11 files changed, 451 insertions, 0 deletions
diff --git a/mwe/ecs-homemade/CMakeLists.txt b/mwe/ecs-homemade/CMakeLists.txt
new file mode 100644
index 0000000..6267c1a
--- /dev/null
+++ b/mwe/ecs-homemade/CMakeLists.txt
@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.5)
+project(ecs-homemade)
+
+# Set the C++ standard (optional, but good practice)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED True)
+
+# Use the debug mode (otherwise breakpoints are not compiled)
+set(CMAKE_BUILD_TYPE Debug)
+
+add_executable(ecs-homemade
+	src/main.cpp
+	src/ComponentManager.cpp
+	src/Components.cpp
+	src/GameObjectMax.cpp
+)
+target_include_directories(ecs-homemade PRIVATE "${CMAKE_SOURCE_DIR}/inc")
diff --git a/mwe/ecs-homemade/inc/ComponentManager.h b/mwe/ecs-homemade/inc/ComponentManager.h
new file mode 100644
index 0000000..0ba358e
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.h
@@ -0,0 +1,58 @@
+#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
+
+	//Add a component of a specific type
+	template <typename T, typename... Args>
+	T & AddComponent(std::uint32_t id, Args &&... args);
+	//Deletes all components of a specific type and id
+	template <typename T>
+	void DeleteComponentsById(std::uint32_t id);
+	//Deletes all components of a specific type
+	template <typename T>
+	void DeleteComponents();
+	//Deletes all components of a specific id
+	void DeleteAllComponentsOfId(std::uint32_t id);
+	//Deletes all components
+	void DeleteAllComponents();
+
+	//Get a vector<> of all components at specific type and id
+	template <typename T>
+	std::vector<std::reference_wrapper<T>>
+	GetComponentsByID(std::uint32_t id) const;
+	//Get a vector<> of all components of a specific type
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> GetComponentsByType() const;
+
+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..92db1d4
--- /dev/null
+++ b/mwe/ecs-homemade/inc/ComponentManager.hpp
@@ -0,0 +1,135 @@
+
+template <typename T, typename... Args>
+T & ComponentManager::AddComponent(std::uint32_t id, Args &&... args) {
+	//Determine the type of T (this is used as the key of the unordered_map<>)
+	std::type_index type = typeid(T);
+
+	//Check if this component type is already in the unordered_map<>
+	if (mComponents.find(type) == mComponents.end()) {
+		//If not, create a new (empty) vector<> of vector<unique_ptr<Component>>
+		mComponents[type]
+			= std::vector<std::vector<std::unique_ptr<Component>>>();
+	}
+
+	//Resize the vector<> if the id is greater than the current size
+	if (id >= mComponents[type].size()) {
+		//Initialize new slots to nullptr (resize does automatically init to nullptr)
+		mComponents[type].resize(id + 1);
+	}
+
+	//Create a new component of type T using perfect forwarding and store its unique_ptr in the vector<>
+	mComponents[type][id].push_back(
+		std::make_unique<T>(std::forward<Args>(args)...));
+
+	return static_cast<T &>(*mComponents[type][id].back().get());
+}
+
+template <typename T>
+void ComponentManager::DeleteComponentsById(std::uint32_t id) {
+	//Determine the type of T (this is used as the key of the unordered_map<>)
+	std::type_index type = typeid(T);
+
+	//Find the type (in the unordered_map<>)
+	if (mComponents.find(type) != mComponents.end()) {
+		//Get the correct vector<>
+		std::vector<std::vector<std::unique_ptr<Component>>> & componentArray
+			= mComponents[type];
+
+		//Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < componentArray.size()) {
+			//Clear the whole vector<> of this specific type and id
+			componentArray[id].clear();
+		}
+	}
+}
+
+template <typename T>
+void ComponentManager::DeleteComponents() {
+	//Determine the type of T (this is used as the key of the unordered_map<>)
+	std::type_index type = typeid(T);
+
+	//Find the type (in the unordered_map<>)
+	if (mComponents.find(type) != mComponents.end()) {
+		//Clear the whole vector<> of this specific type
+		mComponents[type].clear();
+	}
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByID(std::uint32_t id) const {
+	//Determine the type of T (this is used as the key of the unordered_map<>)
+	std::type_index type = typeid(T);
+
+	//Create an empty vector<>
+	std::vector<std::reference_wrapper<T>> componentVector;
+
+	//Find the type (in the unordered_map<>)
+	if (mComponents.find(type) != mComponents.end()) {
+
+		//Get the correct vector<>
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type);
+
+		//Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < componentArray.size()) {
+			//Loop trough the whole vector<>
+			for (const std::unique_ptr<Component> & componentPtr :
+				 componentArray[id]) {
+				//Cast the unique_ptr to a raw pointer
+				T * castedComponent = static_cast<T *>(componentPtr.get());
+
+				//Ensure that the cast was successful
+				if (castedComponent) {
+					//Add the dereferenced raw pointer to the vector<>
+					componentVector.push_back(*castedComponent);
+				}
+			}
+		}
+	}
+
+	//Return the vector<>
+	return componentVector;
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::GetComponentsByType() const {
+	//Determine the type of T (this is used as the key of the unordered_map<>)
+	std::type_index type = typeid(T);
+
+	//Create an empty vector<>
+	std::vector<std::reference_wrapper<T>> componentVector;
+	//std::uint32_t id = 0;	//Set the id to 0 (the id will also be stored in the returned vector<>)
+
+	//Find the type (in the unordered_map<>)
+	if (mComponents.find(type) != mComponents.end()) {
+
+		//Get the correct vector<>
+		const std::vector<std::vector<std::unique_ptr<Component>>> &
+			componentArray
+			= mComponents.at(type);
+
+		//Loop through the whole vector<>
+		for (const std::vector<std::unique_ptr<Component>> & component :
+			 componentArray) {
+			//Loop trough the whole vector<>
+			for (const std::unique_ptr<Component> & componentPtr : component) {
+				//Cast the unique_ptr to a raw pointer
+				T * castedComponent = static_cast<T *>(componentPtr.get());
+
+				//Ensure that the cast was successful
+				if (castedComponent) {
+					//Pair the dereferenced raw pointer and the id and add it to the vector<>
+					componentVector.emplace_back(std::ref(*castedComponent));
+				}
+			}
+
+			//++id;	//Increase the id (the id will also be stored in the returned vector<>)
+		}
+	}
+
+	//Return the vector<>
+	return componentVector;
+}
diff --git a/mwe/ecs-homemade/inc/Components.h b/mwe/ecs-homemade/inc/Components.h
new file mode 100644
index 0000000..ad491e7
--- /dev/null
+++ b/mwe/ecs-homemade/inc/Components.h
@@ -0,0 +1,66 @@
+#pragma once
+
+#include <memory>
+#include <string>
+
+class Component {
+public:
+	Component();
+
+	bool mActive;
+};
+
+class Sprite : public Component {
+public:
+	Sprite(std::string path);
+
+	std::string mPath;
+};
+
+class Rigidbody : public Component {
+public:
+	Rigidbody(int mass, int gravityScale, int bodyType);
+
+	int mMass;
+	int mGravityScale;
+	int mBodyType;
+};
+
+class Colider : public Component {
+public:
+	Colider(int size);
+
+	int mSize;
+};
+
+class IBehaviour {
+public:
+	virtual ~IBehaviour() = default;
+	virtual void onStart() = 0;
+	virtual void onUpdate() = 0;
+};
+
+template <typename T>
+class BehaviourWrapper : public IBehaviour {
+public:
+	BehaviourWrapper();
+	void onStart() override;
+	void onUpdate() override;
+
+private:
+	T instance;
+};
+
+class BehaviourScript : public Component {
+public:
+	template <typename T>
+	void addScript();
+
+	void onStart();
+	void onUpdate();
+
+private:
+	std::unique_ptr<IBehaviour> behaviour;
+};
+
+#include "Components.hpp"
diff --git a/mwe/ecs-homemade/inc/Components.hpp b/mwe/ecs-homemade/inc/Components.hpp
new file mode 100644
index 0000000..436a28c
--- /dev/null
+++ b/mwe/ecs-homemade/inc/Components.hpp
@@ -0,0 +1,20 @@
+#include "Components.h"
+#include <iostream>
+
+template <typename T>
+BehaviourWrapper<T>::BehaviourWrapper() : instance() {}
+
+template <typename T>
+void BehaviourWrapper<T>::onStart() {
+	instance.onStart();
+}
+
+template <typename T>
+void BehaviourWrapper<T>::onUpdate() {
+	instance.onUpdate();
+}
+
+template <typename T>
+void BehaviourScript::addScript() {
+	behaviour = std::make_unique<BehaviourWrapper<T>>();
+}
diff --git a/mwe/ecs-homemade/inc/GameObjectMax.h b/mwe/ecs-homemade/inc/GameObjectMax.h
new file mode 100644
index 0000000..5fab44a
--- /dev/null
+++ b/mwe/ecs-homemade/inc/GameObjectMax.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+class GameObject {
+public:
+	GameObject(std::uint32_t id, std::string name, std::string tag, int layer);
+
+	template <typename T, typename... Args>
+	T & AddComponent(Args &&... args);
+
+	std::uint32_t mId;
+	std::string mName;
+	std::string mTag;
+	bool mActive;
+	int mLayer;
+};
+
+#include "GameObjectMax.hpp"
diff --git a/mwe/ecs-homemade/inc/GameObjectMax.hpp b/mwe/ecs-homemade/inc/GameObjectMax.hpp
new file mode 100644
index 0000000..2f433bb
--- /dev/null
+++ b/mwe/ecs-homemade/inc/GameObjectMax.hpp
@@ -0,0 +1,7 @@
+#include "ComponentManager.h"
+
+template <typename T, typename... Args>
+T & GameObject::AddComponent(Args &&... args) {
+	return ComponentManager::GetInstance().AddComponent<T>(
+		mId, std::forward<Args>(args)...);
+}
diff --git a/mwe/ecs-homemade/src/ComponentManager.cpp b/mwe/ecs-homemade/src/ComponentManager.cpp
new file mode 100644
index 0000000..536c152
--- /dev/null
+++ b/mwe/ecs-homemade/src/ComponentManager.cpp
@@ -0,0 +1,23 @@
+#include "ComponentManager.h"
+
+ComponentManager ComponentManager::mInstance;
+
+ComponentManager & ComponentManager::GetInstance() { return mInstance; }
+
+ComponentManager::ComponentManager() {}
+
+void ComponentManager::DeleteAllComponentsOfId(std::uint32_t id) {
+	for (auto & [type, componentArray] :
+		 mComponents) { //Loop through all the types (in the unordered_map<>)
+		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 components at this specific id
+		}
+	}
+}
+
+void ComponentManager::DeleteAllComponents() {
+	mComponents.clear(); //Clear the whole unordered_map<>
+}
diff --git a/mwe/ecs-homemade/src/Components.cpp b/mwe/ecs-homemade/src/Components.cpp
new file mode 100644
index 0000000..de8753e
--- /dev/null
+++ b/mwe/ecs-homemade/src/Components.cpp
@@ -0,0 +1,23 @@
+#include "Components.h"
+#include <iostream>
+
+Component::Component() : mActive(true) {}
+
+Sprite::Sprite(std::string path) : mPath(path) {}
+
+Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType)
+	: mMass(mass), mGravityScale(gravityScale), mBodyType(bodyType) {}
+
+Colider::Colider(int size) : mSize(size) {}
+
+void BehaviourScript::onStart() {
+	if (behaviour) {
+		behaviour->onStart();
+	}
+}
+
+void BehaviourScript::onUpdate() {
+	if (behaviour) {
+		behaviour->onUpdate();
+	}
+}
diff --git a/mwe/ecs-homemade/src/GameObjectMax.cpp b/mwe/ecs-homemade/src/GameObjectMax.cpp
new file mode 100644
index 0000000..b0c5af7
--- /dev/null
+++ b/mwe/ecs-homemade/src/GameObjectMax.cpp
@@ -0,0 +1,7 @@
+#include "GameObjectMax.h"
+
+#include "ComponentManager.h"
+
+GameObject::GameObject(std::uint32_t id, std::string name, std::string tag,
+					   int layer)
+	: mId(id), mName(name), mTag(tag), mActive(true), mLayer(layer) {}
diff --git a/mwe/ecs-homemade/src/main.cpp b/mwe/ecs-homemade/src/main.cpp
new file mode 100644
index 0000000..70c5d2c
--- /dev/null
+++ b/mwe/ecs-homemade/src/main.cpp
@@ -0,0 +1,75 @@
+#include <chrono>
+#include <cstdint>
+#include <iostream>
+#include <vector>
+
+#include "ComponentManager.h"
+#include "Components.h"
+#include "GameObjectMax.h"
+
+class myScript {
+public:
+	void onStart() { std::cout << "In onStart" << std::endl; }
+
+	void onUpdate() { std::cout << "In onUpdate" << std::endl; }
+};
+
+int main() {
+	auto startAdding = std::chrono::high_resolution_clock::now();
+
+	GameObject * gameObject[100000];
+
+	for (int i = 0; i < 100000; ++i) {
+		gameObject[i] = new GameObject(i, "Name", "Tag", 0);
+
+		gameObject[i]->AddComponent<Sprite>("C:/Test");
+		gameObject[i]->AddComponent<Rigidbody>(0, 0, i);
+		gameObject[i]->AddComponent<Colider>(i);
+		gameObject[i]->AddComponent<BehaviourScript>().addScript<myScript>();
+	}
+
+	auto stopAdding = std::chrono::high_resolution_clock::now();
+
+	//This is what systems would do:
+
+	std::vector<std::reference_wrapper<Sprite>> sprites
+		= ComponentManager::GetInstance().GetComponentsByType<Sprite>();
+	for (Sprite & sprite : sprites) {
+		//std::cout << sprite.get().mPath << std::endl;
+	}
+	//std::cout << std::endl;
+
+	std::vector<std::reference_wrapper<Rigidbody>> rigidBodies
+		= ComponentManager::GetInstance().GetComponentsByType<Rigidbody>();
+	for (Rigidbody & rigidbody : rigidBodies) {
+		//std::cout << rigidbody.get().mMass << " " << rigidbody.get().mGravityScale << " " << rigidbody.get().mBodyType << std::endl;
+	}
+	//std::cout << std::endl;
+
+	std::vector<std::reference_wrapper<Colider>> coliders
+		= ComponentManager::GetInstance().GetComponentsByType<Colider>();
+	for (Colider & colider : coliders) {
+		//std::cout << colider.get().mSize << std::endl;
+	}
+
+	std::vector<std::reference_wrapper<BehaviourScript>> scripts
+		= ComponentManager::GetInstance()
+			  .GetComponentsByType<BehaviourScript>();
+	for (BehaviourScript & script : scripts) {
+		//script.onStart();
+		//script.onUpdate();
+	}
+
+	auto stopLooping = std::chrono::high_resolution_clock::now();
+
+	for (int i = 0; i < 100000; ++i) {
+		delete gameObject[i];
+	}
+
+	auto Addtime = std::chrono::duration_cast<std::chrono::microseconds>(
+		stopAdding - startAdding);
+	auto LoopTime = std::chrono::duration_cast<std::chrono::microseconds>(
+		stopLooping - stopAdding);
+	std::cout << "AddTime: " << Addtime.count() << " us" << std::endl;
+	std::cout << "LoopTime: " << LoopTime.count() << " us" << std::endl;
+}