Merge branch 'master' into niels/UI

19 files changed, 355 insertions, 507 deletions

diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index 46deb67..fb11c8d 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -13,10 +13,7 @@ target_sources(crepe PUBLIC
 	Animator.cpp
 	BoxCollider.cpp
 	CircleCollider.cpp
-	IKeyListener.cpp
-	IMouseListener.cpp
 	LoopManager.cpp
-	LoopTimer.cpp
 	Asset.cpp
 	EventHandler.cpp
 	Script.cpp
@@ -47,10 +44,7 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	EventHandler.h
 	EventHandler.hpp
 	Event.h
-	IKeyListener.h
-	IMouseListener.h
 	LoopManager.h
-	LoopTimer.h
 	Asset.h
 	Button.h
 	UIObject.h
diff --git a/src/crepe/api/IKeyListener.cpp b/src/crepe/api/IKeyListener.cpp
deleted file mode 100644
index 8642655..0000000
--- a/src/crepe/api/IKeyListener.cpp
+++ /dev/null
@@ -1,19 +0,0 @@
-#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
deleted file mode 100644
index 180a0a6..0000000
--- a/src/crepe/api/IKeyListener.h
+++ /dev/null
@@ -1,50 +0,0 @@
-#pragma once
-
-#include "../manager/EventManager.h"
-
-#include "Event.h"
-#include "EventHandler.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
deleted file mode 100644
index 989aeb3..0000000
--- a/src/crepe/api/IMouseListener.cpp
+++ /dev/null
@@ -1,29 +0,0 @@
-#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
deleted file mode 100644
index e19897d..0000000
--- a/src/crepe/api/IMouseListener.h
+++ /dev/null
@@ -1,73 +0,0 @@
-#pragma once
-
-#include "../manager/EventManager.h"
-
-#include "Event.h"
-#include "EventHandler.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/LoopManager.cpp b/src/crepe/api/LoopManager.cpp
index 1f0ba72..b5e5ff7 100644
--- a/src/crepe/api/LoopManager.cpp
+++ b/src/crepe/api/LoopManager.cpp
@@ -1,3 +1,6 @@
+#include "../facade/SDLContext.h"
+#include "../manager/EventManager.h"
+#include "../manager/LoopTimerManager.h"
 #include "../system/AISystem.h"
 #include "../system/AnimatorSystem.h"
 #include "../system/AudioSystem.h"
@@ -7,7 +10,7 @@
 #include "../system/PhysicsSystem.h"
 #include "../system/RenderSystem.h"
 #include "../system/ScriptSystem.h"
-#include "manager/EventManager.h"
+#include "../util/Log.h"
 
 #include "LoopManager.h"
 
@@ -22,62 +25,62 @@ LoopManager::LoopManager() {
 	this->load_system<RenderSystem>();
 	this->load_system<ScriptSystem>();
 	this->load_system<InputSystem>();
+	this->event_manager.subscribe<ShutDownEvent>(
+		[this](const ShutDownEvent & event) { return this->on_shutdown(event); });
 	this->load_system<AudioSystem>();
 	this->load_system<AISystem>();
 }
-
-void LoopManager::process_input() { this->get_system<InputSystem>().update(); }
-
 void LoopManager::start() {
 	this->setup();
 	this->loop();
 }
-void LoopManager::set_running(bool running) { this->game_running = running; }
 
-void LoopManager::fixed_update() {
-	// TODO: retrieve EventManager from direct member after singleton refactor
-	EventManager & ev = this->mediator.event_manager;
-	ev.dispatch_events();
-	this->get_system<ScriptSystem>().update();
-	this->get_system<AISystem>().update();
-	this->get_system<PhysicsSystem>().update();
-	this->get_system<CollisionSystem>().update();
-	this->get_system<AudioSystem>().update();
+void LoopManager::setup() {
+	this->game_running = true;
+	this->loop_timer.start();
+	this->scene_manager.load_next_scene();
 }
 
 void LoopManager::loop() {
-	LoopTimer & timer = this->loop_timer;
-	timer.start();
+	try {
+		while (game_running) {
+			this->loop_timer.update();
 
-	while (game_running) {
-		timer.update();
+			while (this->loop_timer.get_lag() >= this->loop_timer.get_fixed_delta_time()) {
+				this->fixed_update();
+				this->loop_timer.advance_fixed_elapsed_time();
+			}
 
-		while (timer.get_lag() >= timer.get_fixed_delta_time()) {
-			this->process_input();
-			this->fixed_update();
-			timer.advance_fixed_update();
+			this->frame_update();
+			this->loop_timer.enforce_frame_rate();
 		}
-
-		this->update();
-		this->render();
-
-		timer.enforce_frame_rate();
+	} catch (const exception & e) {
+		Log::logf(Log::Level::ERROR, "Exception caught in main loop: {}", e.what());
+		this->event_manager.trigger_event<ShutDownEvent>(ShutDownEvent{});
 	}
 }
 
-void LoopManager::setup() {
-	LoopTimer & timer = this->loop_timer;
-	this->game_running = true;
-	this->scene_manager.load_next_scene();
-	timer.start();
-	timer.set_fps(200);
+// will be called at a fixed interval
+void LoopManager::fixed_update() {
+	this->get_system<InputSystem>().update();
+	this->event_manager.dispatch_events();
+	this->get_system<ScriptSystem>().update();
+	this->get_system<AISystem>().update();
+	this->get_system<PhysicsSystem>().update();
+	this->get_system<CollisionSystem>().update();
+	this->get_system<AudioSystem>().update();
 }
 
-void LoopManager::render() {
-	if (!this->game_running) return;
-
+// will be called every frame
+void LoopManager::frame_update() {
+	this->scene_manager.load_next_scene();
 	this->get_system<AnimatorSystem>().update();
+	//render
 	this->get_system<RenderSystem>().update();
 }
 
-void LoopManager::update() {}
+bool LoopManager::on_shutdown(const ShutDownEvent & e) {
+	this->game_running = false;
+	// propagate to possible user ShutDownEvent listeners
+	return false;
+}
diff --git a/src/crepe/api/LoopManager.h b/src/crepe/api/LoopManager.h
index 1bafa56..2915315 100644
--- a/src/crepe/api/LoopManager.h
+++ b/src/crepe/api/LoopManager.h
@@ -4,16 +4,16 @@
 
 #include "../facade/SDLContext.h"
 #include "../manager/ComponentManager.h"
+#include "../manager/EventManager.h"
+#include "../manager/LoopTimerManager.h"
+#include "../manager/Mediator.h"
 #include "../manager/ResourceManager.h"
 #include "../manager/SaveManager.h"
 #include "../manager/SceneManager.h"
 #include "../system/System.h"
 
-#include "LoopTimer.h"
-#include "manager/ResourceManager.h"
 
 namespace crepe {
-
 /**
  * \brief Main game loop manager
  *
@@ -21,8 +21,14 @@ namespace crepe {
  */
 class LoopManager {
 public:
-	void start();
 	LoopManager();
+	/**
+	 * \brief Start the gameloop
+	 *
+	 * This is the start of the engine where the setup is called and then the loop keeps running until the game stops running.
+	 * The Game programmer needs to call this function to run the game. This should be done after creating and adding all scenes.
+	 */
+	void start();
 
 	/**
 	 * \brief Add a new concrete scene to the scene manager
@@ -47,47 +53,20 @@ private:
 	void loop();
 
 	/**
-	 * \brief Function for handling input-related system calls.
-	 *
-	 * Processes user inputs from keyboard and mouse.
-	 */
-	void process_input();
-
-	/**
 	 * \brief Per-frame update.
 	 *
 	 * Updates the game state based on the elapsed time since the last frame.
 	 */
-	void update();
-
-	/**
-	 * \brief Late update which is called after update().
-	 *
-	 * This function can be used for final adjustments before rendering.
-	 */
-	void late_update();
+	virtual void frame_update();
 
 	/**
 	 * \brief Fixed update executed at a fixed rate.
 	 *
 	 * 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.
-	 *
-	 * Renders the current state of the game to the screen.
-	 */
-	void render();
+	virtual void fixed_update();
 
+	//! Indicates whether the game is running.
 	bool game_running = false;
 
 private:
@@ -98,21 +77,29 @@ private:
 	ComponentManager component_manager{mediator};
 	//! Scene manager instance
 	SceneManager scene_manager{mediator};
+	//! LoopTimerManager instance
+	LoopTimerManager loop_timer{mediator};
+	//! EventManager instance
+	EventManager event_manager{mediator};
 	//! Resource manager instance
 	ResourceManager resource_manager{mediator};
 	//! Save manager instance
 	SaveManager save_manager{mediator};
 	//! SDLContext instance
 	SDLContext sdl_context{mediator};
-	//! LoopTimer instance
-	LoopTimer loop_timer{mediator};
 
 private:
 	/**
+	 * \brief Callback function for ShutDownEvent
+	 *
+	 * This function sets the game_running variable to false, stopping the gameloop and therefor quitting the game.
+	 */
+	bool on_shutdown(const ShutDownEvent & e);
+	/**
 	 * \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.
+	 * constructor of LoopManager using LoopManager::load_system.
 	 */
 	std::unordered_map<std::type_index, std::unique_ptr<System>> systems;
 	/**
diff --git a/src/crepe/api/LoopTimer.cpp b/src/crepe/api/LoopTimer.cpp
deleted file mode 100644
index 56e48d3..0000000
--- a/src/crepe/api/LoopTimer.cpp
+++ /dev/null
@@ -1,79 +0,0 @@
-#include <chrono>
-
-#include "../util/Log.h"
-#include "facade/SDLContext.h"
-#include "manager/Manager.h"
-
-#include "LoopTimer.h"
-
-using namespace crepe;
-
-LoopTimer::LoopTimer(Mediator & mediator) : Manager(mediator) {
-	dbg_trace();
-	mediator.timer = *this;
-}
-
-void LoopTimer::start() {
-	this->last_frame_time = std::chrono::steady_clock::now();
-	this->elapsed_time = std::chrono::milliseconds(0);
-	this->elapsed_fixed_time = std::chrono::milliseconds(0);
-	this->delta_time = std::chrono::milliseconds(0);
-}
-
-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);
-
-	if (this->delta_time > this->maximum_delta_time) {
-		this->delta_time = this->maximum_delta_time;
-	}
-
-	this->delta_time *= this->game_scale;
-	this->elapsed_time += this->delta_time;
-	this->last_frame_time = current_frame_time;
-}
-
-double LoopTimer::get_delta_time() const { return this->delta_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; }
-
-double LoopTimer::get_fixed_delta_time() const { return this->fixed_delta_time.count(); }
-
-void LoopTimer::set_fps(int fps) {
-	this->fps = fps;
-	// target time per frame in seconds
-	this->frame_target_time = std::chrono::duration<double>(1.0) / fps;
-}
-
-int LoopTimer::get_fps() const { return this->fps; }
-
-void LoopTimer::set_game_scale(double value) { this->game_scale = value; }
-
-double LoopTimer::get_game_scale() const { return this->game_scale; }
-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);
-
-	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);
-		if (delay_time.count() > 0) {
-			SDLContext & ctx = this->mediator.sdl_context;
-			ctx.delay(delay_time.count());
-		}
-	}
-
-	this->last_frame_time = current_frame_time;
-}
-
-double LoopTimer::get_lag() const {
-	return (this->elapsed_time - this->elapsed_fixed_time).count();
-}
diff --git a/src/crepe/api/LoopTimer.h b/src/crepe/api/LoopTimer.h
deleted file mode 100644
index 0a73a4c..0000000
--- a/src/crepe/api/LoopTimer.h
+++ /dev/null
@@ -1,138 +0,0 @@
-#pragma once
-
-#include "manager/Manager.h"
-#include <chrono>
-
-namespace crepe {
-
-class LoopTimer : public Manager {
-public:
-	/**
-	 * \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.
-	 */
-	double get_current_time() const;
-
-	/**
-	 * \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.
-	 */
-	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.
-	 */
-	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).
-	 */
-	void set_game_scale(double game_scale);
-
-private:
-	friend class LoopManager;
-
-	/**
-	 * \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.
-	 */
-	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.
-	 */
-	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.
-	 */
-	double get_lag() const;
-
-	/**
-	 * \brief Construct a new LoopTimer object.
-	 *
-	 * Private constructor for singleton pattern to restrict instantiation outside the class.
-	 */
-	LoopTimer(Mediator & mediator);
-
-	/**
-	 * \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.
-	 */
-	void advance_fixed_update();
-
-private:
-	//! Current frames per second
-	int fps = 50;
-	//! Current game scale
-	double game_scale = 1;
-	//! Maximum delta time in seconds to avoid large jumps
-	std::chrono::duration<double> maximum_delta_time{0.25};
-	//! 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::duration<double>(1.0) / fps;
-	//! Fixed delta time for fixed updates in seconds
-	std::chrono::duration<double> fixed_delta_time = std::chrono::duration<double>(1.0) / 50.0;
-	//! Total elapsed game time in seconds
-	std::chrono::duration<double> elapsed_time{0.0};
-	//! Total elapsed time for fixed updates in seconds
-	std::chrono::duration<double> elapsed_fixed_time{0.0};
-	//! Time of the last frame
-	std::chrono::steady_clock::time_point last_frame_time;
-};
-
-} // namespace crepe
diff --git a/src/crepe/facade/SDLContext.cpp b/src/crepe/facade/SDLContext.cpp
index 6644c51..20bb030 100644
--- a/src/crepe/facade/SDLContext.cpp
+++ b/src/crepe/facade/SDLContext.cpp
@@ -335,8 +335,6 @@ void SDLContext::update_camera_view(const Camera & cam, const vec2 & new_pos) {
 	SDL_RenderFillRect(this->game_renderer.get(), &bg);
 }
 
-uint64_t SDLContext::get_ticks() const { return SDL_GetTicks64(); }
-
 std::unique_ptr<SDL_Texture, std::function<void(SDL_Texture *)>>
 SDLContext::texture_from_path(const std::string & path) {
 
@@ -367,8 +365,6 @@ ivec2 SDLContext::get_size(const Texture & ctx) {
 	return size;
 }
 
-void SDLContext::delay(int ms) const { SDL_Delay(ms); }
-
 std::vector<SDLContext::EventData> SDLContext::get_events() {
 	std::vector<SDLContext::EventData> event_list;
 	SDL_Event event;
diff --git a/src/crepe/manager/CMakeLists.txt b/src/crepe/manager/CMakeLists.txt
index 480c8ee..f73e165 100644
--- a/src/crepe/manager/CMakeLists.txt
+++ b/src/crepe/manager/CMakeLists.txt
@@ -4,6 +4,7 @@ target_sources(crepe PUBLIC
 	Manager.cpp
 	SaveManager.cpp
 	SceneManager.cpp
+	LoopTimerManager.cpp
 	ResourceManager.cpp
 )
 
@@ -17,6 +18,7 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	SaveManager.h
 	SceneManager.h
 	SceneManager.hpp
+	LoopTimerManager.h
 	ResourceManager.h
 	ResourceManager.hpp
 )
diff --git a/src/crepe/manager/EventManager.cpp b/src/crepe/manager/EventManager.cpp
index 20f0dd3..6aa49ee 100644
--- a/src/crepe/manager/EventManager.cpp
+++ b/src/crepe/manager/EventManager.cpp
@@ -3,11 +3,9 @@
 using namespace crepe;
 using namespace std;
 
-EventManager & EventManager::get_instance() {
-	static EventManager instance;
-	return instance;
+EventManager::EventManager(Mediator & mediator) : Manager(mediator) {
+	this->mediator.event_manager = *this;
 }
-
 void EventManager::dispatch_events() {
 	for (auto & event : this->events_queue) {
 		this->handle_event(event.type, event.channel, *event.event.get());
diff --git a/src/crepe/manager/EventManager.h b/src/crepe/manager/EventManager.h
index ba5e98b..639e37f 100644
--- a/src/crepe/manager/EventManager.h
+++ b/src/crepe/manager/EventManager.h
@@ -8,6 +8,8 @@
 #include "../api/Event.h"
 #include "../api/EventHandler.h"
 
+#include "Manager.h"
+
 namespace crepe {
 
 //! Event listener unique ID
@@ -22,27 +24,19 @@ typedef size_t subscription_t;
 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 {
+class EventManager : public Manager {
 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.
+	 * \param mediator A reference to a Mediator object used for transfering managers.
 	 */
-	static EventManager & get_instance();
-
+	EventManager(Mediator & mediator);
 	/**
 	 * \brief Subscribe to a specific event type.
 	 *
@@ -108,13 +102,6 @@ public:
 
 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.
 	 */
diff --git a/src/crepe/manager/LoopTimerManager.cpp b/src/crepe/manager/LoopTimerManager.cpp
new file mode 100644
index 0000000..9819632
--- /dev/null
+++ b/src/crepe/manager/LoopTimerManager.cpp
@@ -0,0 +1,91 @@
+#include <chrono>
+#include <thread>
+
+#include "../util/Log.h"
+
+#include "LoopTimerManager.h"
+
+using namespace crepe;
+using namespace std::chrono;
+using namespace std::chrono_literals;
+
+LoopTimerManager::LoopTimerManager(Mediator & mediator) : Manager(mediator) {
+	this->mediator.loop_timer = *this;
+	dbg_trace();
+}
+
+void LoopTimerManager::start() {
+	this->last_frame_time = std::chrono::steady_clock::now();
+
+	this->elapsed_time = elapsed_time_t{0};
+	this->elapsed_fixed_time = elapsed_time_t{0};
+	this->delta_time = duration_t{0};
+}
+
+void LoopTimerManager::update() {
+	time_point_t current_frame_time = std::chrono::steady_clock::now();
+	// Convert to duration in seconds for delta time
+	this->delta_time = current_frame_time - last_frame_time;
+
+	if (this->delta_time > this->maximum_delta_time) {
+		this->delta_time = this->maximum_delta_time;
+	}
+	if (this->delta_time > 0s) {
+		this->actual_fps = 1.0 / duration_cast<seconds>(this->delta_time).count();
+	} else {
+		this->actual_fps = 0;
+	}
+	this->elapsed_time += duration_cast<elapsed_time_t>(this->delta_time);
+	this->last_frame_time = current_frame_time;
+}
+
+duration_t LoopTimerManager::get_delta_time() const {
+	return this->delta_time * this->time_scale;
+}
+
+elapsed_time_t LoopTimerManager::get_elapsed_time() const { return this->elapsed_time; }
+
+void LoopTimerManager::advance_fixed_elapsed_time() {
+	this->elapsed_fixed_time
+		+= std::chrono::duration_cast<elapsed_time_t>(this->fixed_delta_time);
+}
+
+void LoopTimerManager::set_target_framerate(unsigned fps) {
+	this->target_fps = fps;
+	//check if fps is lower or equals 0
+	if (fps <= 0) return;
+	// target time per frame in seconds
+	this->frame_target_time = duration_t(1s) / this->target_fps;
+}
+
+unsigned LoopTimerManager::get_fps() const { return this->actual_fps; }
+
+void LoopTimerManager::set_time_scale(double value) { this->time_scale = value; }
+
+float LoopTimerManager::get_time_scale() const { return this->time_scale; }
+
+void LoopTimerManager::enforce_frame_rate() {
+	time_point_t current_frame_time = std::chrono::steady_clock::now();
+	duration_t frame_duration = current_frame_time - this->last_frame_time;
+	// Check if frame duration is less than the target frame time
+	if (frame_duration < this->frame_target_time) {
+		duration_t delay_time = this->frame_target_time - frame_duration;
+		if (delay_time > 0s) {
+			std::this_thread::sleep_for(delay_time);
+		}
+	}
+}
+
+duration_t LoopTimerManager::get_lag() const {
+	return this->elapsed_time - this->elapsed_fixed_time;
+}
+
+duration_t LoopTimerManager::get_scaled_fixed_delta_time() const {
+	return this->fixed_delta_time * this->time_scale;
+}
+
+void LoopTimerManager::set_fixed_delta_time(float seconds) {
+	this->fixed_delta_time = duration_t(seconds);
+}
+
+duration_t LoopTimerManager::get_fixed_delta_time() const { return this->fixed_delta_time; }
diff --git a/src/crepe/manager/LoopTimerManager.h b/src/crepe/manager/LoopTimerManager.h
new file mode 100644
index 0000000..91403e4
--- /dev/null
+++ b/src/crepe/manager/LoopTimerManager.h
@@ -0,0 +1,175 @@
+#pragma once
+
+#include <chrono>
+
+#include "Manager.h"
+
+namespace crepe {
+
+typedef std::chrono::duration<double> duration_t;
+typedef std::chrono::duration<unsigned long long, std::micro> elapsed_time_t;
+
+/**
+ * \brief Manages timing and frame rate for the game loop.
+ * 
+ * The LoopTimerManager class is responsible for calculating and managing timing functions 
+ * such as delta time, frames per second (FPS), fixed time steps, and time scaling. It ensures 
+ * consistent frame updates and supports game loop operations, such as handling fixed updates 
+ * for physics and other time-sensitive operations.
+ */
+class LoopTimerManager : public Manager {
+public:
+	/**
+	 * \param mediator A reference to a Mediator object used for transfering managers.
+	 */
+	LoopTimerManager(Mediator & mediator);
+	/**
+	 * \brief Get the current delta time for the current frame.
+	 *	
+	 * This value represents the estimated frame duration of the current frame.
+	 * This value can be used in the frame_update to convert pixel based values to time based values.
+	 * 
+	 * \return Delta time in seconds since the last frame.
+	 */
+	duration_t get_delta_time() const;
+
+	/**
+	 * \brief Get the current elapsed time (total time passed )
+	 *
+	 * \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.
+	 */
+	elapsed_time_t get_elapsed_time() const;
+
+	/**
+	 * \brief Set the target frames per second (FPS).
+	 *
+	 * \param fps The desired frames rendered per second.
+	 */
+	void set_target_framerate(unsigned fps);
+
+	/**
+	 * \brief Get the current frames per second (FPS).
+	 *
+	 * \return Current FPS.
+	 */
+	unsigned get_fps() const;
+
+	/**
+	 * \brief Get the current time scale.
+	 *
+	 * \return The current time scale, where (0 = pause, < 1 = slow down, 1 = normal speed, > 1 = speed up).
+	 * up the game.
+	 */
+	float get_time_scale() const;
+
+	/**
+	 * \brief Set the time scale.
+	 *
+	 * time_scale is a value that changes the delta time that can be retrieved using get_delta_time function. 
+	 * 
+	 * \param time_scale The desired time scale (0 = pause, < 1 = slow down, 1 = normal speed, > 1 = speed up).
+	 */
+	void set_time_scale(double time_scale);
+
+	/**
+	 * \brief Get the fixed delta time in seconds without scaling by the time scale.
+	 *
+	 * This value is used in the LoopManager to determine how many times 
+	 * the fixed_update should be called within a given interval.
+	 *
+	 * \return The unscaled fixed delta time in seconds.
+	 */
+	duration_t get_fixed_delta_time() const;
+
+	/**
+	 * \brief Set the fixed_delta_time in seconds.
+	 * 
+	 * \param seconds fixed_delta_time in seconds.
+	 * 
+	 * The fixed_delta_time value is used to determine how many times per second the fixed_update and process_input functions are called.
+	 * 
+	 */
+	void set_fixed_delta_time(float seconds);
+
+	/**
+	 * \brief Retrieves the scaled fixed delta time in seconds.
+	 *
+	 * The scaled fixed delta time is the timing value used within the `fixed_update` function. 
+	 * It is adjusted by the time_scale to account for any changes in the simulation's 
+	 * speed.
+	 *
+	 * \return The fixed delta time, scaled by the current time scale, in seconds.
+	 */
+	duration_t get_scaled_fixed_delta_time() const;
+
+private:
+	//! Friend relation to use start,enforce_frame_rate,get_lag,update,advance_fixed_update.
+	friend class LoopManager;
+	/**
+	 * \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.
+	 */
+	void enforce_frame_rate();
+	/**
+	 * \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.
+	 */
+	duration_t get_lag() const;
+
+	/**
+	 * \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 Progress the elapsed fixed time by the fixed delta time interval.
+	 *
+	 * This method advances the game's fixed update loop by adding the fixed_delta_time 
+	 * to elapsed_fixed_time, ensuring the fixed update catches up with the elapsed time.
+	 */
+	void advance_fixed_elapsed_time();
+
+private:
+	//! Target frames per second.
+	unsigned target_fps = 60;
+	//! Actual frames per second.
+	unsigned actual_fps = 0;
+	//! Time scale for speeding up or slowing down the game (0 = pause, < 1 = slow down, 1 = normal speed, > 1 = speed up).
+	float time_scale = 1;
+	//! Maximum delta time in seconds to avoid large jumps.
+	duration_t maximum_delta_time{0.25};
+	//! Delta time for the current frame in seconds.
+	duration_t delta_time{0.0};
+	//! Target time per frame in seconds
+	duration_t frame_target_time{1.0 / target_fps};
+	//! Fixed delta time for fixed updates in seconds.
+	duration_t fixed_delta_time{1.0 / 50.0};
+	//! Total elapsed game time in microseconds.
+	elapsed_time_t elapsed_time{0};
+	//! Total elapsed time for fixed updates in microseconds.
+	elapsed_time_t elapsed_fixed_time{0};
+
+	typedef std::chrono::steady_clock::time_point time_point_t;
+	//! Time of the last frame.
+	time_point_t last_frame_time;
+};
+
+} // namespace crepe
diff --git a/src/crepe/manager/Mediator.h b/src/crepe/manager/Mediator.h
index 628154a..a336410 100644
--- a/src/crepe/manager/Mediator.h
+++ b/src/crepe/manager/Mediator.h
@@ -2,17 +2,15 @@
 
 #include "../util/OptionalRef.h"
 
-// TODO: remove these singletons:
-#include "EventManager.h"
-
 namespace crepe {
 
 class ComponentManager;
 class SceneManager;
+class EventManager;
+class LoopTimerManager;
 class SaveManager;
 class ResourceManager;
 class SDLContext;
-class LoopTimer;
 
 /**
  * Struct to pass references to classes that would otherwise need to be singletons down to
@@ -30,10 +28,10 @@ struct Mediator {
 	OptionalRef<SDLContext> sdl_context;
 	OptionalRef<ComponentManager> component_manager;
 	OptionalRef<SceneManager> scene_manager;
+	OptionalRef<EventManager> event_manager;
+	OptionalRef<LoopTimerManager> loop_timer;
 	OptionalRef<SaveManager> save_manager;
-	OptionalRef<EventManager> event_manager = EventManager::get_instance();
 	OptionalRef<ResourceManager> resource_manager;
-	OptionalRef<LoopTimer> timer;
 };
 
 } // namespace crepe
diff --git a/src/crepe/manager/SceneManager.cpp b/src/crepe/manager/SceneManager.cpp
index 50a9fbb..d4ca90b 100644
--- a/src/crepe/manager/SceneManager.cpp
+++ b/src/crepe/manager/SceneManager.cpp
@@ -32,4 +32,7 @@ void SceneManager::load_next_scene() {
 
 	// Load the new scene
 	scene->load_scene();
+
+	//clear the next scene
+	next_scene.clear();
 }
diff --git a/src/crepe/system/AISystem.cpp b/src/crepe/system/AISystem.cpp
index 7f04432..d231c7c 100644
--- a/src/crepe/system/AISystem.cpp
+++ b/src/crepe/system/AISystem.cpp
@@ -1,22 +1,24 @@
 #include <algorithm>
 #include <cmath>
 
-#include "api/LoopTimer.h"
 #include "manager/ComponentManager.h"
+#include "manager/LoopTimerManager.h"
 #include "manager/Mediator.h"
 
 #include "AISystem.h"
 
 using namespace crepe;
+using namespace std::chrono;
 
 void AISystem::update() {
 	const Mediator & mediator = this->mediator;
 	ComponentManager & mgr = mediator.component_manager;
-	LoopTimer & timer = mediator.timer;
+	LoopTimerManager & timer = mediator.loop_timer;
 	RefVector<AI> ai_components = mgr.get_components_by_type<AI>();
+	LoopTimerManager & loop_timer = mediator.loop_timer;
 
 	//TODO: Use fixed loop dt (this is not available at master at the moment)
-	double dt = timer.get_delta_time();
+	duration_t dt = loop_timer.get_delta_time();
 
 	// Loop through all AI components
 	for (AI & ai : ai_components) {
@@ -43,7 +45,7 @@ void AISystem::update() {
 		// Calculate the acceleration (using the above calculated force)
 		vec2 acceleration = force / rigidbody.data.mass;
 		// Finally, update Rigidbody's velocity
-		rigidbody.data.linear_velocity += acceleration * dt;
+		rigidbody.data.linear_velocity += acceleration * duration_cast<seconds>(dt).count();
 	}
 }
 
diff --git a/src/crepe/system/AnimatorSystem.cpp b/src/crepe/system/AnimatorSystem.cpp
index d61ba35..31eb85c 100644
--- a/src/crepe/system/AnimatorSystem.cpp
+++ b/src/crepe/system/AnimatorSystem.cpp
@@ -2,7 +2,7 @@
 
 #include "../api/Animator.h"
 #include "../manager/ComponentManager.h"
-#include "api/LoopTimer.h"
+#include "../manager/LoopTimerManager.h"
 
 #include "AnimatorSystem.h"
 
@@ -10,10 +10,10 @@ using namespace crepe;
 
 void AnimatorSystem::update() {
 	ComponentManager & mgr = this->mediator.component_manager;
-	LoopTimer & timer = this->mediator.timer;
+	LoopTimerManager & timer = this->mediator.loop_timer;
 	RefVector<Animator> animations = mgr.get_components_by_type<Animator>();
 
-	double elapsed_time = timer.get_current_time();
+	unsigned long long elapsed_time = timer.get_elapsed_time().count();
 
 	for (Animator & a : animations) {
 		if (!a.active) continue;