Merge branch 'wouter/LoopManager-new' of github.com:lonkaars/crepe

7 files changed, 384 insertions, 1 deletions

diff --git a/src/crepe/api/CMakeLists.txt b/src/crepe/api/CMakeLists.txt
index 87cbb09..85696c4 100644
--- a/src/crepe/api/CMakeLists.txt
+++ b/src/crepe/api/CMakeLists.txt
@@ -18,6 +18,8 @@ target_sources(crepe PUBLIC
 	Vector2.cpp
 	Camera.cpp
 	Animator.cpp
+	LoopManager.cpp
+	LoopTimer.cpp
 )
 
 target_sources(crepe PUBLIC FILE_SET HEADERS FILES
@@ -42,4 +44,6 @@ target_sources(crepe PUBLIC FILE_SET HEADERS FILES
 	SceneManager.hpp
 	Camera.h
 	Animator.h
+	LoopManager.h
+	LoopTimer.h
 )
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/facade/SDLContext.cpp b/src/crepe/facade/SDLContext.cpp
index c4c96e2..39d0d4d 100644
--- a/src/crepe/facade/SDLContext.cpp
+++ b/src/crepe/facade/SDLContext.cpp
@@ -191,3 +191,4 @@ int SDLContext::get_height(const Texture & ctx) const {
 	SDL_QueryTexture(ctx.texture.get(), NULL, NULL, NULL, &h);
 	return h;
 }
+void SDLContext::delay(int ms) const { SDL_Delay(ms); }
diff --git a/src/crepe/facade/SDLContext.h b/src/crepe/facade/SDLContext.h
index e358c21..536dec5 100644
--- a/src/crepe/facade/SDLContext.h
+++ b/src/crepe/facade/SDLContext.h
@@ -58,12 +58,23 @@ private:
 private:
 	//! Will only use get_ticks
 	friend class AnimatorSystem;
-
+	//! Will only use delay
+	friend class LoopTimer;
 	/**
 	 * \brief Gets the current SDL ticks since the program started.
 	 * \return Current ticks in milliseconds as a constant uint64_t.
 	 */
 	uint64_t get_ticks() const;
+	/**
+	 * \brief Pauses the execution for a specified duration.
+	 *
+	 * This function uses SDL's delay function to halt the program execution
+	 * for a given number of milliseconds, allowing for frame rate control
+	 * or other timing-related functionality.
+	 *
+	 * \param ms Duration of the delay in milliseconds.
+	 */
+	void delay(int ms) const;
 
 private:
 	/**