在OpenGl中旋转正方形

#version 330 core
layout (location = 0) in vec3 aPosition;
uniform mat4 uModel;
uniform mat4 uView;
uniform mat4 uProjection;

void main()
{
    gl_Position = uProjection * uView * uModel * vec4(aPosition, 1.0);
}

#version 330 core
out vec4 FragColor;

void main()
{
    FragColor = vec4(1.0, 0.0, 0.0, 1.0); // 使用红色作为正方形的颜色
}

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

// 正方形的顶点坐标
float vertices[] = {
    -0.5f, -0.5f, 0.0f,
    0.5f, -0.5f, 0.0f,
    0.5f, 0.5f, 0.0f,
    -0.5f, 0.5f, 0.0f
};

// 正方形的索引
unsigned int indices[] = {
    0, 1, 2,
    2, 3, 0
};

// 初始化OpenGL窗口和上下文
void initGLFW()
{
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
}

// 创建窗口和上下文
GLFWwindow* createWindow(int width, int height, const char* title)
{
    GLFWwindow* window = glfwCreateWindow(width, height, title, NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        exit(-1);
    }
    glfwMakeContextCurrent(window);
    return window;
}

// 初始化OpenGL函数指针
void initGLAD()
{
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        exit(-1);
    }
}

// 创建顶点缓冲对象(VBO)
unsigned int createVBO()
{
    unsigned int vbo;
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    return vbo;
}

// 创建顶点数组对象(VAO)
unsigned int createVAO()
{
    unsigned int vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);
    return vao;
}

// 绑定顶点属性指针
void bindVertexAttributes()
{
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
}

// 创建索引缓冲对象(EBO)
unsigned int createEBO()
{
    unsigned int ebo;
    glGenBuffers(1, &ebo);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    return ebo;
}

// 编译和链接着色器程序
unsigned int createShaderProgram()
{
    // 编译顶点着色器
    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderCode, NULL);
    glCompileShader(vertexShader);
    
    // 检查顶点着色器是否编译成功
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "Failed to compile vertex shader" << std::endl;
        exit(-1);
    }
    
    // 编译片段着色器
    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderCode, NULL);
    glCompileShader(fragmentShader);
    
    // 检查片段着色器是否编译成功
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "Failed to compile fragment shader" << std::endl;
        exit(-1);
    }
    
    // 创建着色器程序并链接着色器
    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    
    // 检查着色器程序是否链接成功
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success)
    {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "Failed to link shader program" << std::endl;
        exit(-1);
    }
    
    // 删除着色器对象
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);
    
    return shaderProgram;
}

// 渲染循环
void renderLoop(GLFWwindow* window, unsigned int vao, unsigned int ebo, unsigned int shaderProgram)
{
    while (!glfwWindowShouldClose(window))
    {
        // 处理输入事件
        processInput(window);
        
        // 清空屏幕颜色
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        
        // 使用着色器程序
        glUseProgram(shaderProgram);
        
        // 更新模型矩阵以实现旋转
        float angle = glfwGetTime() * 50.0f;
        glm::mat4 model = glm::rotate(glm::mat4(1.0f), glm::radians(angle), glm::vec3(0.0f, 0.0f, 1.0f));
        unsigned int modelLocation = glGetUniformLocation(shaderProgram, "uModel");
        glUniformMatrix4fv(modelLocation, 1, GL_FALSE, glm::value_ptr(model));
        
        // 绑定顶点数组对象(VAO)和索引缓冲对象(EBO)
        glBindVertexArray(vao);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
        
        // 绘制正方形
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        
        // 交换缓冲区并查询事件
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
}

int main()
{
    // 初始化GLFW
    initGLFW();
    
    // 创建窗口和上下文
    GLFWwindow* window = createWindow(800, 600, "OpenGL");
    
    // 初始化GLAD
    initGLAD();
    
    // 创建顶点缓冲对象(VBO)
    unsigned int vbo = createVBO();
    
    // 创建顶点数组对象(VAO)
    unsigned int vao = createVAO();
    
    // 绑定顶点属性指针
    bindVertexAttributes();
    
    // 创建索引缓冲对象(EBO)
    unsigned int ebo = createEBO();
    
    // 编译和链接着色器程序
    unsigned int shaderProgram = createShaderProgram();
    
    // 进入渲染循环
    renderLoop(window, vao, ebo, shaderProgram);
    
    // 清理资源
    glDeleteVertexArrays(1, &vao);
    glDeleteBuffers(1, &vbo);
    glDeleteBuffers(1, &ebo);
    glDeleteProgram(shaderProgram);
    
    // 终止GLFW
    glfwTerminate();
    
    return 0;
}