feat: IGameManager.FindRequiredBehaviour extension method added

Engine.Core/Abstract/IBehaviourController.cs

@@ -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

@@ -32,11 +32,21 @@ public interface IGameManager : IEntity, IEnumerable<IHierarchyObject>
     /// </summary>
     event HierarchyObjectUnRegisteredEventHandler? OnHierarchyObjectUnRegistered;
 
+    /// <summary>
+    /// Current time scale the <see cref="IGameManager"/> operates on.
+    /// </summary>
+    float TimeScale { get; set; }
+
     /// <summary>
     /// Contains time data related to this <see cref="IGameManager"/>.
     /// </summary>
     EngineTime Time { get; }
 
+    /// <summary>
+    /// Contains unscaled time data related to this <see cref="IGameManager"/>.
+    /// </summary>
+    EngineTime UnscaledTime { get; }
+
     /// <summary>
     /// Gets a read-only list of <see cref="IHierarchyObject"/>s managed by the <see cref="IGameManager"/>.
     /// </summary>

Engine.Core/Behaviour.cs

@@ -1,4 +1,5 @@
 using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Helpers;
 
 namespace Syntriax.Engine.Core;
 
@@ -55,6 +56,8 @@ public abstract class Behaviour : BehaviourBase
     protected virtual void OnPreUpdate() { }
     protected virtual void PreUpdate(IBehaviourController _)
     {
+        AssertHelpers.AssertInitialized(this);
+
         OnPreUpdatePreActiveCheck();
 
         if (!IsActive)
@@ -77,6 +80,8 @@ public abstract class Behaviour : BehaviourBase
     protected virtual void OnUpdate() { }
     protected virtual void Update(IBehaviourController _)
     {
+        AssertHelpers.AssertInitialized(this);
+
         OnUpdatePreActiveCheck();
 
         if (!IsActive)
@@ -89,6 +94,8 @@ public abstract class Behaviour : BehaviourBase
     protected virtual void OnPreDraw() { }
     protected virtual void PreDraw(IBehaviourController _)
     {
+        AssertHelpers.AssertInitialized(this);
+
         OnPreDrawPreActiveCheck();
 
         if (!StateEnable.Enabled)

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(_);
     }
 

Engine.Core/BehaviourBase.cs

@@ -1,5 +1,6 @@
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Core.Exceptions;
+using Syntriax.Engine.Core.Helpers;
 
 namespace Syntriax.Engine.Core;
 
@@ -69,9 +70,8 @@ public abstract class BehaviourBase : BaseEntity, IBehaviour
 
     protected override void InitializeInternal()
     {
-        base.InitializeInternal();
-        NotAssignedException.Check(this, _behaviourController);
-        NotAssignedException.Check(this, StateEnable);
+        AssertHelpers.AssertBehaviourControllerAssigned(this);
+        AssertHelpers.AssertStateEnableAssigned(this);
     }
 
     private void OnStateEnabledChanged(IStateEnable sender, bool previousState) => UpdateActive();

Engine.Core/BehaviourController.cs

@@ -4,7 +4,7 @@ using System.Collections.Generic;
 using System.Linq;
 
 using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
+using Syntriax.Engine.Core.Helpers;
 
 namespace Syntriax.Engine.Core;
 
@@ -72,7 +72,7 @@ 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)
@@ -141,7 +141,7 @@ public class BehaviourController : IBehaviourController
         if (IsInitialized)
             return false;
 
-        NotAssignedException.Check(this, _hierarchyObject);
+        AssertHelpers.AssertHierarchyObjectAssigned(this);
 
         foreach (IBehaviour behaviour in behaviours)
             behaviour.Initialize();

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/HierarchyObjectNotFoundException.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Syntriax.Engine.Core.Exceptions;
+
+public class HierarchyObjectNotFoundException(string? message) : Exception(message)
+{
+    public static NotAssignedException FromType<THierarchyObject>()
+        => new($"{typeof(THierarchyObject).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/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.HierarchyObject.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>
@@ -30,7 +40,7 @@ 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="IHierarchyObject"/>'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>
@@ -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="IHierarchyObject"/>'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>
@@ -64,7 +74,16 @@ public static class BehaviourControllerExtensions
     }
 
     /// <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="IHierarchyObject"/>'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.HierarchyObject.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="IHierarchyObject"/>'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>
@@ -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="IHierarchyObject"/>'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>
@@ -93,4 +112,13 @@ public static class BehaviourControllerExtensions
 
         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.HierarchyObject.Name}'s {nameof(IBehaviourController)} does not contain any {typeof(T).FullName} on any children ");
 }

Engine.Core/Extensions/GameManagerExtensions.cs

@@ -1,4 +1,5 @@
 using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Exceptions;
 
 namespace Syntriax.Engine.Core;
 
@@ -6,4 +7,10 @@ public static class GameManagerExtensions
 {
     public static IHierarchyObject InstantiateHierarchyObject(this IGameManager gameManager, params object?[]? args)
         => gameManager.InstantiateHierarchyObject<HierarchyObject>(args);
+
+    public static T GetRequiredHierarchyObject<T>(this IGameManager gameManager) where T : class
+        => gameManager.GetHierarchyObject<T>() ?? throw new HierarchyObjectNotFoundException($"{gameManager.GetType().FullName}({gameManager.Id}) does not contain any {nameof(IHierarchyObject)} object of type {typeof(T).FullName}");
+
+    public static T FindRequiredBehaviour<T>(this IGameManager gameManager) where T : class
+        => gameManager.FindBehaviour<T>() ?? throw new BehaviourNotFoundException($"{gameManager.GetType().FullName}({gameManager.Id}) does not contain any {nameof(IHierarchyObject)} with {nameof(IBehaviour)} of type {typeof(T).FullName}");
 }

Engine.Core/Extensions/HierarchyObjectExtensions.cs

@@ -16,7 +16,7 @@ public static class HierarchyObjectExtensions
         return hierarchyObject;
     }
 
-    public static T? FindHierarchyObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects) where T : class
+    public static T? GetHierarchyObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects) where T : class
     {
         foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
             if (hierarchyObject is T @object)
@@ -25,13 +25,13 @@ public static class HierarchyObjectExtensions
         return default;
     }
 
-    public static bool TryFindHierarchyObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    public static bool TryGetHierarchyObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
     {
-        behaviour = FindHierarchyObject<T>(hierarchyObjects);
+        behaviour = GetHierarchyObject<T>(hierarchyObjects);
         return behaviour is not null;
     }
 
-    public static void FindHierarchyObjects<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, List<T> behaviours) where T : class
+    public static void GetHierarchyObjects<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, List<T> behaviours) where T : class
     {
         behaviours.Clear();
         foreach (IHierarchyObject hierarchyObject in hierarchyObjects)

Engine.Core/Factory/BehaviourControllerFactory.cs

@@ -14,10 +14,10 @@ public class BehaviourControllerFactory
         T behaviourController = TypeFactory.Get<T>(args);
 
         if (!hierarchyObject.Assign(behaviourController))
-            throw AssignException.From(hierarchyObject, behaviourController);
+            throw AssignFailedException.From(hierarchyObject, behaviourController);
 
         if (!behaviourController.Assign(hierarchyObject))
-            throw AssignException.From(behaviourController, hierarchyObject);
+            throw AssignFailedException.From(behaviourController, hierarchyObject);
 
         return behaviourController;
     }

Engine.Core/Factory/BehaviourFactory.cs

@@ -15,12 +15,12 @@ public class BehaviourFactory
 
         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))
-            throw AssignException.From(behaviour, hierarchyObject.BehaviourController);
+            throw AssignFailedException.From(behaviour, hierarchyObject.BehaviourController);
 
         return behaviour;
     }

Engine.Core/Factory/HierarchyObjectFactory.cs

@@ -23,14 +23,14 @@ public class HierarchyObjectFactory
         stateEnable ??= TypeFactory.Get<StateEnable>();
 
         if (!behaviourController.Assign(hierarchyObject))
-            throw AssignException.From(behaviourController, hierarchyObject);
+            throw AssignFailedException.From(behaviourController, hierarchyObject);
         if (!stateEnable.Assign(hierarchyObject))
-            throw AssignException.From(stateEnable, hierarchyObject);
+            throw AssignFailedException.From(stateEnable, hierarchyObject);
 
         if (!hierarchyObject.Assign(behaviourController))
-            throw AssignException.From(hierarchyObject, behaviourController);
+            throw AssignFailedException.From(hierarchyObject, behaviourController);
         if (!hierarchyObject.Assign(stateEnable))
-            throw AssignException.From(hierarchyObject, stateEnable);
+            throw AssignFailedException.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/GameManager.cs

@@ -3,7 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 
 using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
+using Syntriax.Engine.Core.Helpers;
 
 namespace Syntriax.Engine.Core;
 
@@ -18,25 +18,17 @@ public class GameManager : BaseEntity, IGameManager
     public event IGameManager.HierarchyObjectUnRegisteredEventHandler? OnHierarchyObjectUnRegistered = null;
 
     private readonly List<IHierarchyObject> _hierarchyObjects = new(Constants.GAME_OBJECTS_SIZE_INITIAL);
+    private float _timeScale = 1f;
 
     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 EngineTime UnscaledTime { get; private set; } = new();
+    public float TimeScale
+    {
+        get => _timeScale;
+        set => _timeScale = value.Max(0f);
+    }
 
     public void Register(IHierarchyObject hierarchyObject)
     {
@@ -68,6 +60,12 @@ public class GameManager : BaseEntity, IGameManager
     }
 
     public void Remove(IHierarchyObject hierarchyObject)
+    {
+        hierarchyObject.SetParent(null);
+        RemoveIncursive(hierarchyObject);
+    }
+
+    private void RemoveIncursive(IHierarchyObject hierarchyObject)
     {
         if (!_hierarchyObjects.Contains(hierarchyObject))
             throw new Exception($"{nameof(IHierarchyObject)} named {hierarchyObject.Name} is not registered to the {nameof(GameManager)}.");
@@ -79,7 +77,6 @@ public class GameManager : BaseEntity, IGameManager
             Remove(hierarchyObject.Children[i]);
 
         _hierarchyObjects.Remove(hierarchyObject);
-        hierarchyObject.SetParent(null);
 
         if (!hierarchyObject.ExitHierarchy())
             throw new Exception($"{hierarchyObject.Name} can't exit the hierarchy");
@@ -92,9 +89,6 @@ public class GameManager : BaseEntity, IGameManager
 
     protected override void InitializeInternal()
     {
-        base.InitializeInternal();
-        NotAssignedException.Check(this, StateEnable);
-
         foreach (IHierarchyObject hierarchyObject in HierarchyObjects)
             hierarchyObject.Initialize();
     }
@@ -108,18 +102,23 @@ public class GameManager : BaseEntity, IGameManager
 
     public void Update(EngineTime engineTime)
     {
-        Time = engineTime;
+        AssertHelpers.AssertInitialized(this);
 
-        OnPreUpdate?.Invoke(this, engineTime);
+        UnscaledTime = engineTime;
+        Time = new(TimeSpan.FromTicks((long)(Time.TimeSinceStart.Ticks + engineTime.DeltaSpan.Ticks * TimeScale)), TimeSpan.FromTicks((long)(engineTime.DeltaSpan.Ticks * TimeScale)));
+
+        OnPreUpdate?.Invoke(this, Time);
 
         for (int i = 0; i < HierarchyObjects.Count; i++)
             HierarchyObjects[i].BehaviourController.Update();
 
-        OnUpdate?.Invoke(this, engineTime);
+        OnUpdate?.Invoke(this, Time);
     }
 
     public void PreDraw()
     {
+        AssertHelpers.AssertInitialized(this);
+
         for (int i = 0; i < HierarchyObjects.Count; i++)
             HierarchyObjects[i].BehaviourController.UpdatePreDraw();
 

Engine.Core/Helpers/AssertHelpers.cs

@@ -0,0 +1,33 @@
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core.Helpers;
+
+public class AssertHelpers
+{
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertInitialized(IInitializable initializable)
+        => Debug.Assert(initializable.IsInitialized, $"{initializable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertBehaviourControllerAssigned(IHasBehaviourController assignable)
+        => Debug.Assert(assignable.BehaviourController is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertEntityAssigned(IHasEntity assignable)
+        => Debug.Assert(assignable.Entity is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertGameManagerAssigned(IHasGameManager assignable)
+        => Debug.Assert(assignable.GameManager is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertHierarchyObjectAssigned(IHasHierarchyObject assignable)
+        => Debug.Assert(assignable.HierarchyObject is not null, $"{assignable.GetType().Name} must be initialized");
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static void AssertStateEnableAssigned(IHasStateEnable assignable)
+        => Debug.Assert(assignable.StateEnable is not null, $"{assignable.GetType().Name} must be initialized");
+}

Engine.Core/HierarchyObject.cs

@@ -64,7 +64,6 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
 
         OnExitingHierarchy(gameManager);
         _gameManager = null!;
-        SetParent(null);
         OnExitedHierarchy?.Invoke(this, gameManager);
         return true;
     }
@@ -72,7 +71,7 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
     public void SetParent(IHierarchyObject? parent)
     {
         if (parent == this)
-            throw new Exceptions.AssignException($"{Name} can not parent itself");
+            throw new Exceptions.AssignFailedException($"{Name} can not parent itself");
 
         if (Parent == parent)
             return;
@@ -109,13 +108,13 @@ public class HierarchyObject : BaseEntity, IHierarchyObject
         OnChildrenAdded?.Invoke(this, parent);
     }
 
-    public void RemoveChild(IHierarchyObject parent)
+    public void RemoveChild(IHierarchyObject child)
     {
-        if (!_children.Remove(parent))
+        if (!_children.Remove(child))
             return;
 
-        parent.SetParent(null);
-        OnChildrenRemoved?.Invoke(this, parent);
+        child.SetParent(null);
+        OnChildrenRemoved?.Invoke(this, child);
     }
 
     protected virtual void OnAssign(IBehaviourController behaviourController) { }

Engine.Core/Transform2D.cs

@@ -220,7 +220,6 @@ public class Transform2D : Behaviour, ITransform2D
         ITransform2D? previousParent = parentTransform;
         if (previousParent is not null)
         {
-            previousParent.BehaviourController.HierarchyObject.RemoveChild(HierarchyObject);
             previousParent.OnPositionChanged -= RecalculatePosition;
             previousParent.OnScaleChanged -= RecalculateScale;
             previousParent.OnRotationChanged -= RecalculateRotation;
@@ -232,7 +231,6 @@ public class Transform2D : Behaviour, ITransform2D
 
         if (parentTransform is not null)
         {
-            parentTransform.BehaviourController.HierarchyObject.AddChild(HierarchyObject);
             parentTransform.OnPositionChanged += RecalculatePosition;
             parentTransform.OnScaleChanged += RecalculateScale;
             parentTransform.OnRotationChanged += RecalculateRotation;

Engine.Physics2D/PhysicsCoroutineManager.cs

@@ -25,7 +25,7 @@ public class PhysicsCoroutineManager : HierarchyObject
 
     protected override void OnEnteringHierarchy(IGameManager gameManager)
     {
-        physicsEngine = gameManager.FindHierarchyObject<IPhysicsEngine2D>();
+        physicsEngine = gameManager.GetHierarchyObject<IPhysicsEngine2D>();
         if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
             foundPhysicsEngine.OnPhysicsStep += OnPhysicsStep;
         else
@@ -56,7 +56,7 @@ public class PhysicsCoroutineManager : HierarchyObject
         if (GameManager is not IGameManager gameManager)
             return;
 
-        physicsEngine = gameManager.FindHierarchyObject<IPhysicsEngine2D>();
+        physicsEngine = gameManager.GetHierarchyObject<IPhysicsEngine2D>();
         if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
         {
             foundPhysicsEngine.OnPhysicsStep += OnPhysicsStep;

Engine.Systems/Time/TickerBehaviour.cs

@@ -20,13 +20,13 @@ public class TickerBehaviour : StopwatchBehaviour, ITicker
     {
         base.OnUpdate();
 
-        if (Time < nextTick)
-            return;
-
+        while (Time > nextTick)
+        {
             nextTick += Period;
             TickCounter++;
             OnTick?.Invoke(this);
         }
+    }
 
     protected override void OnFinalize()
     {

Engine.Systems/Tween/TweenManager.cs

@@ -54,7 +54,7 @@ public class TweenManager : HierarchyObject
 
     protected override void OnEnteringHierarchy(IGameManager gameManager)
     {
-        coroutineManager = gameManager.FindHierarchyObject<CoroutineManager>() ?? throw new($"No {nameof(CoroutineManager)} was found in the game manager");
+        coroutineManager = gameManager.GetRequiredHierarchyObject<CoroutineManager>();
     }
 
     protected override void OnExitingHierarchy(IGameManager gameManager)

README.md

@@ -1,6 +1,7 @@
 # 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**)