merge with master

45 files changed, 491 insertions, 417 deletions

diff --git a/src/crepe/api/Animator.cpp b/src/crepe/api/Animator.cpp
index 58fee2a..464b0fd 100644
--- a/src/crepe/api/Animator.cpp
+++ b/src/crepe/api/Animator.cpp
@@ -1,7 +1,5 @@
 
-#include <cstdint>
-
-#include "util/log.h"
+#include "util/Log.h"
 
 #include "Animator.h"
 #include "Component.h"
@@ -9,7 +7,7 @@
 
 using namespace crepe;
 
-Animator::Animator(uint32_t id, Sprite & ss, int row, int col, int col_animator)
+Animator::Animator(game_object_id_t id, Sprite & ss, int row, int col, int col_animator)
 	: Component(id),
 	  spritesheet(ss),
 	  row(row),
diff --git a/src/crepe/api/Animator.h b/src/crepe/api/Animator.h
index def0240..53f4b91 100644
--- a/src/crepe/api/Animator.h
+++ b/src/crepe/api/Animator.h
@@ -1,20 +1,19 @@
 #pragma once
 
-#include <cstdint>
-
 #include "Component.h"
 #include "Sprite.h"
 
 namespace crepe {
+
 class AnimatorSystem;
 class SDLContext;
 
 /**
- * \brief The Animator component is used to animate sprites by managing the movement
- *        and frame changes within a sprite sheet.
+ * \brief The Animator component is used to animate sprites by managing the movement and frame
+ * changes within a sprite sheet.
  *
- * This component allows for controlling sprite animation through rows and columns of a sprite sheet.
- * It can be used to play animations, loop them, or stop them.
+ * This component allows for controlling sprite animation through rows and columns of a sprite
+ * sheet. It can be used to play animations, loop them, or stop them.
  */
 class Animator : public Component {
 
@@ -28,15 +27,17 @@ public:
 	 * \brief Constructs an Animator object that will control animations for a sprite sheet.
 	 *
 	 * \param id The unique identifier for the component, typically assigned automatically.
-	 * \param spritesheet A reference to the Sprite object which holds the sprite sheet for animation.
+	 * \param spritesheet A reference to the Sprite object which holds the sprite sheet for
+	 * animation.
 	 * \param row The maximum number of rows in the sprite sheet.
 	 * \param col The maximum number of columns in the sprite sheet.
-	 * \param col__animate The specific col index of the sprite sheet to animate. This allows selecting which col to animate from multiple col in the sheet.
+	 * \param col_animate The specific col index of the sprite sheet to animate. This allows
+	 * selecting which col to animate from multiple col in the sheet.
 	 *
-	 * This constructor sets up the Animator with the given parameters, and initializes the animation system.
+	 * This constructor sets up the Animator with the given parameters, and initializes the
+	 * animation system.
 	 */
-	Animator(uint32_t id, Sprite & spritesheet, int row, int col,
-			 int col_animate);
+	Animator(uint32_t id, Sprite & spritesheet, int row, int col, int col_animate);
 
 	~Animator(); // dbg_trace
 	Animator(const Animator &) = delete;
diff --git a/src/crepe/api/AssetManager.cpp b/src/crepe/api/AssetManager.cpp
index b891760..3925758 100644
--- a/src/crepe/api/AssetManager.cpp
+++ b/src/crepe/api/AssetManager.cpp
@@ -1,4 +1,4 @@
-#include "util/log.h"
+#include "util/Log.h"
 
 #include "AssetManager.h"
 
diff --git a/src/crepe/api/AssetManager.h b/src/crepe/api/AssetManager.h
index 86a9902..fee6780 100644
--- a/src/crepe/api/AssetManager.h
+++ b/src/crepe/api/AssetManager.h
@@ -8,13 +8,12 @@
 namespace crepe {
 
 /**
- * \brief The AssetManager is responsible for storing and managing assets over
- * multiple scenes.
+ * \brief The AssetManager is responsible for storing and managing assets over multiple scenes.
  * 
- * The AssetManager ensures that assets are loaded once and can be accessed
- * across different scenes. It caches assets to avoid reloading them every time
- * a scene is loaded. Assets are retained in memory until the AssetManager is
- * destroyed, at which point the cached assets are cleared.
+ * The AssetManager ensures that assets are loaded once and can be accessed across different
+ * scenes. It caches assets to avoid reloading them every time a scene is loaded. Assets are
+ * retained in memory until the AssetManager is destroyed, at which point the cached assets are
+ * cleared.
  */
 class AssetManager {
 
@@ -44,20 +43,18 @@ public:
 	 * \brief Caches an asset by loading it from the given file path.
 	 *
 	 * \param file_path The path to the asset file to load.
-	 * \param reload If true, the asset will be reloaded from the file, even if
-	 * it is already cached.
+	 * \param reload If true, the asset will be reloaded from the file, even if it is already
+	 * cached.
 	 * \tparam T The type of asset to cache (e.g., texture, sound, etc.).
 	 * 
 	 * \return A shared pointer to the cached asset.
 	 * 
-	 * This template function caches the asset at the given file path. If the
-	 * asset is already cached and `reload` is false, the existing cached version
-	 * will be returned. Otherwise, the asset will be reloaded and added to the
-	 * cache.
+	 * This template function caches the asset at the given file path. If the asset is already
+	 * cached and `reload` is false, the existing cached version will be returned. Otherwise, the
+	 * asset will be reloaded and added to the cache.
 	 */
 	template <typename T>
-	std::shared_ptr<T> cache(const std::string & file_path,
-							 bool reload = false);
+	std::shared_ptr<T> cache(const std::string & file_path, bool reload = false);
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/AssetManager.hpp b/src/crepe/api/AssetManager.hpp
index 977b4e1..1c0e978 100644
--- a/src/crepe/api/AssetManager.hpp
+++ b/src/crepe/api/AssetManager.hpp
@@ -5,16 +5,14 @@
 namespace crepe {
 
 template <typename asset>
-std::shared_ptr<asset> AssetManager::cache(const std::string & file_path,
-										   bool reload) {
+std::shared_ptr<asset> AssetManager::cache(const std::string & file_path, bool reload) {
 	auto it = asset_cache.find(file_path);
 
 	if (!reload && it != asset_cache.end()) {
 		return std::any_cast<std::shared_ptr<asset>>(it->second);
 	}
 
-	std::shared_ptr<asset> new_asset
-		= std::make_shared<asset>(file_path.c_str());
+	std::shared_ptr<asset> new_asset = std::make_shared<asset>(file_path.c_str());
 
 	asset_cache[file_path] = new_asset;
 
diff --git a/src/crepe/api/AudioSource.cpp b/src/crepe/api/AudioSource.cpp
deleted file mode 100644
index 63fd0d7..0000000
--- a/src/crepe/api/AudioSource.cpp
+++ /dev/null
@@ -1,23 +0,0 @@
-#include <memory>
-
-#include "../facade/Sound.h"
-
-#include "AudioSource.h"
-
-using namespace crepe;
-
-AudioSource::AudioSource(std::unique_ptr<Asset> audio_clip) {
-	this->sound = std::make_unique<crepe::Sound>(std::move(audio_clip));
-}
-
-void AudioSource::play() { return this->play(false); }
-
-void AudioSource::play(bool looping) {
-	this->sound->set_looping(looping);
-	this->sound->play();
-}
-
-void AudioSource::stop() {
-	this->sound->pause();
-	this->sound->rewind();
-}
diff --git a/src/crepe/api/AudioSource.h b/src/crepe/api/AudioSource.h
deleted file mode 100644
index 1e24ae8..0000000
--- a/src/crepe/api/AudioSource.h
+++ /dev/null
@@ -1,39 +0,0 @@
-#pragma once
-
-#include <memory>
-
-#include "../Asset.h"
-#include "../Component.h"
-
-namespace crepe {
-
-class Sound;
-
-//! Audio source component
-class AudioSource : public Component {
-public:
-	AudioSource(std::unique_ptr<Asset> audio_clip);
-	virtual ~AudioSource() = default;
-
-public:
-	//! Start or resume this audio source
-	void play();
-	void play(bool looping);
-	//! Stop this audio source
-	void stop();
-
-public:
-	//! Sample file location
-	std::unique_ptr<Asset> audio_clip;
-	//! TODO: ?????
-	bool play_on_awake;
-	//! Repeat the current audio clip during playback
-	bool loop;
-	//! Normalized volume (0.0 - 1.0)
-	float volume;
-
-private:
-	std::unique_ptr<Sound> sound;
-};
-
-} // namespace crepe
diff --git a/src/crepe/api/BehaviorScript.cpp b/src/crepe/api/BehaviorScript.cpp
index e69de29..7bbace0 100644
--- a/src/crepe/api/BehaviorScript.cpp
+++ b/src/crepe/api/BehaviorScript.cpp
@@ -0,0 +1,15 @@
+#include "BehaviorScript.h"
+#include "Component.h"
+#include "GameObject.h"
+
+using namespace crepe;
+
+BehaviorScript::BehaviorScript(game_object_id_t id, ComponentManager & mgr)
+	: Component(id),
+	  component_manager(mgr) {}
+
+template <>
+BehaviorScript & GameObject::add_component<BehaviorScript>() {
+	ComponentManager & mgr = this->component_manager;
+	return mgr.add_component<BehaviorScript>(this->id, mgr);
+}
diff --git a/src/crepe/api/BehaviorScript.h b/src/crepe/api/BehaviorScript.h
index 6b1fec7..9d85d4c 100644
--- a/src/crepe/api/BehaviorScript.h
+++ b/src/crepe/api/BehaviorScript.h
@@ -4,29 +4,69 @@
 
 #include "../Component.h"
 
+#include "GameObject.h"
+
 namespace crepe {
 
 class ScriptSystem;
 class ComponentManager;
 class Script;
 
+/**
+ * \brief Script component
+ *
+ * This class acts as a (component) wrapper around an instance of (a class derivatived from) \c
+ * Script. \c BehaviorScript is the only ECS component that stores member function
+ * implementations as data.
+ */
 class BehaviorScript : public Component {
 protected:
-	friend class crepe::ComponentManager;
-	using Component::Component;
-
-public:
-	virtual ~BehaviorScript() = default;
+	/**
+	 * \param id Parent \c GameObject id
+	 * \param component_manager Reference to component manager (passed through to \c Script
+	 * instance)
+	 *
+	 * \note Calls to this constructor (should) always pass through \c GameObject::add_component,
+	 * which has an exception for this specific component type. This was done so the user does
+	 * not have to pass references used within \c Script to each \c BehaviorScript instance.
+	 */
+	BehaviorScript(game_object_id_t id, ComponentManager & component_manager);
+	//! Only ComponentManager is allowed to instantiate BehaviorScript
+	friend class ComponentManager;
 
 public:
+	/**
+	 * \brief Set the concrete script of this component
+	 *
+	 * \tparam T Concrete script type (derived from \c crepe::Script)
+	 *
+	 * \returns Reference to BehaviorScript component (`*this`)
+	 */
 	template <class T>
 	BehaviorScript & set_script();
 
 protected:
-	friend class crepe::ScriptSystem;
+	//! Script instance
 	std::unique_ptr<Script> script = nullptr;
+	//! ScriptSystem needs direct access to the script instance
+	friend class ScriptSystem;
+
+protected:
+	//! Reference to component manager (passed to Script)
+	ComponentManager & component_manager;
 };
 
+/**
+ * \brief Add a BehaviorScript component to this game object
+ *
+ * The \c BehaviorScript class is the only exception to the ECS harmony, and requires a
+ * reference to the component manager passed to its constructor in order to function normally.
+ * This is because the \c BehaviorScript (and \c Script) classes are the only component-related
+ * classes that store implemented member functions as data.
+ */
+template <>
+BehaviorScript & GameObject::add_component<BehaviorScript>();
+
 } // namespace crepe
 
 #include "BehaviorScript.hpp"
diff --git a/src/crepe/api/BehaviorScript.hpp b/src/crepe/api/BehaviorScript.hpp
index 4751607..d80321d 100644
--- a/src/crepe/api/BehaviorScript.hpp
+++ b/src/crepe/api/BehaviorScript.hpp
@@ -2,7 +2,7 @@
 
 #include <type_traits>
 
-#include "../util/log.h"
+#include "../util/Log.h"
 
 #include "BehaviorScript.h"
 #include "Script.h"
@@ -11,10 +11,11 @@ namespace crepe {
 
 template <class T>
 BehaviorScript & BehaviorScript::set_script() {
-	static_assert(std::is_base_of<Script, T>::value);
 	dbg_trace();
+	static_assert(std::is_base_of<Script, T>::value);
 	Script * s = new T();
-	s->parent = this;
+	s->game_object_id = this->game_object_id;
+	s->component_manager_ref = &this->component_manager;
 	this->script = std::unique_ptr<Script>(s);
 	return *this;
 }
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index 07341e2..07b3a82 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -1,7 +1,6 @@
 target_sources(crepe PUBLIC
 	# AudioSource.cpp
 	BehaviorScript.cpp
-	Script.cpp
 	GameObject.cpp
 	Rigidbody.cpp
 	ParticleEmitter.cpp
diff --git a/src/crepe/api/Camera.cpp b/src/crepe/api/Camera.cpp
index 6355a03..5835bdd 100644
--- a/src/crepe/api/Camera.cpp
+++ b/src/crepe/api/Camera.cpp
@@ -1,7 +1,4 @@
-
-#include <cstdint>
-
-#include "util/log.h"
+#include "util/Log.h"
 
 #include "Camera.h"
 #include "Color.h"
@@ -9,7 +6,7 @@
 
 using namespace crepe;
 
-Camera::Camera(uint32_t id, const Color & bg_color)
+Camera::Camera(game_object_id_t id, const Color & bg_color)
 	: Component(id),
 	  bg_color(bg_color) {
 	dbg_trace();
diff --git a/src/crepe/api/Camera.h b/src/crepe/api/Camera.h
index ba3a9ef..e0cda34 100644
--- a/src/crepe/api/Camera.h
+++ b/src/crepe/api/Camera.h
@@ -1,7 +1,5 @@
 #pragma once
 
-#include <cstdint>
-
 #include "Color.h"
 #include "Component.h"
 
@@ -11,9 +9,8 @@ namespace crepe {
  * \class Camera
  * \brief Represents a camera component for rendering in the game.
  *
- * The Camera class defines the view parameters, including background color, 
- * aspect ratio, position, and zoom level. It controls what part of the game 
- * world is visible on the screen.
+ * The Camera class defines the view parameters, including background color, aspect ratio,
+ * position, and zoom level. It controls what part of the game world is visible on the screen.
  */
 class Camera : public Component {
 
@@ -23,7 +20,7 @@ public:
 	 * \param id Unique identifier for the camera component.
 	 * \param bg_color Background color for the camera view.
 	 */
-	Camera(uint32_t id, const Color & bg_color);
+	Camera(game_object_id_t id, const Color & bg_color);
 	~Camera(); // dbg_trace only
 
 public:
diff --git a/src/crepe/api/Config.h b/src/crepe/api/Config.h
index 8c9e643..3ab877a 100644
--- a/src/crepe/api/Config.h
+++ b/src/crepe/api/Config.h
@@ -1,19 +1,24 @@
 #pragma once
 
-#include "../util/log.h"
+#include "../util/Log.h"
 
 namespace crepe {
 
+/**
+ * \brief Global configuration interface
+ *
+ * This class stores engine default settings. Properties on this class are only supposed to be
+ * modified *before* execution is handed over from the game programmer to the engine (i.e. the
+ * main loop is started).
+ */
 class Config {
-private:
-	Config() = default;
-
-public:
-	~Config() = default;
-
 public:
 	//! Retrieve handle to global Config instance
 	static Config & get_instance();
+
+private:
+	Config() = default;
+
 	// singleton
 	Config(const Config &) = delete;
 	Config(Config &&) = delete;
@@ -26,10 +31,9 @@ public:
 		/**
 		 * \brief Log level
 		 *
-		 * Only messages with equal or higher priority than this value will be
-		 * logged.
+		 * Only messages with equal or higher priority than this value will be logged.
 		 */
-		LogLevel level = LogLevel::INFO;
+		Log::Level level = Log::Level::INFO;
 		/**
 		 * \brief Colored log output
 		 *
@@ -43,8 +47,8 @@ public:
 		/**
 		 * \brief Save file location
 		 *
-		 * This location is used by the constructor of SaveManager, and should be
-		 * set before save manager functionality is attempted to be used.
+		 * This location is used by the constructor of SaveManager, and should be set before save
+		 * manager functionality is attempted to be used.
 		 */
 		std::string location = "save.crepe.db";
 	} savemgr;
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index d252e77..287e81d 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -1,23 +1,26 @@
 #include "api/Transform.h"
 
+#include "BehaviorScript.h"
 #include "GameObject.h"
 #include "Metadata.h"
 
 using namespace crepe;
 using namespace std;
 
-GameObject::GameObject(game_object_id_t id, const std::string & name,
-					   const std::string & tag, const Vector2 & position,
-					   double rotation, double scale)
-	: id(id) {
+GameObject::GameObject(ComponentManager & component_manager, game_object_id_t id,
+					   const std::string & name, const std::string & tag,
+					   const Vector2 & position, double rotation, double scale)
+	: id(id),
+	  component_manager(component_manager) {
+
 	// Add Transform and Metadata components
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 	mgr.add_component<Transform>(this->id, position, rotation, scale);
 	mgr.add_component<Metadata>(this->id, name, tag);
 }
 
 void GameObject::set_parent(const GameObject & parent) {
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 
 	// Set parent on own Metadata component
 	vector<reference_wrapper<Metadata>> this_metadata
diff --git a/src/crepe/api/GameObject.h b/src/crepe/api/GameObject.h
index d703730..34ef8bb 100644
--- a/src/crepe/api/GameObject.h
+++ b/src/crepe/api/GameObject.h
@@ -2,25 +2,26 @@
 
 #include <string>
 
+#include "Vector2.h"
 #include "types.h"
 
 namespace crepe {
 
-class Vector2;
+class ComponentManager;
 
 /**
  * \brief Represents a GameObject
  * 
- * This class represents a GameObject. The GameObject class is only used
- * as an interface for the game programmer. The actual implementation is
- * done in the ComponentManager.
+ * This class represents a GameObject. The GameObject class is only used as an interface for
+ * the game programmer. The actual implementation is done in the ComponentManager.
  */
 class GameObject {
-public:
+private:
 	/**
-	 * This constructor creates a new GameObject. It creates a new
-	 * Transform and Metadata component and adds them to the ComponentManager.
+	 * This constructor creates a new GameObject. It creates a new Transform and Metadata
+	 * component and adds them to the ComponentManager.
 	 * 
+	 * \param component_manager Reference to component_manager
 	 * \param id The id of the GameObject
 	 * \param name The name of the GameObject
 	 * \param tag The tag of the GameObject
@@ -28,15 +29,19 @@ public:
 	 * \param rotation The rotation of the GameObject
 	 * \param scale The scale of the GameObject
 	 */
-	GameObject(game_object_id_t id, const std::string & name,
-			   const std::string & tag, const Vector2 & position,
+	GameObject(ComponentManager & component_manager, game_object_id_t id,
+			   const std::string & name, const std::string & tag, const Vector2 & position,
 			   double rotation, double scale);
+	//! ComponentManager instances GameObject
+	friend class ComponentManager;
+
+public:
 	/**
 	 * \brief Set the parent of this GameObject
 	 * 
-	 * This method sets the parent of this GameObject. It sets the parent
-	 * in the Metadata component of this GameObject and adds this GameObject
-	 * to the children list of the parent GameObject.
+	 * This method sets the parent of this GameObject. It sets the parent in the Metadata
+	 * component of this GameObject and adds this GameObject to the children list of the parent
+	 * GameObject.
 	 * 
 	 * \param parent The parent GameObject
 	 */
@@ -44,8 +49,8 @@ public:
 	/**
 	 * \brief Add a component to the GameObject
 	 * 
-	 * This method adds a component to the GameObject. It forwards the
-	 * arguments to the ComponentManager.
+	 * This method adds a component to the GameObject. It forwards the arguments to the
+	 * ComponentManager.
 	 * 
 	 * \tparam T The type of the component
 	 * \tparam Args The types of the arguments
@@ -58,6 +63,9 @@ public:
 public:
 	//! The id of the GameObject
 	const game_object_id_t id;
+
+protected:
+	ComponentManager & component_manager;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/GameObject.hpp b/src/crepe/api/GameObject.hpp
index bfba7fe..17b17d7 100644
--- a/src/crepe/api/GameObject.hpp
+++ b/src/crepe/api/GameObject.hpp
@@ -8,7 +8,7 @@ namespace crepe {
 
 template <typename T, typename... Args>
 T & GameObject::add_component(Args &&... args) {
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 	return mgr.add_component<T>(this->id, std::forward<Args>(args)...);
 }
 
diff --git a/src/crepe/api/LoopManager.cpp b/src/crepe/api/LoopManager.cpp
index f9c5362..a4bc101 100644
--- a/src/crepe/api/LoopManager.cpp
+++ b/src/crepe/api/LoopManager.cpp
@@ -1,5 +1,9 @@
-
 #include "../facade/SDLContext.h"
+
+#include "../system/AnimatorSystem.h"
+#include "../system/CollisionSystem.h"
+#include "../system/ParticleSystem.h"
+#include "../system/PhysicsSystem.h"
 #include "../system/RenderSystem.h"
 #include "../system/ScriptSystem.h"
 #include "..//system/PhysicsSystem.h"
@@ -9,11 +13,21 @@
 #include "LoopTimer.h"
 
 using namespace crepe;
+using namespace std;
+
+LoopManager::LoopManager() {
+	this->load_system<AnimatorSystem>();
+	this->load_system<CollisionSystem>();
+	this->load_system<ParticleSystem>();
+	this->load_system<PhysicsSystem>();
+	this->load_system<RenderSystem>();
+	this->load_system<ScriptSystem>();
+}
 
-LoopManager::LoopManager() {}
 void LoopManager::process_input() {
 	SDLContext::get_instance().handle_events(this->game_running);
 }
+
 void LoopManager::start() {
 	this->setup();
 	this->loop();
@@ -55,7 +69,7 @@ void LoopManager::setup() {
 
 void LoopManager::render() {
 	if (this->game_running) {
-		RenderSystem::get_instance().update();
+		this->get_system<RenderSystem>().update();
 	}
 }
 
diff --git a/src/crepe/api/LoopManager.h b/src/crepe/api/LoopManager.h
index 2f03193..f6904be 100644
--- a/src/crepe/api/LoopManager.h
+++ b/src/crepe/api/LoopManager.h
@@ -2,15 +2,9 @@
 
 #include <memory>
 
-class RenderSystem;
-class SDLContext;
-class LoopTimer;
-class ScriptSystem;
-class SoundSystem;
-class ParticleSystem;
-class PhysicsSystem;
-class AnimatorSystem;
-class CollisionSystem;
+#include "../ComponentManager.h"
+#include "../system/System.h"
+
 namespace crepe {
 
 class LoopManager {
@@ -73,7 +67,35 @@ private:
 	void render();
 
 	bool game_running = false;
-	//#TODO add system instances
+
+private:
+	//! Component manager instance
+	ComponentManager component_manager{};
+
+private:
+	/**
+	 * \brief Collection of System instances
+	 *
+	 * This map holds System instances indexed by the system's class typeid. It is filled in the
+	 * constructor of \c LoopManager using LoopManager::load_system.
+	 */
+	std::unordered_map<std::type_index, std::unique_ptr<System>> systems;
+	/**
+	 * \brief Initialize a system
+	 * \tparam T System type (must be derivative of \c System)
+	 */
+	template <class T>
+	void load_system();
+	/**
+	 * \brief Retrieve a reference to ECS system
+	 * \tparam T System type
+	 * \returns Reference to system instance
+	 * \throws std::runtime_error if the System is not initialized
+	 */
+	template <class T>
+	T & get_system();
 };
 
 } // namespace crepe
+
+#include "LoopManager.hpp"
diff --git a/src/crepe/api/LoopManager.hpp b/src/crepe/api/LoopManager.hpp
new file mode 100644
index 0000000..0b14fdb
--- /dev/null
+++ b/src/crepe/api/LoopManager.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <cassert>
+#include <format>
+#include <memory>
+
+#include "../system/System.h"
+
+#include "LoopManager.h"
+
+namespace crepe {
+
+template <class T>
+T & LoopManager::get_system() {
+	using namespace std;
+	static_assert(is_base_of<System, T>::value,
+				  "get_system must recieve a derivative class of System");
+
+	const type_info & type = typeid(T);
+	if (!this->systems.contains(type))
+		throw runtime_error(format("LoopManager: {} is not initialized", type.name()));
+
+	System * system = this->systems.at(type).get();
+	T * concrete_system = dynamic_cast<T *>(system);
+	assert(concrete_system != nullptr);
+
+	return *concrete_system;
+}
+
+template <class T>
+void LoopManager::load_system() {
+	using namespace std;
+	static_assert(is_base_of<System, T>::value,
+				  "load_system must recieve a derivative class of System");
+
+	System * system = new T(this->component_manager);
+	this->systems[typeid(T)] = unique_ptr<System>(system);
+}
+
+} // namespace crepe
diff --git a/src/crepe/api/LoopTimer.cpp b/src/crepe/api/LoopTimer.cpp
index 8f09e41..a9800b7 100644
--- a/src/crepe/api/LoopTimer.cpp
+++ b/src/crepe/api/LoopTimer.cpp
@@ -1,7 +1,7 @@
 #include <chrono>
 
 #include "../facade/SDLContext.h"
-#include "../util/log.h"
+#include "../util/Log.h"
 
 #include "LoopTimer.h"
 
@@ -24,9 +24,8 @@ void LoopTimer::start() {
 void LoopTimer::update() {
 	auto current_frame_time = std::chrono::steady_clock::now();
 	// Convert to duration in seconds for delta time
-	this->delta_time
-		= std::chrono::duration_cast<std::chrono::duration<double>>(
-			current_frame_time - last_frame_time);
+	this->delta_time = std::chrono::duration_cast<std::chrono::duration<double>>(
+		current_frame_time - last_frame_time);
 
 	if (this->delta_time > this->maximum_delta_time) {
 		this->delta_time = this->maximum_delta_time;
@@ -39,17 +38,11 @@ void LoopTimer::update() {
 
 double LoopTimer::get_delta_time() const { return this->delta_time.count(); }
 
-double LoopTimer::get_current_time() const {
-	return this->elapsed_time.count();
-}
+double LoopTimer::get_current_time() const { return this->elapsed_time.count(); }
 
-void LoopTimer::advance_fixed_update() {
-	this->elapsed_fixed_time += this->fixed_delta_time;
-}
+void LoopTimer::advance_fixed_update() { this->elapsed_fixed_time += this->fixed_delta_time; }
 
-double LoopTimer::get_fixed_delta_time() const {
-	return this->fixed_delta_time.count();
-}
+double LoopTimer::get_fixed_delta_time() const { return this->fixed_delta_time.count(); }
 
 void LoopTimer::set_fps(int fps) {
 	this->fps = fps;
@@ -66,13 +59,13 @@ void LoopTimer::enforce_frame_rate() {
 	std::chrono::steady_clock::time_point current_frame_time
 		= std::chrono::steady_clock::now();
 	std::chrono::milliseconds frame_duration
-		= std::chrono::duration_cast<std::chrono::milliseconds>(
-			current_frame_time - this->last_frame_time);
+		= std::chrono::duration_cast<std::chrono::milliseconds>(current_frame_time
+																- this->last_frame_time);
 
 	if (frame_duration < this->frame_target_time) {
 		std::chrono::milliseconds delay_time
-			= std::chrono::duration_cast<std::chrono::milliseconds>(
-				this->frame_target_time - frame_duration);
+			= std::chrono::duration_cast<std::chrono::milliseconds>(this->frame_target_time
+																	- frame_duration);
 		if (delay_time.count() > 0) {
 			SDLContext::get_instance().delay(delay_time.count());
 		}
diff --git a/src/crepe/api/LoopTimer.h b/src/crepe/api/LoopTimer.h
index 85687be..f277d7b 100644
--- a/src/crepe/api/LoopTimer.h
+++ b/src/crepe/api/LoopTimer.h
@@ -1,124 +1,123 @@
 #pragma once
 
 #include <chrono>
-#include <cstdint>
 
 namespace crepe {
 
 class LoopTimer {
 public:
 	/**
-     * \brief Get the singleton instance of LoopTimer.
-     *
-     * \return A reference to the LoopTimer instance.
-     */
+	 * \brief Get the singleton instance of LoopTimer.
+	 *
+	 * \return A reference to the LoopTimer instance.
+	 */
 	static LoopTimer & get_instance();
 
 	/**
-     * \brief Get the current delta time for the current frame.
-     *
-     * \return Delta time in seconds since the last frame.
-     */
+	 * \brief Get the current delta time for the current frame.
+	 *
+	 * \return Delta time in seconds since the last frame.
+	 */
 	double get_delta_time() const;
 
 	/**
-     * \brief Get the current game time.
-     *
-     * \note The current game time may vary from real-world elapsed time.
-     * It is the cumulative sum of each frame's delta time.
-     *
-     * \return Elapsed game time in seconds.
-     */
+	 * \brief Get the current game time.
+	 *
+	 * \note The current game time may vary from real-world elapsed time. It is the cumulative
+	 * sum of each frame's delta time.
+	 *
+	 * \return Elapsed game time in seconds.
+	 */
 	double get_current_time() const;
 
 	/**
-     * \brief Set the target frames per second (FPS).
-     *
-     * \param fps The desired frames rendered per second.
-     */
+	 * \brief Set the target frames per second (FPS).
+	 *
+	 * \param fps The desired frames rendered per second.
+	 */
 	void set_fps(int fps);
 
 	/**
-     * \brief Get the current frames per second (FPS).
-     *
-     * \return Current FPS.
-     */
+	 * \brief Get the current frames per second (FPS).
+	 *
+	 * \return Current FPS.
+	 */
 	int get_fps() const;
 
 	/**
-     * \brief Get the current game scale.
-     *
-     * \return The current game scale, where 0 = paused, 1 = normal speed, and values > 1 speed up the game.
-     */
+	 * \brief Get the current game scale.
+	 *
+	 * \return The current game scale, where 0 = paused, 1 = normal speed, and values > 1 speed
+	 * up the game.
+	 */
 	double get_game_scale() const;
 
 	/**
-     * \brief Set the game scale.
-     *
-     * \param game_scale The desired game scale (0 = pause, 1 = normal speed, > 1 = speed up).
-     */
+	 * \brief Set the game scale.
+	 *
+	 * \param game_scale The desired game scale (0 = pause, 1 = normal speed, > 1 = speed up).
+	 */
 	void set_game_scale(double game_scale);
 
 private:
 	friend class LoopManager;
 
 	/**
-     * \brief Start the loop timer.
-     *
-     * Initializes the timer to begin tracking frame times.
-     */
+	 * \brief Start the loop timer.
+	 *
+	 * Initializes the timer to begin tracking frame times.
+	 */
 	void start();
 
 	/**
-     * \brief Enforce the frame rate limit.
-     *
-     * Ensures that the game loop does not exceed the target FPS by delaying
-     * frame updates as necessary.
-     */
+	 * \brief Enforce the frame rate limit.
+	 *
+	 * Ensures that the game loop does not exceed the target FPS by delaying frame updates as
+	 * necessary.
+	 */
 	void enforce_frame_rate();
 
 	/**
-     * \brief Get the fixed delta time for consistent updates.
-     *
-     * Fixed delta time is used for operations that require uniform time steps,
-     * such as physics calculations.
-     *
-     * \return Fixed delta time in seconds.
-     */
+	 * \brief Get the fixed delta time for consistent updates.
+	 *
+	 * Fixed delta time is used for operations that require uniform time steps, such as physics
+	 * calculations.
+	 *
+	 * \return Fixed delta time in seconds.
+	 */
 	double get_fixed_delta_time() const;
 
 	/**
-     * \brief Get the accumulated lag in the game loop.
-     *
-     * Lag represents the difference between the target frame time and the
-     * actual frame time, useful for managing fixed update intervals.
-     *
-     * \return Accumulated lag in seconds.
-     */
+	 * \brief Get the accumulated lag in the game loop.
+	 *
+	 * Lag represents the difference between the target frame time and the actual frame time,
+	 * useful for managing fixed update intervals.
+	 *
+	 * \return Accumulated lag in seconds.
+	 */
 	double get_lag() const;
 
 	/**
-     * \brief Construct a new LoopTimer object.
-     *
-     * Private constructor for singleton pattern to restrict instantiation
-     * outside the class.
-     */
+	 * \brief Construct a new LoopTimer object.
+	 *
+	 * Private constructor for singleton pattern to restrict instantiation outside the class.
+	 */
 	LoopTimer();
 
 	/**
-     * \brief Update the timer to the current frame.
-     *
-     * Calculates and updates the delta time for the current frame and adds it to
-     * the cumulative game time.
-     */
+	 * \brief Update the timer to the current frame.
+	 *
+	 * Calculates and updates the delta time for the current frame and adds it to the cumulative
+	 * game time.
+	 */
 	void update();
 
 	/**
-     * \brief Advance the game loop by a fixed update interval.
-     *
-     * This method progresses the game state by a consistent, fixed time step,
-     * allowing for stable updates independent of frame rate fluctuations.
-     */
+	 * \brief Advance the game loop by a fixed update interval.
+	 *
+	 * This method progresses the game state by a consistent, fixed time step, allowing for
+	 * stable updates independent of frame rate fluctuations.
+	 */
 	void advance_fixed_update();
 
 private:
@@ -131,11 +130,9 @@ private:
 	//! Delta time for the current frame in seconds
 	std::chrono::duration<double> delta_time{0.0};
 	//! Target time per frame in seconds
-	std::chrono::duration<double> frame_target_time
-		= std::chrono::seconds(1) / fps;
+	std::chrono::duration<double> frame_target_time = std::chrono::seconds(1) / fps;
 	//! Fixed delta time for fixed updates in seconds
-	std::chrono::duration<double> fixed_delta_time
-		= std::chrono::seconds(1) / 50;
+	std::chrono::duration<double> fixed_delta_time = std::chrono::seconds(1) / 50;
 	//! Total elapsed game time in seconds
 	std::chrono::duration<double> elapsed_time{0.0};
 	//! Total elapsed time for fixed updates in seconds
diff --git a/src/crepe/api/Metadata.h b/src/crepe/api/Metadata.h
index c61e006..235d42f 100644
--- a/src/crepe/api/Metadata.h
+++ b/src/crepe/api/Metadata.h
@@ -10,8 +10,8 @@ namespace crepe {
 /**
  * \brief Metadata component
  * 
- * This class represents the Metadata component. It stores the name, tag, parent
- * and children of a GameObject.
+ * This class represents the Metadata component. It stores the name, tag, parent and children
+ * of a GameObject.
  */
 class Metadata : public Component {
 public:
@@ -20,8 +20,7 @@ public:
 	 * \param name The name of the GameObject
 	 * \param tag The tag of the GameObject
 	 */
-	Metadata(game_object_id_t id, const std::string & name,
-			 const std::string & tag);
+	Metadata(game_object_id_t id, const std::string & name, const std::string & tag);
 	/**
 	 * \brief Get the maximum number of instances for this component
 	 *
diff --git a/src/crepe/api/ParticleEmitter.cpp b/src/crepe/api/ParticleEmitter.cpp
index 35f960d..90b77a0 100644
--- a/src/crepe/api/ParticleEmitter.cpp
+++ b/src/crepe/api/ParticleEmitter.cpp
@@ -2,8 +2,7 @@
 
 using namespace crepe;
 
-ParticleEmitter::ParticleEmitter(game_object_id_t game_object_id,
-								 const Data & data)
+ParticleEmitter::ParticleEmitter(game_object_id_t game_object_id, const Data & data)
 	: Component(game_object_id),
 	  data(data) {
 	for (size_t i = 0; i < this->data.max_particles; i++) {
diff --git a/src/crepe/api/ParticleEmitter.h b/src/crepe/api/ParticleEmitter.h
index a9e872f..33112e1 100644
--- a/src/crepe/api/ParticleEmitter.h
+++ b/src/crepe/api/ParticleEmitter.h
@@ -13,16 +13,16 @@ class Sprite;
 /**
  * \brief Data holder for particle emission parameters.
  *
- * The ParticleEmitter class stores configuration data for particle properties,
- * defining the characteristics and boundaries of particle emissions.
+ * The ParticleEmitter class stores configuration data for particle properties, defining the
+ * characteristics and boundaries of particle emissions.
  */
 class ParticleEmitter : public Component {
 public:
 	/**
 	 * \brief Defines the boundary within which particles are constrained.
 	 *
-	 * This structure specifies the boundary's size and offset, as well as the
-	 * behavior of particles upon reaching the boundary limits.
+	 * This structure specifies the boundary's size and offset, as well as the behavior of
+	 * particles upon reaching the boundary limits.
 	 */
 	struct Boundary {
 		//! boundary width (midpoint is emitter location)
@@ -38,8 +38,8 @@ public:
 	/**
 	 * \brief Holds parameters that control particle emission.
 	 *
-	 * Contains settings for the emitter’s position, particle speed, angle, lifespan,
-	 * boundary, and the sprite used for rendering particles.
+	 * Contains settings for the emitter’s position, particle speed, angle, lifespan, boundary,
+	 * and the sprite used for rendering particles.
 	 */
 	struct Data {
 		//! position of the emitter
diff --git a/src/crepe/api/Rigidbody.cpp b/src/crepe/api/Rigidbody.cpp
index 3bf1c5b..6b87695 100644
--- a/src/crepe/api/Rigidbody.cpp
+++ b/src/crepe/api/Rigidbody.cpp
@@ -2,8 +2,8 @@
 
 using namespace crepe;
 
-crepe::Rigidbody::Rigidbody(uint32_t game_object_id, const Data & data)
-	: Component(game_object_id),
+crepe::Rigidbody::Rigidbody(game_object_id_t id, const Data & data)
+	: Component(id),
 	  data(data) {}
 
 void crepe::Rigidbody::add_force_linear(const Vector2 & force) {
diff --git a/src/crepe/api/Rigidbody.h b/src/crepe/api/Rigidbody.h
index a007107..fddbf5c 100644
--- a/src/crepe/api/Rigidbody.h
+++ b/src/crepe/api/Rigidbody.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include <cmath>
-#include <cstdint>
 
 #include "../Component.h"
 
@@ -12,8 +11,8 @@ namespace crepe {
 /**
  * \brief Rigidbody class
  * 
- * This class is used by the physics sytem and collision system. 
- * It configures how to system interact with the gameobject for movement and collisions.
+ * This class is used by the physics sytem and collision system. It configures how to system
+ * interact with the gameobject for movement and collisions.
  */
 class Rigidbody : public Component {
 public:
@@ -33,8 +32,8 @@ public:
 	/**
 	 * \brief PhysicsConstraints to constrain movement
 	 * 
-	 * This struct configures the movement constraint for this object.
-	 * If a constraint is enabled the systems will not move the object.
+	 * This struct configures the movement constraint for this object. If a constraint is enabled
+	 * the systems will not move the object.
 	 */
 	struct PhysicsConstraints {
 		//! X constraint
@@ -87,7 +86,7 @@ public:
 	 * \param game_object_id id of the gameobject the rigibody is added to.
 	 * \param data struct to configure the rigidbody.
 	 */
-	Rigidbody(uint32_t game_object_id, const Data & data);
+	Rigidbody(game_object_id_t id, const Data & data);
 	//! struct to hold data of rigidbody
 	Data data;
 
diff --git a/src/crepe/api/SaveManager.cpp b/src/crepe/api/SaveManager.cpp
index 43276c5..c5f43ea 100644
--- a/src/crepe/api/SaveManager.cpp
+++ b/src/crepe/api/SaveManager.cpp
@@ -1,5 +1,5 @@
 #include "../facade/DB.h"
-#include "../util/log.h"
+#include "../util/Log.h"
 
 #include "Config.h"
 #include "SaveManager.h"
@@ -139,14 +139,11 @@ ValueBroker<T> SaveManager::get(const string & key, const T & default_value) {
 }
 template ValueBroker<uint8_t> SaveManager::get(const string &, const uint8_t &);
 template ValueBroker<int8_t> SaveManager::get(const string &, const int8_t &);
-template ValueBroker<uint16_t> SaveManager::get(const string &,
-												const uint16_t &);
+template ValueBroker<uint16_t> SaveManager::get(const string &, const uint16_t &);
 template ValueBroker<int16_t> SaveManager::get(const string &, const int16_t &);
-template ValueBroker<uint32_t> SaveManager::get(const string &,
-												const uint32_t &);
+template ValueBroker<uint32_t> SaveManager::get(const string &, const uint32_t &);
 template ValueBroker<int32_t> SaveManager::get(const string &, const int32_t &);
-template ValueBroker<uint64_t> SaveManager::get(const string &,
-												const uint64_t &);
+template ValueBroker<uint64_t> SaveManager::get(const string &, const uint64_t &);
 template ValueBroker<int64_t> SaveManager::get(const string &, const int64_t &);
 template ValueBroker<float> SaveManager::get(const string &, const float &);
 template ValueBroker<double> SaveManager::get(const string &, const double &);
diff --git a/src/crepe/api/SaveManager.h b/src/crepe/api/SaveManager.h
index 4be85fb..3d8c852 100644
--- a/src/crepe/api/SaveManager.h
+++ b/src/crepe/api/SaveManager.h
@@ -24,7 +24,8 @@ public:
 	 * \brief Get a read/write reference to a value and initialize it if it does not yet exist
 	 *
 	 * \param key  The value key
-	 * \param default_value  Value to initialize \c key with if it does not already exist in the database
+	 * \param default_value  Value to initialize \c key with if it does not already exist in the
+	 * database
 	 *
 	 * \return Read/write reference to the value
 	 */
@@ -38,8 +39,8 @@ public:
 	 *
 	 * \return Read/write reference to the value
 	 *
-	 * \note Attempting to read this value before it is initialized (i.e. set)
-	 * will result in an exception
+	 * \note Attempting to read this value before it is initialized (i.e. set) will result in an
+	 * exception
 	 */
 	template <typename T>
 	ValueBroker<T> get(const std::string & key);
@@ -102,8 +103,8 @@ private:
 	 *
 	 * \returns DB instance
 	 *
-	 * This function exists because DB is a facade class, which can't directly be
-	 * used in the API without workarounds
+	 * This function exists because DB is a facade class, which can't directly be used in the API
+	 * without workarounds
 	 *
 	 * TODO: better solution
 	 */
diff --git a/src/crepe/api/Scene.cpp b/src/crepe/api/Scene.cpp
index 933edf4..88aa82d 100644
--- a/src/crepe/api/Scene.cpp
+++ b/src/crepe/api/Scene.cpp
@@ -2,4 +2,6 @@
 
 using namespace crepe;
 
-Scene::Scene(const std::string & name) : name(name) {}
+Scene::Scene(ComponentManager & mgr, const std::string & name)
+	: component_manager(mgr),
+	  name(name) {}
diff --git a/src/crepe/api/Scene.h b/src/crepe/api/Scene.h
index f8bcc3d..0e516b6 100644
--- a/src/crepe/api/Scene.h
+++ b/src/crepe/api/Scene.h
@@ -4,14 +4,23 @@
 
 namespace crepe {
 
+class SceneManager;
+class ComponentManager;
+
 class Scene {
+protected:
+	Scene(ComponentManager & mgr, const std::string & name);
+	friend class SceneManager;
+
 public:
-	Scene(const std::string & name);
 	virtual ~Scene() = default;
-	virtual void load_scene() = 0;
 
 public:
-	std::string name;
+	virtual void load_scene() = 0;
+	const std::string name;
+
+protected:
+	ComponentManager & component_manager;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/SceneManager.cpp b/src/crepe/api/SceneManager.cpp
index dfed6ee..7fb5cb0 100644
--- a/src/crepe/api/SceneManager.cpp
+++ b/src/crepe/api/SceneManager.cpp
@@ -8,10 +8,7 @@
 using namespace crepe;
 using namespace std;
 
-SceneManager & SceneManager::get_instance() {
-	static SceneManager instance;
-	return instance;
-}
+SceneManager::SceneManager(ComponentManager & mgr) : component_manager(mgr) {}
 
 void SceneManager::set_next_scene(const string & name) { next_scene = name; }
 
@@ -19,18 +16,17 @@ void SceneManager::load_next_scene() {
 	// next scene not set
 	if (this->next_scene.empty()) return;
 
-	auto it
-		= find_if(this->scenes.begin(), this->scenes.end(),
-				  [&next_scene = this->next_scene](unique_ptr<Scene> & scene) {
-					  return scene->name == next_scene;
-				  });
+	auto it = find_if(this->scenes.begin(), this->scenes.end(),
+					  [&next_scene = this->next_scene](unique_ptr<Scene> & scene) {
+						  return scene->name == next_scene;
+					  });
 
 	// next scene not found
 	if (it == this->scenes.end()) return;
 	unique_ptr<Scene> & scene = *it;
 
 	// Delete all components of the current scene
-	ComponentManager & mgr = ComponentManager::get_instance();
+	ComponentManager & mgr = this->component_manager;
 	mgr.delete_all_components();
 
 	// Load the new scene
diff --git a/src/crepe/api/SceneManager.h b/src/crepe/api/SceneManager.h
index 1e0e670..e854794 100644
--- a/src/crepe/api/SceneManager.h
+++ b/src/crepe/api/SceneManager.h
@@ -8,14 +8,11 @@
 
 namespace crepe {
 
+class ComponentManager;
+
 class SceneManager {
 public:
-	// Singleton
-	static SceneManager & get_instance();
-	SceneManager(const SceneManager &) = delete;
-	SceneManager(SceneManager &&) = delete;
-	SceneManager & operator=(const SceneManager &) = delete;
-	SceneManager & operator=(SceneManager &&) = delete;
+	SceneManager(ComponentManager & mgr);
 
 public:
 	/**
@@ -38,11 +35,9 @@ public:
 	void load_next_scene();
 
 private:
-	SceneManager() = default;
-
-private:
 	std::vector<std::unique_ptr<Scene>> scenes;
 	std::string next_scene;
+	ComponentManager & component_manager;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/SceneManager.hpp b/src/crepe/api/SceneManager.hpp
index 8bad7b2..714f690 100644
--- a/src/crepe/api/SceneManager.hpp
+++ b/src/crepe/api/SceneManager.hpp
@@ -1,13 +1,16 @@
+#pragma once
+
 #include "SceneManager.h"
 
 namespace crepe {
 
 template <typename T>
 void SceneManager::add_scene(const std::string & name) {
-	static_assert(std::is_base_of<Scene, T>::value,
-				  "T must be derived from Scene");
+	using namespace std;
+	static_assert(is_base_of<Scene, T>::value, "T must be derived from Scene");
 
-	scenes.emplace_back(make_unique<T>(name));
+	Scene * scene = new T(this->component_manager, name);
+	this->scenes.emplace_back(unique_ptr<Scene>(scene));
 
 	// The first scene added, is the one that will be loaded at the beginning
 	if (next_scene.empty()) {
diff --git a/src/crepe/api/Script.cpp b/src/crepe/api/Script.cpp
deleted file mode 100644
index 390cec7..0000000
--- a/src/crepe/api/Script.cpp
+++ /dev/null
@@ -1,3 +0,0 @@
-#include "Script.h"
-
-using namespace crepe;
diff --git a/src/crepe/api/Script.h b/src/crepe/api/Script.h
index 0a10848..2b70379 100644
--- a/src/crepe/api/Script.h
+++ b/src/crepe/api/Script.h
@@ -2,35 +2,85 @@
 
 #include <vector>
 
-namespace crepe {
-class ScriptSystem;
-}
+#include "../types.h"
 
 namespace crepe {
 
+class ScriptSystem;
 class BehaviorScript;
+class ComponentManager;
 
+/**
+ * \brief Script interface
+ *
+ * This class is used as a base class for user-defined scripts that can be added to game
+ * objects using the \c BehaviorScript component.
+ *
+ * \note Additional *events* (like Unity's OnDisable and OnEnable) should be implemented as
+ * member or lambda methods in derivative user script classes and registered in \c init().
+ */
 class Script {
-	friend class crepe::ScriptSystem;
-
 protected:
+	/**
+	 * \brief Script initialization function
+	 *
+	 * This function is called during the ScriptSystem::update() routine *before*
+	 * Script::update() if it (a) has not yet been called and (b) the \c BehaviorScript component
+	 * holding this script instance is active.
+	 */
 	virtual void init() {}
+	/**
+	 * \brief Script update function
+	 *
+	 * This function is called during the ScriptSystem::update() routine if the \c BehaviorScript
+	 * component holding this script instance is active.
+	 */
 	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.
+	//! ScriptSystem calls \c init() and \c update()
+	friend class crepe::ScriptSystem;
 
 protected:
+	/**
+	 * \brief Get single component of type \c T on this game object (utility)
+	 *
+	 * \tparam T Type of component
+	 *
+	 * \returns Reference to component
+	 *
+	 * \throws nullptr if this game object does not have a component matching type \c T
+	 */
 	template <typename T>
-	T & get_component();
+	T & get_component() const;
+	// TODO: make get_component calls for component types that can have more than 1 instance
+	// cause compile-time errors
 
+	/**
+	 * \brief Get all components of type \c T on this game object (utility)
+	 *
+	 * \tparam T Type of component
+	 *
+	 * \returns List of component references
+	 */
 	template <typename T>
-	std::vector<std::reference_wrapper<T>> get_components();
+	std::vector<std::reference_wrapper<T>> get_components() const;
+
+protected:
+	// NOTE: Script must have a constructor without arguments so the game programmer doesn't need
+	// to manually add `using Script::Script` to their concrete script class.
+	Script() = default;
+	//! Only \c BehaviorScript instantiates Script
+	friend class BehaviorScript;
+
+private:
+	// These references are set by BehaviorScript immediately after calling the constructor of
+	// Script.
+	game_object_id_t game_object_id = -1;
+	ComponentManager * component_manager_ref = nullptr;
+	// TODO: use OptionalRef instead of pointer
 
-public:
-	friend class crepe::BehaviorScript;
-	BehaviorScript * parent = nullptr;
+private:
+	//! Flag to indicate if \c init() has been called already
+	bool initialized = false;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/Script.hpp b/src/crepe/api/Script.hpp
index d96c0e8..a064a90 100644
--- a/src/crepe/api/Script.hpp
+++ b/src/crepe/api/Script.hpp
@@ -8,18 +8,21 @@
 namespace crepe {
 
 template <typename T>
-T & Script::get_component() {
-	std::vector<std::reference_wrapper<T>> all_components
-		= this->get_components<T>();
-	if (all_components.size() < 1) throw nullptr; // TODO
+T & Script::get_component() const {
+	using namespace std;
+	vector<reference_wrapper<T>> all_components = this->get_components<T>();
+	if (all_components.size() < 1)
+		throw runtime_error(
+			format("Script: no component found with type = {}", typeid(T).name()));
 
 	return all_components.back().get();
 }
 
 template <typename T>
-std::vector<std::reference_wrapper<T>> Script::get_components() {
-	ComponentManager & mgr = ComponentManager::get_instance();
-	return mgr.get_components_by_id<T>(this->parent->game_object_id);
+std::vector<std::reference_wrapper<T>> Script::get_components() const {
+	auto & mgr = *this->component_manager_ref;
+
+	return mgr.get_components_by_id<T>(this->game_object_id);
 }
 
 } // namespace crepe
diff --git a/src/crepe/api/Sprite.cpp b/src/crepe/api/Sprite.cpp
index 6f0433f..bd2d5cf 100644
--- a/src/crepe/api/Sprite.cpp
+++ b/src/crepe/api/Sprite.cpp
@@ -1,6 +1,6 @@
 #include <memory>
 
-#include "../util/log.h"
+#include "../util/Log.h"
 #include "facade/SDLContext.h"
 
 #include "Component.h"
@@ -10,8 +10,8 @@
 using namespace std;
 using namespace crepe;
 
-Sprite::Sprite(game_object_id_t id, const shared_ptr<Texture> image,
-			   const Color & color, const FlipSettings & flip)
+Sprite::Sprite(game_object_id_t id, const shared_ptr<Texture> image, const Color & color,
+			   const FlipSettings & flip)
 	: Component(id),
 	  color(color),
 	  flip(flip),
diff --git a/src/crepe/api/Sprite.h b/src/crepe/api/Sprite.h
index deb3f93..0192793 100644
--- a/src/crepe/api/Sprite.h
+++ b/src/crepe/api/Sprite.h
@@ -1,6 +1,5 @@
 #pragma once
 
-#include <cstdint>
 #include <memory>
 
 #include "Color.h"
@@ -28,8 +27,8 @@ class AnimatorSystem;
 /**
  * \brief Represents a renderable sprite component.
  *
- * A renderable sprite that can be displayed in the game. It includes a texture,
- * color, and flip settings, and is managed in layers with defined sorting orders.
+ * A renderable sprite that can be displayed in the game. It includes a texture, color, and
+ * flip settings, and is managed in layers with defined sorting orders.
  */
 class Sprite : public Component {
 
@@ -43,8 +42,8 @@ public:
 	 * \param color Color tint applied to the sprite.
 	 * \param flip Flip settings for horizontal and vertical orientation.
 	 */
-	Sprite(game_object_id_t id, const std::shared_ptr<Texture> image,
-		   const Color & color, const FlipSettings & flip);
+	Sprite(game_object_id_t id, const std::shared_ptr<Texture> image, const Color & color,
+		   const FlipSettings & flip);
 
 	/**
 	 * \brief Destroys the Sprite instance.
@@ -81,7 +80,8 @@ private:
 	//! Reads the all the variables plus the  sprite_rect
 	friend class AnimatorSystem;
 
-	//! Render area of the sprite this will also be adjusted by the AnimatorSystem if an Animator object is present in GameObject
+	//! Render area of the sprite this will also be adjusted by the AnimatorSystem if an Animator
+	// object is present in GameObject
 	Rect sprite_rect;
 };
 
diff --git a/src/crepe/api/Texture.cpp b/src/crepe/api/Texture.cpp
index 5ebd23d..de0d0ea 100644
--- a/src/crepe/api/Texture.cpp
+++ b/src/crepe/api/Texture.cpp
@@ -1,7 +1,7 @@
 #include <SDL2/SDL_render.h>
 
 #include "../facade/SDLContext.h"
-#include "../util/log.h"
+#include "../util/Log.h"
 
 #include "Asset.h"
 #include "Texture.h"
@@ -26,7 +26,7 @@ Texture::~Texture() {
 
 void Texture::load(unique_ptr<Asset> res) {
 	SDLContext & ctx = SDLContext::get_instance();
-	this->texture = std::move(ctx.texture_from_path(res->canonical()));
+	this->texture = std::move(ctx.texture_from_path(res->get_canonical()));
 }
 
 int Texture::get_width() const {
diff --git a/src/crepe/api/Texture.h b/src/crepe/api/Texture.h
index b89bc17..6965223 100644
--- a/src/crepe/api/Texture.h
+++ b/src/crepe/api/Texture.h
@@ -1,8 +1,7 @@
 #pragma once
 
-// FIXME: this header can't be included because this is an API header, and SDL2
-// development headers won't be bundled with crepe. Why is this facade in the
-// API namespace?
+// FIXME: this header can't be included because this is an API header, and SDL2 development
+// headers won't be bundled with crepe. Why is this facade in the API namespace?
 
 #include <SDL2/SDL_render.h>
 #include <functional>
@@ -19,8 +18,8 @@ class Animator;
  * \class Texture
  * \brief Manages texture loading and properties.
  *
- * The Texture class is responsible for loading an image from a source
- * and providing access to its dimensions. Textures can be used for rendering.
+ * The Texture class is responsible for loading an image from a source and providing access to
+ * its dimensions. Textures can be used for rendering.
  */
 class Texture {
 
@@ -41,8 +40,7 @@ public:
 	 * \brief Destroys the Texture instance, freeing associated resources.
 	 */
 	~Texture();
-	// FIXME: this constructor shouldn't be necessary because this class doesn't
-	// manage memory
+	// FIXME: this constructor shouldn't be necessary because this class doesn't manage memory
 
 	/**
 	 * \brief Gets the width of the texture.
diff --git a/src/crepe/api/Transform.cpp b/src/crepe/api/Transform.cpp
index e401120..cd944bd 100644
--- a/src/crepe/api/Transform.cpp
+++ b/src/crepe/api/Transform.cpp
@@ -1,11 +1,10 @@
-#include "util/log.h"
+#include "../util/Log.h"
 
 #include "Transform.h"
 
 using namespace crepe;
 
-Transform::Transform(game_object_id_t id, const Vector2 & point,
-					 double rotation, double scale)
+Transform::Transform(game_object_id_t id, const Vector2 & point, double rotation, double scale)
 	: Component(id),
 	  position(point),
 	  rotation(rotation),
diff --git a/src/crepe/api/Transform.h b/src/crepe/api/Transform.h
index 756e45b..18aa293 100644
--- a/src/crepe/api/Transform.h
+++ b/src/crepe/api/Transform.h
@@ -9,33 +9,33 @@ namespace crepe {
 /**
  * \brief Transform component
  * 
- * This class represents the Transform component. It stores the position,
- * rotation and scale of a GameObject.
+ * This class represents the Transform component. It stores the position, rotation and scale of
+ * a GameObject.
  */
 class Transform : public Component {
 public:
+	//! Translation (shift)
+	Vector2 position = {0, 0};
+	//! Rotation, in degrees
+	double rotation = 0;
+	//! Multiplication factor
+	double scale = 0;
+
+protected:
 	/**
 	 * \param id The id of the GameObject this component belongs to
 	 * \param point The position of the GameObject
 	 * \param rotation The rotation of the GameObject
 	 * \param scale The scale of the GameObject
 	 */
-	Transform(game_object_id_t id, const Vector2 & point, double rotation,
-			  double scale);
+	Transform(game_object_id_t id, const Vector2 & point, double rotation, double scale);
 	/**
-	 * \brief Get the maximum number of instances for this component
-	 *
-	 * \return The maximum number of instances for this component
+	 * There is always exactly one transform component per entity
+	 * \return 1
 	 */
 	virtual int get_instances_max() const { return 1; }
-
-public:
-	//! Translation (shift)
-	Vector2 position;
-	//! Rotation, in degrees
-	double rotation;
-	//! Multiplication factor
-	double scale;
+	//! ComponentManager instantiates all components
+	friend class ComponentManager;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/Vector2.cpp b/src/crepe/api/Vector2.cpp
index 947c49e..30b968e 100644
--- a/src/crepe/api/Vector2.cpp
+++ b/src/crepe/api/Vector2.cpp
@@ -1,61 +1,33 @@
 #include "Vector2.h"
 
-namespace crepe {
+using namespace crepe;
 
-// Constructor with initial values
-Vector2::Vector2(double x, double y) : x(x), y(y) {}
+Vector2 Vector2::operator-(const Vector2 & other) const { return {x - other.x, y - other.y}; }
 
-// Subtracts another vector from this vector and returns the result.
-Vector2 Vector2::operator-(const Vector2 & other) const {
-	return {x - other.x, y - other.y};
-}
+Vector2 Vector2::operator+(const Vector2 & other) const { return {x + other.x, y + other.y}; }
 
-// Adds another vector to this vector and returns the result.
-Vector2 Vector2::operator+(const Vector2 & other) const {
-	return {x + other.x, y + other.y};
-}
+Vector2 Vector2::operator*(double scalar) const { return {x * scalar, y * scalar}; }
 
-// Multiplies this vector by a scalar and returns the result.
-Vector2 Vector2::operator*(double scalar) const {
-	return {x * scalar, y * scalar};
-}
-
-// Multiplies this vector by another vector element-wise and updates this vector.
 Vector2 & Vector2::operator*=(const Vector2 & other) {
 	x *= other.x;
 	y *= other.y;
 	return *this;
 }
 
-// Adds another vector to this vector and updates this vector.
 Vector2 & Vector2::operator+=(const Vector2 & other) {
 	x += other.x;
 	y += other.y;
 	return *this;
 }
 
-// Adds a scalar value to both components of this vector and updates this vector.
 Vector2 & Vector2::operator+=(double other) {
 	x += other;
 	y += other;
 	return *this;
 }
 
-// Returns the negation of this vector.
 Vector2 Vector2::operator-() const { return {-x, -y}; }
 
-// Checks if this vector is equal to another vector.
-bool Vector2::operator==(const Vector2 & other) const {
-	return x == other.x && y == other.y;
-}
-
-// Checks if this vector is not equal to another vector.
-bool Vector2::operator!=(const Vector2 & other) const {
-	return !(*this == other);
-}
-
-double Vector2::dot(const Vector2& other) const {
-	return this->x * other.x + this->y * other.y;
-}
+bool Vector2::operator==(const Vector2 & other) const { return x == other.x && y == other.y; }
 
-} // namespace crepe
+bool Vector2::operator!=(const Vector2 & other) const { return !(*this == other); }
diff --git a/src/crepe/api/Vector2.h b/src/crepe/api/Vector2.h
index 90d9d57..438fde6 100644
--- a/src/crepe/api/Vector2.h
+++ b/src/crepe/api/Vector2.h
@@ -2,19 +2,12 @@
 
 namespace crepe {
 
-//! Vector2 class
-class Vector2 {
-public:
+//! 2D vector
+struct Vector2 {
 	//! X component of the vector
-	double x;
+	double x = 0;
 	//! Y component of the vector
-	double y;
-
-	//! Default constructor
-	Vector2() = default;
-
-	//! Constructor with initial values
-	Vector2(double x, double y);
+	double y = 0;
 
 	//! Subtracts another vector from this vector and returns the result.
 	Vector2 operator-(const Vector2 & other) const;