrete.OnCompleted += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnEnd(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnEnded += _ => callback.Invoke();
+        tweenConcrete.OnEnded += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnUpdate(this ITween tween, Action callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnUpdated += _ => callback.Invoke();
+        tweenConcrete.OnUpdated += _ => callback.InvokeSafe();
         return tween;
     }
     public static ITween OnDeltaUpdate(this ITween tween, Action<float> callback)
     {
         Tween tweenConcrete = (Tween)tween;
-        tweenConcrete.OnDeltaUpdated += (_, delta) => callback.Invoke(delta);
+        tweenConcrete.OnDeltaUpdated += (_, delta) => callback.InvokeSafe(delta);
         return tween;
     }
 }

Engine.Systems/Tween/TweenManager.cs

@@ -5,7 +5,7 @@ using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Systems.Tween;
 
-public class TweenManager : HierarchyObject
+public class TweenManager : UniverseObject
 {
     private CoroutineManager coroutineManager = null!;
 
@@ -14,7 +14,7 @@ public class TweenManager : HierarchyObject
     public ITween StartTween(float duration, TweenSetCallback? setCallback = null)
     {
         Tween tween = new(duration);
-        tween.OnUpdated += tween => setCallback?.Invoke(tween.Value);
+        tween.OnUpdated += tween => setCallback?.InvokeSafe(tween.Value);
         runningCoroutines.Add(tween, coroutineManager.StartCoroutine(RunTween(tween)));
         return tween;
     }
@@ -35,7 +35,7 @@ public class TweenManager : HierarchyObject
                 continue;
             }
 
-            tween.Counter += GameManager.Time.DeltaTime;
+            tween.Counter += Universe.Time.DeltaTime;
             yield return null;
         }
 
@@ -52,12 +52,12 @@ public class TweenManager : HierarchyObject
         runningCoroutines.Remove(tween);
     }
 
-    protected override void OnEnteringHierarchy(IGameManager gameManager)
+    protected override void OnEnteringUniverse(IUniverse universe)
     {
-        coroutineManager = gameManager.FindHierarchyObject<CoroutineManager>() ?? throw new($"No {nameof(CoroutineManager)} was found in the game manager");
+        coroutineManager = universe.GetRequiredUniverseObject<CoroutineManager>();
     }
 
-    protected override void OnExitingHierarchy(IGameManager gameManager)
+    protected override void OnExitingUniverse(IUniverse universe)
     {
         coroutineManager = null!;
     }

README.md

@@ -1,12 +1,13 @@
 # Work In Progress
 
-This engine is still in development but the implemented features include:
+This engine is still in development so there **WILL** be breaking changes, but the implemented features include:
+
 - Modular Systems
 - Behaviour System
 - 2D Physics Engine(**Not Fully Completed, but usable**)
-    - Rigid Body Simulations
+  - Rigid Body Simulations
-    - Collision Detection (Convex Shape & Circle)
+  - Collision Detection (Convex Shape & Circle)
-    - Collision Resolution (**Not Fully Completed**)
+  - Collision Resolution (**Not Fully Completed**)
 - Vector2D, AABB, Circle, Line, LineEquation, Projection & Shape Data Types
 - General Math