• GLFW初体验


    GLFW初体验

    网上关于OpenGL的教程大多是基于GLUT的,但是GLUT已经相对陈旧了,博主参考着learnopengl学习一下GLFW。

    基本流程

    根据GLFW官网给出的样例,基本流程是:

    • 初始化窗口
    • 注册事件
    • 开始循环直到退出
      • 渲染窗口
      • 交换窗口内容和buffer内容(即更新)
      • 轮询注册的事件
    #include <GLFW/glfw3.h>
    
    int main(void)
    {
        GLFWwindow* window;
    
        /* Initialize the library */
        if (!glfwInit())
            return -1;
    
        /* Create a windowed mode window and its OpenGL context */
        window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
        if (!window)
        {
            glfwTerminate();
            return -1;
        }
    
        /* Make the window's context current */
        glfwMakeContextCurrent(window);
    
        /* Loop until the user closes the window */
        while (!glfwWindowShouldClose(window))
        {
            /* Render here */
            glClear(GL_COLOR_BUFFER_BIT);
    
            /* Swap front and back buffers */
            glfwSwapBuffers(window);
    
            /* Poll for and process events */
            glfwPollEvents();
        }
    
        glfwTerminate();
        return 0;
    }
    

    测试代码

    #include <GL/glew.h>
    #include <GLFW/glfw3.h>
    #include <iostream>
    using namespace std;
    
    void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
    {
        //如果按下ESC,把windowShouldClose设置为True,外面的循环会关闭应用
        if(key==GLFW_KEY_ESCAPE && action == GLFW_PRESS)
            glfwSetWindowShouldClose(window, GL_TRUE);
        std::cout<<"ESC"<<mode;
    }
    
    int main(void)
    {
        //初始化GLFW库
        if(!glfwInit())
            return -1;
        //创建窗口以及上下文
        GLFWwindow* window = glfwCreateWindow(640, 480, "hello world", NULL, NULL);
        if(!window)
        {
            //创建失败会返回NULL
            glfwTerminate();
        }
        //建立当前窗口的上下文
        glfwMakeContextCurrent(window);
        
        glfwSetKeyCallback(window, key_callback); //注册回调函数
        //循环,直到用户关闭窗口
        while(!glfwWindowShouldClose(window))
        {
            /*******轮询事件*******/
            glfwPollEvents();
            
            /*******渲染*******/
            //选择清空的颜色RGBA
            glClearColor(0.2, 0.3, 0.3, 1);
            glClear(GL_COLOR_BUFFER_BIT);
            
            //开始画一个三角形
            glBegin(GL_TRIANGLES);
            glColor3f(1, 0, 0); //Red
            glVertex3f(0, 1, 1);
            
            glColor3f(0, 1, 0); //Green
            glVertex3f(-1, -1, 0);
            
            glColor3f(0, 0, 1); //Blue
            glVertex3f(1, -1, 0);
            //结束一个画图步骤
            glEnd();
            
            glBegin(GL_POLYGON);
            //再画个梯形,需要注意笔顺
            glColor3f(0.5, 0.5, 0.5); //Grey
            glVertex2d(0.5, 0.5);
            glVertex2d(1, 1);
            glVertex2d(1, 0);
            glVertex2d(0.5, 0);
            glEnd();
            
            
            /******交换缓冲区,更新window上的内容******/
            glfwSwapBuffers(window);   
        }
        glfwTerminate();
        return 0;
    }
    

    测试结果

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  • 原文地址:https://www.cnblogs.com/fanghao/p/7571937.html
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