15 files changed, 513 insertions, 67 deletions

diff --git a/src/crepe/api/Animator.cpp b/src/crepe/api/Animator.cpp
index 8b396af..58fee2a 100644
--- a/src/crepe/api/Animator.cpp
+++ b/src/crepe/api/Animator.cpp
@@ -10,7 +10,10 @@
 using namespace crepe;
 
 Animator::Animator(uint32_t id, Sprite & ss, int row, int col, int col_animator)
-	: Component(id), spritesheet(ss), row(row), col(col) {
+	: Component(id),
+	  spritesheet(ss),
+	  row(row),
+	  col(col) {
 	dbg_trace();
 
 	animator_rect = spritesheet.sprite_rect;
diff --git a/src/crepe/api/AssetManager.h b/src/crepe/api/AssetManager.h
index fefbed9..86a9902 100644
--- a/src/crepe/api/AssetManager.h
+++ b/src/crepe/api/AssetManager.h
@@ -7,9 +7,19 @@
 
 namespace crepe {
 
+/**
+ * \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.
+ */
 class AssetManager {
 
 private:
+	//! A cache that holds all the assets, accessible by their file path, over multiple scenes.
 	std::unordered_map<std::string, std::any> asset_cache;
 
 private:
@@ -22,12 +32,32 @@ public:
 	AssetManager & operator=(const AssetManager &) = delete;
 	AssetManager & operator=(AssetManager &&) = delete;
 
+	/**
+	 * \brief Retrieves the singleton instance of the AssetManager.
+	 *
+	 * \return A reference to the single instance of the AssetManager.
+	 */
 	static AssetManager & get_instance();
 
 public:
-	template <typename asset>
-	std::shared_ptr<asset> cache(const std::string & file_path,
-								 bool reload = false);
+	/**
+	 * \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.
+	 * \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.
+	 */
+	template <typename T>
+	std::shared_ptr<T> cache(const std::string & file_path,
+							 bool reload = false);
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index 6915074..de1b4b3 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -18,8 +18,13 @@ target_sources(crepe PUBLIC
 	Vector2.cpp
 	Camera.cpp
 	Animator.cpp
+<<<<<<< HEAD
 	BoxCollider.cpp
 	CircleCollider.cpp
+=======
+	LoopManager.cpp
+	LoopTimer.cpp
+>>>>>>> be1e97bc7a494963ab1567492fafcda99e36f683
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -44,6 +49,11 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	SceneManager.hpp
 	Camera.h
 	Animator.h
+<<<<<<< HEAD
 	BoxCollider.h
 	CircleCollider.h
+=======
+	LoopManager.h
+	LoopTimer.h
+>>>>>>> be1e97bc7a494963ab1567492fafcda99e36f683
 )
diff --git a/src/crepe/api/Camera.cpp b/src/crepe/api/Camera.cpp
index 820a6a8..6355a03 100644
--- a/src/crepe/api/Camera.cpp
+++ b/src/crepe/api/Camera.cpp
@@ -10,7 +10,8 @@
 using namespace crepe;
 
 Camera::Camera(uint32_t id, const Color & bg_color)
-	: Component(id), bg_color(bg_color) {
+	: Component(id),
+	  bg_color(bg_color) {
 	dbg_trace();
 }
 
diff --git a/src/crepe/api/CircleCollider.h b/src/crepe/api/CircleCollider.h
index 29a9c1e..e4f0452 100644
--- a/src/crepe/api/CircleCollider.h
+++ b/src/crepe/api/CircleCollider.h
@@ -8,8 +8,15 @@ namespace crepe {
 
 class CircleCollider : public Collider {
 public:
+<<<<<<< HEAD
 	CircleCollider(game_object_id_t game_object_id,Vector2 offset, int radius);
 	double radius;
+=======
+	CircleCollider(game_object_id_t game_object_id, int radius)
+		: Collider(game_object_id),
+		  radius(radius) {}
+	int radius;
+>>>>>>> be1e97bc7a494963ab1567492fafcda99e36f683
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/LoopManager.cpp b/src/crepe/api/LoopManager.cpp
new file mode 100644
index 0000000..2e9823f
--- /dev/null
+++ b/src/crepe/api/LoopManager.cpp
@@ -0,0 +1,55 @@
+
+#include "../facade/SDLContext.h"
+#include "../system/RenderSystem.h"
+#include "../system/ScriptSystem.h"
+
+#include "LoopManager.h"
+#include "LoopTimer.h"
+
+using namespace crepe;
+
+LoopManager::LoopManager() {}
+void LoopManager::process_input() {
+	SDLContext::get_instance().handle_events(this->game_running);
+}
+void LoopManager::start() {
+	this->setup();
+	this->loop();
+}
+void LoopManager::set_running(bool running) { this->game_running = running; }
+
+void LoopManager::fixed_update() {}
+
+void LoopManager::loop() {
+	LoopTimer & timer = LoopTimer::get_instance();
+	timer.start();
+
+	while (game_running) {
+		timer.update();
+
+		while (timer.get_lag() >= timer.get_fixed_delta_time()) {
+			this->process_input();
+			this->fixed_update();
+			timer.advance_fixed_update();
+		}
+
+		this->update();
+		this->render();
+
+		timer.enforce_frame_rate();
+	}
+}
+
+void LoopManager::setup() {
+	this->game_running = true;
+	LoopTimer::get_instance().start();
+	LoopTimer::get_instance().set_fps(60);
+}
+
+void LoopManager::render() {
+	if (this->game_running) {
+		RenderSystem::get_instance().update();
+	}
+}
+
+void LoopManager::update() { LoopTimer & timer = LoopTimer::get_instance(); }
diff --git a/src/crepe/api/LoopManager.h b/src/crepe/api/LoopManager.h
new file mode 100644
index 0000000..2f03193
--- /dev/null
+++ b/src/crepe/api/LoopManager.h
@@ -0,0 +1,79 @@
+#pragma once
+
+#include <memory>
+
+class RenderSystem;
+class SDLContext;
+class LoopTimer;
+class ScriptSystem;
+class SoundSystem;
+class ParticleSystem;
+class PhysicsSystem;
+class AnimatorSystem;
+class CollisionSystem;
+namespace crepe {
+
+class LoopManager {
+public:
+	void start();
+	LoopManager();
+
+private:
+	/**
+	 * \brief Setup function for one-time initialization.
+	 *
+	 * This function initializes necessary components for the game.
+	 */
+	void setup();
+	/**
+	 * \brief Main game loop function.
+	 *
+	 * This function runs the main loop, handling game updates and rendering.
+	 */
+	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();
+
+	/**
+	 * \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();
+
+	bool game_running = false;
+	//#TODO add system instances
+};
+
+} // namespace crepe
diff --git a/src/crepe/api/LoopTimer.cpp b/src/crepe/api/LoopTimer.cpp
new file mode 100644
index 0000000..8f09e41
--- /dev/null
+++ b/src/crepe/api/LoopTimer.cpp
@@ -0,0 +1,86 @@
+#include <chrono>
+
+#include "../facade/SDLContext.h"
+#include "../util/log.h"
+
+#include "LoopTimer.h"
+
+using namespace crepe;
+
+LoopTimer::LoopTimer() { dbg_trace(); }
+
+LoopTimer & LoopTimer::get_instance() {
+	static LoopTimer instance;
+	return instance;
+}
+
+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::seconds(1) / 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::get_instance().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
new file mode 100644
index 0000000..85687be
--- /dev/null
+++ b/src/crepe/api/LoopTimer.h
@@ -0,0 +1,147 @@
+#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.
+     */
+	static LoopTimer & get_instance();
+
+	/**
+     * \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();
+
+	/**
+     * \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::seconds(1) / fps;
+	//! Fixed delta time for fixed updates in seconds
+	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
+	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/api/Metadata.cpp b/src/crepe/api/Metadata.cpp
index 76f11d7..d421de5 100644
--- a/src/crepe/api/Metadata.cpp
+++ b/src/crepe/api/Metadata.cpp
@@ -4,4 +4,6 @@ using namespace crepe;
 using namespace std;
 
 Metadata::Metadata(game_object_id_t id, const string & name, const string & tag)
-	: Component(id), name(name), tag(tag) {}
+	: Component(id),
+	  name(name),
+	  tag(tag) {}
diff --git a/src/crepe/api/ParticleEmitter.cpp b/src/crepe/api/ParticleEmitter.cpp
index 3b2e2f2..35f960d 100644
--- a/src/crepe/api/ParticleEmitter.cpp
+++ b/src/crepe/api/ParticleEmitter.cpp
@@ -1,36 +1,12 @@
-#include <ctime>
-#include <iostream>
-
-#include "Particle.h"
 #include "ParticleEmitter.h"
 
 using namespace crepe;
 
-ParticleEmitter::ParticleEmitter(game_object_id_t id, uint32_t max_particles,
-								 uint32_t emission_rate, uint32_t speed,
-								 uint32_t speed_offset, uint32_t angle,
-								 uint32_t angleOffset, float begin_lifespan,
-								 float end_lifespan)
-	: Component(id), max_particles(max_particles), emission_rate(emission_rate),
-	  speed(speed), speed_offset(speed_offset), position{0, 0},
-	  begin_lifespan(begin_lifespan), end_lifespan(end_lifespan) {
-	std::srand(
-		static_cast<uint32_t>(std::time(nullptr))); // initialize random seed
-	std::cout << "Create emitter" << std::endl;
-	// FIXME: Why do these expressions start with `360 +`, only to be `% 360`'d
-	// right after? This does not make any sense to me.
-	min_angle = (360 + angle - (angleOffset % 360)) % 360;
-	max_angle = (360 + angle + (angleOffset % 360)) % 360;
-	position.x = 400; // FIXME: what are these magic values?
-	position.y = 400;
-	for (size_t i = 0; i < max_particles; i++) {
-		this->particles.emplace_back();
-	}
-}
-
-ParticleEmitter::~ParticleEmitter() {
-	std::vector<Particle>::iterator it = this->particles.begin();
-	while (it != this->particles.end()) {
-		it = this->particles.erase(it);
+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++) {
+		this->data.particles.emplace_back();
 	}
 }
diff --git a/src/crepe/api/ParticleEmitter.h b/src/crepe/api/ParticleEmitter.h
index 5939723..a9e872f 100644
--- a/src/crepe/api/ParticleEmitter.h
+++ b/src/crepe/api/ParticleEmitter.h
@@ -1,42 +1,85 @@
 #pragma once
 
-#include <cstdint>
 #include <vector>
 
 #include "Component.h"
 #include "Particle.h"
+#include "Vector2.h"
 
 namespace crepe {
 
+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.
+ */
 class ParticleEmitter : public Component {
 public:
-	ParticleEmitter(game_object_id_t id, uint32_t max_particles,
-					uint32_t emission_rate, uint32_t speed,
-					uint32_t speed_offset, uint32_t angle, uint32_t angleOffset,
-					float begin_lifespan, float end_lifespan);
-	~ParticleEmitter();
-
-	//! position of the emitter
-	Position position;
-	//! maximum number of particles
-	uint32_t max_particles;
-	//! rate of particle emission
-	uint32_t emission_rate;
-	//! base speed of the particles
-	uint32_t speed;
-	//! offset for random speed variation
-	uint32_t speed_offset;
-	//! min angle of particle emission
-	uint32_t min_angle;
-	//! max angle of particle emission
-	uint32_t max_angle;
-	//! begin Lifespan of particle (only visual)
-	float begin_lifespan;
-	//! begin Lifespan of particle
-	float end_lifespan;
-
-	//! collection of particles
-	std::vector<Particle> particles;
+	/**
+	 * \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.
+	 */
+	struct Boundary {
+		//! boundary width (midpoint is emitter location)
+		double width = 0.0;
+		//! boundary height (midpoint is emitter location)
+		double height = 0.0;
+		//! boundary offset from particle emitter location
+		Vector2 offset;
+		//! reset on exit or stop velocity and set max postion
+		bool reset_on_exit = false;
+	};
+
+	/**
+	 * \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.
+	 */
+	struct Data {
+		//! position of the emitter
+		Vector2 position;
+		//! maximum number of particles
+		const unsigned int max_particles = 0;
+		//! rate of particle emission per update (Lowest value = 0.001 any lower is ignored)
+		double emission_rate = 0;
+		//! min speed of the particles
+		double min_speed = 0;
+		//! min speed of the particles
+		double max_speed = 0;
+		//! min angle of particle emission
+		double min_angle = 0;
+		//! max angle of particle emission
+		double max_angle = 0;
+		//! begin Lifespan of particle (only visual)
+		double begin_lifespan = 0.0;
+		//! end Lifespan of particle
+		double end_lifespan = 0.0;
+		//! force over time (physics)
+		Vector2 force_over_time;
+		//! particle boundary
+		Boundary boundary;
+		//! collection of particles
+		std::vector<Particle> particles;
+		//! sprite reference
+		const Sprite & sprite;
+	};
+
+public:
+	/**
+	 * \param game_object_id  Identifier for the game object using this emitter.
+	 * \param data            Configuration data defining particle properties.
+	 */
+	ParticleEmitter(game_object_id_t game_object_id, const Data & data);
+
+public:
+	//! Configuration data for particle emission settings.
+	Data data;
 };
 
 } // namespace crepe
diff --git a/src/crepe/api/Rigidbody.cpp b/src/crepe/api/Rigidbody.cpp
index cbf1325..3bf1c5b 100644
--- a/src/crepe/api/Rigidbody.cpp
+++ b/src/crepe/api/Rigidbody.cpp
@@ -3,7 +3,8 @@
 using namespace crepe;
 
 crepe::Rigidbody::Rigidbody(uint32_t game_object_id, const Data & data)
-	: Component(game_object_id), data(data) {}
+	: Component(game_object_id),
+	  data(data) {}
 
 void crepe::Rigidbody::add_force_linear(const Vector2 & force) {
 	this->data.linear_velocity += force;
diff --git a/src/crepe/api/Sprite.cpp b/src/crepe/api/Sprite.cpp
index f9cd761..6f0433f 100644
--- a/src/crepe/api/Sprite.cpp
+++ b/src/crepe/api/Sprite.cpp
@@ -12,7 +12,10 @@ using namespace crepe;
 
 Sprite::Sprite(game_object_id_t id, const shared_ptr<Texture> image,
 			   const Color & color, const FlipSettings & flip)
-	: Component(id), color(color), flip(flip), sprite_image(image) {
+	: Component(id),
+	  color(color),
+	  flip(flip),
+	  sprite_image(image) {
 	dbg_trace();
 
 	this->sprite_rect.w = sprite_image->get_width();
diff --git a/src/crepe/api/Transform.cpp b/src/crepe/api/Transform.cpp
index a244bc5..e401120 100644
--- a/src/crepe/api/Transform.cpp
+++ b/src/crepe/api/Transform.cpp
@@ -6,6 +6,9 @@ using namespace crepe;
 
 Transform::Transform(game_object_id_t id, const Vector2 & point,
 					 double rotation, double scale)
-	: Component(id), position(point), rotation(rotation), scale(scale) {
+	: Component(id),
+	  position(point),
+	  rotation(rotation),
+	  scale(scale) {
 	dbg_trace();
 }