Add managed entity and script component.

Added ManagedEntity and related methods in EntityManager;
Added ScriptComponent to write game play logic in oop;

Ghost.Core/Handle.cs

@@ -5,7 +5,6 @@ public interface IIdentifierType;
 public interface IKeyType;
 
 public readonly struct Handle<T> : IEquatable<Handle<T>>
-    where T : IHandleType
 {
     public readonly int id;
     public readonly int generation;
@@ -58,7 +57,6 @@ public readonly struct Handle<T> : IEquatable<Handle<T>>
 }
 
 public readonly struct Identifier<T> : IEquatable<Identifier<T>>
-    where T : IIdentifierType
 {
     public readonly int value;
 
@@ -132,7 +130,6 @@ public readonly struct Identifier<T> : IEquatable<Identifier<T>>
 }
 
 public readonly struct Key<T>
-    where T : IKeyType
 {
     public readonly ulong value;
 

Ghost.Entities.Test/EntityTest.cs

@@ -29,8 +29,12 @@ public partial class EntityTest : ITest
 
     public void Run()
     {
-        var entity1 = _world.EntityManager.CreateEntity(ComponentTypeID<Transform>.value);
+        var entity1 = _world.EntityManager.CreateEntity(ComponentTypeID<Transform>.value, ComponentTypeID<ManagedEntityRef>.value);
         _world.EntityManager.AddComponent(entity1, new Mesh { index = 1 });
+        _world.EntityManager.SetComponent(entity1, new ManagedEntityRef
+        {
+            entity = _world.EntityManager.CreateManagedEntity()
+        });
 
         var entity2 = _world.EntityManager.CreateEntity(ComponentTypeID<Transform>.value);
         _world.EntityManager.SetComponent(entity2, new Transform { position = new float3(1, 2, 3) });
@@ -38,32 +42,38 @@ public partial class EntityTest : ITest
         var queryID = new QueryBuilder().WithAll<Transform>().Build(_world);
         ref var query = ref _world.GetEntityQueryReference(queryID);
 
-        var testJob = new TestEntityQueryJob();
+        // var testJob = new TestEntityQueryJob();
-        var handle = query.ScheduleChunkParallel(testJob, 64, JobHandle.Invalid);
+        // var handle = query.ScheduleChunkParallel(testJob, 64, JobHandle.Invalid);
-        _jobScheduler.WaitComplete(handle);
+        // _jobScheduler.WaitComplete(handle);
+
+        _world.EntityManager.AddScriptComponent<TestScriptComponent>(entity1);
+        _world.EntityManager.RemoveComponent<ManagedEntityRef>(entity1); // This should destory the managed entity and call OnDestroy
 
         query.ForEach<Transform>((e, ref t) =>
         {
             Console.WriteLine($"Entity {e} Has Position: {t.position}");
         });
 
-        foreach (var (entity, transform) in query.GetEntityComponentIterator<Transform>())
+        // foreach (var (entity, transform) in query.GetEntityComponentIterator<Transform>())
-        {
+        // {
-            Console.WriteLine($"Entity {entity} Updated Position: {transform.Get().position}");
+        //     Console.WriteLine($"Entity {entity} Updated Position: {transform.Get().position}");
-        }
+        // }
+        //
+        // foreach (var chunk in query.GetChunkIterator())
+        // {
+        //     var transforms = chunk.GetComponentData<Transform>();
+        //     var entities = chunk.GetEntities();
+        //     var bits = chunk.GetEnableBits<Transform>();
+        //
+        //     var it = bits.GetIterator();
+        //     while (it.Next(out var index) && index < chunk.Count)
+        //     {
+        //         Console.WriteLine($"Entity {entities[index]} Updated Position: {transforms[index].position}");
+        //     }
+        // }
 
-        foreach (var chunk in query.GetChunkIterator())
+        _world.EntityManager.DestroyEntity(entity1);
-        {
+        _world.EntityManager.DestroyEntity(entity2);
-            var transforms = chunk.GetComponentData<Transform>();
-            var entities = chunk.GetEntities();
-            var bits = chunk.GetEnableBits<Transform>();
-
-            var it = bits.GetIterator();
-            while (it.Next(out var index) && index < chunk.Count)
-            {
-                Console.WriteLine($"Entity {entities[index]} Updated Position: {transforms[index].position}");
-            }
-        }
     }
 
     public void Cleanup()
@@ -83,3 +93,18 @@ public struct Mesh : IComponent
 {
     public int index;
 }
+
+public class TestScriptComponent : ScriptComponent
+{
+    public override void OnCreate()
+    {
+        Console.WriteLine($"TestScriptComponent OnCreate called for Entity {Entity}");
+        ref var transform = ref GetComponent<Transform>();
+        transform.position += new float3(0, 1, 0);
+    }
+
+    public override void OnDestroy()
+    {
+        Console.WriteLine($"TestScriptComponent OnDestroy called for Entity {Entity}");
+    }
+}

Ghost.Entities/Archetype.cs

@@ -2,32 +2,126 @@ using Ghost.Core;
 using Misaki.HighPerformance.LowLevel.Buffer;
 using Misaki.HighPerformance.LowLevel.Collections;
 using Misaki.HighPerformance.LowLevel.Utilities;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
 
 namespace Ghost.Entities;
 
+internal unsafe sealed class ChunkDebugView
+{
+    [DebuggerDisplay("{Name,nq}: {Data}")]
+    internal class ComponentArrayView
+    {
+        public string Name { get; }
+        [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
+        public object Data { get; }
+
+        public ComponentArrayView(string name, object data)
+        {
+            Name = name;
+            Data = data;
+        }
+    }
+
+    public byte* pData;
+    public int count;
+    public int capacity;
+    public int worldID;
+    public int archetypeID;
+
+    public ChunkDebugView(Chunk chunk)
+    {
+        pData = chunk.GetUnsafePtr();
+        count = chunk._count;
+        capacity = chunk._capacity;
+#if DEBUG || GHOST_EDITOR
+        worldID = chunk._worldID;
+        archetypeID = chunk._archetypeID;
+#else
+        worldID = -1;
+        archetypeID = -1;
+#endif
+    }
+
+    [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
+    public object[] Items
+    {
+        get
+        {
+#if DEBUG || GHOST_EDITOR
+#else
+            if (count == 0)
+#endif
+            {
+                return [];
+            }
+
+#pragma warning disable CS0162 // Unreachable code detected
+            var views = new List<object>();
+#pragma warning restore CS0162 // Unreachable code detected
+            ref var archetype = ref World.GetWorld(worldID).GetValueOrThrow()
+                .GetArchetypeReference(archetypeID);
+
+            foreach (var layout in archetype._layouts)
+            {
+                var type = Type.GetTypeFromHandle(RuntimeTypeHandle.FromIntPtr(ComponentRegister.s_runtimeIDToTypeHandle[layout.componentID]));
+                var readMethod = typeof(ChunkDebugView)
+                    .GetMethod(nameof(ReadComponentArray), System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)
+                    .MakeGenericMethod(type);
+
+                // 3. Invoke it to get a Position[] or Velocity[]
+                var array = readMethod.Invoke(this, [layout.offset]);
+
+                // 4. Wrap it in a nice label so the debugger shows "Position[]"
+                views.Add(new ComponentArrayView(type.Name, array));
+            }
+
+            return [.. views];
+        }
+    }
+
+    private T[] ReadComponentArray<T>(int offsetInChunk)
+        where T : unmanaged
+    {
+        var result = new T[count];
+        unsafe
+        {
+            var basePtr = pData + offsetInChunk;
+
+            var sizeOfT = sizeof(T);
+            for (int i = 0; i < count; i++)
+            {
+                // Read directly from raw memory
+                result[i] = Unsafe.Read<T>(basePtr + (i * sizeOfT));
+            }
+        }
+        return result;
+    }
+}
+
+[DebuggerTypeProxy(typeof(ChunkDebugView))]
 internal unsafe struct Chunk : IDisposable
 {
-    public const int CHUNK_SIZE = 16384; // 16 KB
+    public const int CHUNK_BUFFER_SIZE = 16384; // 16 KB
     public const int BIT_ALIGNMENT = 8;
     public const int BIT_SHIFT = 3; // log2(BIT_ALIGNMENT)
     public const int BIT_ALIGNMENT_MINUS_ONE = BIT_ALIGNMENT - 1;
 
     private UnsafeArray<byte> _data;
-    private int _count;
-    private readonly int _capacity;
 
-    public int Count
+    internal int _version;
+    internal int _count;
+    internal readonly int _capacity;
+
+#if DEBUG || GHOST_EDITOR
+    // For debugging purpose
+    internal int _worldID;
+    internal int _archetypeID;
+#endif
+
+    public Chunk(int bufferSize, int capacity)
     {
-        readonly get => _count;
+        _data = new UnsafeArray<byte>(bufferSize, Allocator.Persistent, AllocationOption.Clear);
-        set => _count = value;
-    }
-
-    public readonly int Capacity => _capacity;
-
-    public Chunk(int size, int capacity)
-    {
-        _data = new UnsafeArray<byte>(size, Allocator.Persistent, AllocationOption.Clear);
         _capacity = capacity;
         _count = 0;
     }
@@ -60,9 +154,6 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
         public int targetArchetype; // can't use Identifier<Archetype> because cycle causer
     }
 
-    private readonly Identifier<Archetype> _id;
-    private readonly Identifier<World> _worldID;
-
     internal UnsafeBitSet _signature;
     internal UnsafeList<Chunk> _chunks;
     internal UnsafeArray<ComponentMemoryLayout> _layouts;
@@ -72,6 +163,9 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
     private UnsafeList<Edge> _edgesAdd;
     private UnsafeList<Edge> _edgesRemove;
 
+    private readonly Identifier<Archetype> _id;
+    private readonly Identifier<World> _worldID;
+
     private readonly int _hash;
     private int _entityCapacity;
     private int _maxComponentID;
@@ -98,7 +192,7 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
             _hash = 0;
 
             _signature.ClearAll();
-            _entityCapacity = Chunk.CHUNK_SIZE / sizeof(Entity);
+            _entityCapacity = Chunk.CHUNK_BUFFER_SIZE / sizeof(Entity);
 
             return;
         }
@@ -144,7 +238,7 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
         }
 
         _maxComponentID = maxComponentID;
-        _entityCapacity = Chunk.CHUNK_SIZE / bytesPerEntity;
+        _entityCapacity = Chunk.CHUNK_BUFFER_SIZE / bytesPerEntity;
         _layouts = new UnsafeArray<ComponentMemoryLayout>(components.Length, Allocator.Persistent);
         _componentIDToLayoutIndex = new UnsafeArray<int>(_maxComponentID + 1, Allocator.Persistent);
 
@@ -186,7 +280,7 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
 
                 tempBitmaskOffsets[i] = bitmaskOffset;
 
-                if (currentOffset > Chunk.CHUNK_SIZE)
+                if (currentOffset > Chunk.CHUNK_BUFFER_SIZE)
                 {
                     fits = false;
                     break;
@@ -220,10 +314,10 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
         for (var i = 0; i < _chunks.Count; i++)
         {
             ref var chunk = ref _chunks[i];
-            if (chunk.Count < _entityCapacity)
+            if (chunk._count < _entityCapacity)
             {
-                rowIndex = chunk.Count;
+                rowIndex = chunk._count;
-                chunk.Count++;
+                chunk._count++;
                 chunkIndex = i;
 
                 return;
@@ -231,7 +325,11 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
         }
 
         // Need to allocate a new chunk
-        var newChunk = new Chunk(Chunk.CHUNK_SIZE, _entityCapacity);
+        var newChunk = new Chunk(Chunk.CHUNK_BUFFER_SIZE, _entityCapacity);
+#if DEBUG || GHOST_EDITOR
+        newChunk._worldID = _worldID;
+        newChunk._archetypeID = _id;
+#endif
 
         // Set all enable to true by default for enableable components
         for (var i = 0; i < _layouts.Count; i++)
@@ -246,7 +344,7 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
         }
 
         rowIndex = 0;
-        newChunk.Count++;
+        newChunk._count++;
         chunkIndex = _chunks.Count;
 
         _chunks.Add(newChunk);
@@ -331,7 +429,7 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
         }
 
         ref var chunk = ref _chunks[chunkIndex];
-        var lastIndex = chunk.Count - 1;
+        var lastIndex = chunk._count - 1;
 
         // If we are NOT removing the very last entity, we must swap.
         if (rowIndex != lastIndex)
@@ -366,7 +464,7 @@ internal unsafe struct Archetype : IIdentifierType, IDisposable
             }
         }
 
-        chunk.Count--;
+        chunk._count--;
         return ErrorStatus.None;
     }
 

Ghost.Entities/Component.cs

@@ -32,8 +32,11 @@ internal static class ComponentRegister
     private static int s_nextComponentTypeID = 0;
 
     private static readonly List<ComponentInfo> s_registeredComponents = new();
-    private static readonly Dictionary<IntPtr, Identifier<IComponent>> s_typeHandleToID = new();
+    private static readonly Dictionary<IntPtr, int> s_typeHandleToID = new();
-    private static readonly Dictionary<string, Identifier<IComponent>> s_nameToRuntimeID = new();
+    private static readonly Dictionary<string, int> s_nameToRuntimeID = new();
+#if DEBUG || GHOST_EDITOR
+    internal static readonly Dictionary<int, IntPtr> s_runtimeIDToTypeHandle = new();
+#endif
 
     public static unsafe Identifier<IComponent> GetOrRegisterComponent<T>()
         where T : unmanaged, IComponent
@@ -66,6 +69,9 @@ internal static class ComponentRegister
 
             s_typeHandleToID[typeHandle] = newID;
             s_nameToRuntimeID[stableName] = newID;
+#if DEBUG || GHOST_EDITOR
+            s_runtimeIDToTypeHandle[newID.value] = typeHandle;
+#endif
 
             return newID;
         }

Ghost.Entities/Entity.cs

@@ -4,7 +4,7 @@ using System.Runtime.InteropServices;
 namespace Ghost.Entities;
 
 [StructLayout(LayoutKind.Sequential, Size = 8)]
-public readonly struct Entity : IEquatable<Entity>, IComparable<Entity>
+public readonly record struct Entity
 {
     public const EntityID INVALID_ID = -1;
 
@@ -41,36 +41,6 @@ public readonly struct Entity : IEquatable<Entity>, IComparable<Entity>
         _generation = generation;
     }
 
-    public bool Equals(Entity other)
-    {
-        return _id == other._id && _generation == other._generation;
-    }
-
-    public int CompareTo(Entity other)
-    {
-        return _id.CompareTo(other._id);
-    }
-
-    public override bool Equals(object? obj)
-    {
-        return obj is Entity other && Equals(other);
-    }
-
-    public override int GetHashCode()
-    {
-        return _id ^ _generation << 16;
-    }
-
-    public static bool operator ==(Entity left, Entity right)
-    {
-        return left.Equals(right);
-    }
-
-    public static bool operator !=(Entity left, Entity right)
-    {
-        return !(left == right);
-    }
-
     public override string ToString()
     {
         return $"Entity {{ Index: {ID}, Generation: {Generation} }}";

Ghost.Entities/EntityManager.Managed.cs

@@ -0,0 +1,197 @@
+using Misaki.HighPerformance.Collections;
+
+namespace Ghost.Entities;
+
+public partial class EntityManager
+{
+    private readonly SlotMap<List<ScriptComponent>> _scriptComponents = [];
+
+    internal SlotMap<List<ScriptComponent>> ScriptComponents => _scriptComponents;
+
+    /// <summary>
+    /// Creates a new ManagedEntity and associates it with the given Entity.
+    /// </summary>
+    /// <param name="entity">The Entity to associate with the ManagedEntity.</param>
+    /// <returns>The created ManagedEntity.</returns>
+    public ManagedEntity CreateManagedEntity(Entity entity)
+    {
+        var managedEntity = CreateManagedEntity();
+        AddComponent(entity, new ManagedEntityRef
+        {
+            entity = managedEntity
+        });
+
+        return managedEntity;
+    }
+
+    /// <summary>
+    /// Creates a new ManagedEntity.
+    /// </summary>
+    /// <remarks>
+    /// You must call this if you add <see cref="ManagedEntityRef"/> manually to an entity.
+    /// Otherwise, use <see cref="CreateManagedEntity(Entity)"/>.
+    /// </remarks>
+    /// <returns>The created ManagedEntity.</returns>
+    public ManagedEntity CreateManagedEntity()
+    {
+        var id = _scriptComponents.Add(new(8), out var generation);
+        var managedEntity = new ManagedEntity
+        {
+            id = id,
+            generation = generation
+        };
+
+        return managedEntity;
+    }
+
+    /// <summary>
+    /// Destroys the given ManagedEntity and calls OnDestroy on all associated ScriptComponents.
+    /// </summary>
+    /// <param name="managedEntity">The ManagedEntity to destroy.</param>
+    public void DestroyManagedEntity(ManagedEntity managedEntity)
+    {
+        if (_scriptComponents.TryGetElement(managedEntity.id, managedEntity.generation, out var scripts))
+        {
+            foreach (var script in scripts)
+            {
+                script.OnDestroy();
+            }
+
+            _scriptComponents.Remove(managedEntity.id, managedEntity.generation);
+        }
+    }
+
+    /// <summary>
+    /// Checks if the given ManagedEntity exists.
+    /// </summary>
+    /// <param name="managedEntity">The ManagedEntity to check.</param>
+    /// <returns>True if the ManagedEntity exists, false otherwise.</returns>
+    public bool Exists(ManagedEntity managedEntity)
+    {
+        return _scriptComponents.Contain(managedEntity.id, managedEntity.generation);
+    }
+
+    /// <summary>
+    /// Adds a ScriptComponent of type T to the given ManagedEntity and Entity.
+    /// </summary>
+    /// <typeparam name="T">The type of ScriptComponent to add.</typeparam>
+    /// <param name="managedEntity">The ManagedEntity to add the ScriptComponent to.</
+    /// <param name="entity">The Entity associated with the ManagedEntity.</param>
+    public void AddScriptComponent<T>(ManagedEntity managedEntity, Entity entity)
+        where T : ScriptComponent, new()
+    {
+        if (_scriptComponents.TryGetElement(managedEntity.id, managedEntity.generation, out var scripts))
+        {
+            var script = new T
+            {
+                _world = _world,
+                _entity = entity,
+                _managedEntity = managedEntity
+            };
+
+            scripts.Add(script);
+            script.OnCreate();
+
+            return;
+        }
+
+        throw new InvalidOperationException($"ManagedEntity {managedEntity} does not exist.");
+    }
+
+    /// <summary>
+    /// Adds a ScriptComponent of type T to the given Entity.
+    /// </summary>
+    /// <typeparam name="T">The type of ScriptComponent to add.</typeparam>
+    /// <param name="entity">The Entity to add the ScriptComponent to.</param>
+    public unsafe void AddScriptComponent<T>(Entity entity)
+        where T : ScriptComponent, new()
+    {
+        var location = _entityLocations.GetElementAt(entity.ID, entity.Generation);
+        ref var archetype = ref _world.GetArchetypeReference(location.archetypeID);
+
+        var pManagedEntityRef = (ManagedEntityRef*)archetype.GetComponentData(location.chunkIndex, location.rowIndex, ComponentTypeID<ManagedEntityRef>.value);
+        if (pManagedEntityRef == null)
+        {
+            throw new InvalidOperationException($"Entity {entity} does not have ManagedEntityRef component.");
+        }
+
+        AddScriptComponent<T>(pManagedEntityRef->entity, entity);
+    }
+
+    /// <summary>
+    /// Destroys the ScriptComponent of type T associated with the given ManagedEntity.
+    /// </summary>
+    /// <typeparam name="T">The type of ScriptComponent to destroy.</typeparam>
+    /// <param name="managedEntity">The ManagedEntity whose ScriptComponent is to be destroyed </param>
+    /// <returns>True if the ScriptComponent was found and destroyed, false otherwise.</returns
+    public bool DestroyScriptComponent<T>(ManagedEntity managedEntity)
+        where T : ScriptComponent
+    {
+        if (_scriptComponents.TryGetElement(managedEntity.id, managedEntity.generation, out var scripts))
+        {
+            for (var i = 0; i < scripts.Count; i++)
+            {
+                if (scripts[i] is T script)
+                {
+                    script.OnDestroy();
+                    scripts.RemoveAt(i);
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        throw new InvalidOperationException($"ManagedEntity {managedEntity} does not exist.");
+    }
+
+    /// <summary>
+    /// Checks if the given ManagedEntity has a ScriptComponent of type T.
+    /// </summary>
+    /// <typeparam name="T">The type of ScriptComponent to check for.</typeparam>
+    /// <param name="managedEntity">The ManagedEntity to check.</param>
+    /// <returns>True if the ManagedEntity has a ScriptComponent of type T, false </returns>
+    public bool HasScriptComponent<T>(ManagedEntity managedEntity)
+        where T : ScriptComponent
+    {
+        if (_scriptComponents.TryGetElement(managedEntity.id, managedEntity.generation, out var scripts))
+        {
+            foreach (var script in scripts)
+            {
+                if (script is T)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        throw new InvalidOperationException($"ManagedEntity {managedEntity} does not exist.");
+    }
+
+    /// <summary>
+    /// Gets the ScriptComponent of type T associated with the given ManagedEntity.
+    /// </summary>
+    /// <typeparam name="T">The type of ScriptComponent to get.</typeparam>
+    /// <param name="managedEntity">The ManagedEntity whose ScriptComponent is to be retrieved
+    /// <returns>The ScriptComponent of type T.</returns>
+    public T GetScriptComponent<T>(ManagedEntity managedEntity)
+        where T : ScriptComponent
+    {
+        if (_scriptComponents.TryGetElement(managedEntity.id, managedEntity.generation, out var scripts))
+        {
+            foreach (var script in scripts)
+            {
+                if (script is T typedScript)
+                {
+                    return typedScript;
+                }
+            }
+
+            throw new InvalidOperationException($"ManagedEntity {managedEntity} does not have script component of type {typeof(T)}.");
+        }
+
+        throw new InvalidOperationException($"ManagedEntity {managedEntity} does not exist.");
+    }
+}

Ghost.Entities/EntityManager.cs

@@ -18,7 +18,7 @@ public unsafe partial class EntityManager : IDisposable
 {
     private struct EntityLocation
     {
-        public Identifier<Archetype> archetypeID;
+        public int archetypeID;
         public int chunkIndex;
         public int rowIndex;
     }
@@ -209,6 +209,13 @@ public unsafe partial class EntityManager : IDisposable
         }
 
         ref var archetype = ref _world.GetArchetypeReference(location.archetypeID);
+
+        var pManagedRef = archetype.GetComponentData(location.chunkIndex, location.rowIndex, ComponentTypeID<ManagedEntityRef>.value);
+        if (pManagedRef != null)
+        {
+            DestroyManagedEntity(((ManagedEntityRef*)pManagedRef)->entity);
+        }
+
         var r = archetype.RemoveEntity(location.chunkIndex, location.rowIndex);
         if (r != ErrorStatus.None)
         {
@@ -336,9 +343,10 @@ public unsafe partial class EntityManager : IDisposable
 
             var src = oldArch._chunks[oldChunk].GetUnsafePtr() + layout.offset + (layout.size * oldRow);
             var r = newArch.GetLayout(layout.componentID);
-            Debug.Assert(r.Error == ErrorStatus.None); // This should always be true if the system is consistent.
             if (r.Error != ErrorStatus.None)
             {
+                // New archetype does not have this component, skip it.
+                // This can happen when removing components.
                 continue;
             }
 
@@ -514,6 +522,9 @@ public unsafe partial class EntityManager : IDisposable
         // Move entity data
         ref var newArchetype = ref _world.GetArchetypeReference(newArcID);
         newArchetype.AllocateEntity(out var newChunkIndex, out var newRowIndex);
+        CopyData(ref oldArchetype, location.chunkIndex, location.rowIndex,
+                 ref newArchetype, newChunkIndex, newRowIndex);
+
         newArchetype.SetEntity(newChunkIndex, newRowIndex, entity);
 
         var r = oldArchetype.RemoveEntity(location.chunkIndex, location.rowIndex);
@@ -523,6 +534,12 @@ public unsafe partial class EntityManager : IDisposable
             return r;
         }
 
+        var pManagedRef = oldArchetype.GetComponentData(location.chunkIndex, location.rowIndex, ComponentTypeID<ManagedEntityRef>.value);
+        if (pManagedRef != null)
+        {
+            DestroyManagedEntity(((ManagedEntityRef*)pManagedRef)->entity);
+        }
+
         // Update location
         location.archetypeID = newArcID;
         location.chunkIndex = newChunkIndex;
@@ -697,6 +714,9 @@ public unsafe partial class EntityManager : IDisposable
             return;
         }
 
+        Debug.Assert(_entityLocations.Count == 0, "There are still entities alive when disposing EntityManager.");
+        Debug.Assert(_scriptComponents.Count == 0, "There are still managed entities alive when disposing EntityManager.");
+
         _entityLocations.Dispose();
         _disposed = true;
 

Ghost.Entities/ManagedEntity.cs

@@ -0,0 +1,74 @@
+using System.Runtime.CompilerServices;
+
+namespace Ghost.Entities;
+
+public record struct ManagedEntity
+{
+    public int id;
+    public int generation;
+
+    public override readonly string ToString()
+    {
+        return $"ManagedEntity({id}, {generation})";
+    }
+}
+
+public struct ManagedEntityRef : IComponent
+{
+    public ManagedEntity entity;
+}
+
+public abstract class ScriptComponent : IComponent
+{
+    internal World _world = null!;
+    internal Entity _entity;
+    internal ManagedEntity _managedEntity;
+
+    public World World => _world;
+    public Entity Entity => _entity;
+    public ManagedEntity ManagedEntity => _managedEntity;
+
+    protected ref T GetComponent<T>()
+        where T : unmanaged, IComponent
+    {
+        ref var value = ref _world.EntityManager.GetComponent<T>(_entity);
+        if (Unsafe.IsNullRef(ref value))
+        {
+            throw new InvalidOperationException($"Entity {_entity} does not have component of type {typeof(T)}");
+        }
+
+        return ref value;
+    }
+
+    public virtual void OnCreate()
+    {
+    }
+
+    public virtual void OnDestroy()
+    {
+    }
+
+    public virtual void OnEnable()
+    {
+    }
+
+    public virtual void OnDisable()
+    {
+    }
+
+    public virtual void Start()
+    {
+    }
+
+    public virtual void Update()
+    {
+    }
+
+    public virtual void FixedUpdate()
+    {
+    }
+
+    public virtual void LateUpdate()
+    {
+    }
+}

Ghost.Entities/Query.cs

@@ -84,15 +84,18 @@ public readonly unsafe ref struct ChunkView
     private readonly byte* _pChunkData;
     private readonly int _entityOffset;
     private readonly int _entityCount;
+    private readonly int _version;
 
     public readonly int Count => _entityCount;
+    public readonly int Version => _version;
 
-    internal ChunkView(ReadOnlyUnsafeCollection<Archetype.ComponentMemoryLayout> layouts, byte* pChunkData, int entityOffset, int entityCount)
+    internal ChunkView(ReadOnlyUnsafeCollection<Archetype.ComponentMemoryLayout> layouts, byte* pChunkData, int entityOffset, int entityCount, int version)
     {
         _layouts = layouts;
         _pChunkData = pChunkData;
         _entityOffset = entityOffset;
         _entityCount = entityCount;
+        _version = version;
     }
 
     internal ChunkView(ref readonly Archetype archetype, ref readonly Chunk chunk)
@@ -100,14 +103,21 @@ public readonly unsafe ref struct ChunkView
         _layouts = archetype._layouts.AsReadOnly();
         _pChunkData = chunk.GetUnsafePtr();
         _entityOffset = archetype.EntityIDsOffset;
-        _entityCount = chunk.Count;
+        _entityCount = chunk._count;
+        _version = chunk._version;
+    }
+
+    // TODO: We do not have a proper versioning system yet.
+    public bool HasChanged(int version)
+    {
+        return _version != version;
     }
 
     /// <summary>
     /// Returns a read-only span containing structuralAll entities stored in the current chunk.
     /// </summary>
     /// <returns>A read-only span of <see cref="Entity"/> values representing the entities in the chunk.</returns>
-    public readonly ReadOnlySpan<Entity> GetEntities()
+    public ReadOnlySpan<Entity> GetEntities()
     {
         var pEntity = (Entity*)(_pChunkData + _entityOffset);
         return new ReadOnlySpan<Entity>(pEntity, _entityCount);
@@ -119,7 +129,7 @@ public readonly unsafe ref struct ChunkView
     /// <typeparam name="T">The type of component to access. Must be an unmanaged type that implements <see cref="Component"/>.</typeparam>
     /// <returns>A span of type <see cref="{T}"/> containing the component data for each entity in the chunk.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the specified component type is not present in the archetype.</exception>
-    public readonly Span<T> GetComponentData<T>()
+    public Span<T> GetComponentData<T>()
         where T : unmanaged, IComponent
     {
         var layout = _layouts[ComponentTypeID<T>.value];
@@ -134,7 +144,7 @@ public readonly unsafe ref struct ChunkView
     /// <typeparam name="T">The component type for which to retrieve enablement bits. Must be unmanaged and implement <see cref="IEnableableComponent"/>.</typeparam>
     /// <returns>A <see cref="SpanBitSet"/> that provides access to the enablement bits for all instances of the specified component type in the chunk.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the specified component type does not support enablement.</exception>
-    public readonly SpanBitSet GetEnableBits<T>()
+    public SpanBitSet GetEnableBits<T>()
         where T : unmanaged, IEnableableComponent
     {
         var layout = _layouts[ComponentTypeID<T>.value];
@@ -154,7 +164,7 @@ public readonly unsafe ref struct ChunkView
     /// <param name="index">The zero-based index of the component instance to check within the chunk.</param>
     /// <returns>true if the component at the specified index is enabled; otherwise, false.</returns>
     /// <exception cref="InvalidOperationException">Thrown if the specified component type <typeparamref name="T"/> does not support enable/disable functionality.</exception>
-    public readonly bool IsComponentEnabled<T>(int index)
+    public bool IsComponentEnabled<T>(int index)
         where T : unmanaged, IEnableableComponent
     {
         var layout = _layouts[ComponentTypeID<T>.value];

Ghost.Entities/Templates/EntityQuery.ComponentIterator.gen.cs

@@ -49,7 +49,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 1; index++)
                 {
@@ -65,7 +65,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -216,7 +216,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 2; index++)
                 {
@@ -232,7 +232,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -393,7 +393,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 3; index++)
                 {
@@ -409,7 +409,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -580,7 +580,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 4; index++)
                 {
@@ -596,7 +596,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -777,7 +777,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 5; index++)
                 {
@@ -793,7 +793,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -984,7 +984,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 6; index++)
                 {
@@ -1000,7 +1000,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -1201,7 +1201,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 7; index++)
                 {
@@ -1217,7 +1217,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -1428,7 +1428,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 8; index++)
                 {
@@ -1444,7 +1444,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))

Ghost.Entities/Templates/EntityQuery.ComponentIterator.tt

@@ -94,7 +94,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < <#= i #>; index++)
                 {
@@ -110,7 +110,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))

Ghost.Entities/Templates/EntityQuery.EntityComponentIterator.gen.cs

@@ -72,7 +72,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 1; index++)
                 {
@@ -88,7 +88,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -246,7 +246,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 2; index++)
                 {
@@ -262,7 +262,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -430,7 +430,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 3; index++)
                 {
@@ -446,7 +446,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -624,7 +624,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 4; index++)
                 {
@@ -640,7 +640,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -828,7 +828,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 5; index++)
                 {
@@ -844,7 +844,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -1042,7 +1042,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 6; index++)
                 {
@@ -1058,7 +1058,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -1266,7 +1266,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 7; index++)
                 {
@@ -1282,7 +1282,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))
@@ -1500,7 +1500,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < 8; index++)
                 {
@@ -1516,7 +1516,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))

Ghost.Entities/Templates/EntityQuery.EntityComponentIterator.tt

@@ -95,7 +95,7 @@ public unsafe partial struct EntityQuery
             {
                 _currentChunk = ref _currentArchetype.GetChunkReference(chunkIndex);
                 _chunkBasePtr = _currentChunk.GetUnsafePtr();
-                _currentChunkEntityCount = _currentChunk.Count;
+                _currentChunkEntityCount = _currentChunk._count;
 
                 for (var index = 0; index < <#= i #>; index++)
                 {
@@ -111,7 +111,7 @@ public unsafe partial struct EntityQuery
                 while (true)
                 {
                     _currentEntityIndex++;
-                    if (_currentEntityIndex < _currentChunk.Count)
+                    if (_currentEntityIndex < _currentChunk._count)
                     {
                         var pChunkData = _currentChunk.GetUnsafePtr();
                         if (IsEntityValid(pChunkData, _currentEntityIndex, in _currentArchetype, in _mask))

Ghost.Entities/Templates/EntityQuery.ForEach.gen.cs

@@ -44,7 +44,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -100,7 +100,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -158,7 +158,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -218,7 +218,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -280,7 +280,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -344,7 +344,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -410,7 +410,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -478,7 +478,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -540,7 +540,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -597,7 +597,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -656,7 +656,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -717,7 +717,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -780,7 +780,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -845,7 +845,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -912,7 +912,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {
@@ -981,7 +981,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {

Ghost.Entities/Templates/EntityQuery.ForEach.tt

@@ -61,7 +61,7 @@ public unsafe partial struct EntityQuery
                     basePtrs[index] = pChunkData + offsets[index];
                 }
 
-                for (var entityIndex = 0; entityIndex < chunk.Count; entityIndex++)
+                for (var entityIndex = 0; entityIndex < chunk._count; entityIndex++)
                 {
                     if (!IsEntityValid(pChunkData, entityIndex, in archetype, in _mask))
                     {

Ghost.Entities/Templates/EntityQuery.JobEntity.gen.cs

@@ -798,7 +798,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -906,7 +906,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -1035,7 +1035,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -1185,7 +1185,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -1356,7 +1356,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -1548,7 +1548,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -1761,7 +1761,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);
@@ -1995,7 +1995,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
                 offsets0.Add(layout0.offset);

Ghost.Entities/Templates/EntityQuery.JobEntity.tt

@@ -138,7 +138,7 @@ public unsafe partial struct EntityQuery
                 ref var chunkRef = ref arch.GetChunkReference(i);
 
                 chunkList.Add((IntPtr)chunkRef.GetUnsafePtr());
-                chunkEntityCounts.Add(chunkRef.Count);
+                chunkEntityCounts.Add(chunkRef._count);
                 entityOffsets.Add(arch.EntityIDsOffset);
 
 <# for (var j = 0; j < i; j++){ #>