engine.hpp

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#pragma once
 
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <functional>
#include <string>

namespace lmgl {

namespace core {

enum class Key {
    // Numbers
    Key0 = 48,
    Key1 = 49,
    Key2 = 50,
    Key3 = 51,
    Key4 = 52,
    Key5 = 53,
    Key6 = 54,
    Key7 = 55,
    Key8 = 56,
    Key9 = 57,
    // Letters
    A = 65,
    B = 66,
    C = 67,
    D = 68,
    E = 69,
    F = 70,
    G = 71,
    H = 72,
    I = 73,
    J = 74,
    K = 75,
    L = 76,
    M = 77,
    N = 78,
    O = 79,
    P = 80,
    Q = 81,
    R = 82,
    S = 83,
    T = 84,
    U = 85,
    V = 86,
    W = 87,
    X = 88,
    Y = 89,
    Z = 90,
    // Specials
    Space = 32,
    Esc = 256,
    Enter = 257,
    Tab = 258,
    Backspace = 259,
    Right = 262,
    Left = 263,
    Down = 264,
    Up = 265,
    // Fn Keys
    F1 = 290,
    F2 = 291,
    F3 = 292,
    F4 = 293,
    F5 = 294,
    F6 = 295,
    F7 = 296,
    F8 = 297,
    F9 = 298,
    F10 = 299,
    F11 = 300,
    F12 = 301,
    // Modifiers
    LShift = 340,
    LCtrl = 341,
    LAlt = 342,
    RShift = 344,
    RCtrl = 345,
    RAlt = 346
};

enum class MouseButton { Left = 0, Right = 1, Middle = 2 };

enum class InputState { Released = 0, Pressed = 1, Repeat = 2 };

enum class CursorMode {
    Normal,  
    Hidden,  
    Disabled 
};

enum class VSyncMode {
    Off = 0,      
    On = 1,       
    Adaptive = -1 
};

class Engine {
  public:
    static Engine &get_instance();

    bool init(int w, int h, std::string title, bool resizable = true, bool vsync = true);

    void run(std::function<void(float)> update_callback);

    void free();

    bool is_running() const;

    void shutdown();

    void clear(float r, float g, float b, float a = 1.0f);

    void set_vsync(VSyncMode mode);

    inline int get_width() const { return m_width; };

    inline int get_height() const { return m_height; };

    float get_aspect_ratio() const;

    void set_size(int width, int height);

    void set_title(const std::string &title);

    void set_fullscreen(bool fullscreen);

    inline bool is_fullscreen() const { return m_fullscreen; };

    void maximize();

    void minimize();

    void restore();

    bool is_key_pressed(Key key) const;

    bool is_key_just_pressed(Key key) const;

    bool is_key_just_released(Key key) const;

    bool is_mouse_button_pressed(MouseButton button) const;

    inline double get_mouse_x() const { return m_mouse_x; };

    inline double get_mouse_y() const { return m_mouse_y; };

    void get_mouse_delta(double &dx, double &dy) const;

    void set_mouse_position(double x, double y);

    void set_cursor_mode(CursorMode mode);

    void get_scroll_offset(double &xoffs, double &yoffs) const;

    inline GLFWwindow *get_window() const { return m_window; };

    inline void set_resize_callback(std::function<void(int, int)> callback) { m_resize_callback = callback; };

    inline float get_delta_time() const { return m_delta_time; };

    inline float get_time() const { return m_time; };

    inline float get_fps() const { return m_fps; };
 
  private:
    Engine() = default;

    ~Engine() = default;

    Engine(const Engine &) = delete;

    Engine &operator=(const Engine &) = delete;

    static void fb_size_callback(GLFWwindow *window, int w, int h);

    static void key_callback(GLFWwindow *window, int key, int scancode, int action, int mods);

    static void mouse_button_callback(GLFWwindow *window, int button, int action, int mods);

    static void cursor_position_callback(GLFWwindow *window, double xpos, double ypos);

    static void scroll_callback(GLFWwindow *window, double xoffs, double yoffs);

    void update_input_state();

    GLFWwindow *m_window = nullptr;

    int m_width = 0;

    int m_height = 0;

    bool m_fullscreen = false;

    float m_delta_time = 0.0f;

    float m_last_frame_time = 0.0f;

    float m_time = 0.0f;

    float m_fps = 0.0f;

    int m_frame_count = 0;

    float m_fps_timer = 0.0f;

    bool m_key_states[512] = {false};

    bool m_key_just_pressed[512] = {false};

    bool m_key_just_released[512] = {false};

    bool m_mouse_button_states[8] = {false};

    double m_mouse_x = 0.0;

    double m_mouse_y = 0.0;

    double m_last_mouse_x = 0.0;

    double m_last_mouse_y = 0.0;

    double m_scroll_x = 0.0;

    double m_scroll_y = 0.0;

    std::function<void(int, int)> m_resize_callback;
};
 
} // namespace core
 
} // namespace lmgl