26 files changed, 512 insertions, 22 deletions

diff --git a/src/crepe/CMakeLists.txt b/src/crepe/CMakeLists.txt
index c7f18cd..a02e991 100644
--- a/src/crepe/CMakeLists.txt
+++ b/src/crepe/CMakeLists.txt
@@ -8,6 +8,14 @@ target_sources(crepe PUBLIC
 	ParticleEmitter.cpp
 	ParticleSystem.cpp
 	SDLApp.cpp
+	ComponentManager.cpp
+	Component.cpp
+	GameObject.cpp
+	Collider.cpp
+	Rigidbody.cpp
+	Sprite.cpp
+	ScriptSystem.cpp
+	Script.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -18,6 +26,16 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	ParticleSystem.hpp
 	Particle.hpp
 	SDLApp.hpp
+	ComponentManager.h
+	ComponentManager.hpp
+	Component.h
+	GameObject.h
+	GameObject.hpp
+	Collider.h
+	Rigidbody.h
+	Sprite.h
+	System.h
+	ScriptSystem.h
 )
 
 add_subdirectory(api)
diff --git a/src/crepe/Collider.cpp b/src/crepe/Collider.cpp
new file mode 100644
index 0000000..3f12afd
--- /dev/null
+++ b/src/crepe/Collider.cpp
@@ -0,0 +1,5 @@
+#include "Collider.h"
+
+using namespace crepe;
+
+Collider::Collider(int size) : size(size) {}
diff --git a/src/crepe/Collider.h b/src/crepe/Collider.h
new file mode 100644
index 0000000..120da05
--- /dev/null
+++ b/src/crepe/Collider.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include "Component.h"
+
+namespace crepe {
+
+class Collider : public Component {
+public:
+	Collider(int size);
+
+	int size;
+};
+
+} // namespace crepe
diff --git a/src/crepe/Component.cpp b/src/crepe/Component.cpp
new file mode 100644
index 0000000..d14159c
--- /dev/null
+++ b/src/crepe/Component.cpp
@@ -0,0 +1,5 @@
+#include "Component.h"
+
+using namespace crepe;
+
+Component::Component() : active(true) {}
diff --git a/src/crepe/Component.h b/src/crepe/Component.h
new file mode 100644
index 0000000..16a4ce5
--- /dev/null
+++ b/src/crepe/Component.h
@@ -0,0 +1,14 @@
+#pragma once
+
+namespace crepe {
+
+class Component {
+public:
+	Component();
+	// TODO: shouldn't this constructor be deleted because this class will never
+	// directly be instantiated?
+
+	bool active;
+};
+
+} // namespace crepe
diff --git a/src/crepe/ComponentManager.cpp b/src/crepe/ComponentManager.cpp
new file mode 100644
index 0000000..9a3fec7
--- /dev/null
+++ b/src/crepe/ComponentManager.cpp
@@ -0,0 +1,24 @@
+#include "ComponentManager.h"
+
+using namespace crepe;
+
+ComponentManager & ComponentManager::get_instance() {
+	static ComponentManager instance;
+	return instance;
+}
+
+void ComponentManager::delete_all_components_of_id(uint32_t id) {
+	// Loop through all the types (in the unordered_map<>)
+	for (auto & [type, componentArray] : components) {
+		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < componentArray.size()) {
+			// Clear the components at this specific id
+			componentArray[id].clear();
+		}
+	}
+}
+
+void ComponentManager::delete_all_components() {
+	// Clear the whole unordered_map<>
+	components.clear();
+}
diff --git a/src/crepe/ComponentManager.h b/src/crepe/ComponentManager.h
new file mode 100644
index 0000000..2ab9dc8
--- /dev/null
+++ b/src/crepe/ComponentManager.h
@@ -0,0 +1,62 @@
+#pragma once
+
+#include <cstdint>
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+#include "Component.h"
+
+namespace crepe {
+
+class ComponentManager {
+public:
+	// Singleton
+	static ComponentManager & get_instance();
+	ComponentManager(const ComponentManager &) = delete;
+	ComponentManager(ComponentManager &&) = delete;
+	ComponentManager & operator=(const ComponentManager &) = delete;
+	ComponentManager & operator=(ComponentManager &&) = delete;
+
+public:
+	//! Add a component of a specific type
+	template <typename T, typename... Args>
+	void add_component(uint32_t id, Args &&... args);
+	//! Deletes all components of a specific type and id
+	template <typename T>
+	void delete_components_by_id(uint32_t id);
+	//! Deletes all components of a specific type
+	template <typename T>
+	void delete_components();
+	//! Deletes all components of a specific id
+	void delete_all_components_of_id(uint32_t id);
+	//! Deletes all components
+	void delete_all_components();
+
+	//! Get a vector<> of all components at specific type and id
+	template <typename T>
+	std::vector<std::reference_wrapper<T>>
+	get_components_by_id(uint32_t id) const;
+	//! Get a vector<> of all components of a specific type
+	template <typename T>
+	std::vector<std::reference_wrapper<T>> get_components_by_type() const;
+
+private:
+	ComponentManager() = default;
+
+	/*
+	 * 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>>>>
+		components;
+};
+
+} // namespace crepe
+
+#include "ComponentManager.hpp"
diff --git a/src/crepe/ComponentManager.hpp b/src/crepe/ComponentManager.hpp
new file mode 100644
index 0000000..084cd33
--- /dev/null
+++ b/src/crepe/ComponentManager.hpp
@@ -0,0 +1,152 @@
+#pragma once
+
+#include <type_traits>
+
+#include "ComponentManager.h"
+
+namespace crepe {
+
+template <class T, typename... Args>
+void ComponentManager::add_component(uint32_t id, Args &&... args) {
+	using namespace std;
+
+	static_assert(is_base_of<Component, T>::value, "add_component must recieve a derivative class of Component");
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Check if this component type is already in the unordered_map<>
+	if (components.find(type) == components.end()) {
+		//If not, create a new (empty) vector<> of vector<unique_ptr<Component>>
+		components[type] = vector<vector<unique_ptr<Component>>>();
+	}
+
+	// Resize the vector<> if the id is greater than the current size
+	if (id >= components[type].size()) {
+		// Initialize new slots to nullptr (resize does automatically init to nullptr)
+		components[type].resize(id + 1);
+	}
+
+	// Create a new component of type T (arguments directly forwarded). The
+	// constructor must be called by ComponentManager.
+	T * instance = new T(forward<Args>(args)...);
+	// store its unique_ptr in the vector<>
+	components[type][id].push_back(unique_ptr<T>(instance));
+}
+
+template <typename T>
+void ComponentManager::delete_components_by_id(uint32_t id) {
+	using namespace std;
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+		// Get the correct vector<>
+		vector<vector<unique_ptr<Component>>> & component_array
+			= components[type];
+
+		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < component_array.size()) {
+			// Clear the whole vector<> of this specific type and id
+			component_array[id].clear();
+		}
+	}
+}
+
+template <typename T>
+void ComponentManager::delete_components() {
+	// 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 (components.find(type) != components.end()) {
+		// Clear the whole vector<> of this specific type
+		components[type].clear();
+	}
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::get_components_by_id(uint32_t id) const {
+	using namespace std;
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Create an empty vector<>
+	vector<reference_wrapper<T>> component_vector;
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+		// Get the correct vector<>
+		const vector<vector<unique_ptr<Component>>> & component_array
+			= components.at(type);
+
+		// Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+		if (id < component_array.size()) {
+			// Loop trough the whole vector<>
+			for (const unique_ptr<Component> & component_ptr :
+				 component_array[id]) {
+				// Cast the unique_ptr to a raw pointer
+				T * casted_component = static_cast<T *>(component_ptr.get());
+
+				// Ensure that the cast was successful
+				if (casted_component) {
+					// Add the dereferenced raw pointer to the vector<>
+					component_vector.push_back(*casted_component);
+				}
+			}
+		}
+	}
+
+	// Return the vector<>
+	return component_vector;
+}
+
+template <typename T>
+std::vector<std::reference_wrapper<T>>
+ComponentManager::get_components_by_type() const {
+	using namespace std;
+
+	// Determine the type of T (this is used as the key of the unordered_map<>)
+	type_index type = typeid(T);
+
+	// Create an empty vector<>
+	vector<reference_wrapper<T>> component_vector;
+	// Set the id to 0 (the id will also be stored in the returned vector<>)
+	// uint32_t id = 0;
+
+	// Find the type (in the unordered_map<>)
+	if (components.find(type) != components.end()) {
+
+		// Get the correct vector<>
+		const vector<vector<unique_ptr<Component>>> & component_array
+			= components.at(type);
+
+		// Loop through the whole vector<>
+		for (const vector<unique_ptr<Component>> & component :
+			 component_array) {
+			// Loop trough the whole vector<>
+			for (const unique_ptr<Component> & component_ptr : component) {
+				// Cast the unique_ptr to a raw pointer
+				T * casted_component = static_cast<T *>(component_ptr.get());
+
+				// Ensure that the cast was successful
+				if (casted_component) {
+					// Pair the dereferenced raw pointer and the id and add it to the vector<>
+					component_vector.emplace_back(ref(*casted_component));
+				}
+			}
+
+			// Increase the id (the id will also be stored in the returned vector<>)
+			//++id;
+		}
+	}
+
+	// Return the vector<>
+	return component_vector;
+}
+
+} // namespace crepe
diff --git a/src/crepe/GameObject.cpp b/src/crepe/GameObject.cpp
new file mode 100644
index 0000000..de3beb6
--- /dev/null
+++ b/src/crepe/GameObject.cpp
@@ -0,0 +1,7 @@
+#include "GameObject.h"
+
+using namespace crepe;
+
+GameObject::GameObject(uint32_t id, std::string name, std::string tag,
+					   int layer)
+	: id(id), name(name), tag(tag), active(true), layer(layer) {}
diff --git a/src/crepe/GameObject.h b/src/crepe/GameObject.h
new file mode 100644
index 0000000..3588d9a
--- /dev/null
+++ b/src/crepe/GameObject.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+namespace crepe {
+
+class GameObject {
+public:
+	GameObject(uint32_t id, std::string name, std::string tag, int layer);
+
+	template <typename T, typename... Args>
+	void add_component(Args &&... args);
+
+	uint32_t id;
+	std::string name;
+	std::string tag;
+	bool active;
+	int layer;
+};
+
+} // namespace crepe
+
+#include "GameObject.hpp"
diff --git a/src/crepe/GameObject.hpp b/src/crepe/GameObject.hpp
new file mode 100644
index 0000000..5966fbf
--- /dev/null
+++ b/src/crepe/GameObject.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "GameObject.h"
+
+#include "ComponentManager.h"
+
+namespace crepe {
+
+template <typename T, typename... Args>
+void GameObject::add_component(Args &&... args) {
+	auto & mgr = ComponentManager::get_instance();
+	mgr.add_component<T>(id, std::forward<Args>(args)...);
+}
+
+} // namespace crepe
diff --git a/src/crepe/Rigidbody.cpp b/src/crepe/Rigidbody.cpp
new file mode 100644
index 0000000..495d908
--- /dev/null
+++ b/src/crepe/Rigidbody.cpp
@@ -0,0 +1,6 @@
+#include "Rigidbody.h"
+
+using namespace crepe;
+
+Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType)
+	: mass(mass), gravity_scale(gravityScale), body_type(bodyType) {}
diff --git a/src/crepe/Rigidbody.h b/src/crepe/Rigidbody.h
new file mode 100644
index 0000000..63a8877
--- /dev/null
+++ b/src/crepe/Rigidbody.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "Component.h"
+
+namespace crepe {
+
+class Rigidbody : public Component {
+public:
+	Rigidbody(int mass, int gravityScale, int bodyType);
+
+	int mass;
+	int gravity_scale;
+	int body_type;
+};
+
+} // namespace crepe
diff --git a/src/crepe/Script.cpp b/src/crepe/Script.cpp
new file mode 100644
index 0000000..42e3666
--- /dev/null
+++ b/src/crepe/Script.cpp
@@ -0,0 +1,7 @@
+#include "Script.h"
+
+using namespace crepe;
+
+void Script::init() { }
+void Script::update() { }
+
diff --git a/src/crepe/Script.h b/src/crepe/Script.h
new file mode 100644
index 0000000..ba4073a
--- /dev/null
+++ b/src/crepe/Script.h
@@ -0,0 +1,16 @@
+#pragma once
+
+namespace crepe {
+
+class Script {
+protected:
+	virtual void init();
+	virtual void update();
+	// NOTE: additional *events* (like unity's OnDisable and OnEnable) should be
+	// implemented as member methods in derivative user script classes and
+	// registered in init(), otherwise this class will balloon in size with each
+	// added event.
+};
+
+}
+
diff --git a/src/crepe/ScriptSystem.cpp b/src/crepe/ScriptSystem.cpp
new file mode 100644
index 0000000..e301c71
--- /dev/null
+++ b/src/crepe/ScriptSystem.cpp
@@ -0,0 +1,22 @@
+#include "util/log.h"
+
+#include "ScriptSystem.h"
+
+using namespace crepe;
+
+ScriptSystem::ScriptSystem() {
+	dbg_trace();
+}
+ScriptSystem::~ScriptSystem() {
+	dbg_trace();
+}
+
+ScriptSystem & ScriptSystem::get_instance() {
+	static ScriptSystem instance;
+	return instance;
+}
+
+void ScriptSystem::update() {
+	dbg_trace();
+}
+
diff --git a/src/crepe/ScriptSystem.h b/src/crepe/ScriptSystem.h
new file mode 100644
index 0000000..e1ed290
--- /dev/null
+++ b/src/crepe/ScriptSystem.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "System.h"
+
+namespace crepe {
+
+class ScriptSystem : public System {
+public:
+	static ScriptSystem & get_instance();
+	virtual void update();
+
+private:
+	ScriptSystem();
+	~ScriptSystem();
+};
+
+}
+
diff --git a/src/crepe/Sprite.cpp b/src/crepe/Sprite.cpp
new file mode 100644
index 0000000..a5a5e68
--- /dev/null
+++ b/src/crepe/Sprite.cpp
@@ -0,0 +1,8 @@
+#include <string>
+
+#include "Sprite.h"
+
+using namespace crepe;
+using namespace std;
+
+Sprite::Sprite(string path) : path(path) {}
diff --git a/src/crepe/Sprite.h b/src/crepe/Sprite.h
new file mode 100644
index 0000000..143e702
--- /dev/null
+++ b/src/crepe/Sprite.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <string>
+
+#include "Component.h"
+
+namespace crepe {
+
+class Sprite : public Component {
+public:
+	Sprite(std::string path);
+
+	std::string path;
+};
+
+} // namespace crepe
diff --git a/src/crepe/System.h b/src/crepe/System.h
new file mode 100644
index 0000000..3fe3d66
--- /dev/null
+++ b/src/crepe/System.h
@@ -0,0 +1,23 @@
+#pragma once
+
+namespace crepe {
+
+class System {
+public:
+	static System & get_instance();
+	virtual void update() = 0;
+
+protected:
+	System() { };
+	virtual ~System() { };
+
+private:
+	// singleton
+	System(const System &) = delete;
+	System(System &&) = delete;
+	System & operator=(const System &) = delete;
+	System & operator=(System &&) = delete;
+};
+
+}
+
diff --git a/src/crepe/api/BehaviorScript.cpp b/src/crepe/api/BehaviorScript.cpp
new file mode 100644
index 0000000..2dd933e
--- /dev/null
+++ b/src/crepe/api/BehaviorScript.cpp
@@ -0,0 +1,10 @@
+#include "../util/log.h"
+
+#include "BehaviorScript.h"
+
+using namespace crepe::api;
+
+BehaviorScript::BehaviorScript() {
+	dbg_trace();
+}
+
diff --git a/src/crepe/api/BehaviorScript.h b/src/crepe/api/BehaviorScript.h
new file mode 100644
index 0000000..e9542c1
--- /dev/null
+++ b/src/crepe/api/BehaviorScript.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include "../Script.h"
+#include "../Component.h"
+
+namespace crepe::api {
+
+class BehaviorScript : public Script, public Component {
+	// only allow ComponentManager to instantiate scripts
+	friend class ComponentManager;
+
+protected:
+	BehaviorScript();
+};
+
+}
+
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index 9548594..86623de 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -1,9 +1,10 @@
 target_sources(crepe PUBLIC
 	# AudioSource.cpp
+	BehaviorScript.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
-	AudioSource.h
-	Component.h
+	# AudioSource.h
+	BehaviorScript.h
 )
 
diff --git a/src/crepe/api/Component.h b/src/crepe/api/Component.h
deleted file mode 100644
index d5e0499..0000000
--- a/src/crepe/api/Component.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#pragma once
-
-namespace crepe::api {
-
-class Component {
-public:
-	bool active;
-};
-
-} // namespace crepe::api
diff --git a/src/crepe/util/log.cpp b/src/crepe/util/log.cpp
index 6829ec3..f91d52c 100644
--- a/src/crepe/util/log.cpp
+++ b/src/crepe/util/log.cpp
@@ -8,10 +8,10 @@
 using namespace crepe::util;
 
 static const char * const LOG_PREFIX[] = {
-	[log_level::debug] = "[DBG] ",
-	[log_level::info] = "[INFO] ",
-	[log_level::warning] = "[WARN] ",
-	[log_level::error] = "[ERR] ",
+	[log_level::DEBUG] = "[DBG] ",
+	[log_level::INFO] = "[INFO] ",
+	[log_level::WARNING] = "[WARN] ",
+	[log_level::ERROR] = "[ERR] ",
 };
 
 static void va_logf(enum log_level level, va_list args, const std::string fmt) {
@@ -38,7 +38,7 @@ static void va_logf(enum log_level level, va_list args, const std::string fmt) {
 void crepe::util::logf(const char * fmt, ...) {
 	va_list args;
 	va_start(args, fmt);
-	va_logf(crepe::util::log_level::debug, args, fmt);
+	va_logf(crepe::util::log_level::DEBUG, args, fmt);
 	va_end(args);
 }
 
diff --git a/src/crepe/util/log.h b/src/crepe/util/log.h
index bfe7291..2b0fbe1 100644
--- a/src/crepe/util/log.h
+++ b/src/crepe/util/log.h
@@ -7,7 +7,7 @@
 
 // utility macros
 #define _crepe_logf_here(fmt, ...) \
-	crepe::util::logf(util::log_level::debug, "%s%s (%s:%d)" fmt "\n", \
+	crepe::util::logf(util::log_level::DEBUG, "%s%s (%s:%d)" fmt "\n", \
 					  crepe::util::color::FG_WHITE, __PRETTY_FUNCTION__, \
 					  __FILE_NAME__, __LINE__, crepe::util::color::RESET, \
 					  __VA_ARGS__)
@@ -24,10 +24,10 @@
 namespace crepe::util {
 
 enum log_level {
-	debug,
-	info,
-	warning,
-	error,
+	DEBUG,
+	INFO,
+	WARNING,
+	ERROR,
 };
 
 void logf(const char * fmt, ...);