#include <glad/glad.h>
#include <GLFW/glfw3.h>
void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
    glViewport(0, 0, width, height);
}
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, "LearnOpenGL", NULL, NULL);
    if (window == NULL) {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return 1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    // 初始化GLAD
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return 1;
    }
    // 创建顶点着色器
    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    const char* vertexShaderSource = "#version 330 core
"
                                    "layout (location = 0) in vec3 aPos;
"
                                    "void main()
"
                                    "{
"
                                    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
"
                                    "}\0";
    glShaderSource(vertexShader, 1, &vertexShaderSource, nullptr);
    glCompileShader(vertexShader);
    // 创建片段着色器
    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    const char* fragmentShaderSource = "#version 330 core
"
                                    "out vec4 FragColor;
"
                                    "void main()
"
                                    "{
"
                                    "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
"
                                    "}
\0";
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, nullptr);
    glCompileShader(fragmentShader);
    // 链接着色器程序
    unsigned int shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    // 删除着色器（它们已经链接到程序中了）
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    // 渲染循环
    while (!glfwWindowShouldClose(window)) {
        // 输入
        if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
            glfwSetWindowShouldClose(window, true);
        // 渲染指令
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        // 绘制...
        glUseProgram(shaderProgram);
        // 因为这里没有设置顶点数据和属性指针，所以实际上不会绘制任何东西
        // 交换缓冲区和轮询IO事件
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
    // 释放资源
    glDeleteProgram(shaderProgram);
    glfwTerminate();
    return 0;
}
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