Allowing entities to be created and removed

lib/wal/sources/Entity/Entity.cpp

@@ -11,17 +11,19 @@ namespace WAL
 {
 	unsigned Entity::nextID = 0;
 
-	Entity::Entity(Scene &scene, std::string name)
+	Entity::Entity(Scene &scene, std::string name, bool notifyScene)
 		: _uid(Entity::nextID++),
 		_scene(scene),
-		_name(std::move(name))
+		_name(std::move(name)),
+		_notifyScene(notifyScene)
 	{ }
 
 	Entity::Entity(const Entity &other)
 		: _uid(Entity::nextID++),
 		_scene(other._scene),
 		_name(other._name),
-		_disabled(other._disabled)
+		_disabled(other._disabled),
+		_notifyScene(other._notifyScene)
 	{
 		for (const auto &cmp : other._components)
 			this->addComponent(*cmp.second);
@@ -53,7 +55,8 @@ namespace WAL
 		if (this->hasComponent(type, false))
 			throw DuplicateError("A component of the type \"" + std::string(type.name()) + "\" already exists.");
 		this->_components.emplace(type, component.clone(*this));
-		this->_scene._componentAdded(*this, type);
+		if (this->_notifyScene)
+			this->_scene._componentAdded(*this, type);
 		return *this;
 	}
 

lib/wal/sources/Entity/Entity.hpp

@@ -28,6 +28,8 @@ namespace WAL
 		bool _disabled = false;
 		//! @brief Has this entity been scheduled for deletion?
 		bool _shouldDelete = false;
+		//! @brief Should this entity notify the scene of component changes?
+		bool _notifyScene;
 		//! @brief The list of the components of this entity
 		std::unordered_map<std::type_index, std::unique_ptr<Component>> _components = {};
 
@@ -40,6 +42,8 @@ namespace WAL
 		//! @brief Callback called when a component is removed
 		//! @param type The type of component
 		void _componentRemoved(const std::type_index &type);
+
+		friend Scene;
 	protected:
 		//! @brief A reference to the ECS.
 		Scene &_scene;
@@ -141,7 +145,8 @@ namespace WAL
 			if (this->hasComponent(type))
 				throw DuplicateError("A component of the type \"" + std::string(type.name()) + "\" already exists.");
 			this->_components[type] = std::make_unique<T>(*this, TypeHolder<TNested>()..., std::forward<Types>(params)...);
-			this->_componentAdded(type);
+			if (this->_notifyScene)
+				this->_componentAdded(type);
 			return *this;
 		}
 
@@ -160,12 +165,13 @@ namespace WAL
 			if (existing == this->_components.end())
 				throw NotFoundError("No component could be found with the type \"" + std::string(type.name()) + "\".");
 			this->_components.erase(existing);
-			this->_componentRemoved(type);
+			if (this->_notifyScene)
+				this->_componentRemoved(type);
 			return *this;
 		}
 
 		//! @brief A default constructor
-		explicit Entity(Scene &wal, std::string name);
+		explicit Entity(Scene &wal, std::string name, bool notifyScene = true);
 		//! @brief An entity is copyable
 		Entity(const Entity &);
 		//! @brief An entity is movable.

lib/wal/sources/Scene/Scene.cpp

@@ -24,6 +24,11 @@ namespace WAL
 		return this->_entities.emplace_back(*this, name);
 	}
 
+	Entity &Scene::scheduleNewEntity(const std::string &name)
+	{
+		return this->_newEntities.emplace_back(*this, name, false);
+	}
+
 	void Scene::_componentAdded(Entity &entity, const std::type_index &type)
 	{
 		for (auto &view : this->_views) {
@@ -52,7 +57,7 @@ namespace WAL
 			view->erase(entity);
 	}
 
-	void Scene::deleteMarkedEntities()
+	void Scene::applyChanges()
 	{
 		this->_entities.remove_if([this](auto &entity) {
 			if (!entity.shouldDelete())
@@ -60,5 +65,16 @@ namespace WAL
 			this->_entityRemoved(entity);
 			return true;
 		});
+		for (auto &entity : this->_newEntities) {
+			for (auto &view : this->_views) {
+				bool valid = std::all_of(view->getTypes().begin(), view->getTypes().end(), [&entity](const auto &type){
+					return entity.hasComponent(type);
+				});
+				if (valid)
+					view->emplace_back(entity);
+			}
+			entity._notifyScene = true;
+		}
+		this->_entities.splice(this->_entities.end(), this->_newEntities);
 	}
 } // namespace WAL

lib/wal/sources/Scene/Scene.hpp

@@ -23,6 +23,8 @@ namespace WAL
 
 		//! @brief The list of registered entities
 		std::list<Entity> _entities = {};
+		//! @brief The list of entities to add on the next call to applyChanges.
+		std::list<Entity> _newEntities = {};
 		//! @brief The list of cached views to update.
 		std::vector<std::shared_ptr<IView>> _views = {};
 
@@ -46,6 +48,11 @@ namespace WAL
 		//! @return The created entity is returned.
 		Entity &addEntity(const std::string &name);
 
+		//! @brief Add a new entity to the scene, this entity will be added on the next call to applyChanges.
+		//! @param name The name of the created entity.
+		//! @return The created entity is returned.
+		Entity &scheduleNewEntity(const std::string &name);
+
 		template<typename ...Components>
 		View<Components...> &view()
 		{
@@ -59,8 +66,8 @@ namespace WAL
 			return *view;
 		}
 
-		//! @brief Delete entities marked as deleted.
-		void deleteMarkedEntities();
+		//! @brief Delete entities marked as deleted and create scheduled entities.
+		void applyChanges();
 
 		//! @brief A default constructor
 		Scene() = default;

lib/wal/sources/View/View.hpp

@@ -179,8 +179,10 @@ namespace WAL
 		void erase(const Entity &entity) override
 		{
 			this->_entities.erase(std::remove_if(this->_entities.begin(), this->_entities.end(), [&entity](const auto &ref){
-				return &std::get<0>(ref).get() == &entity;
-			}));
+				if (std::get<0>(ref).get().getUid() == entity.getUid())
+					return true;
+				return std::get<0>(ref).get().getUid() == entity.getUid();
+			}), this->_entities.end());
 		}
 
 		//! @brief Construct a view from a list of entities.

lib/wal/sources/Wal.hpp

@@ -52,7 +52,7 @@ namespace WAL
 				}
 				for (auto &system : this->_systems)
 					system->update(dtime);
-				this->scene->deleteMarkedEntities();
+				this->scene->applyChanges();
 				callback(*this, state);
 			}
 		}
@@ -76,7 +76,7 @@ namespace WAL
 			}
 			for (auto &system : wal._systems)
 				system->update(dtime);
-			wal.scene->deleteMarkedEntities();
+			wal.scene->applyChanges();
 			callback(wal, state);
 		}
 #endif