3 files changed, 189 insertions, 0 deletions
diff --git a/mwe/ecs-homemade/inc/ComponentManager.h b/mwe/ecs-homemade/inc/ComponentManager.h
new file mode 100644
index 0000000..d368516
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include "Components.h"
+#include <cstdint>
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+class ComponentManager {
+public:
+	static ComponentManager & GetInstance(); //Singleton
+
+	ComponentManager(const ComponentManager &) = delete; //Singleton
+	ComponentManager(ComponentManager &&) = delete; //Singleton
+	ComponentManager & operator=(const ComponentManager &) = delete; //Singleton
+	ComponentManager & operator=(ComponentManager &&) = delete; //Singleton
+
+	template <typename T, typename... Args>
+	void AddComponent(std::uint32_t id,
+					  Args &&... args); //Add a component of a specific type
+	template <typename T>
+	void DeleteComponentsById(
+		std::uint32_t id); //Deletes all components of a specific type and id
+	template <typename T>
+	void DeleteComponents(); //Deletes all components of a specific type
+	void DeleteAllComponentsOfId(
+		std::uint32_t id); //Deletes all components of a specific id
+	void DeleteAllComponents(); //Deletes all components
+
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByID(std::uint32_t id)
+		const; //Get a vector<> of all components at specific type and id
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByType()
+		const; //Get a vector<> of all components of a specific type
+
+private:
+	static ComponentManager mInstance; //Singleton
+
+	ComponentManager(); //Singleton
+
+	/*
+	 * The std::unordered_map<std::type_index, std::vector<std::vector<std::unique_ptr<Component>>>> below might seem a bit strange, let me explain this structure:
+	 * The std::unordered_map<> has a key and value. The key is a std::type_index and the value is a std::vector. So, a new std::vector will be created for each new std::type_index.
+	 * The first std::vector<> stores another vector<>. This first vector<> is to bind the entity's id to a component.
+	 * The second std::vector<> stores unique_ptrs. Each component can be gathered via an unique_ptr. This second vector<> allows multiple components of the same std::type_index for one entity (id).
+	 */
+	std::unordered_map<std::type_index,
+					   std::vector<std::vector<std::unique_ptr<Component>>>>
+		mComponents;
+};
+
+#include "ComponentManager.hpp"
diff --git a/mwe/ecs-homemade/inc/ComponentManager.hpp b/mwe/ecs-homemade/inc/ComponentManager.hpp
new file mode 100644
index 0000000..d6da8e8
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.hpp
@@ -0,0 +1,127 @@
+
+template <typename T, typename... Args>
+void ComponentManager::AddComponent(std::uint32_t id, Args &&... args) {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		== mComponents
+			   .end()) { //Check if this component type is already in the unordered_map<>
+		mComponents[type] = std::vector<std::vector<std::unique_ptr<
+			Component>>>(); //If not, create a new (empty) vector<> of vector<unique_ptr<Component>>
+	}
+
+	if (id
+		>= mComponents[type]
+			   .size()) { //Resize the vector<> if the id is greater than the current size
+		mComponents[type].resize(
+			id
+			+ 1); //Initialize new slots to nullptr (resize does automatically init to nullptr)
+	}
+
+	mComponents[type][id].push_back(std::make_unique<T>(std::forward<Args>(
+		args)...)); //Create a new component of type T using perfect forwarding and store its unique_ptr in the vector<>
+}
+
+template <typename T>
+void ComponentManager::DeleteComponentsById(std::uint32_t id) {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+		std::vector<std::vector<std::unique_ptr<Component>>> & componentArray
+			= mComponents[type]; //Get the correct vector<>
+
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			componentArray[id]
+				.clear(); //Clear the whole vector<> of this specific type and id
+		}
+	}
+}
+
+template <typename T>
+void ComponentManager::DeleteComponents() {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+		mComponents[type]
+			.clear(); //Clear the whole vector<> of this specific type
+	}
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByID(std::uint32_t id) const {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	std::vector<std::reference_wrapper<T>>
+		componentVector; //Create an empty vector<>
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type); //Get the correct vector<>
+
+		if (id
+			< componentArray
+				  .size()) { //Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 componentArray[id]) { //Loop trough the whole vector<>
+				T * castedComponent = static_cast<T *>(
+					componentPtr.get()); //Cast the unique_ptr to a raw pointer
+
+				if (castedComponent) { //Ensure that the cast was successful
+					componentVector.push_back(
+						*castedComponent); //Add the dereferenced raw pointer to the vector<>
+				}
+			}
+		}
+	}
+
+	return componentVector; //Return the vector<>
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByType() const {
+	std::type_index type = typeid(
+		T); //Determine the type of T (this is used as the key of the unordered_map<>)
+
+	std::vector<std::reference_wrapper<T>>
+		componentVector; //Create an empty vector<>
+	//std::uint32_t id = 0;	//Set the id to 0 (the id will also be stored in the returned vector<>)
+
+	if (mComponents.find(type)
+		!= mComponents.end()) { //Find the type (in the unordered_map<>)
+
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type); //Get the correct vector<>
+
+		for (const std::vector<std::unique_ptr<Component>> & component :
+			 componentArray) { //Loop through the whole vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 component) { //Loop trough the whole vector<>
+				T * castedComponent = static_cast<T *>(
+					componentPtr.get()); //Cast the unique_ptr to a raw pointer
+
+				if (castedComponent) { //Ensure that the cast was successful
+					componentVector.emplace_back(std::ref(
+						*castedComponent)); //Pair the dereferenced raw pointer and the id and add it to the vector<>
+				}
+			}
+
+			//++id;	//Increase the id (the id will also be stored in the returned vector<>)
+		}
+	}
+
+	return componentVector; //Return the vector<>
+}
diff --git a/mwe/ecs-homemade/inc/GameObjectMax.hpp b/mwe/ecs-homemade/inc/GameObjectMax.hpp
new file mode 100644
index 0000000..91d51ea
--- /dev/null
+++ b/mwe/ecs-homemade/inc/GameObjectMax.hpp
@@ -0,0 +1,7 @@
+#include "ComponentManager.h"
+
+template <typename T, typename... Args>
+void GameObject::AddComponent(Args &&... args) {
+	ComponentManager::GetInstance().AddComponent<T>(
+		mId, std::forward<Args>(args)...);
+}