Entity Creation and Destruction from scripts

- ScriptEngine: Allow destroying scripts during runtime
- Scripting:
    - Create new entities using Constructors
    - Added Destroy functions for Entities
    - Added SetScript/RemoveScript functions for Entities
    - Allow adding multiple components at once
    - Added Is-Method
- Mono Wrapper: Added Array-Functions
- WorldEnumerator: Fixed crash due to dangling list pointer after entity creation
- Scene:
    - Basic create Rigidbodies during runtime
    - Start of entity copying (For runtime use)
    - Added DestroyEntityDeferred
- SceneSerializer:
    - Added option to assign new IDs to entities

GlitchyEngine/src/World/Scene.bf

@@ -51,14 +51,17 @@ namespace GlitchyEngine.World
 				cameraComponent.Camera.SetViewportSize(e.Scene._viewportWidth, e.Scene._viewportHeight);
 			});
 
-			/*_onComponentAddedHandlers.Add(typeof(Rigidbody2DComponent), (e, t, c) => {
-				if ()
+			_onComponentAddedHandlers.Add(typeof(Rigidbody2DComponent), (e, t, c) => {
+				Rigidbody2DComponent* rigidbodyComponent = (.)c;
 
+				Scene scene = e.Scene;
 
-				Rigidbody2DComponent* rigidBodyComponent = (.)c;
-
-				//cameraComponent.Camera.SetViewportSize(e.Scene._viewportWidth, e.Scene._viewportHeight);
-			});*/
+				if (scene._physicsWorld2D != null)
+				{
+					// TODO: Add rigidbody
+					Log.EngineLogger.Error("Should have added a rigidbody");
+				}
+			});
 		}
 
 		public ~this()
@@ -154,6 +157,14 @@ namespace GlitchyEngine.World
 				targetEntity.AddComponent<TComponent>(*sourceComponent);
 			}
 		}
+
+		private static void CopyComponent<TComponent>(Entity source, Entity target) where TComponent : struct, new
+		{
+			if (source.TryGetComponent<TComponent>(let component))
+			{
+				target.AddComponent<TComponent>(*component);
+			}
+		}
 		
 		b2Vec2 _gravity2D = .(0.0f, -9.8f);
 
@@ -562,7 +573,7 @@ namespace GlitchyEngine.World
 			Runtime = Scripts | Physics,
 		}
 
-		//private append List<UUID> _destroyQueue = .();
+		private append List<Entity> _destroyQueue = .();
 
 		public void Update(GameTime gameTime, UpdateMode mode)
 		{
@@ -680,6 +691,17 @@ namespace GlitchyEngine.World
 					}
 				}
 			}
+
+			if (!_destroyQueue.IsEmpty)
+			{
+				for (let entity in _destroyQueue)
+				{
+					DestroyEntity(entity);
+				}
+
+				_destroyQueue.Clear();
+
+			}
 		}
 
 		/// Creates a new Entity with the given name.
@@ -719,6 +741,46 @@ namespace GlitchyEngine.World
 			
 			_ecsWorld.RemoveEntity(entity.Handle);
 		}
+		
+		/** Marks the given entity and it's children, so that they will be destroyed at the end of the frame.
+		 * @param entity The entity to delete.
+		 */
+		public void DestroyEntityDeferred(Entity entity)
+		{
+			_destroyQueue.Add(entity);
+
+			for (Entity child in entity.EnumerateChildren)
+			{
+				DestroyEntityDeferred(child);
+			}
+		}
+
+		/** Creates a copy of the given entity, including all components and children.
+		 * @param entity the entity to copy.
+		 * @returns the newly create entity.
+		 */
+		public Entity CreateInstance(Entity entity)
+		{
+			Entity CopyEntityAndChildren(Entity original)
+			{
+				Entity copy = CreateEntity(original.Name);
+
+				// TODO: Copy components
+
+				// This is kinda slow because it's in O(n*m) where n is the tree depth and m is the total number of entities in the scene...
+				for (let child in original.EnumerateChildren)
+				{
+					Entity childCopy = CopyEntityAndChildren(child);
+					childCopy.Parent = copy;
+				}
+
+				return copy;
+			}
+
+			Entity newEntity = CopyEntityAndChildren(entity);
+
+			return newEntity;
+		}
 
 		public Result<Entity> GetEntityByID(UUID id)
 		{

GlitchyEngine/src/World/SceneSerializer.bf

@@ -22,6 +22,9 @@ class SceneSerializer
 	private Dictionary<UUID, Entity> _parentIdToChild;
 
 	private List<(Entity Entity, UUID ParentId)> _entitiesMissingParent;
+	
+	// Maps from ID in the prefab file to the actual ID in the scene.
+	private Dictionary<UUID, UUID> _fileToSceneId;
 
 	public this(Scene scene)
 	{
@@ -262,12 +265,13 @@ class SceneSerializer
 		Runtime.NotImplemented();
 	}
 	
-	public Result<void> Deserialize(StringView filePath)
+	public Result<void> Deserialize(StringView filePath, bool loadAsPrefab = false)
 	{
 		Debug.Profiler.ProfileResourceFunction!();
 
 		_parentIdToChild = scope Dictionary<UUID, Entity>();
 		_entitiesMissingParent = scope List<(Entity Entity, UUID ParentId)>();
+		_fileToSceneId = scope Dictionary<UUID, UUID>();
 
 		String buffer = scope String();
 		File.ReadAllText(filePath, buffer);
@@ -298,7 +302,7 @@ class SceneSerializer
 				Try!(reader.EntryEnd());
 			}
 			
-			Try!(DeserializeEntity(reader));
+			Try!(DeserializeEntity(reader, loadAsPrefab));
 
 			first = false;
 		}
@@ -325,23 +329,12 @@ class SceneSerializer
 		return .Ok;
 	}
 
-	private Result<void> DeserializeEntity(BonReader reader)
+	/// Deserializes the next entity in the file
+	/// @param reader the reader
+	/// @param replaceId If false, the ID that is stored in the file will be used as ID in the scene.
+	/// If true, the ID in the file will be replaced with a new id (e.g. for loading prefabs)
+	private Result<void> DeserializeEntity(BonReader reader, bool newId)
 	{
-		/*mixin DeserializeAsset<T>(StringView identifier) where T : Asset
-		{
-			Asset asset = null;
-
-			Try!(Deserialize.Value(reader, identifier, out asset));
-
-			if (asset != null && !(asset is T))
-			{
-				Log.EngineLogger.Error($"Asset {asset.Identifier} is not a {nameof(T)}.");
-				return .Err;
-			}
-
-			(T)asset
-		}*/
-
 		mixin DeserializeAssetHandle<T>(StringView identifier) where T : Asset
 		{
 			Asset asset = null;
@@ -357,11 +350,29 @@ class SceneSerializer
 			asset?.Handle ?? .Invalid
 		}
 
+		UUID RemapId(UUID id)
+		{
+			if (!newId)
+				return id;
+
+			if (_fileToSceneId.TryGetValue(id, let sceneId))
+				return sceneId;
+
+			// If we remap IDs map the file Id to a random Id.
+			UUID newId = UUID.Create();
+
+			_fileToSceneId.Add(id, newId);
+
+			return newId;
+		}
+
 		Try!(reader.ObjectBlock());
 		
-		Deserialize.Value<uint64>(reader, "Id", let uuid);
+		Deserialize.Value<uint64>(reader, "Id", let rawUuid);
 
-		Entity entity = _scene.CreateEntity("", UUID(uuid));
+		UUID uuid = RemapId(UUID(rawUuid));
+
+		Entity entity = _scene.CreateEntity("", uuid);
 
 		while(reader.ObjectHasMore())
 		{
@@ -416,11 +427,13 @@ class SceneSerializer
 					let nextId = Try!(reader.Identifier());
 					if (nextId == "ParentId")
 					{
-						UUID pId;
-						Deserialize.Value(reader, out pId);
+						UUID rawParentId;
+						Deserialize.Value(reader, out rawParentId);
 						reader.EntryEnd();
 
-						var parentEntity = _scene.GetEntityByID(pId);
+						UUID parentId = RemapId(rawParentId);
+
+						var parentEntity = _scene.GetEntityByID(parentId);
 
 						if (parentEntity case .Ok(let parent))
 						{
@@ -428,7 +441,7 @@ class SceneSerializer
 						}
 						else
 						{
-							_entitiesMissingParent.Add((entity, pId));
+							_entitiesMissingParent.Add((entity, parentId));
 						}
 
 						Deserialize.Value(reader, "Position", out component.[Friend]_position);

GlitchyEngine/src/World/WorldEnumerator.bf

@@ -10,16 +10,14 @@ namespace GlitchyEngine.World
 	{
 		internal EcsWorld _world;
 		internal BitArray _bitMask;
-		internal EcsWorld.BitmaskEntry* _currentEntry;
-		internal EcsWorld.BitmaskEntry* _endEntry;
+		internal List<EcsWorld.BitmaskEntry>.Enumerator _entitiesEnumerator;
 
 		public bool IsEmpty => _bitMask == null;
 
 		public this(EcsWorld world, Type[] componentTypes)
 		{
 			_world = world;
-			_currentEntry = _world._entities.Ptr;
-			_endEntry = _world._entities.Ptr + _world._entities.Count;
+			_entitiesEnumerator = _world._entities.GetEnumerator();
 
 			_bitMask = new BitArray(_world._componentPools.Count);
 			for(var type in componentTypes)
@@ -39,7 +37,6 @@ namespace GlitchyEngine.World
 					Log.EngineLogger.Warning($"Queried component of type \"{type}\" is not registered for this world. The query will never return any results.");
 #endif
 					DeleteAndNullify!(_bitMask);
-					_endEntry = _currentEntry;
 					break;
 				}
 			}
@@ -47,9 +44,12 @@ namespace GlitchyEngine.World
 
 		public Result<EcsEntity> GetNext() mut
 		{
-			while(_currentEntry < _endEntry)
+			if (IsEmpty)
+				return .Err;
+
+			while(_entitiesEnumerator.GetNext() case .Ok(let entry))
 			{
-				EcsWorld.BitmaskEntry* entry = _currentEntry++;
+				//EcsWorld.BitmaskEntry* entry = _currentEntry++;
 
 				// Skip deleted entities
 				if(entry.ID.Index == EcsEntity.InvalidEntity.Index)