Merge branch 'master' into niels/decoupling_pixel_and_pos

30 files changed, 1049 insertions, 86 deletions

diff --git a/src/crepe/api/Asset.cpp b/src/crepe/api/Asset.cpp
new file mode 100644
index 0000000..e148367
--- /dev/null
+++ b/src/crepe/api/Asset.cpp
@@ -0,0 +1,54 @@
+#include <filesystem>
+#include <stdexcept>
+#include <whereami.h>
+
+#include "api/Config.h"
+
+#include "Asset.h"
+
+using namespace crepe;
+using namespace std;
+
+Asset::Asset(const string & src) : src(find_asset(src)) {}
+Asset::Asset(const char * src) : src(find_asset(src)) {}
+
+const string & Asset::get_path() const noexcept { return this->src; }
+
+string Asset::find_asset(const string & src) const {
+	auto & cfg = Config::get_instance();
+	string & root_pattern = cfg.asset.root_pattern;
+
+	// if root_pattern is empty, find_asset must return all paths as-is
+	if (root_pattern.empty()) return src;
+
+	// absolute paths do not need to be resolved, only canonicalized
+	filesystem::path path = src;
+	if (path.is_absolute()) return filesystem::canonical(path);
+
+	// find directory matching root_pattern
+	filesystem::path root = this->whereami();
+	while (1) {
+		if (filesystem::exists(root / root_pattern)) break;
+		if (!root.has_parent_path())
+			throw runtime_error(format("Asset: Cannot find root pattern ({})", root_pattern));
+		root = root.parent_path();
+	}
+
+	// join path to root (base directory) and canonicalize
+	return filesystem::canonical(root / path);
+}
+
+string Asset::whereami() const noexcept {
+	string path;
+	size_t path_length = wai_getExecutablePath(NULL, 0, NULL);
+	path.resize(path_length + 1); // wai writes null byte
+	wai_getExecutablePath(path.data(), path_length, NULL);
+	path.resize(path_length);
+	return path;
+}
+
+bool Asset::operator==(const Asset & other) const noexcept { return this->src == other.src; }
+
+size_t std::hash<const Asset>::operator()(const Asset & asset) const noexcept {
+	return std::hash<string>{}(asset.get_path());
+};
diff --git a/src/crepe/api/Asset.h b/src/crepe/api/Asset.h
new file mode 100644
index 0000000..bfd0ac7
--- /dev/null
+++ b/src/crepe/api/Asset.h
@@ -0,0 +1,84 @@
+#pragma once
+
+#include <string>
+
+namespace crepe {
+
+/**
+ * \brief Asset location helper
+ *
+ * This class is used to locate game asset files, and should *always* be used
+ * instead of reading file paths directly.
+ */
+class Asset {
+public:
+	/**
+	 * \param src  Unique identifier to asset
+	 */
+	Asset(const std::string & src);
+	/**
+	 * \param src  Unique identifier to asset
+	 */
+	Asset(const char * src);
+
+public:
+	/**
+	 * \brief Get the path to this asset
+	 * \return path to this asset
+	 */
+	const std::string & get_path() const noexcept;
+
+	/**
+	 * \brief Comparison operator
+	 * \param other Possibly different instance of \c Asset to test equality against
+	 * \return True if \c this and \c other are equal
+	 */
+	bool operator==(const Asset & other) const noexcept;
+
+private:
+	//! path to asset
+	const std::string src;
+
+private:
+	/**
+	 * \brief Locate asset path, or throw exception if it cannot be found
+	 *
+	 * This function resolves asset locations relative to crepe::Config::root_pattern if it is
+	 * set and \p src is a relative path. If \p src is an absolute path, it is canonicalized.
+	 * This function only returns if the file can be found.
+	 *
+	 * \param src Arbitrary path to resource file
+	 *
+	 * \returns \p src if crepe::Config::root_pattern is empty
+	 * \returns Canonical path to \p src
+	 *
+	 * \throws std::runtime_error if root_pattern cannot be found
+	 * \throws std::filesystem::filesystem_error if the resolved path does not exist
+	 * \throws std::filesystem::filesystem_error if the path cannot be canonicalized
+	 */
+	std::string find_asset(const std::string & src) const;
+	/**
+	 * \returns The path to the current executable
+	 */
+	std::string whereami() const noexcept;
+};
+
+} // namespace crepe
+
+namespace std {
+
+//! Hash helper struct
+template <>
+struct hash<const crepe::Asset> {
+	/**
+	 * \brief Hash operator for crepe::Asset
+	 *
+	 * This function hashes a crepe::Asset instance, allowing it to be used as a key in an \c
+	 * std::unordered_map.
+	 *
+	 * \returns Hash value
+	 */
+	size_t operator()(const crepe::Asset & asset) const noexcept;
+};
+
+} // namespace std
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index f9b370f..d6b6801 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -17,8 +17,13 @@ target_sources(crepe PUBLIC
 	Vector2.cpp
 	Camera.cpp
 	Animator.cpp
+	EventManager.cpp
+	IKeyListener.cpp
+	IMouseListener.cpp
 	LoopManager.cpp
 	LoopTimer.cpp
+	Asset.cpp
+	EventHandler.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -43,6 +48,14 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	SceneManager.hpp
 	Camera.h
 	Animator.h
+	EventManager.h
+	EventManager.hpp
+	EventHandler.h
+	EventHandler.hpp
+	Event.h
+	IKeyListener.h
+	IMouseListener.h
 	LoopManager.h
 	LoopTimer.h
+	Asset.h
 )
diff --git a/src/crepe/api/Color.cpp b/src/crepe/api/Color.cpp
index 9e5f187..29bd77a 100644
--- a/src/crepe/api/Color.cpp
+++ b/src/crepe/api/Color.cpp
@@ -2,32 +2,11 @@
 
 using namespace crepe;
 
-Color Color::white = Color(255, 255, 255, 0);
-Color Color::red = Color(255, 0, 0, 0);
-Color Color::green = Color(0, 255, 0, 0);
-Color Color::blue = Color(0, 0, 255, 0);
-Color Color::black = Color(0, 0, 0, 0);
-Color Color::cyan = Color(0, 255, 255, 0);
-Color Color::yellow = Color(255, 255, 0, 0);
-Color Color::magenta = Color(255, 0, 255, 0);
-
-Color::Color(uint8_t red, uint8_t green, uint8_t blue, uint8_t alpha) {
-	this->a = alpha;
-	this->r = red;
-	this->g = green;
-	this->b = blue;
-};
-
-const Color & Color::get_white() { return Color::white; };
-
-const Color & Color::get_red() { return Color::red; };
-const Color & Color::get_green() { return Color::green; };
-const Color & Color::get_blue() { return Color::blue; };
-
-const Color & Color::get_black() { return Color::black; };
-
-const Color & Color::get_cyan() { return Color::cyan; };
-
-const Color & Color::get_yellow() { return Color::yellow; };
-
-const Color & Color::get_magenta() { return Color::magenta; };
+const Color Color::WHITE{0xff, 0xff, 0xff};
+const Color Color::RED{0xff, 0x00, 0x00};
+const Color Color::GREEN{0x00, 0xff, 0x00};
+const Color Color::BLUE{0x00, 0x00, 0xff};
+const Color Color::BLACK{0x00, 0x00, 0x00};
+const Color Color::CYAN{0x00, 0xff, 0xff};
+const Color Color::YELLOW{0xff, 0xff, 0x00};
+const Color Color::MAGENTA{0xff, 0x00, 0xff};
diff --git a/src/crepe/api/Color.h b/src/crepe/api/Color.h
index aa47bf4..84edb5c 100644
--- a/src/crepe/api/Color.h
+++ b/src/crepe/api/Color.h
@@ -4,41 +4,20 @@
 
 namespace crepe {
 
-// TODO: make Color a struct w/o constructors/destructors
-class Color {
-
-	// FIXME: can't these colors be defined as a `static constexpr const Color`
-	// instead?
-
-public:
-	Color(uint8_t red, uint8_t green, uint8_t blue, uint8_t alpha);
-	static const Color & get_white();
-	static const Color & get_red();
-	static const Color & get_green();
-	static const Color & get_blue();
-	static const Color & get_cyan();
-	static const Color & get_magenta();
-	static const Color & get_yellow();
-	static const Color & get_black();
-
-private:
-	// TODO: why are these private!?
-	uint8_t r;
-	uint8_t g;
-	uint8_t b;
-	uint8_t a;
-
-	static Color white;
-	static Color red;
-	static Color green;
-	static Color blue;
-	static Color cyan;
-	static Color magenta;
-	static Color yellow;
-	static Color black;
-
-private:
-	friend class SDLContext;
+struct Color {
+	uint8_t r = 0x00;
+	uint8_t g = 0x00;
+	uint8_t b = 0x00;
+	uint8_t a = 0xff;
+
+	static const Color WHITE;
+	static const Color RED;
+	static const Color GREEN;
+	static const Color BLUE;
+	static const Color CYAN;
+	static const Color MAGENTA;
+	static const Color YELLOW;
+	static const Color BLACK;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/Config.h b/src/crepe/api/Config.h
index 3ab877a..13eabd1 100644
--- a/src/crepe/api/Config.h
+++ b/src/crepe/api/Config.h
@@ -62,6 +62,20 @@ public:
 		 */
 		double gravity = 1;
 	} physics;
+
+	//! Asset loading options
+	struct {
+		/**
+		 * \brief Pattern to match for Asset base directory
+		 *
+		 * All non-absolute paths resolved using \c Asset will be made relative to
+		 * the first parent directory relative to the calling executable where
+		 * appending this pattern results in a path that exists. If this string is
+		 * empty, path resolution is disabled, and Asset will return all paths
+		 * as-is.
+		 */
+		std::string root_pattern = ".crepe-root";
+	} asset;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/Event.h b/src/crepe/api/Event.h
new file mode 100644
index 0000000..06cf7f3
--- /dev/null
+++ b/src/crepe/api/Event.h
@@ -0,0 +1,112 @@
+// TODO discussing the location of these events
+#pragma once
+
+#include <string>
+
+#include "KeyCodes.h"
+
+/**
+ * \brief Base class for all event types in the system.
+ */
+class Event {};
+
+/**
+ * \brief Event triggered when a key is pressed.
+ */
+class KeyPressEvent : public Event {
+public:
+	//! false if first time press, true if key is repeated
+	bool repeat = false;
+
+	//! The key that was pressed.
+	Keycode key = Keycode::NONE;
+};
+
+/**
+ * \brief Event triggered when a key is released.
+ */
+class KeyReleaseEvent : public Event {
+public:
+	//! The key that was released.
+	Keycode key = Keycode::NONE;
+};
+
+/**
+ * \brief Event triggered when a mouse button is pressed.
+ */
+class MousePressEvent : public Event {
+public:
+	//! X-coordinate of the mouse position at the time of the event.
+	int mouse_x = 0;
+
+	//! Y-coordinate of the mouse position at the time of the event.
+	int mouse_y = 0;
+
+	//! The mouse button that was pressed.
+	MouseButton button = MouseButton::NONE;
+};
+
+/**
+ * \brief Event triggered when a mouse button is clicked (press and release).
+ */
+class MouseClickEvent : public Event {
+public:
+	//! X-coordinate of the mouse position at the time of the event.
+	int mouse_x = 0;
+
+	//! Y-coordinate of the mouse position at the time of the event.
+	int mouse_y = 0;
+
+	//! The mouse button that was clicked.
+	MouseButton button = MouseButton::NONE;
+};
+
+/**
+ * \brief Event triggered when a mouse button is released.
+ */
+class MouseReleaseEvent : public Event {
+public:
+	//! X-coordinate of the mouse position at the time of the event.
+	int mouse_x = 0;
+
+	//! Y-coordinate of the mouse position at the time of the event.
+	int mouse_y = 0;
+
+	//! The mouse button that was released.
+	MouseButton button = MouseButton::NONE;
+};
+
+/**
+ * \brief Event triggered when the mouse is moved.
+ */
+class MouseMoveEvent : public Event {
+public:
+	//! X-coordinate of the mouse position at the time of the event.
+	int mouse_x = 0;
+
+	//! Y-coordinate of the mouse position at the time of the event.
+	int mouse_y = 0;
+};
+
+/**
+ * \brief Event triggered during a collision between objects.
+ */
+class CollisionEvent : public Event {
+public:
+	//! Data describing the collision (currently not implemented).
+	// Collision collisionData;
+};
+
+/**
+ * \brief Event triggered when text is submitted, e.g., from a text input.
+ */
+class TextSubmitEvent : public Event {
+public:
+	//! The submitted text.
+	std::string text = "";
+};
+
+/**
+ * \brief Event triggered to indicate the application is shutting down.
+ */
+class ShutDownEvent : public Event {};
diff --git a/src/crepe/api/EventHandler.cpp b/src/crepe/api/EventHandler.cpp
new file mode 100644
index 0000000..4dc232f
--- /dev/null
+++ b/src/crepe/api/EventHandler.cpp
@@ -0,0 +1,5 @@
+#include "EventHandler.h"
+
+using namespace crepe;
+
+bool IEventHandlerWrapper::exec(const Event & e) { return this->call(e); }
diff --git a/src/crepe/api/EventHandler.h b/src/crepe/api/EventHandler.h
new file mode 100644
index 0000000..ef659fd
--- /dev/null
+++ b/src/crepe/api/EventHandler.h
@@ -0,0 +1,96 @@
+#pragma once
+
+#include <functional>
+#include <string>
+
+#include "Event.h"
+
+namespace crepe {
+/**
+ * \brief A type alias for an event handler function.
+ * 
+ * The EventHandler is a std::function that takes an EventType reference and returns a boolean value 
+ * indicating whether the event is handled.
+ * 
+ * \tparam EventType The type of event this handler will handle.
+ * 
+ * Returning \c false from an event handler results in the event being propogated to other listeners for the same event type, while returning \c true stops propogation altogether.
+ */
+template <typename EventType>
+using EventHandler = std::function<bool(const EventType & e)>;
+
+/**
+ * \class IEventHandlerWrapper
+ * \brief An abstract base class for event handler wrappers.
+ * 
+ * This class provides the interface for handling events. Derived classes must implement the
+ * `call()` method to process events
+ */
+class IEventHandlerWrapper {
+public:
+	/**
+     * \brief Virtual destructor for IEventHandlerWrapper.
+     */
+	virtual ~IEventHandlerWrapper() = default;
+
+	/**
+     * \brief Executes the handler with the given event.
+     * 
+     * This method calls the `call()` method of the derived class, passing the event to the handler.
+     * 
+     * \param e The event to be processed.
+     * \return A boolean value indicating whether the event is handled.
+     */
+	bool exec(const Event & e);
+
+private:
+	/**
+     * \brief The method responsible for handling the event.
+     * 
+     * This method is implemented by derived classes to process the event.
+     * 
+     * \param e The event to be processed.
+     * \return A boolean value indicating whether the event is handled.
+     */
+	virtual bool call(const Event & e) = 0;
+};
+
+/**
+ * \class EventHandlerWrapper
+ * \brief A wrapper for event handler functions.
+ * 
+ * This class wraps an event handler function of a specific event type. It implements the 
+ * `call()` and `get_type()` methods to allow the handler to be executed and its type to be 
+ * queried.
+ * 
+ * \tparam EventType The type of event this handler will handle.
+ */
+template <typename EventType>
+class EventHandlerWrapper : public IEventHandlerWrapper {
+public:
+	/**
+     * \brief Constructs an EventHandlerWrapper with a given handler.
+     * 
+     * The constructor takes an event handler function and stores it in the wrapper.
+     * 
+     * \param handler The event handler function.
+     */
+	explicit EventHandlerWrapper(const EventHandler<EventType> & handler);
+
+private:
+	/**
+     * \brief Calls the stored event handler with the event.
+     * 
+     * This method casts the event to the appropriate type and calls the handler.
+     * 
+     * \param e The event to be handled.
+     * \return A boolean value indicating whether the event is handled.
+     */
+	bool call(const Event & e) override;
+	//! The event handler function.
+	EventHandler<EventType> handler;
+};
+
+} // namespace crepe
+
+#include "EventHandler.hpp"
diff --git a/src/crepe/api/EventHandler.hpp b/src/crepe/api/EventHandler.hpp
new file mode 100644
index 0000000..391dcca
--- /dev/null
+++ b/src/crepe/api/EventHandler.hpp
@@ -0,0 +1,18 @@
+#include <typeindex>
+
+#include "EventHandler.h"
+
+namespace crepe {
+
+// Implementation of EventHandlerWrapper constructor
+template <typename EventType>
+EventHandlerWrapper<EventType>::EventHandlerWrapper(const EventHandler<EventType> & handler)
+	: handler(handler) {}
+
+// Implementation of EventHandlerWrapper::call
+template <typename EventType>
+bool EventHandlerWrapper<EventType>::call(const Event & e) {
+	return this->handler(static_cast<const EventType &>(e));
+}
+
+} //namespace crepe
diff --git a/src/crepe/api/EventManager.cpp b/src/crepe/api/EventManager.cpp
new file mode 100644
index 0000000..20f0dd3
--- /dev/null
+++ b/src/crepe/api/EventManager.cpp
@@ -0,0 +1,46 @@
+#include "EventManager.h"
+
+using namespace crepe;
+using namespace std;
+
+EventManager & EventManager::get_instance() {
+	static EventManager instance;
+	return instance;
+}
+
+void EventManager::dispatch_events() {
+	for (auto & event : this->events_queue) {
+		this->handle_event(event.type, event.channel, *event.event.get());
+	}
+	this->events_queue.clear();
+}
+
+void EventManager::handle_event(type_index type, event_channel_t channel, const Event & data) {
+	auto handlers_it = this->subscribers.find(type);
+	if (handlers_it == this->subscribers.end()) return;
+
+	vector<CallbackEntry> & handlers = handlers_it->second;
+	for (auto & handler : handlers) {
+		bool check_channel = handler.channel != CHANNEL_ALL || channel != CHANNEL_ALL;
+		if (check_channel && handler.channel != channel) continue;
+
+		bool handled = handler.callback->exec(data);
+		if (handled) return;
+	}
+}
+
+void EventManager::clear() {
+	this->subscribers.clear();
+	this->events_queue.clear();
+}
+
+void EventManager::unsubscribe(subscription_t id) {
+	for (auto & [event_type, handlers] : this->subscribers) {
+		for (auto it = handlers.begin(); it != handlers.end(); it++) {
+			// find listener with subscription id
+			if ((*it).id != id) continue;
+			it = handlers.erase(it);
+			return;
+		}
+	}
+}
diff --git a/src/crepe/api/EventManager.h b/src/crepe/api/EventManager.h
new file mode 100644
index 0000000..348a04d
--- /dev/null
+++ b/src/crepe/api/EventManager.h
@@ -0,0 +1,161 @@
+#pragma once
+
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <vector>
+
+#include "Event.h"
+#include "EventHandler.h"
+
+namespace crepe {
+
+//! Event listener unique ID
+typedef size_t subscription_t;
+
+/**
+ * \brief Event channel
+ *
+ * Events can be sent to a specific channel, which prevents listeners on other channels from
+ * being called. The default channel is EventManager::CHANNEL_ALL, which calls all listeners.
+ */
+typedef size_t event_channel_t;
+
+/**
+ * \class EventManager
+ * \brief Manages event subscriptions, triggers, and queues, enabling decoupled event handling.
+ * 
+ * The `EventManager` acts as a centralized event system. It allows for registering callbacks
+ * for specific event types, triggering events synchronously, queueing events for later
+ * processing, and managing subscriptions via unique identifiers.
+ */
+class EventManager {
+public:
+	static constexpr const event_channel_t CHANNEL_ALL = -1;
+
+	/**
+	 * \brief Get the singleton instance of the EventManager.
+	 * 
+	 * This method returns the unique instance of the EventManager, creating it if it
+	 * doesn't already exist. Ensures only one instance is active in the program.
+	 * 
+	 * \return Reference to the singleton instance of the EventManager.
+	 */
+	static EventManager & get_instance();
+
+	/**
+	 * \brief Subscribe to a specific event type.
+	 * 
+	 * Registers a callback for a given event type and optional channel. Each callback
+	 * is assigned a unique subscription ID that can be used for later unsubscription.
+	 * 
+	 * \tparam EventType The type of the event to subscribe to.
+	 * \param callback The callback function to be invoked when the event is triggered.
+	 * \param channel The channel number to subscribe to (default is CHANNEL_ALL, which listens to all channels).
+	 * \return A unique subscription ID associated with the registered callback.
+	 */
+	template <typename EventType>
+	subscription_t subscribe(const EventHandler<EventType> & callback,
+							 event_channel_t channel = CHANNEL_ALL);
+
+	/**
+	 * \brief Unsubscribe a previously registered callback.
+	 * 
+	 * Removes a callback from the subscription list based on its unique subscription ID.
+	 * 
+	 * \param event_id The unique subscription ID of the callback to remove.
+	 */
+	void unsubscribe(subscription_t event_id);
+
+	/**
+	 * \brief Trigger an event immediately.
+	 * 
+	 * Synchronously invokes all registered callbacks for the given event type on the specified channel.
+	 * 
+	 * \tparam EventType The type of the event to trigger.
+	 * \param event The event instance to pass to the callbacks.
+	 * \param channel The channel to trigger the event on (default is CHANNEL_ALL, which triggers on all channels).
+	 */
+	template <typename EventType>
+	void trigger_event(const EventType & event, event_channel_t channel = CHANNEL_ALL);
+
+	/**
+	 * \brief Queue an event for later processing.
+	 * 
+	 * Adds an event to the event queue to be processed during the next call to `dispatch_events`.
+	 * 
+	 * \tparam EventType The type of the event to queue.
+	 * \param event The event instance to queue.
+	 * \param channel The channel to associate with the event (default is CHANNEL_ALL).
+	 */
+	template <typename EventType>
+	void queue_event(const EventType & event, event_channel_t channel = CHANNEL_ALL);
+
+	/**
+	 * \brief Process all queued events.
+	 * 
+	 * Iterates through the event queue and triggers callbacks for each queued event.
+	 * Events are removed from the queue once processed.
+	 */
+	void dispatch_events();
+
+	/**
+	 * \brief Clear all subscriptions.
+	 * 
+	 * Removes all registered event handlers and clears the subscription list.
+	 */
+	void clear();
+
+private:
+	/**
+	 * \brief Default constructor for the EventManager.
+	 * 
+	 * Constructor is private to enforce the singleton pattern.
+	 */
+	EventManager() = default;
+
+	/**
+	 * \struct QueueEntry
+	 * \brief Represents an entry in the event queue.
+	 */
+	struct QueueEntry {
+		std::unique_ptr<Event> event; ///< The event instance.
+		event_channel_t channel = CHANNEL_ALL; ///< The channel associated with the event.
+		std::type_index type; ///< The type of the event.
+	};
+
+	/**
+	 * \brief Internal event handler
+	 *
+	 * This function processes a single event, and is used to process events both during
+	 * EventManager::dispatch_events and inside EventManager::trigger_event
+	 *
+	 * \param type \c typeid of concrete Event class
+	 * \param channel Event channel
+	 * \param data Event data
+	 */
+	void handle_event(std::type_index type, event_channel_t channel, const Event & data);
+
+	/**
+	 * \struct CallbackEntry
+	 * \brief Represents a registered event handler callback.
+	 */
+	struct CallbackEntry {
+		std::unique_ptr<IEventHandlerWrapper> callback; ///< The callback function wrapper.
+		event_channel_t channel = CHANNEL_ALL; ///< The channel this callback listens to.
+		subscription_t id = -1; ///< Unique subscription ID.
+	};
+
+	//! The queue of events to be processed during dispatch.
+	std::vector<QueueEntry> events_queue;
+
+	//! A map of event type to registered callbacks.
+	std::unordered_map<std::type_index, std::vector<CallbackEntry>> subscribers;
+
+	//! Counter to generate unique subscription IDs.
+	subscription_t subscription_counter = 0;
+};
+
+} // namespace crepe
+
+#include "EventManager.hpp"
diff --git a/src/crepe/api/EventManager.hpp b/src/crepe/api/EventManager.hpp
new file mode 100644
index 0000000..a5f4556
--- /dev/null
+++ b/src/crepe/api/EventManager.hpp
@@ -0,0 +1,36 @@
+#pragma once
+
+#include "EventManager.h"
+
+namespace crepe {
+
+template <typename EventType>
+subscription_t EventManager::subscribe(const EventHandler<EventType> & callback,
+									   event_channel_t channel) {
+	subscription_counter++;
+	std::type_index event_type = typeid(EventType);
+	std::unique_ptr<EventHandlerWrapper<EventType>> handler
+		= std::make_unique<EventHandlerWrapper<EventType>>(callback);
+	std::vector<CallbackEntry> & handlers = this->subscribers[event_type];
+	handlers.emplace_back(CallbackEntry{
+		.callback = std::move(handler), .channel = channel, .id = subscription_counter});
+	return subscription_counter;
+}
+
+template <typename EventType>
+void EventManager::queue_event(const EventType & event, event_channel_t channel) {
+	static_assert(std::is_base_of<Event, EventType>::value,
+				  "EventType must derive from Event");
+	this->events_queue.push_back(QueueEntry{
+		.event = std::make_unique<EventType>(event),
+		.channel = channel,
+		.type = typeid(EventType),
+	});
+}
+
+template <typename EventType>
+void EventManager::trigger_event(const EventType & event, event_channel_t channel) {
+	this->handle_event(typeid(EventType), channel, event);
+}
+
+} // namespace crepe
diff --git a/src/crepe/api/GameObject.cpp b/src/crepe/api/GameObject.cpp
index 287e81d..4874426 100644
--- a/src/crepe/api/GameObject.cpp
+++ b/src/crepe/api/GameObject.cpp
@@ -23,12 +23,10 @@ void GameObject::set_parent(const GameObject & parent) {
 	ComponentManager & mgr = this->component_manager;
 
 	// Set parent on own Metadata component
-	vector<reference_wrapper<Metadata>> this_metadata
-		= mgr.get_components_by_id<Metadata>(this->id);
+	RefVector<Metadata> this_metadata = mgr.get_components_by_id<Metadata>(this->id);
 	this_metadata.at(0).get().parent = parent.id;
 
 	// Add own id to children list of parent's Metadata component
-	vector<reference_wrapper<Metadata>> parent_metadata
-		= mgr.get_components_by_id<Metadata>(parent.id);
+	RefVector<Metadata> parent_metadata = mgr.get_components_by_id<Metadata>(parent.id);
 	parent_metadata.at(0).get().children.push_back(this->id);
 }
diff --git a/src/crepe/api/IKeyListener.cpp b/src/crepe/api/IKeyListener.cpp
new file mode 100644
index 0000000..8642655
--- /dev/null
+++ b/src/crepe/api/IKeyListener.cpp
@@ -0,0 +1,19 @@
+#include "IKeyListener.h"
+
+using namespace crepe;
+
+// Constructor with specified channel
+IKeyListener::IKeyListener(event_channel_t channel)
+	: event_manager(EventManager::get_instance()) {
+	this->press_id = event_manager.subscribe<KeyPressEvent>(
+		[this](const KeyPressEvent & event) { return this->on_key_pressed(event); }, channel);
+	this->release_id = event_manager.subscribe<KeyReleaseEvent>(
+		[this](const KeyReleaseEvent & event) { return this->on_key_released(event); },
+		channel);
+}
+
+// Destructor, unsubscribe events
+IKeyListener::~IKeyListener() {
+	event_manager.unsubscribe(this->press_id);
+	event_manager.unsubscribe(this->release_id);
+}
diff --git a/src/crepe/api/IKeyListener.h b/src/crepe/api/IKeyListener.h
new file mode 100644
index 0000000..328a4c2
--- /dev/null
+++ b/src/crepe/api/IKeyListener.h
@@ -0,0 +1,49 @@
+#pragma once
+
+#include "Event.h"
+#include "EventHandler.h"
+#include "EventManager.h"
+
+namespace crepe {
+
+/**
+ * \class IKeyListener
+ * \brief Interface for keyboard event handling in the application.
+ */
+class IKeyListener {
+public:
+	/**
+     * \brief Constructs an IKeyListener with a specified channel.
+     * \param channel The channel ID for event handling.
+     */
+	IKeyListener(event_channel_t channel = EventManager::CHANNEL_ALL);
+	virtual ~IKeyListener();
+	IKeyListener(const IKeyListener &) = delete;
+	IKeyListener & operator=(const IKeyListener &) = delete;
+	IKeyListener & operator=(IKeyListener &&) = delete;
+	IKeyListener(IKeyListener &&) = delete;
+
+	/**
+     * \brief Pure virtual function to handle key press events.
+     * \param event The key press event to handle.
+     * \return True if the event was handled, false otherwise.
+     */
+	virtual bool on_key_pressed(const KeyPressEvent & event) = 0;
+
+	/**
+     * \brief Pure virtual function to handle key release events.
+     * \param event The key release event to handle.
+     * \return True if the event was handled, false otherwise.
+     */
+	virtual bool on_key_released(const KeyReleaseEvent & event) = 0;
+
+private:
+	//! Key press event id
+	subscription_t press_id = -1;
+	//! Key release event id
+	subscription_t release_id = -1;
+	//! EventManager reference
+	EventManager & event_manager;
+};
+
+} // namespace crepe
diff --git a/src/crepe/api/IMouseListener.cpp b/src/crepe/api/IMouseListener.cpp
new file mode 100644
index 0000000..989aeb3
--- /dev/null
+++ b/src/crepe/api/IMouseListener.cpp
@@ -0,0 +1,29 @@
+#include "IMouseListener.h"
+
+using namespace crepe;
+
+IMouseListener::IMouseListener(event_channel_t channel)
+	: event_manager(EventManager::get_instance()) {
+	this->click_id = event_manager.subscribe<MouseClickEvent>(
+		[this](const MouseClickEvent & event) { return this->on_mouse_clicked(event); },
+		channel);
+
+	this->press_id = event_manager.subscribe<MousePressEvent>(
+		[this](const MousePressEvent & event) { return this->on_mouse_pressed(event); },
+		channel);
+
+	this->release_id = event_manager.subscribe<MouseReleaseEvent>(
+		[this](const MouseReleaseEvent & event) { return this->on_mouse_released(event); },
+		channel);
+
+	this->move_id = event_manager.subscribe<MouseMoveEvent>(
+		[this](const MouseMoveEvent & event) { return this->on_mouse_moved(event); }, channel);
+}
+
+IMouseListener::~IMouseListener() {
+	// Unsubscribe event handlers
+	event_manager.unsubscribe(this->click_id);
+	event_manager.unsubscribe(this->press_id);
+	event_manager.unsubscribe(this->release_id);
+	event_manager.unsubscribe(this->move_id);
+}
diff --git a/src/crepe/api/IMouseListener.h b/src/crepe/api/IMouseListener.h
new file mode 100644
index 0000000..15e1619
--- /dev/null
+++ b/src/crepe/api/IMouseListener.h
@@ -0,0 +1,72 @@
+#pragma once
+
+#include "Event.h"
+#include "EventHandler.h"
+#include "EventManager.h"
+
+namespace crepe {
+
+/**
+ * \class IMouseListener
+ * \brief Interface for mouse event handling in the application.
+ */
+class IMouseListener {
+public:
+	/**
+     * \brief Constructs an IMouseListener with a specified channel.
+     * \param channel The channel ID for event handling.
+     */
+	IMouseListener(event_channel_t channel = EventManager::CHANNEL_ALL);
+	virtual ~IMouseListener();
+	IMouseListener & operator=(const IMouseListener &) = delete;
+	IMouseListener(const IMouseListener &) = delete;
+	IMouseListener & operator=(const IMouseListener &&) = delete;
+	IMouseListener(IMouseListener &&) = delete;
+
+	/**
+     * \brief Move assignment operator (deleted).
+     */
+	IMouseListener & operator=(IMouseListener &&) = delete;
+
+	/**
+     * \brief Handles a mouse click event.
+     * \param event The mouse click event to handle.
+     * \return True if the event was handled, false otherwise.
+     */
+	virtual bool on_mouse_clicked(const MouseClickEvent & event) = 0;
+
+	/**
+     * \brief Handles a mouse press event.
+     * \param event The mouse press event to handle.
+     * \return True if the event was handled, false otherwise.
+     */
+	virtual bool on_mouse_pressed(const MousePressEvent & event) = 0;
+
+	/**
+     * \brief Handles a mouse release event.
+     * \param event The mouse release event to handle.
+     * \return True if the event was handled, false otherwise.
+     */
+	virtual bool on_mouse_released(const MouseReleaseEvent & event) = 0;
+
+	/**
+     * \brief Handles a mouse move event.
+     * \param event The mouse move event to handle.
+     * \return True if the event was handled, false otherwise.
+     */
+	virtual bool on_mouse_moved(const MouseMoveEvent & event) = 0;
+
+private:
+	//! Mouse click event id
+	subscription_t click_id = -1;
+	//! Mouse press event id
+	subscription_t press_id = -1;
+	//! Mouse release event id
+	subscription_t release_id = -1;
+	//! Mouse move event id
+	subscription_t move_id = -1;
+	//! EventManager reference
+	EventManager & event_manager;
+};
+
+} //namespace crepe
diff --git a/src/crepe/api/KeyCodes.h b/src/crepe/api/KeyCodes.h
new file mode 100644
index 0000000..9e173e0
--- /dev/null
+++ b/src/crepe/api/KeyCodes.h
@@ -0,0 +1,153 @@
+#pragma once
+
+//! Enumeration for mouse button inputs, including standard and extended buttons.
+enum class MouseButton {
+	NONE = 0, //!< No mouse button input.
+	LEFT_MOUSE = 1, //!< Left mouse button.
+	RIGHT_MOUSE = 2, //!< Right mouse button.
+	MIDDLE_MOUSE = 3, //!< Middle mouse button (scroll wheel press).
+	X1_MOUSE = 4, //!< First extended mouse button.
+	X2_MOUSE = 5, //!< Second extended mouse button.
+	SCROLL_UP = 6, //!< Scroll wheel upward movement.
+	SCROLL_DOWN = 7, //!< Scroll wheel downward movement.
+};
+
+//! Enumeration for keyboard key inputs, including printable characters, function keys, and keypad keys.
+enum class Keycode {
+	NONE = 0, //!< No key input.
+	SPACE = 32, //!< Spacebar.
+	APOSTROPHE = 39, //!< Apostrophe (').
+	COMMA = 44, //!< Comma (,).
+	MINUS = 45, //!< Minus (-).
+	PERIOD = 46, //!< Period (.).
+	SLASH = 47, //!< Slash (/).
+	D0 = 48, //!< Digit 0.
+	D1 = 49, //!< Digit 1.
+	D2 = 50, //!< Digit 2.
+	D3 = 51, //!< Digit 3.
+	D4 = 52, //!< Digit 4.
+	D5 = 53, //!< Digit 5.
+	D6 = 54, //!< Digit 6.
+	D7 = 55, //!< Digit 7.
+	D8 = 56, //!< Digit 8.
+	D9 = 57, //!< Digit 9.
+	SEMICOLON = 59, //!< Semicolon (;).
+	EQUAL = 61, //!< Equal sign (=).
+	A = 65, //!< Key 'A'.
+	B = 66, //!< Key 'B'.
+	C = 67, //!< Key 'C'.
+	D = 68, //!< Key 'D'.
+	E = 69, //!< Key 'E'.
+	F = 70, //!< Key 'F'.
+	G = 71, //!< Key 'G'.
+	H = 72, //!< Key 'H'.
+	I = 73, //!< Key 'I'.
+	J = 74, //!< Key 'J'.
+	K = 75, //!< Key 'K'.
+	L = 76, //!< Key 'L'.
+	M = 77, //!< Key 'M'.
+	N = 78, //!< Key 'N'.
+	O = 79, //!< Key 'O'.
+	P = 80, //!< Key 'P'.
+	Q = 81, //!< Key 'Q'.
+	R = 82, //!< Key 'R'.
+	S = 83, //!< Key 'S'.
+	T = 84, //!< Key 'T'.
+	U = 85, //!< Key 'U'.
+	V = 86, //!< Key 'V'.
+	W = 87, //!< Key 'W'.
+	X = 88, //!< Key 'X'.
+	Y = 89, //!< Key 'Y'.
+	Z = 90, //!< Key 'Z'.
+	LEFT_BRACKET = 91, //!< Left bracket ([).
+	BACKSLASH = 92, //!< Backslash (\).
+	RIGHT_BRACKET = 93, //!< Right bracket (]).
+	GRAVE_ACCENT = 96, //!< Grave accent (`).
+	WORLD1 = 161, //!< Non-US key #1.
+	WORLD2 = 162, //!< Non-US key #2.
+	ESCAPE = 256, //!< Escape key.
+	ENTER = 257, //!< Enter key.
+	TAB = 258, //!< Tab key.
+	BACKSPACE = 259, //!< Backspace key.
+	INSERT = 260, //!< Insert key.
+	DELETE = 261, //!< Delete key.
+	RIGHT = 262, //!< Right arrow key.
+	LEFT = 263, //!< Left arrow key.
+	DOWN = 264, //!< Down arrow key.
+	UP = 265, //!< Up arrow key.
+	PAGE_UP = 266, //!< Page Up key.
+	PAGE_DOWN = 267, //!< Page Down key.
+	HOME = 268, //!< Home key.
+	END = 269, //!< End key.
+	CAPS_LOCK = 280, //!< Caps Lock key.
+	SCROLL_LOCK = 281, //!< Scroll Lock key.
+	NUM_LOCK = 282, //!< Num Lock key.
+	PRINT_SCREEN = 283, //!< Print Screen key.
+	PAUSE = 284, //!< Pause key.
+	/**
+	 * \name Function keys (F1-F25).
+	 * \{
+	 */
+	F1 = 290,
+	F2 = 291,
+	F3 = 292,
+	F4 = 293,
+	F5 = 294,
+	F6 = 295,
+	F7 = 296,
+	F8 = 297,
+	F9 = 298,
+	F10 = 299,
+	F11 = 300,
+	F12 = 301,
+	F13 = 302,
+	F14 = 303,
+	F15 = 304,
+	F16 = 305,
+	F17 = 306,
+	F18 = 307,
+	F19 = 308,
+	F20 = 309,
+	F21 = 310,
+	F22 = 311,
+	F23 = 312,
+	F24 = 313,
+	F25 = 314,
+	/// \}
+	/**
+	 * \name Keypad digits and operators.
+	 * \{
+	 */
+	KP0 = 320,
+	KP1 = 321,
+	KP2 = 322,
+	KP3 = 323,
+	KP4 = 324,
+	KP5 = 325,
+	KP6 = 326,
+	KP7 = 327,
+	KP8 = 328,
+	KP9 = 329,
+	KP_DECIMAL = 330,
+	KP_DIVIDE = 331,
+	KP_MULTIPLY = 332,
+	KP_SUBTRACT = 333,
+	KP_ADD = 334,
+	KP_ENTER = 335,
+	KP_EQUAL = 336,
+	/// \}
+	/**
+	 * \name Modifier keys.
+	 * \{
+	 */
+	LEFT_SHIFT = 340,
+	LEFT_CONTROL = 341,
+	LEFT_ALT = 342,
+	LEFT_SUPER = 343,
+	RIGHT_SHIFT = 344,
+	RIGHT_CONTROL = 345,
+	RIGHT_ALT = 346,
+	RIGHT_SUPER = 347,
+	/// \}
+	MENU = 348, //!< Menu key.
+};
diff --git a/src/crepe/api/LoopManager.h b/src/crepe/api/LoopManager.h
index f6904be..13e6dac 100644
--- a/src/crepe/api/LoopManager.h
+++ b/src/crepe/api/LoopManager.h
@@ -4,14 +4,28 @@
 
 #include "../ComponentManager.h"
 #include "../system/System.h"
+#include "api/SceneManager.h"
 
 namespace crepe {
 
+/**
+ * \brief Main game loop manager
+ *
+ * This class is responsible for managing the game loop, including initialization and updating.
+ */
 class LoopManager {
 public:
 	void start();
 	LoopManager();
 
+	/**
+	 * \brief Add a new concrete scene to the scene manager
+	 *
+	 * \tparam T  Type of concrete scene
+	 */
+	template <typename T>
+	void add_scene();
+
 private:
 	/**
 	 * \brief Setup function for one-time initialization.
@@ -53,12 +67,14 @@ private:
 	 * This function updates physics and game logic based on LoopTimer's fixed_delta_time.
 	 */
 	void fixed_update();
+
 	/**
 	 * \brief Set game running variable
 	 *
 	 * \param running running (false = game shutdown, true = game running)
 	 */
 	void set_running(bool running);
+
 	/**
 	 * \brief Function for executing render-related systems.
 	 *
@@ -71,6 +87,8 @@ private:
 private:
 	//! Component manager instance
 	ComponentManager component_manager{};
+	//! Scene manager instance
+	SceneManager scene_manager{component_manager};
 
 private:
 	/**
diff --git a/src/crepe/api/LoopManager.hpp b/src/crepe/api/LoopManager.hpp
index 0b14fdb..9cf470b 100644
--- a/src/crepe/api/LoopManager.hpp
+++ b/src/crepe/api/LoopManager.hpp
@@ -11,6 +11,11 @@
 namespace crepe {
 
 template <class T>
+void LoopManager::add_scene() {
+	this->scene_manager.add_scene<T>();
+}
+
+template <class T>
 T & LoopManager::get_system() {
 	using namespace std;
 	static_assert(is_base_of<System, T>::value,
diff --git a/src/crepe/api/Scene.cpp b/src/crepe/api/Scene.cpp
index 88aa82d..849945e 100644
--- a/src/crepe/api/Scene.cpp
+++ b/src/crepe/api/Scene.cpp
@@ -2,6 +2,4 @@
 
 using namespace crepe;
 
-Scene::Scene(ComponentManager & mgr, const std::string & name)
-	: component_manager(mgr),
-	  name(name) {}
+Scene::Scene(ComponentManager & mgr) : component_manager(mgr) {}
diff --git a/src/crepe/api/Scene.h b/src/crepe/api/Scene.h
index 0e516b6..869bf6f 100644
--- a/src/crepe/api/Scene.h
+++ b/src/crepe/api/Scene.h
@@ -7,19 +7,36 @@ namespace crepe {
 class SceneManager;
 class ComponentManager;
 
+/**
+ * \brief Represents a Scene
+ * 
+ * This class represents a Scene. The Scene class is only used as an interface for the game
+ * programmer.
+ */
 class Scene {
 protected:
-	Scene(ComponentManager & mgr, const std::string & name);
+	//TODO: Use Loek's custom reference class to set ComponentManger via SceneManager instead of via constructor
+	/**
+	 * \param mgr  Reference to the ComponentManager
+	 */
+	Scene(ComponentManager & mgr);
+	//! SceneManager instances Scene
 	friend class SceneManager;
 
 public:
 	virtual ~Scene() = default;
 
 public:
+	//! Load the scene
 	virtual void load_scene() = 0;
-	const std::string name;
+	/**
+	 * \brief Get the scene's name
+	 * \return The scene's name
+	 */
+	virtual std::string get_name() const = 0;
 
 protected:
+	//! Reference to the ComponentManager
 	ComponentManager & component_manager;
 };
 
diff --git a/src/crepe/api/SceneManager.cpp b/src/crepe/api/SceneManager.cpp
index 7fb5cb0..1f783ad 100644
--- a/src/crepe/api/SceneManager.cpp
+++ b/src/crepe/api/SceneManager.cpp
@@ -18,7 +18,7 @@ void SceneManager::load_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;
+						  return scene.get()->get_name() == next_scene;
 					  });
 
 	// next scene not found
diff --git a/src/crepe/api/SceneManager.h b/src/crepe/api/SceneManager.h
index e854794..45ba668 100644
--- a/src/crepe/api/SceneManager.h
+++ b/src/crepe/api/SceneManager.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include <memory>
-#include <queue>
 #include <vector>
 
 #include "Scene.h"
@@ -10,8 +9,15 @@ namespace crepe {
 
 class ComponentManager;
 
+/**
+ * \brief Manages scenes
+ *
+ * This class manages scenes. It can add new scenes and load them. It also manages the current scene
+ * and the next scene.
+ */
 class SceneManager {
 public:
+	//! \param mgr  Reference to the ComponentManager
 	SceneManager(ComponentManager & mgr);
 
 public:
@@ -19,10 +25,9 @@ public:
 	 * \brief Add a new concrete scene to the scene manager
 	 *
 	 * \tparam T  Type of concrete scene
-	 * \param name  Name of new scene
 	 */
 	template <typename T>
-	void add_scene(const std::string & name);
+	void add_scene();
 	/**
 	 * \brief Set the next scene
 	 *
@@ -35,8 +40,11 @@ public:
 	void load_next_scene();
 
 private:
+	//! Vector of concrete scenes (added by add_scene())
 	std::vector<std::unique_ptr<Scene>> scenes;
+	//! Next scene to load
 	std::string next_scene;
+	//! Reference to the ComponentManager
 	ComponentManager & component_manager;
 };
 
diff --git a/src/crepe/api/SceneManager.hpp b/src/crepe/api/SceneManager.hpp
index 714f690..94e5946 100644
--- a/src/crepe/api/SceneManager.hpp
+++ b/src/crepe/api/SceneManager.hpp
@@ -5,16 +5,16 @@
 namespace crepe {
 
 template <typename T>
-void SceneManager::add_scene(const std::string & name) {
+void SceneManager::add_scene() {
 	using namespace std;
 	static_assert(is_base_of<Scene, T>::value, "T must be derived from Scene");
 
-	Scene * scene = new T(this->component_manager, name);
+	Scene * scene = new T(this->component_manager);
 	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()) {
-		next_scene = name;
+		next_scene = scene->get_name();
 	}
 }
 
diff --git a/src/crepe/api/Script.h b/src/crepe/api/Script.h
index 2b70379..839d937 100644
--- a/src/crepe/api/Script.h
+++ b/src/crepe/api/Script.h
@@ -62,7 +62,7 @@ protected:
 	 * \returns List of component references
 	 */
 	template <typename T>
-	std::vector<std::reference_wrapper<T>> get_components() const;
+	RefVector<T> get_components() const;
 
 protected:
 	// NOTE: Script must have a constructor without arguments so the game programmer doesn't need
diff --git a/src/crepe/api/Script.hpp b/src/crepe/api/Script.hpp
index a064a90..a85d814 100644
--- a/src/crepe/api/Script.hpp
+++ b/src/crepe/api/Script.hpp
@@ -10,7 +10,7 @@ namespace crepe {
 template <typename T>
 T & Script::get_component() const {
 	using namespace std;
-	vector<reference_wrapper<T>> all_components = this->get_components<T>();
+	RefVector<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()));
@@ -19,9 +19,8 @@ T & Script::get_component() const {
 }
 
 template <typename T>
-std::vector<std::reference_wrapper<T>> Script::get_components() const {
+RefVector<T> Script::get_components() const {
 	auto & mgr = *this->component_manager_ref;
-
 	return mgr.get_components_by_id<T>(this->game_object_id);
 }
 
diff --git a/src/crepe/api/Sprite.h b/src/crepe/api/Sprite.h
index 0192793..74a55d4 100644
--- a/src/crepe/api/Sprite.h
+++ b/src/crepe/api/Sprite.h
@@ -2,8 +2,9 @@
 
 #include <memory>
 
+#include "../Component.h"
+
 #include "Color.h"
-#include "Component.h"
 #include "Texture.h"
 
 namespace crepe {
diff --git a/src/crepe/api/Texture.cpp b/src/crepe/api/Texture.cpp
index 734a5bb..9be9421 100644
--- a/src/crepe/api/Texture.cpp
+++ b/src/crepe/api/Texture.cpp
@@ -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->get_canonical()));
+	this->texture = std::move(ctx.texture_from_path(res->get_path()));
 }
 
 int Texture::get_width() const {