OpenGL的2D示例

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

int main()
{
    // 初始化GLFW
    if (!glfwInit())
    {
        fprintf(stderr, "Failed to initialize GLFW\n");
        return -1;
    }

    // 创建窗口
    GLFWwindow* window = glfwCreateWindow(640, 480, "OpenGL 2D Example", NULL, NULL);
    if (!window)
    {
        fprintf(stderr, "Failed to create GLFW window\n");
        glfwTerminate();
        return -1;
    }

    // 设置窗口上下文
    glfwMakeContextCurrent(window);

    // 初始化GLEW
    if (glewInit() != GLEW_OK)
    {
        fprintf(stderr, "Failed to initialize GLEW\n");
        glfwTerminate();
        return -1;
    }

    // 设置OpenGL状态
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    // 顶点数据
    GLfloat vertices[] = {
        // 位置              // 颜色
        0.0f, 0.5f, 0.0f,   1.0f, 0.0f, 0.0f,
        0.5f, -0.5f, 0.0f,  0.0f, 1.0f, 0.0f,
        -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f
    };

    // 创建顶点数组对象
    GLuint VAO;
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);

    // 创建顶点缓冲区对象
    GLuint VBO;
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // 设置顶点属性指针
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0);
    glEnableVertexAttribArray(0);

    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
    glEnableVertexAttribArray(1);

    // 设置视口
    glViewport(0, 0, 640, 480);

    // 主循环
    while (!glfwWindowShouldClose(window))
    {
        // 处理输入
        if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        {
            glfwSetWindowShouldClose(window, GL_TRUE);
        }

        // 清除颜色缓冲区
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // 绘制矩形
        glUseProgram(0);
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 3);

        // 交换缓冲区
        glfwSwapBuffers(window);

        // 轮询事件
        glfwPollEvents();
    }

    // 释放资源
    glfwTerminate();
    return 0;
}