1 files changed, 145 insertions, 0 deletions
diff --git a/src/crepe/manager/LoopTimerManager.h b/src/crepe/manager/LoopTimerManager.h
new file mode 100644
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+++ b/src/crepe/manager/LoopTimerManager.h
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+#pragma once
+
+#include <chrono>
+
+#include "Manager.h"
+
+namespace crepe {
+
+/**
+ * \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:
+	LoopTimerManager(Mediator & mediator);
+	/**
+	 * \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_target_fps(int fps);
+
+	/**
+	 * \brief Get the current frames per second (FPS).
+	 *
+	 * \return Current FPS.
+	 */
+	int 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.
+	 */
+	double 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);
+
+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 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:
+	//! Target frames per second
+	int target_fps = 50;
+	//! Actual frames per second
+	int actual_fps = 0;
+	//! time scale for speeding up or slowing down the game (0 = pause, < 1 = slow down, 1 = normal speed, > 1 = speed up)
+	double time_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) / target_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