opengl - 如何使用GL_POINTS绘制正方形像素

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

// 顶点数据
GLfloat vertices[] = {
    // 位置信息       // 颜色信息
    -0.5f, 0.5f, 1.0f, 0.0f, 0.0f, // 左上角顶点
    0.5f, 0.5f, 0.0f, 1.0f, 0.0f,  // 右上角顶点
    0.5f, -0.5f, 0.0f, 0.0f, 1.0f, // 右下角顶点
    -0.5f, -0.5f, 1.0f, 1.0f, 1.0f // 左下角顶点
};

// 顶点着色器源码
const char* vertexShaderSource = R"(
    #version 330 core
    layout (location = 0) in vec2 aPos;
    layout (location = 1) in vec3 aColor;
    out vec3 color;
    void main()
    {
        gl_Position = vec4(aPos, 0.0, 1.0);
        color = aColor;
    }
)";

// 片段着色器源码
const char* fragmentShaderSource = R"(
    #version 330 core
    in vec3 color;
    out vec4 FragColor;
    void main()
    {
        FragColor = vec4(color, 1.0);
    }
)";

int main()
{
    // 初始化GLFW
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    // 创建窗口
    GLFWwindow* window = glfwCreateWindow(800, 600, "OpenGL", NULL, NULL);
    if (window == NULL)
    {
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);

    // 初始化GLEW
    glewExperimental = GL_TRUE;
    if (glewInit() != GLEW_OK)
    {
        return -1;
    }

    // 创建顶点数组对象和顶点缓冲对象
    GLuint VAO, VBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    // 绑定VAO和VBO
    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);

    // 将顶点数据传输到VBO中
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // 设置顶点属性指针
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void*)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (void*)(2 * sizeof(GLfloat)));
    glEnableVertexAttribArray(1);

    // 创建顶点着色器
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);

    // 创建片段着色器
    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);

    // 创建着色器程序
    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    // 渲染循环
    while (!glfwWindowShouldClose(window))
    {
        // 清空颜色缓冲
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // 使用着色器程序
        glUseProgram(shaderProgram);

        // 绑定VAO和VBO
        glBindVertexArray(VAO);
        glBindBuffer(GL_ARRAY_BUFFER, VBO);

        // 绘制正方形像素
        glDrawArrays(GL_POINTS, 0, 4);

        // 交换缓冲并查询事件
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // 清理资源
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    glDeleteProgram(shaderProgram);

    // 终止GLFW
    glfwTerminate();
    return 0;
}