OpenGL学习笔记（一）：使用GLFW 和GLEW 库来创建一个窗口

#include <iostream>

// GLEW
//声明为静态
#define GLEW_STATIC
#include <GL/glew.h>

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


// Window dimensions
const GLuint WIDTH = 800, HEIGHT = 600;

// The MAIN function, from here we start the application and run the game loop
int main()
{
    std::cout << "Starting GLFW context, OpenGL 3.3" << std::endl;
    // Init GLFW
    //实例化glfw窗口并配置
    glfwInit();
    // Set all the required options for GLFW
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
    //创建窗口对象
    // Create a GLFWwindow object that we can use for GLFW's functions
    GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "ILoveLearnOpenGL", nullptr, nullptr);
    if (window == nullptr)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    //将窗口上下文设置为当前主线程的上下文
    glfwMakeContextCurrent(window);
    // Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
   //使用glew库来管理OpenGL的指针，GL_TRUE表示使用现代化的技术
    glewExperimental = GL_TRUE;
    // Initialize GLEW to setup the OpenGL Function pointers
    if (glewInit() != GLEW_OK)
    {
        std::cout << "Failed to initialize GLEW" << std::endl;
        return -1;
    }

    // Define the viewport dimensions
    //根据屏幕来获取屏幕的w,h
    int width, height;
    glfwGetFramebufferSize(window, &width, &height);
    glViewport(0, 0, width, height);

    // Game loop 游戏循环
    while (!glfwWindowShouldClose(window))
    {
        // Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
        //键盘鼠标响应事件
        glfwPollEvents();
        // Swap the screen buffers  交换颜色缓冲
        //前缓冲保存着最终输出的图像，它会在屏幕上显示；
        // 而所有的的渲染指令都会在后缓冲上绘制。当所有的渲染指令执行完毕后
        // 我们交换(Swap)前缓冲和后缓冲
        //这样图像就立即呈显出来，之前提到的不真实感就消除了。
        glfwSwapBuffers(window);
    }

    // Terminate GLFW, clearing any resources allocated by GLFW.
    glfwTerminate();
    return 0;
}

代码运行结果为：