chore: added an experimental ordered fast list class

Engine.Core/ActiveBehaviourCollectorSorted.cs

@@ -1,67 +0,0 @@
-using System;
-using System.Collections.Generic;
-
-namespace Engine.Core;
-
-public class ActiveBehaviourCollectorSorted<T> : ActiveBehaviourCollector<T> where T : class, IBehaviour
-{
-    private readonly Event<IBehaviour, IBehaviour.PriorityChangedArguments>.EventHandler delegateOnPriorityChanged = null!;
-
-    private IComparer<T>? _sortBy = null;
-    public IComparer<T>? SortBy
-    {
-        get => _sortBy;
-        set
-        {
-            _sortBy = value;
-
-            if (value is not null)
-                activeBehaviours.Sort(value);
-        }
-    }
-
-    protected override void AddBehaviour(T behaviour)
-    {
-        if (SortBy is null)
-        {
-            activeBehaviours.Add(behaviour);
-            return;
-        }
-
-        int insertionIndex = activeBehaviours.BinarySearch(behaviour, SortBy);
-
-        if (insertionIndex < 0)
-            insertionIndex = ~insertionIndex;
-
-        activeBehaviours.Insert(insertionIndex, behaviour);
-    }
-
-    protected override void OnBehaviourAdd(IBehaviour behaviour)
-    {
-        behaviour.OnPriorityChanged.AddListener(delegateOnPriorityChanged);
-    }
-
-    protected override void OnBehaviourRemove(IBehaviour behaviour)
-    {
-        behaviour.OnPriorityChanged.RemoveListener(delegateOnPriorityChanged);
-    }
-
-    private void OnPriorityChanged(IBehaviour sender, IBehaviour.PriorityChangedArguments args)
-    {
-        T behaviour = (T)sender;
-        activeBehaviours.Remove(behaviour);
-        AddBehaviour(behaviour);
-    }
-
-    public ActiveBehaviourCollectorSorted()
-    {
-        delegateOnPriorityChanged = OnPriorityChanged;
-    }
-
-    public ActiveBehaviourCollectorSorted(IUniverse universe, Comparison<T> sortBy) : base(universe)
-    {
-        delegateOnPriorityChanged = OnPriorityChanged;
-
-        SortBy = Comparer<T>.Create(sortBy);
-    }
-}

Engine.Core/BehaviourCollectorSorted.cs

@@ -1,67 +0,0 @@
-using System;
-using System.Collections.Generic;
-
-namespace Engine.Core;
-
-public class BehaviourCollectorSorted<T> : BehaviourCollector<T> where T : class
-{
-    private readonly Event<IBehaviour, IBehaviour.PriorityChangedArguments>.EventHandler delegateOnPriorityChanged = null!;
-
-    private IComparer<T>? _sortBy = null;
-    public IComparer<T>? SortBy
-    {
-        get => _sortBy;
-        set
-        {
-            _sortBy = value;
-
-            if (value is not null)
-                behaviours.Sort(value);
-        }
-    }
-
-    protected override void AddBehaviour(T behaviour)
-    {
-        if (SortBy is null)
-        {
-            behaviours.Add(behaviour);
-            return;
-        }
-
-        int insertionIndex = behaviours.BinarySearch(behaviour, SortBy);
-
-        if (insertionIndex < 0)
-            insertionIndex = ~insertionIndex;
-
-        behaviours.Insert(insertionIndex, behaviour);
-    }
-
-    protected override void OnBehaviourAdd(IBehaviour behaviour)
-    {
-        behaviour.OnPriorityChanged.AddListener(delegateOnPriorityChanged);
-    }
-
-    protected override void OnBehaviourRemove(IBehaviour behaviour)
-    {
-        behaviour.OnPriorityChanged.RemoveListener(delegateOnPriorityChanged);
-    }
-
-    private void OnPriorityChanged(IBehaviour sender, IBehaviour.PriorityChangedArguments args)
-    {
-        T behaviour = (T)sender;
-        behaviours.Remove(behaviour);
-        AddBehaviour(behaviour);
-    }
-
-    public BehaviourCollectorSorted()
-    {
-        delegateOnPriorityChanged = OnPriorityChanged;
-    }
-
-    public BehaviourCollectorSorted(IUniverse universe, Comparison<T> sortBy) : base(universe)
-    {
-        delegateOnPriorityChanged = OnPriorityChanged;
-
-        SortBy = Comparer<T>.Create(sortBy);
-    }
-}

Engine.Core/Collectors/ActiveBehaviourCollector.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace Engine.Core;
+
+public class ActiveBehaviourCollector<T> : ActiveBehaviourCollectorBase<T> where T : class, IBehaviour
+{
+    protected readonly FastList<T> activeBehaviours = new(32);
+    public override T this[Index index] => activeBehaviours[index];
+    public override int Count => activeBehaviours.Count;
+
+    public ActiveBehaviourCollector() { }
+    public ActiveBehaviourCollector(IUniverse universe) : base(universe) { }
+
+    protected override void AddBehaviour(T behaviour) => activeBehaviours.Add(behaviour);
+    protected override bool RemoveBehaviour(T tBehaviour) => activeBehaviours.Remove(tBehaviour);
+}

Engine.Core/Collectors/ActiveBehaviourCollectorBase.cs

@@ -3,12 +3,10 @@ using System.Collections.Generic;
 
 namespace Engine.Core;
 
-public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : class, IBehaviour
+public abstract class ActiveBehaviourCollectorBase<T> : IBehaviourCollector<T> where T : class, IBehaviour
 {
-    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourCollectedArguments> OnCollected { get; } = new();
+    protected readonly Dictionary<IActive, T> monitoringActiveToBehaviour = new(32);
-    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourRemovedArguments> OnRemoved { get; } = new();
+    protected readonly FastList<T> monitoringBehaviours = new(32);
-    public Event<IHasUniverse> OnUniverseAssigned { get; } = new();
-    public Event<IAssignable>? OnUnassigned { get; } = new();
 
     private readonly Event<IBehaviourController, IBehaviourController.BehaviourAddedArguments>.EventHandler delegateOnBehaviourAdded = null!;
     private readonly Event<IBehaviourController, IBehaviourController.BehaviourRemovedArguments>.EventHandler delegateOnBehaviourRemoved = null!;
@@ -16,80 +14,16 @@ public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : clas
     private readonly Event<IUniverse, IUniverse.UniverseObjectRegisteredArguments>.EventHandler delegateOnUniverseObjectRegistered = null!;
     private readonly Event<IUniverse, IUniverse.UniverseObjectUnRegisteredArguments>.EventHandler delegateOnUniverseObjectUnregistered = null!;
 
-    private readonly FastList<T> monitoringBehaviours = new(32);
+    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourCollectedArguments> OnCollected { get; } = new();
-    protected readonly FastList<T> activeBehaviours = new(32);
+    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourRemovedArguments> OnRemoved { get; } = new();
-    protected readonly Dictionary<IActive, T> monitoringActiveToBehaviour = new(32);
+    public Event<IHasUniverse> OnUniverseAssigned { get; } = new();
+    public Event<IAssignable>? OnUnassigned { get; } = new();
 
+    public abstract int Count { get; }
+
+    public abstract T this[Index index] { get; }
     public IUniverse Universe { get; private set; } = null!;
 
-    private void OnUniverseObjectRegistered(IUniverse manager, IUniverse.UniverseObjectRegisteredArguments args)
-    {
-        IUniverseObject universeObject = args.UniverseObjectRegistered;
-
-        universeObject.BehaviourController.OnBehaviourAdded.AddListener(delegateOnBehaviourAdded);
-        universeObject.BehaviourController.OnBehaviourRemoved.AddListener(delegateOnBehaviourRemoved);
-
-        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
-            OnBehaviourAdded(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
-    }
-
-    private void OnUniverseObjectUnregistered(IUniverse manager, IUniverse.UniverseObjectUnRegisteredArguments args)
-    {
-        IUniverseObject universeObject = args.UniverseObjectUnregistered;
-
-        universeObject.BehaviourController.OnBehaviourAdded.RemoveListener(delegateOnBehaviourAdded);
-        universeObject.BehaviourController.OnBehaviourRemoved.RemoveListener(delegateOnBehaviourRemoved);
-
-        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
-            OnBehaviourRemoved(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
-    }
-
-    protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
-    private void OnBehaviourAdded(IBehaviourController controller, IBehaviourController.BehaviourAddedArguments args)
-    {
-        if (args.BehaviourAdded is not T tBehaviour)
-            return;
-
-        monitoringBehaviours.Add(tBehaviour);
-        monitoringActiveToBehaviour.Add(tBehaviour, tBehaviour);
-        tBehaviour.OnActiveChanged.AddListener(delegateOnBehaviourStateChanged);
-        OnBehaviourStateChanged(tBehaviour, new(!tBehaviour.IsActive));
-    }
-
-    protected virtual void AddBehaviour(T behaviour) => activeBehaviours.Add(behaviour);
-    private void OnBehaviourStateChanged(IActive sender, IActive.ActiveChangedArguments args)
-    {
-        T behaviour = monitoringActiveToBehaviour[sender];
-        if (sender.IsActive)
-        {
-            AddBehaviour(behaviour);
-            OnBehaviourAdd(behaviour);
-            OnCollected?.Invoke(this, new(behaviour));
-        }
-        else if (activeBehaviours.Remove(behaviour))
-        {
-            OnBehaviourRemove(behaviour);
-            OnRemoved?.Invoke(this, new(behaviour));
-        }
-    }
-
-    protected virtual void OnBehaviourRemove(IBehaviour behaviour) { }
-    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviourController.BehaviourRemovedArguments args)
-    {
-        if (args.BehaviourRemoved is not T tBehaviour)
-            return;
-
-        if (!monitoringBehaviours.Remove(tBehaviour) || !monitoringActiveToBehaviour.Remove(tBehaviour))
-            return;
-
-        tBehaviour.OnActiveChanged.RemoveListener(delegateOnBehaviourStateChanged);
-        if (activeBehaviours.Remove(tBehaviour))
-        {
-            OnBehaviourRemove(tBehaviour);
-            OnRemoved?.Invoke(this, new(tBehaviour));
-        }
-    }
-
     public bool Assign(IUniverse universe)
     {
         if (Universe is not null)
@@ -123,10 +57,75 @@ public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : clas
         return true;
     }
 
-    public int Count => activeBehaviours.Count;
+    protected abstract void AddBehaviour(T behaviour);
-    public T this[Index index] => activeBehaviours[index];
+    protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
+    private void OnBehaviourAdded(IBehaviourController controller, IBehaviourController.BehaviourAddedArguments args)
+    {
+        if (args.BehaviourAdded is not T tBehaviour)
+            return;
 
-    public ActiveBehaviourCollector()
+        monitoringBehaviours.Add(tBehaviour);
+        monitoringActiveToBehaviour.Add(tBehaviour, tBehaviour);
+        tBehaviour.OnActiveChanged.AddListener(delegateOnBehaviourStateChanged);
+        OnBehaviourStateChanged(tBehaviour, new(!tBehaviour.IsActive));
+    }
+
+    protected abstract bool RemoveBehaviour(T behaviour);
+    protected virtual void OnBehaviourRemove(IBehaviour behaviour) { }
+    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviourController.BehaviourRemovedArguments args)
+    {
+        if (args.BehaviourRemoved is not T tBehaviour)
+            return;
+
+        if (!monitoringBehaviours.Remove(tBehaviour) || !monitoringActiveToBehaviour.Remove(tBehaviour))
+            return;
+
+        tBehaviour.OnActiveChanged.RemoveListener(delegateOnBehaviourStateChanged);
+        if (!RemoveBehaviour(tBehaviour))
+            return;
+
+        OnBehaviourRemove(tBehaviour);
+        OnRemoved?.Invoke(this, new(tBehaviour));
+    }
+    private void OnBehaviourStateChanged(IActive sender, IActive.ActiveChangedArguments args)
+    {
+        T behaviour = monitoringActiveToBehaviour[sender];
+        if (sender.IsActive)
+        {
+            AddBehaviour(behaviour);
+            OnBehaviourAdd(behaviour);
+            OnCollected?.Invoke(this, new(behaviour));
+        }
+        else if (RemoveBehaviour(behaviour))
+        {
+            OnBehaviourRemove(behaviour);
+            OnRemoved?.Invoke(this, new(behaviour));
+        }
+    }
+
+    private void OnUniverseObjectRegistered(IUniverse manager, IUniverse.UniverseObjectRegisteredArguments args)
+    {
+        IUniverseObject universeObject = args.UniverseObjectRegistered;
+
+        universeObject.BehaviourController.OnBehaviourAdded.AddListener(delegateOnBehaviourAdded);
+        universeObject.BehaviourController.OnBehaviourRemoved.AddListener(delegateOnBehaviourRemoved);
+
+        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
+            OnBehaviourAdded(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
+    }
+
+    private void OnUniverseObjectUnregistered(IUniverse manager, IUniverse.UniverseObjectUnRegisteredArguments args)
+    {
+        IUniverseObject universeObject = args.UniverseObjectUnregistered;
+
+        universeObject.BehaviourController.OnBehaviourAdded.RemoveListener(delegateOnBehaviourAdded);
+        universeObject.BehaviourController.OnBehaviourRemoved.RemoveListener(delegateOnBehaviourRemoved);
+
+        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
+            OnBehaviourRemoved(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
+    }
+
+    public ActiveBehaviourCollectorBase()
     {
         delegateOnBehaviourAdded = OnBehaviourAdded;
         delegateOnBehaviourRemoved = OnBehaviourRemoved;
@@ -135,7 +134,7 @@ public class ActiveBehaviourCollector<T> : IBehaviourCollector<T> where T : clas
         delegateOnUniverseObjectUnregistered = OnUniverseObjectUnregistered;
     }
 
-    public ActiveBehaviourCollector(IUniverse universe)
+    public ActiveBehaviourCollectorBase(IUniverse universe)
     {
         delegateOnBehaviourAdded = OnBehaviourAdded;
         delegateOnBehaviourRemoved = OnBehaviourRemoved;

Engine.Core/Collectors/ActiveBehaviourCollectorOrdered.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+
+namespace Engine.Core;
+
+public class ActiveBehaviourCollectorOrdered<TIndex, TItem> : ActiveBehaviourCollector<TItem> where TItem : class, IBehaviour where TIndex : IComparable
+{
+    private readonly Event<IBehaviour, IBehaviour.PriorityChangedArguments>.EventHandler delegateOnPriorityChanged = null!;
+
+    private readonly SortedDictionary<TIndex, FastList<TItem>> behaviours = null!;
+
+    private readonly Func<TItem, TIndex> getIndexFunc = null!;
+    private readonly IComparer<TIndex> sortBy = null!;
+
+    private int count = 0;
+    public override int Count => count;
+
+    public override TItem this[Index index]
+    {
+        get
+        {
+            int actualIndex = index.IsFromEnd
+                ? count - index.Value
+                : index.Value;
+
+            if (actualIndex < 0 || actualIndex >= count)
+                throw new IndexOutOfRangeException();
+
+            int leftIndex = actualIndex;
+            foreach ((TIndex i, FastList<TItem> list) in behaviours)
+            {
+                if (leftIndex < list.Count)
+                    return list[leftIndex];
+                leftIndex -= list.Count;
+            }
+            throw new IndexOutOfRangeException();
+        }
+    }
+
+    protected override bool RemoveBehaviour(TItem tBehaviour)
+    {
+        TIndex index = getIndexFunc(tBehaviour);
+        if (!behaviours.TryGetValue(index, out FastList<TItem>? list))
+            throw new Exceptions.NotFoundException($"Index of '{index}' is not found in the collector");
+
+        if (!list.Remove(tBehaviour))
+            return false;
+
+        count--;
+        return true;
+    }
+
+    protected override void AddBehaviour(TItem behaviour)
+    {
+        TIndex key = getIndexFunc(behaviour);
+        if (!behaviours.TryGetValue(key, out FastList<TItem>? list))
+            behaviours[key] = list = [];
+
+        count++;
+        list.Add(behaviour);
+    }
+
+    protected override void OnBehaviourAdd(IBehaviour behaviour) => behaviour.OnPriorityChanged.AddListener(delegateOnPriorityChanged);
+    protected override void OnBehaviourRemove(IBehaviour behaviour) => behaviour.OnPriorityChanged.RemoveListener(delegateOnPriorityChanged);
+
+    private void OnPriorityChanged(IBehaviour sender, IBehaviour.PriorityChangedArguments args)
+    {
+        TItem behaviour = (TItem)sender;
+        RemoveBehaviour(behaviour);
+        AddBehaviour(behaviour);
+    }
+
+    public ActiveBehaviourCollectorOrdered(Func<TItem, TIndex> getIndexFunc, Comparison<TIndex> sortBy)
+    {
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = Comparer<TIndex>.Create(sortBy);
+        behaviours = new(this.sortBy);
+    }
+
+    public ActiveBehaviourCollectorOrdered(IUniverse universe, Func<TItem, TIndex> getIndexFunc, Comparison<TIndex> sortBy) : base(universe)
+    {
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = Comparer<TIndex>.Create(sortBy);
+        behaviours = new(this.sortBy);
+    }
+
+    public ActiveBehaviourCollectorOrdered(Func<TItem, TIndex> getIndexFunc, IComparer<TIndex> sortBy)
+    {
+        this.getIndexFunc = getIndexFunc;
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.sortBy = sortBy;
+        behaviours = new(sortBy);
+    }
+
+    public ActiveBehaviourCollectorOrdered(IUniverse universe, Func<TItem, TIndex> getIndexFunc, IComparer<TIndex> sortBy) : base(universe)
+    {
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = sortBy;
+        behaviours = new(sortBy);
+    }
+}

Engine.Core/Collectors/BehaviourCollector.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace Engine.Core;
+
+public class BehaviourCollector<T> : BehaviourCollectorBase<T> where T : class
+{
+    protected readonly FastList<T> behaviours = new(32);
+
+    public override T this[Index index] => behaviours[index];
+    public override int Count => behaviours.Count;
+
+    protected override void AddBehaviour(T behaviour) => behaviours.Add(behaviour);
+    protected override bool RemoveBehaviour(T tBehaviour) => behaviours.Remove(tBehaviour);
+
+    public BehaviourCollector() { }
+    public BehaviourCollector(IUniverse universe) : base(universe) { }
+}

Engine.Core/Collectors/BehaviourCollectorBase.cs

@@ -2,70 +2,24 @@ using System;
 
 namespace Engine.Core;
 
-public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
+public abstract class BehaviourCollectorBase<T> : IBehaviourCollector<T> where T : class
 {
-    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourCollectedArguments> OnCollected { get; } = new();
-    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourRemovedArguments> OnRemoved { get; } = new();
-    public Event<IHasUniverse> OnUniverseAssigned { get; } = new();
-    public Event<IAssignable>? OnUnassigned { get; } = new();
-
     private readonly Event<IBehaviourController, IBehaviourController.BehaviourAddedArguments>.EventHandler delegateOnBehaviourAdded = null!;
     private readonly Event<IBehaviourController, IBehaviourController.BehaviourRemovedArguments>.EventHandler delegateOnBehaviourRemoved = null!;
     private readonly Event<IUniverse, IUniverse.UniverseObjectRegisteredArguments>.EventHandler delegateOnUniverseObjectRegistered = null!;
     private readonly Event<IUniverse, IUniverse.UniverseObjectUnRegisteredArguments>.EventHandler delegateOnUniverseObjectUnregistered = null!;
 
-    protected readonly FastList<T> behaviours = new(32);
+    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourCollectedArguments> OnCollected { get; } = new();
+    public Event<IBehaviourCollector<T>, IBehaviourCollector<T>.BehaviourRemovedArguments> OnRemoved { get; } = new();
+    public Event<IHasUniverse> OnUniverseAssigned { get; } = new();
+    public Event<IAssignable>? OnUnassigned { get; } = new();
 
     public IUniverse Universe { get; private set; } = null!;
 
-    private void OnUniverseObjectRegistered(IUniverse manager, IUniverse.UniverseObjectRegisteredArguments args)
+    public abstract int Count { get; }
-    {
-        IUniverseObject universeObject = args.UniverseObjectRegistered;
 
-        universeObject.BehaviourController.OnBehaviourAdded.AddListener(delegateOnBehaviourAdded);
+    public abstract T this[Index index] { get; }
-        universeObject.BehaviourController.OnBehaviourRemoved.AddListener(delegateOnBehaviourRemoved);
 
-        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
-            OnBehaviourAdded(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
-    }
-
-    private void OnUniverseObjectUnregistered(IUniverse manager, IUniverse.UniverseObjectUnRegisteredArguments args)
-    {
-        IUniverseObject universeObject = args.UniverseObjectUnregistered;
-
-        universeObject.BehaviourController.OnBehaviourAdded.RemoveListener(delegateOnBehaviourAdded);
-        universeObject.BehaviourController.OnBehaviourRemoved.RemoveListener(delegateOnBehaviourRemoved);
-
-        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
-            OnBehaviourRemoved(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
-    }
-
-    protected virtual void AddBehaviour(T behaviour) => behaviours.Add(behaviour);
-    protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
-    private void OnBehaviourAdded(IBehaviourController controller, IBehaviourController.BehaviourAddedArguments args)
-    {
-        if (args.BehaviourAdded is not T tBehaviour)
-            return;
-
-        AddBehaviour(tBehaviour);
-        OnBehaviourAdd(args.BehaviourAdded);
-        OnCollected?.Invoke(this, new(tBehaviour));
-    }
-
-    protected virtual void OnBehaviourRemove(IBehaviour behaviour) { }
-    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviourController.BehaviourRemovedArguments args)
-    {
-        if (args.BehaviourRemoved is not T tBehaviour)
-            return;
-
-        if (!behaviours.Remove(tBehaviour))
-            return;
-
-        OnBehaviourRemove(args.BehaviourRemoved);
-        OnRemoved?.Invoke(this, new(tBehaviour));
-    }
-
-    protected virtual void OnAssign(IUniverse universe) { }
     public bool Assign(IUniverse universe)
     {
         if (Universe is not null)
@@ -100,10 +54,57 @@ public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
         return true;
     }
 
-    public int Count => behaviours.Count;
+    protected virtual void OnAssign(IUniverse universe) { }
-    public T this[Index index] => behaviours[index];
 
-    public BehaviourCollector()
+    protected abstract void AddBehaviour(T behaviour);
+    protected virtual void OnBehaviourAdd(IBehaviour behaviour) { }
+    private void OnBehaviourAdded(IBehaviourController controller, IBehaviourController.BehaviourAddedArguments args)
+    {
+        if (args.BehaviourAdded is not T tBehaviour)
+            return;
+
+        AddBehaviour(tBehaviour);
+        OnBehaviourAdd(args.BehaviourAdded);
+        OnCollected?.Invoke(this, new(tBehaviour));
+    }
+
+    protected abstract bool RemoveBehaviour(T tBehaviour);
+    protected virtual void OnBehaviourRemove(IBehaviour behaviour) { }
+    private void OnBehaviourRemoved(IBehaviourController controller, IBehaviourController.BehaviourRemovedArguments args)
+    {
+        if (args.BehaviourRemoved is not T tBehaviour)
+            return;
+
+        if (!RemoveBehaviour(tBehaviour))
+            return;
+
+        OnBehaviourRemove(args.BehaviourRemoved);
+        OnRemoved?.Invoke(this, new(tBehaviour));
+    }
+
+    private void OnUniverseObjectRegistered(IUniverse manager, IUniverse.UniverseObjectRegisteredArguments args)
+    {
+        IUniverseObject universeObject = args.UniverseObjectRegistered;
+
+        universeObject.BehaviourController.OnBehaviourAdded.AddListener(delegateOnBehaviourAdded);
+        universeObject.BehaviourController.OnBehaviourRemoved.AddListener(delegateOnBehaviourRemoved);
+
+        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
+            OnBehaviourAdded(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
+    }
+
+    private void OnUniverseObjectUnregistered(IUniverse manager, IUniverse.UniverseObjectUnRegisteredArguments args)
+    {
+        IUniverseObject universeObject = args.UniverseObjectUnregistered;
+
+        universeObject.BehaviourController.OnBehaviourAdded.RemoveListener(delegateOnBehaviourAdded);
+        universeObject.BehaviourController.OnBehaviourRemoved.RemoveListener(delegateOnBehaviourRemoved);
+
+        for (int i = 0; i < universeObject.BehaviourController.Count; i++)
+            OnBehaviourRemoved(universeObject.BehaviourController, new(universeObject.BehaviourController[i]));
+    }
+
+    public BehaviourCollectorBase()
     {
         delegateOnBehaviourAdded = OnBehaviourAdded;
         delegateOnBehaviourRemoved = OnBehaviourRemoved;
@@ -111,7 +112,7 @@ public class BehaviourCollector<T> : IBehaviourCollector<T> where T : class
         delegateOnUniverseObjectUnregistered = OnUniverseObjectUnregistered;
     }
 
-    public BehaviourCollector(IUniverse universe)
+    public BehaviourCollectorBase(IUniverse universe)
     {
         delegateOnBehaviourAdded = OnBehaviourAdded;
         delegateOnBehaviourRemoved = OnBehaviourRemoved;

Engine.Core/Collectors/BehaviourCollectorOrdered.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+
+namespace Engine.Core;
+
+public class BehaviourCollectorOrdered<TIndex, TItem> : BehaviourCollectorBase<TItem> where TItem : class where TIndex : IComparable
+{
+    private readonly Event<IBehaviour, IBehaviour.PriorityChangedArguments>.EventHandler delegateOnPriorityChanged = null!;
+
+    private readonly SortedDictionary<TIndex, FastList<TItem>> behaviours = null!;
+
+    private readonly Func<TItem, TIndex> getIndexFunc = null!;
+    private readonly IComparer<TIndex> sortBy = null!;
+
+    private int count = 0;
+    public override int Count => count;
+
+    public override TItem this[Index index]
+    {
+        get
+        {
+            int actualIndex = index.IsFromEnd
+                ? count - index.Value
+                : index.Value;
+
+            if (actualIndex < 0 || actualIndex >= count)
+                throw new IndexOutOfRangeException();
+
+            int leftIndex = actualIndex;
+            foreach ((TIndex i, FastList<TItem> list) in behaviours)
+            {
+                if (leftIndex < list.Count)
+                    return list[leftIndex];
+                leftIndex -= list.Count;
+            }
+            throw new IndexOutOfRangeException();
+        }
+    }
+
+    protected override bool RemoveBehaviour(TItem tBehaviour)
+    {
+        TIndex index = getIndexFunc(tBehaviour);
+        if (!behaviours.TryGetValue(index, out FastList<TItem>? list))
+            throw new Exceptions.NotFoundException($"Index of '{index}' is not found in the collector");
+
+        if (!list.Remove(tBehaviour))
+            return false;
+
+        count--;
+        return true;
+    }
+
+    protected override void AddBehaviour(TItem behaviour)
+    {
+        TIndex key = getIndexFunc(behaviour);
+        if (!behaviours.TryGetValue(key, out FastList<TItem>? list))
+            behaviours[key] = list = [];
+
+        count++;
+        list.Add(behaviour);
+    }
+
+    protected override void OnBehaviourAdd(IBehaviour behaviour) => behaviour.OnPriorityChanged.AddListener(delegateOnPriorityChanged);
+    protected override void OnBehaviourRemove(IBehaviour behaviour) => behaviour.OnPriorityChanged.RemoveListener(delegateOnPriorityChanged);
+
+    private void OnPriorityChanged(IBehaviour sender, IBehaviour.PriorityChangedArguments args)
+    {
+        TItem behaviour = (TItem)sender;
+        RemoveBehaviour(behaviour);
+        AddBehaviour(behaviour);
+    }
+
+    public BehaviourCollectorOrdered(Func<TItem, TIndex> getIndexFunc, Comparison<TIndex> sortBy)
+    {
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = Comparer<TIndex>.Create(sortBy);
+        behaviours = new(this.sortBy);
+    }
+
+    public BehaviourCollectorOrdered(IUniverse universe, Func<TItem, TIndex> getIndexFunc, Comparison<TIndex> sortBy) : base(universe)
+    {
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = Comparer<TIndex>.Create(sortBy);
+        behaviours = new(this.sortBy);
+    }
+
+    public BehaviourCollectorOrdered(Func<TItem, TIndex> getIndexFunc, IComparer<TIndex> sortBy)
+    {
+        this.getIndexFunc = getIndexFunc;
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.sortBy = sortBy;
+        behaviours = new(sortBy);
+    }
+
+    public BehaviourCollectorOrdered(IUniverse universe, Func<TItem, TIndex> getIndexFunc, IComparer<TIndex> sortBy) : base(universe)
+    {
+        delegateOnPriorityChanged = OnPriorityChanged;
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = sortBy;
+        behaviours = new(sortBy);
+    }
+}

Engine.Core/Helpers/FastList.cs

@@ -3,17 +3,30 @@ using System.Collections.Generic;
 
 namespace Engine.Core;
 
-public class FastList<T> : IReadOnlyList<T>, IEnumerable<T> where T : notnull
+public class FastList<T> : IList<T>, IReadOnlyList<T>, IEnumerable<T> where T : notnull
 {
     private readonly List<T> items = [];
     private readonly Dictionary<T, int> indexMap = [];
 
+    public bool IsReadOnly { get; set; } = false;
     public int Count => items.Count;
+    public T this[int index]
+    {
+        get => items[index];
+        set
+        {
+            if (IsReadOnly)
+                throw new System.Data.ReadOnlyException();
 
-    public T this[int index] => items[index];
+            items[index] = value;
+        }
+    }
 
     public void Add(T item)
     {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
         indexMap[item] = items.Count;
         items.Add(item);
     }
@@ -21,6 +34,9 @@ public class FastList<T> : IReadOnlyList<T>, IEnumerable<T> where T : notnull
     public void RemoveAt(int i) => Remove(items[i], i);
     public bool Remove(T item)
     {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
         if (!indexMap.TryGetValue(item, out int index))
             return false;
 
@@ -43,6 +59,9 @@ public class FastList<T> : IReadOnlyList<T>, IEnumerable<T> where T : notnull
 
     public void Insert(int index, T item)
     {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
         items.Insert(index, item);
 
         for (int i = index; i < items.Count; i++)
@@ -51,21 +70,30 @@ public class FastList<T> : IReadOnlyList<T>, IEnumerable<T> where T : notnull
 
     public void Clear()
     {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
         items.Clear();
         indexMap.Clear();
     }
 
     public bool Contains(T item) => indexMap.ContainsKey(item);
-
+    public int IndexOf(T item) => items.IndexOf(item);
     public int BinarySearch(T item, IComparer<T>? comparer = null) => items.BinarySearch(item, comparer);
+
     public void Sort(IComparer<T> comparer)
     {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
         items.Sort(comparer);
 
         for (int i = 0; i < items.Count; i++)
             indexMap[items[i]] = i;
     }
 
+    public void CopyTo(T[] array, int arrayIndex) => items.CopyTo(array, arrayIndex);
+
     public IEnumerator<T> GetEnumerator() => items.GetEnumerator();
     IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 

Engine.Core/Helpers/FastListOrdered.cs

@@ -0,0 +1,172 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Engine.Core;
+
+/// <summary>
+/// TODO This is VEERY experimental, and doesn't work well with the indices access. Use with caution
+/// </summary>
+/// <typeparam name="TIndex"></typeparam>
+/// <typeparam name="TItem"></typeparam>
+public class FastListOrdered<TIndex, TItem> : IList<TItem>, IReadOnlyList<TItem>, IEnumerable<TItem> where TItem : notnull where TIndex : IComparable
+{
+    private readonly SortedDictionary<TIndex, FastList<TItem>> items = null!;
+
+    private readonly Func<TItem, TIndex> getIndexFunc = null!;
+    private readonly IComparer<TIndex> sortBy = null!;
+
+    private int count = 0;
+    public int Count => count;
+
+    public bool IsReadOnly { get; set; } = false;
+
+    public TItem this[int index]
+    {
+        get { (TIndex tIndex, int i) = GetAt(index); return items[tIndex][i]; }
+        set
+        {
+            if (IsReadOnly)
+                throw new System.Data.ReadOnlyException();
+            (TIndex tIndex, int i) = GetAt(index); items[tIndex][i] = value;
+        }
+    }
+
+    private (TIndex TIndex, int i) GetAt(Index index)
+    {
+        int actualIndex = index.IsFromEnd
+                ? count - index.Value
+                : index.Value;
+
+        if (actualIndex < 0 || actualIndex >= count)
+            throw new IndexOutOfRangeException();
+
+        int leftIndex = actualIndex;
+        foreach ((TIndex i, FastList<TItem> list) in items)
+        {
+            if (leftIndex < list.Count)
+                return (i, leftIndex);
+            leftIndex -= list.Count;
+        }
+        throw new IndexOutOfRangeException();
+    }
+
+    public int IndexOf(TItem item)
+    {
+        int indexCounter = 0;
+        foreach ((TIndex index, FastList<TItem> list) in items)
+        {
+            int i = list.IndexOf(item);
+            if (i != -1)
+                return indexCounter + i;
+            indexCounter += list.Count;
+        }
+
+        return -1;
+    }
+
+    public void Add(TItem item)
+    {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
+        TIndex key = getIndexFunc(item);
+        if (!items.TryGetValue(key, out FastList<TItem>? list))
+            items[key] = list = [];
+
+        list.Add(item);
+        count++;
+    }
+
+    public void Insert(int index, TItem item)
+    {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
+        TIndex tIndex = getIndexFunc(item);
+        if (!items.TryGetValue(tIndex, out FastList<TItem>? list))
+            items[tIndex] = list = [];
+
+        list.Insert(index, item);
+        count++;
+    }
+
+    public bool Remove(TItem item)
+    {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
+        TIndex index = getIndexFunc(item);
+        if (!items.TryGetValue(index, out FastList<TItem>? list))
+            throw new Exceptions.NotFoundException($"Index of '{index}' is not found in the collector");
+
+        if (!list.Remove(item))
+            return false;
+
+        count--;
+        return true;
+    }
+
+    public void RemoveAt(int index)
+    {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
+        (TIndex tIndex, int i) = GetAt(index);
+        items[tIndex].RemoveAt(i);
+        count--;
+    }
+
+    public void Clear()
+    {
+        if (IsReadOnly)
+            throw new System.Data.ReadOnlyException();
+
+        foreach ((TIndex index, FastList<TItem> list) in items)
+            list.Clear();
+
+        count = 0;
+    }
+
+    public bool Contains(TItem item)
+    {
+        foreach ((TIndex index, FastList<TItem> list) in items)
+            if (list.Contains(item))
+                return true;
+        return false;
+    }
+
+    public void CopyTo(TItem[] array, int arrayIndex)
+    {
+        int indexCounter = 0;
+
+        foreach ((TIndex index, FastList<TItem> list) in items)
+        {
+            list.CopyTo(array, indexCounter);
+            indexCounter += list.Count;
+        }
+    }
+
+    public IEnumerator<TItem> GetEnumerator()
+    {
+        foreach ((TIndex index, FastList<TItem> list) in items)
+            foreach (TItem item in list)
+                yield return item;
+    }
+
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+    public FastListOrdered(Func<TItem, TIndex> getIndexFunc, Comparison<TIndex> sortBy)
+    {
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = Comparer<TIndex>.Create(sortBy);
+        items = new(this.sortBy);
+    }
+
+    public FastListOrdered(Func<TItem, TIndex> getIndexFunc, IComparer<TIndex> sortBy)
+    {
+        this.getIndexFunc = getIndexFunc;
+        this.sortBy = sortBy;
+        items = new(sortBy);
+    }
+}

Engine.Core/Systems/DrawManager.cs

@@ -5,11 +5,12 @@ namespace Engine.Core;
 public class DrawManager : Behaviour
 {
     // We use Descending order because draw calls are running from last to first
-    private static Comparer<IBehaviour> SortByDescendingPriority() => Comparer<IBehaviour>.Create((x, y) => y.Priority.CompareTo(x.Priority));
+    private static Comparer<int> SortByDescendingPriority() => Comparer<int>.Create((x, y) => y.CompareTo(x));
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
 
-    private readonly ActiveBehaviourCollectorSorted<IPreDraw> preDrawEntities = new() { SortBy = SortByDescendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IPreDraw> preDrawEntities = new(GetPriority(), SortByDescendingPriority());
-    private readonly ActiveBehaviourCollectorSorted<IDraw> drawEntities = new() { SortBy = SortByDescendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IDraw> drawEntities = new(GetPriority(), SortByDescendingPriority());
-    private readonly ActiveBehaviourCollectorSorted<IPostDraw> postDrawEntities = new() { SortBy = SortByDescendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IPostDraw> postDrawEntities = new(GetPriority(), SortByDescendingPriority());
 
     private void OnPreDraw(IUniverse sender)
     {

Engine.Core/Systems/UniverseEntranceManager.cs

@@ -5,10 +5,11 @@ namespace Engine.Core;
 public class UniverseEntranceManager : Behaviour
 {
     // We use Ascending order because we are using reverse for loop to call them
-    private static Comparer<IBehaviour> SortByAscendingPriority() => Comparer<IBehaviour>.Create((x, y) => x.Priority.CompareTo(y.Priority));
+    private static Comparer<int> SortByAscendingPriority() => Comparer<int>.Create((x, y) => x.CompareTo(y));
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
 
-    private readonly ActiveBehaviourCollectorSorted<IEnterUniverse> enterUniverses = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IEnterUniverse> enterUniverses = new(GetPriority(), SortByAscendingPriority());
-    private readonly ActiveBehaviourCollectorSorted<IExitUniverse> exitUniverses = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IExitUniverse> exitUniverses = new(GetPriority(), SortByAscendingPriority());
 
     private readonly List<IEnterUniverse> toCallEnterUniverses = new(32);
     private readonly List<IExitUniverse> toCallExitUniverses = new(32);

Engine.Core/Systems/UpdateManager.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 
 namespace Engine.Core;
@@ -6,13 +5,14 @@ namespace Engine.Core;
 public class UpdateManager : Behaviour
 {
     // We use Ascending order because we are using reverse for loop to call them
-    private static Comparer<IBehaviour> SortByAscendingPriority() => Comparer<IBehaviour>.Create((x, y) => x.Priority.CompareTo(y.Priority));
+    private static Comparer<int> SortByAscendingPriority() => Comparer<int>.Create((x, y) => x.CompareTo(y));
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
 
-    private readonly ActiveBehaviourCollectorSorted<IFirstFrameUpdate> firstFrameUpdates = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IFirstFrameUpdate> firstFrameUpdates = new(GetPriority(), SortByAscendingPriority());
     private readonly ActiveBehaviourCollector<ILastFrameUpdate> lastFrameUpdates = new();
-    private readonly ActiveBehaviourCollectorSorted<IPreUpdate> preUpdateEntities = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IPreUpdate> preUpdateEntities = new(GetPriority(), SortByAscendingPriority());
-    private readonly ActiveBehaviourCollectorSorted<IUpdate> updateEntities = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IUpdate> updateEntities = new(GetPriority(), SortByAscendingPriority());
-    private readonly ActiveBehaviourCollectorSorted<IPostUpdate> postUpdateEntities = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IPostUpdate> postUpdateEntities = new(GetPriority(), SortByAscendingPriority());
 
     private readonly List<IFirstFrameUpdate> toCallFirstFrameUpdates = new(32);
 

Engine.Core/Universe.cs

@@ -22,7 +22,7 @@ public class Universe : BaseEntity, IUniverse
     private readonly Event<IInitializable>.EventHandler delegateOnUniverseObjectFinalize = null!;
     private readonly Event<IUniverseObject, IUniverseObject.ExitedUniverseArguments>.EventHandler delegateOnUniverseObjectExitedUniverse = null!;
 
-    private readonly List<IUniverseObject> _universeObjects = new(Constants.UNIVERSE_OBJECTS_SIZE_INITIAL);
+    private readonly FastList<IUniverseObject> _universeObjects = new(Constants.UNIVERSE_OBJECTS_SIZE_INITIAL);
     private float _timeScale = 1f;
 
     public Universe()

Engine.Core/UniverseObject.cs

@@ -19,7 +19,7 @@ public class UniverseObject : BaseEntity, IUniverseObject
     private IUniverse _universe = null!;
     private IBehaviourController _behaviourController = null!;
     private bool _isActive = false;
-    private readonly List<IUniverseObject> _children = [];
+    private readonly FastList<IUniverseObject> _children = [];
     private IUniverseObject? _parent = null;
 
     public IReadOnlyList<IUniverseObject> Children => _children;

Engine.Integration/Engine.Integration.MonoGame/Behaviours/LoadContentManager.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+
 using Engine.Core;
 
 namespace Engine.Integration.MonoGame;
@@ -6,9 +7,10 @@ namespace Engine.Integration.MonoGame;
 public class LoadContentManager : Behaviour, IFirstFrameUpdate
 {
     // We use Ascending order because we are using reverse for loop to call them
-    private static Comparer<IBehaviour> SortByAscendingPriority() => Comparer<IBehaviour>.Create((x, y) => x.Priority.CompareTo(y.Priority));
+    private static Comparer<int> SortByAscendingPriority() => Comparer<int>.Create((x, y) => x.CompareTo(y));
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
 
-    private readonly ActiveBehaviourCollectorSorted<ILoadContent> loadContents = new() { SortBy = SortByAscendingPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, ILoadContent> loadContents = new(GetPriority(), SortByAscendingPriority());
     private readonly List<ILoadContent> toCallLoadContents = new(32);
 
     private MonoGameWindowContainer monoGameWindowContainer = null!;

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

@@ -6,12 +6,13 @@ namespace Engine.Integration.MonoGame;
 
 public class SpriteBatcher : BehaviourBase, IFirstFrameUpdate, IDraw
 {
-    private static Comparer<IBehaviour> SortByPriority() => Comparer<IBehaviour>.Create((x, y) => y.Priority.CompareTo(x.Priority));
+    private static Comparer<int> SortByPriority() => Comparer<int>.Create((x, y) => y.CompareTo(x));
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
 
     private ISpriteBatch spriteBatch = null!;
     private MonoGameCamera2D camera2D = null!;
 
-    private readonly ActiveBehaviourCollectorSorted<IDrawableSprite> drawableSprites = new() { SortBy = SortByPriority() };
+    private readonly ActiveBehaviourCollectorOrdered<int, IDrawableSprite> drawableSprites = new(GetPriority(), SortByPriority());
 
     public void FirstActiveFrame()
     {

Engine.Integration/Engine.Integration.MonoGame/Behaviours/TriangleBatcher.cs

@@ -8,11 +8,13 @@ namespace Engine.Integration.MonoGame;
 
 public class TriangleBatcher : BehaviourBase, ITriangleBatch, IFirstFrameUpdate, IDraw
 {
-    private static Comparer<IBehaviour> SortByAscendingPriority() => Comparer<IBehaviour>.Create((x, y) => x.Priority.CompareTo(y.Priority));
+    private static Comparer<int> SortByAscendingPriority() => Comparer<int>.Create((x, y) => x.CompareTo(y));
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
 
     private TriangleBatch triangleBatch = null!;
     private MonoGameCamera2D camera2D = null!;
-    private readonly ActiveBehaviourCollectorSorted<IDrawableTriangle> drawableShapes = new() { SortBy = SortByAscendingPriority() };
+
+    private readonly ActiveBehaviourCollectorOrdered<int, IDrawableTriangle> drawableShapes = new(GetPriority(), SortByAscendingPriority());
 
     public void FirstActiveFrame()
     {

Engine.Physics2D/PhysicsEngine2D.cs

@@ -17,11 +17,12 @@ public class PhysicsEngine2D : Behaviour, IPreUpdate, IPhysicsEngine2D
     protected readonly ICollisionResolver2D collisionResolver = null!;
     protected readonly IRaycastResolver2D raycastResolver = null!;
 
-    private static Comparer<IBehaviour> SortByPriority() => Comparer<IBehaviour>.Create((x, y) => y.Priority.CompareTo(x.Priority));
+    private static Comparer<int> SortByPriority() => Comparer<int>.Create((x, y) => y.CompareTo(x));
-    protected ActiveBehaviourCollectorSorted<IPrePhysicsUpdate> physicsPreUpdateCollector = new() { SortBy = SortByPriority() };
+    private static System.Func<IBehaviour, int> GetPriority() => (b) => b.Priority;
-    protected ActiveBehaviourCollectorSorted<IPhysicsUpdate> physicsUpdateCollector = new() { SortBy = SortByPriority() };
+    protected ActiveBehaviourCollectorOrdered<int, IPrePhysicsUpdate> physicsPreUpdateCollector = new(GetPriority(), SortByPriority());
-    protected ActiveBehaviourCollectorSorted<IPhysicsIteration> physicsIterationCollector = new() { SortBy = SortByPriority() };
+    protected ActiveBehaviourCollectorOrdered<int, IPhysicsUpdate> physicsUpdateCollector = new(GetPriority(), SortByPriority());
-    protected ActiveBehaviourCollectorSorted<IPostPhysicsUpdate> physicsPostUpdateCollector = new() { SortBy = SortByPriority() };
+    protected ActiveBehaviourCollectorOrdered<int, IPhysicsIteration> physicsIterationCollector = new(GetPriority(), SortByPriority());
+    protected ActiveBehaviourCollectorOrdered<int, IPostPhysicsUpdate> physicsPostUpdateCollector = new(GetPriority(), SortByPriority());
     protected BehaviourCollector<IRigidBody2D> rigidBodyCollector = new();
     protected BehaviourCollector<ICollider2D> colliderCollector = new();