/*
    Reshape window

    CC BY-SA Edouard.Thiel@univ-amu.fr - 24/12/2024
*/

#include <iostream>
#include <GLFW/glfw3.h>


class MyApp
{
    bool m_ok = false;
    GLFWwindow* m_window = nullptr;


    void displayGL()
    {
        std::cout << __func__ << std::endl;

        glClear (GL_COLOR_BUFFER_BIT);

        glRectd (-0.5, -0.5, 0.5, 0.5);
    }


    static void on_reshape_func (GLFWwindow* window, int width, int height)
    {
        std::cout << __func__ << " "
            << width << " " << height << std::endl;

        MyApp* that = static_cast<MyApp*>(glfwGetWindowUserPointer (window));
        std::cout << "Test userPointer: "
            << (window == that->m_window ? "ok" : "bad") << std::endl;

        glViewport(0, 0, width, height);
    }


    static void on_error_func (int error, const char* description)
    {
        std::cerr << "Error: " << description << std::endl;
    }

public:

    MyApp()
    {
        if (!glfwInit()) {
            std::cerr << "GLFW: initialization failed" << std::endl;
            return;
        }
        glfwSetErrorCallback (on_error_func);

        m_window = glfwCreateWindow (640, 480, "Reshape window", NULL, NULL);
        if (!m_window) {
            std::cerr << "GLFW: window creation failed" << std::endl;
            return;
        }

        // Les callbacks pour GLFW étant statiques, on mémorise l'instance
        glfwSetWindowUserPointer (m_window, this);
        glfwSetWindowSizeCallback (m_window, on_reshape_func);

        glfwMakeContextCurrent (m_window);
        m_ok = true;
    }


    void run()
    {
        while (m_ok && !glfwWindowShouldClose (m_window))
        {
            displayGL();
            glfwSwapBuffers (m_window);
            glfwWaitEvents();
        }
    }

    ~MyApp()
    {
        if (m_window) glfwDestroyWindow (m_window);
        glfwTerminate();
    }

}; // MyApp


int main() 
{
    MyApp app;
    app.run();
}