2.7 摄像机

摄像机

摄像机的位置由其在世界空间的位置、观察的方向、一个指向他右侧的向量、指向它上方的向量构成。实际上，我们创建了一个三个单位轴相互垂直的、以摄像机位置为原点的坐标系。

摄像机位置

摄像机位置使用一个指向摄像机位置的向量来表示。

$Z$轴从屏幕指向我。

摄像机方向

摄像机指向$Z$轴的负方向，我们希望摄相机的方向向量指向$Z$轴的正向，因此
$$方向向量direction=摄像机位置-观察位置$$

上向量

上向量$up$是自己定义的。先定义上向量，然后使用叉乘计算出右向量。

右向量

右向量代表了摄像机的$X$轴正方向。因此,
$$right=up\times direction$$

look at

$LookAt$矩阵的作用是将物体的世界坐标变换到摄影空间坐标，推导过程如下。设我们考虑的点为$u$，其在世界坐标为$u=(x,y,z,1)$，我们需要求出其在摄像机空间的坐标$u_{camera}=(x^{\prime },y^{\prime },z^{\prime },1)$。设摄像机的位置向量为$P$，上向量为$U$，右向量为$R$，方向向量为$D$。则显然有
$$u^{\prime }+P=u$$
展开得
$$\begin{gathered} x^{\prime }R+y^{\prime }U+z^{\prime }D+P=\left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right] \\ {x}^{\prime }R+y^{\prime }U+z^{\prime }D=\left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right]-P=\left[\begin{array}{c}x-P_x\\ y-P_y\\ z-P_z\\ 1\end{array}\right]=\left[\begin{array}{cccc}1& 0& 0& -P_x\\ 0& 1& 0& -P_y\\ 0& 0& 1& -P_z\\ 0& 0& 0& 1\end{array}\right]\ast \left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right] \end{gathered}$$
而
$$x^{\prime }R+y^{\prime }U+z^{\prime }D+P=\left[\begin{array}{cccc}{R}_x& U_x& D_x& 0\\ R_y& U_y& D_y& 0\\ R_z& U_z& D_z& 0\\ 0& 0& 0& 1\end{array}\right]\ast \left[\begin{array}{c}{x}^{\prime }\\ y^{\prime }\\ z^{\prime }\\ 1\end{array}\right]$$
而左侧的矩阵显然可逆，因此
$$\left[\begin{array}{c}{x}^{\prime }\\ y^{\prime }\\ z^{\prime }\\ 1\end{array}\right]=\left[\begin{array}{cccc}{R}_x& R_y& R_z& 0\\ U_x& U_y& U_z& 0\\ D_x& D_y& D_z& 0\\ 0& 0& 0& 1\end{array}\right]\ast \left[\begin{array}{cccc}1& 0& 0& -P_x\\ 0& 1& 0& -P_y\\ 0& 0& 1& -P_z\\ 0& 0& 0& 1\end{array}\right]\ast \left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right]$$

欧拉角

欧拉角有三种，俯仰角pitch、偏航角yaw、滚转角roll。分别是绕$X$轴、$Y$轴和$Z$轴旋转。

在不考虑滚转角的前提下，物体绕俯仰角和偏航角的旋转矩阵为
$$\left[\begin{array}{cccc}\cos \alpha & 0& \sin \alpha & 0\\ 0& 1& 0& 0\\ -\sin \alpha & 0& \cos \alpha & 0\\ 0& 0& 0& 1\end{array}\right]\ast \left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos \theta & -\sin \theta & 0\\ 0& \sin \theta & \cos \theta & 0\\ 0& 0& 0& 1\end{array}\right]$$
其中
$$\begin{gathered} \alpha =pitch \\ \theta =yaw \end{gathered}$$
化简得
$$\left[\begin{array}{cccc}\cos \alpha & \sin \alpha \sin \theta & \sin \alpha \cos \theta & 0\\ 0& \cos \theta & -\sin \theta & 0\\ -\sin \alpha & \cos \alpha \sin \theta & \cos \alpha \cos \theta & 0\\ 0& 0& 0& 1\end{array}\right]$$

code

着色器均使用”MVP过程“的着色器。

LookAt矩阵的定义

#include "../env/glm/glm.hpp"
#include "../env/glm/gtc/matrix_transform.hpp"
#include "../env/glm/gtc/type_ptr.hpp"
#include <iostream>

#define STB_IMAGE_IMPLEMENTATION
#include "../env/std_image.h"
#include "../env/glad.h"
#include "../env/glfw3.h"
#include <fstream>

#define WIDTH 800
#define HEIGHT 600

GLFWwindow *initialize(int width, int height);
GLuint complieVertexShader(const std::string &filename);
GLuint complieFragmentShader(const std::string &filename);
GLuint getShaderProgram(GLuint vertexShader, GLuint fragmentShader);

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void processInput(GLFWwindow *window);
std::string getShaderSource(const std::string &filename);

int main()
{
    
    
    GLFWwindow *window = initialize(WIDTH, HEIGHT);
    GLuint vertexShader = complieVertexShader("6-vertex.glsl");
    GLuint fragmentShader = complieFragmentShader("6-fragment.glsl");
    GLuint shaderProgram = getShaderProgram(vertexShader, fragmentShader);

    GLuint myVAO;
    glGenVertexArrays(1, &myVAO);
    glBindVertexArray(myVAO);

    float vertices[] = {
    
    
        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, -0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,

        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
        -0.5f, 0.5f, 0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,

        -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,

        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, 0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f};

    glm::vec3 cubePositions[] = {
    
    
        glm::vec3(0.0f, 0.0f, 0.0f),
        glm::vec3(2.0f, 5.0f, -15.0f),
        glm::vec3(-1.5f, -2.2f, -2.5f),
        glm::vec3(-3.8f, -2.0f, -12.3f),
        glm::vec3(2.4f, -0.4f, -3.5f),
        glm::vec3(-1.7f, 3.0f, -7.5f),
        glm::vec3(1.3f, -2.0f, -2.5f),
        glm::vec3(1.5f, 2.0f, -2.5f),
        glm::vec3(1.5f, 0.2f, -1.5f),
        glm::vec3(-1.3f, 1.0f, -1.5f)};

    unsigned int myVBO;
    glGenBuffers(1, &myVBO);
    glBindBuffer(GL_ARRAY_BUFFER, myVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(3 * sizeof(float)));

    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);

    int width, height, channel;
    unsigned char *data = stbi_load("../images/container.jpg", &width, &height, &channel, 0);

    GLuint texture1;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(data);

    stbi_set_flip_vertically_on_load(true);
    data = stbi_load("../images/awesomeface.png", &width, &height, &channel, 0);

    GLuint texture2;
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(data);

    // 激活不同的纹理单元
    glUseProgram(shaderProgram);
    GLint texture1Location = glGetUniformLocation(shaderProgram, "texture1");
    glUniform1i(texture1Location, 0);
    GLint texture2Location = glGetUniformLocation(shaderProgram, "texture2");
    glUniform1i(texture2Location, 1);

    // 获取着色器中定义的变换矩阵的位置
    GLint modelMatrixLocation = glGetUniformLocation(shaderProgram, "model");
    GLint viewMatrixLocation = glGetUniformLocation(shaderProgram, "view");
    GLint projectionMatrixLocation = glGetUniformLocation(shaderProgram, "projection");

    glEnable(GL_DEPTH_TEST);

    while (!glfwWindowShouldClose(window))
    {
    
    
        glUseProgram(shaderProgram);
        // 激活不同的纹理单元
        // glm中的矩阵是列主序的
        glm::mat4 model = glm::mat4(1.0f);
        glm::mat4 view = glm::mat4(1.0f);
        glm::mat4 projection = glm::mat4(1.0f);

        projection = glm::perspective(glm::radians(45.0f), 1.0f * WIDTH / HEIGHT, 0.1f, 100.0f);

        // 定义照相机的lookat矩阵
        // 参数1：摄像机位置
        // 参数2：目标
        // 参数3：上向量
        view = glm::lookAt(glm::vec3(0.0f, 0.0f, 3.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
       
        glm::mat4 rotate = glm::mat4(1.0f);
        rotate = glm::rotate(rotate, (float)(glfwGetTime()), glm::vec3(0.0f, 1.0f, 0.0f));
        glm::vec3 position = rotate * glm::vec4(0.0f, 0.0f, 9.0f, 1.0f);

        view = glm::lookAt( position, glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));

        glUniformMatrix4fv(viewMatrixLocation, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projectionMatrixLocation, 1, GL_FALSE, glm::value_ptr(projection)); 
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);
        glBindVertexArray(myVAO);

        for (int i = 0; i < 10; ++i)
        {
    
    
            model = glm::mat4(1.0f);
            model = glm::translate(model, cubePositions[i]);
            model = glm::rotate(model, glm::radians(20.0f * i), glm::vec3(1.0f, 0.3f, 0.5f));
            glUniformMatrix4fv(modelMatrixLocation, 1, GL_FALSE, glm::value_ptr(model));
            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        processInput(window);
        glfwSwapBuffers(window);
        glfwPollEvents();
        glClearColor(0.2, 0.3, 0.3, 1.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    }

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
    
    
    glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window)
{
    
    
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    {
    
    
        glfwSetWindowShouldClose(window, true);
    }
}

GLFWwindow *initialize(int width, int height)
{
    
    
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow *window = glfwCreateWindow(WIDTH, HEIGHT, "2", nullptr, nullptr);
    if (!window)
    {
    
    
        exit(-1);
    }

    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
    
    
        exit(-1);
    }

    glViewport(0, 0, width, height);

    glfwSetWindowSizeCallback(window, framebuffer_size_callback);

    return window;
}

std::string getShaderSource(const std::string &filename)
{
    
    

    std::ifstream in;
    in.open(filename, std::ios::in);
    if (!in.is_open())
    {
    
    
        exit(-1);
    }

    std::string ans, line;
    while (!in.eof())
    {
    
    
        getline(in, line);
        ans += line;
        ans.push_back('\n');
    }

    return ans;
}

GLuint complieVertexShader(const std::string &filename)
{
    
    
    const char *charPtr = nullptr;

    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    std::string vertexShaderSource = getShaderSource(filename);
    if (vertexShaderSource.empty())
        exit(-1);

    charPtr = vertexShaderSource.c_str();
    // 把这个着色器源码附加到着色器对象上，然后编译
    glShaderSource(vertexShader, 1, &charPtr, nullptr);
    glCompileShader(vertexShader);

    // 获取顶点着色器编译信息
    int success;
    char info[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
    
    
        glGetShaderInfoLog(vertexShader, 512, nullptr, info);
        std::cout << "Complie vertex shader error: " << info << std::endl;
        exit(-1);
    }

    return vertexShader;
}

GLuint complieFragmentShader(const std::string &filename)
{
    
    
    const char *charPtr = nullptr;

    // 编译片段着色器
    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    std::string fragmentShaderSource = getShaderSource(filename);
    if (fragmentShaderSource.empty())
    {
    
    
        exit(-1);
    }
    charPtr = fragmentShaderSource.c_str();
    glShaderSource(fragmentShader, 1, &charPtr, nullptr);
    glCompileShader(fragmentShader);

    int success;
    char info[512];
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
    
    
        glGetShaderInfoLog(fragmentShader, 512, nullptr, info);
        std::cout << "Complie fragment shader error: " << info << std::endl;
        exit(-1);
    }

    return fragmentShader;
}

GLuint getShaderProgram(GLuint vertexShader, GLuint fragmentShader)
{
    
    
    // 创建着色器程序对象
    GLuint shaderProgram;
    shaderProgram = glCreateProgram();

    // 链接着色器到程序对象
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    // 删除着色器对象
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    return shaderProgram;
}

键盘事件

#include "../env/glm/glm.hpp"
#include "../env/glm/gtc/matrix_transform.hpp"
#include "../env/glm/gtc/type_ptr.hpp"
#include <iostream>

#define STB_IMAGE_IMPLEMENTATION
#include "../env/std_image.h"
#include "../env/glad.h"
#include "../env/glfw3.h"
#include <fstream>

#define WIDTH 800
#define HEIGHT 600

GLFWwindow *initialize(int width, int height);
GLuint complieVertexShader(const std::string &filename);
GLuint complieFragmentShader(const std::string &filename);
GLuint getShaderProgram(GLuint vertexShader, GLuint fragmentShader);

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void processInput(GLFWwindow *window);
std::string getShaderSource(const std::string &filename);

glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
float cameraSpeed = 2.5f;
float lastTime;

int main()
{
    
    
    GLFWwindow *window = initialize(WIDTH, HEIGHT);
    GLuint vertexShader = complieVertexShader("6-vertex.glsl");
    GLuint fragmentShader = complieFragmentShader("6-fragment.glsl");
    GLuint shaderProgram = getShaderProgram(vertexShader, fragmentShader);

    GLuint myVAO;
    glGenVertexArrays(1, &myVAO);
    glBindVertexArray(myVAO);

    float vertices[] = {
    
    
        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, -0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,

        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
        -0.5f, 0.5f, 0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,

        -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,

        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, 0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f};

    glm::vec3 cubePositions[] = {
    
    
        glm::vec3(0.0f, 0.0f, 0.0f),
        glm::vec3(2.0f, 5.0f, -15.0f),
        glm::vec3(-1.5f, -2.2f, -2.5f),
        glm::vec3(-3.8f, -2.0f, -12.3f),
        glm::vec3(2.4f, -0.4f, -3.5f),
        glm::vec3(-1.7f, 3.0f, -7.5f),
        glm::vec3(1.3f, -2.0f, -2.5f),
        glm::vec3(1.5f, 2.0f, -2.5f),
        glm::vec3(1.5f, 0.2f, -1.5f),
        glm::vec3(-1.3f, 1.0f, -1.5f)};

    unsigned int myVBO;
    glGenBuffers(1, &myVBO);
    glBindBuffer(GL_ARRAY_BUFFER, myVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(3 * sizeof(float)));

    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);

    int width, height, channel;
    unsigned char *data = stbi_load("../images/container.jpg", &width, &height, &channel, 0);

    GLuint texture1;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(data);

    stbi_set_flip_vertically_on_load(true);
    data = stbi_load("../images/awesomeface.png", &width, &height, &channel, 0);

    GLuint texture2;
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(data);

    // 激活不同的纹理单元
    glUseProgram(shaderProgram);
    GLint texture1Location = glGetUniformLocation(shaderProgram, "texture1");
    glUniform1i(texture1Location, 0);
    GLint texture2Location = glGetUniformLocation(shaderProgram, "texture2");
    glUniform1i(texture2Location, 1);

    // 获取着色器中定义的变换矩阵的位置
    GLint modelMatrixLocation = glGetUniformLocation(shaderProgram, "model");
    GLint viewMatrixLocation = glGetUniformLocation(shaderProgram, "view");
    GLint projectionMatrixLocation = glGetUniformLocation(shaderProgram, "projection");

    glEnable(GL_DEPTH_TEST);

    lastTime = glfwGetTime();

    while (!glfwWindowShouldClose(window))
    {
    
    
        glUseProgram(shaderProgram);
        // 激活不同的纹理单元
        // glm中的矩阵是列主序的
        glm::mat4 model = glm::mat4(1.0f);
        glm::mat4 view = glm::mat4(1.0f);
        glm::mat4 projection = glm::mat4(1.0f);

        projection = glm::perspective(glm::radians(45.0f), 1.0f * WIDTH / HEIGHT, 0.1f, 100.0f);

        // 定义照相机的lookat矩阵
        // 参数1：摄像机位置
        // 参数2：目标
        // 参数3：上向量
        view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);

        glUniformMatrix4fv(viewMatrixLocation, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projectionMatrixLocation, 1, GL_FALSE, glm::value_ptr(projection));
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);
        glBindVertexArray(myVAO);

        for (int i = 0; i < 10; ++i)
        {
    
    
            model = glm::mat4(1.0f);
            model = glm::translate(model, cubePositions[i]);
            model = glm::rotate(model, glm::radians(20.0f * i), glm::vec3(1.0f, 0.3f, 0.5f));
            glUniformMatrix4fv(modelMatrixLocation, 1, GL_FALSE, glm::value_ptr(model));
            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        processInput(window);
        glfwSwapBuffers(window);
        glfwPollEvents();
        glClearColor(0.2, 0.3, 0.3, 1.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    }

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
    
    
    glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window)
{
    
    
    float currentTime = glfwGetTime();
    float delta = currentTime - lastTime;
    lastTime = currentTime;

    // 移动照相机位置
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    {
    
    
        glfwSetWindowShouldClose(window, true);
    }
    else if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
    {
    
    
        cameraPos += cameraSpeed * delta * cameraFront;
    }
    else if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
    {
    
    
        cameraPos -= cameraSpeed * delta * cameraFront;
    }
    else if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    {
    
    
        cameraPos -= cameraSpeed * delta * glm::normalize(glm::cross(cameraFront, cameraUp));
    }
    else if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
    {
    
    
        cameraPos += cameraSpeed * delta * glm::normalize(glm::cross(cameraFront, cameraUp));
    }
    else if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS)
    {
    
    
        cameraPos -= cameraSpeed * delta * cameraUp;
    }
    else if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
    {
    
    
        cameraPos += cameraSpeed * delta * cameraUp;
    }
}

GLFWwindow *initialize(int width, int height)
{
    
    
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow *window = glfwCreateWindow(WIDTH, HEIGHT, "2", nullptr, nullptr);
    if (!window)
    {
    
    
        exit(-1);
    }

    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
    
    
        exit(-1);
    }

    glViewport(0, 0, width, height);

    glfwSetWindowSizeCallback(window, framebuffer_size_callback);

    return window;
}

std::string getShaderSource(const std::string &filename)
{
    
    

    std::ifstream in;
    in.open(filename, std::ios::in);
    if (!in.is_open())
    {
    
    
        exit(-1);
    }

    std::string ans, line;
    while (!in.eof())
    {
    
    
        getline(in, line);
        ans += line;
        ans.push_back('\n');
    }

    return ans;
}

GLuint complieVertexShader(const std::string &filename)
{
    
    
    const char *charPtr = nullptr;

    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    std::string vertexShaderSource = getShaderSource(filename);
    if (vertexShaderSource.empty())
        exit(-1);

    charPtr = vertexShaderSource.c_str();
    // 把这个着色器源码附加到着色器对象上，然后编译
    glShaderSource(vertexShader, 1, &charPtr, nullptr);
    glCompileShader(vertexShader);

    // 获取顶点着色器编译信息
    int success;
    char info[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
    
    
        glGetShaderInfoLog(vertexShader, 512, nullptr, info);
        std::cout << "Complie vertex shader error: " << info << std::endl;
        exit(-1);
    }

    return vertexShader;
}

GLuint complieFragmentShader(const std::string &filename)
{
    
    
    const char *charPtr = nullptr;

    // 编译片段着色器
    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    std::string fragmentShaderSource = getShaderSource(filename);
    if (fragmentShaderSource.empty())
    {
    
    
        exit(-1);
    }
    charPtr = fragmentShaderSource.c_str();
    glShaderSource(fragmentShader, 1, &charPtr, nullptr);
    glCompileShader(fragmentShader);

    int success;
    char info[512];
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
    
    
        glGetShaderInfoLog(fragmentShader, 512, nullptr, info);
        std::cout << "Complie fragment shader error: " << info << std::endl;
        exit(-1);
    }

    return fragmentShader;
}

GLuint getShaderProgram(GLuint vertexShader, GLuint fragmentShader)
{
    
    
    // 创建着色器程序对象
    GLuint shaderProgram;
    shaderProgram = glCreateProgram();

    // 链接着色器到程序对象
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    // 删除着色器对象
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    return shaderProgram;
}

光标事件

#include "../env/glm/glm.hpp"
#include "../env/glm/gtc/matrix_transform.hpp"
#include "../env/glm/gtc/type_ptr.hpp"
#include <iostream>

#define STB_IMAGE_IMPLEMENTATION
#include "../env/std_image.h"
#include "../env/glad.h"
#include "../env/glfw3.h"
#include <fstream>

#define WIDTH 800
#define HEIGHT 600

GLFWwindow *initialize(int width, int height);
GLuint complieVertexShader(const std::string &filename);
GLuint complieFragmentShader(const std::string &filename);
GLuint getShaderProgram(GLuint vertexShader, GLuint fragmentShader);

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void mouse_callback(GLFWwindow *window, double xpos, double ypos);
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);

void processInput(GLFWwindow *window);
std::string getShaderSource(const std::string &filename);

glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
float cameraSpeed = 2.5f;
float lastTime;

float lastXPos;
float lastYPos;
bool firstMouse;
float yaw;
float pitch;
float fov = 45.0f;

int main()
{
    
    
    GLFWwindow *window = initialize(WIDTH, HEIGHT);
    GLuint vertexShader = complieVertexShader("6-vertex.glsl");
    GLuint fragmentShader = complieFragmentShader("6-fragment.glsl");
    GLuint shaderProgram = getShaderProgram(vertexShader, fragmentShader);

    GLuint myVAO;
    glGenVertexArrays(1, &myVAO);
    glBindVertexArray(myVAO);

    float vertices[] = {
    
    
        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, -0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f,

        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 1.0f,
        -0.5f, 0.5f, 0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,

        -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,

        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, -0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, -0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, -0.5f, -0.5f, 0.0f, 1.0f,

        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f,
        0.5f, 0.5f, -0.5f, 1.0f, 1.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        0.5f, 0.5f, 0.5f, 1.0f, 0.0f,
        -0.5f, 0.5f, 0.5f, 0.0f, 0.0f,
        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f};

    glm::vec3 cubePositions[] = {
    
    
        glm::vec3(0.0f, 0.0f, 0.0f),
        glm::vec3(2.0f, 5.0f, -15.0f),
        glm::vec3(-1.5f, -2.2f, -2.5f),
        glm::vec3(-3.8f, -2.0f, -12.3f),
        glm::vec3(2.4f, -0.4f, -3.5f),
        glm::vec3(-1.7f, 3.0f, -7.5f),
        glm::vec3(1.3f, -2.0f, -2.5f),
        glm::vec3(1.5f, 2.0f, -2.5f),
        glm::vec3(1.5f, 0.2f, -1.5f),
        glm::vec3(-1.3f, 1.0f, -1.5f)};

    unsigned int myVBO;
    glGenBuffers(1, &myVBO);
    glBindBuffer(GL_ARRAY_BUFFER, myVBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(3 * sizeof(float)));

    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);

    int width, height, channel;
    unsigned char *data = stbi_load("../images/container.jpg", &width, &height, &channel, 0);

    GLuint texture1;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(data);

    stbi_set_flip_vertically_on_load(true);
    data = stbi_load("../images/awesomeface.png", &width, &height, &channel, 0);

    GLuint texture2;
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);

    stbi_image_free(data);

    // 激活不同的纹理单元
    glUseProgram(shaderProgram);
    GLint texture1Location = glGetUniformLocation(shaderProgram, "texture1");
    glUniform1i(texture1Location, 0);
    GLint texture2Location = glGetUniformLocation(shaderProgram, "texture2");
    glUniform1i(texture2Location, 1);

    // 获取着色器中定义的变换矩阵的位置
    GLint modelMatrixLocation = glGetUniformLocation(shaderProgram, "model");
    GLint viewMatrixLocation = glGetUniformLocation(shaderProgram, "view");
    GLint projectionMatrixLocation = glGetUniformLocation(shaderProgram, "projection");

    glEnable(GL_DEPTH_TEST);

    lastTime = glfwGetTime();

    while (!glfwWindowShouldClose(window))
    {
    
    
        glUseProgram(shaderProgram);
        // 激活不同的纹理单元
        // glm中的矩阵是列主序的
        glm::mat4 model = glm::mat4(1.0f);
        glm::mat4 view = glm::mat4(1.0f);
        glm::mat4 projection = glm::mat4(1.0f);

        projection = glm::perspective(glm::radians(fov), 1.0f * WIDTH / HEIGHT, 0.1f, 100.0f);

        // 定义照相机的lookat矩阵
        // 参数1：摄像机位置
        // 参数2：目标
        // 参数3：上向量
        view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);

        glUniformMatrix4fv(viewMatrixLocation, 1, GL_FALSE, glm::value_ptr(view));
        glUniformMatrix4fv(projectionMatrixLocation, 1, GL_FALSE, glm::value_ptr(projection));
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);
        glBindVertexArray(myVAO);

        for (int i = 0; i < 10; ++i)
        {
    
    
            model = glm::mat4(1.0f);
            model = glm::translate(model, cubePositions[i]);
            model = glm::rotate(model, glm::radians(20.0f * i), glm::vec3(1.0f, 0.3f, 0.5f));
            glUniformMatrix4fv(modelMatrixLocation, 1, GL_FALSE, glm::value_ptr(model));
            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        processInput(window);
        glfwSwapBuffers(window);
        glfwPollEvents();
        glClearColor(0.2, 0.3, 0.3, 1.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    }

    glfwTerminate();
    return 0;
}

void framebuffer_size_callback(GLFWwindow *window, int width, int height)
{
    
    
    glViewport(0, 0, width, height);
}

void processInput(GLFWwindow *window)
{
    
    
    float currentTime = glfwGetTime();
    float delta = currentTime - lastTime;
    lastTime = currentTime;

    // 移动照相机位置
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    {
    
    
        glfwSetWindowShouldClose(window, true);
    }
    else if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
    {
    
    
        cameraPos += cameraSpeed * delta * cameraFront;
    }
    else if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
    {
    
    
        cameraPos -= cameraSpeed * delta * cameraFront;
    }
    else if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    {
    
    
        cameraPos -= cameraSpeed * delta * glm::normalize(glm::cross(cameraFront, cameraUp));
    }
    else if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
    {
    
    
        cameraPos += cameraSpeed * delta * glm::normalize(glm::cross(cameraFront, cameraUp));
    }
    else if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS)
    {
    
    
        cameraPos -= cameraSpeed * delta * cameraUp;
    }
    else if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
    {
    
    
        cameraPos += cameraSpeed * delta * cameraUp;
    }
}

GLFWwindow *initialize(int width, int height)
{
    
    
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow *window = glfwCreateWindow(WIDTH, HEIGHT, "2", nullptr, nullptr);
    if (!window)
    {
    
    
        exit(-1);
    }

    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
    
    
        exit(-1);
    }

    glViewport(0, 0, width, height);

    glfwSetWindowSizeCallback(window, framebuffer_size_callback);

    // 光标初始位置
    lastXPos = 400;
    lastYPos = 300;
    firstMouse = true;
    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
    glfwSetCursorPosCallback(window, mouse_callback);

    glfwSetScrollCallback(window, scroll_callback);

    return window;
}

void mouse_callback(GLFWwindow *window, double xpos, double ypos)
{
    
    
    if (firstMouse)
    {
    
    
        lastXPos = xpos;
        lastYPos = ypos;
        firstMouse = false;
    }

    float sensitivity = 0.05f;
    float xOffset = (xpos - lastXPos) * sensitivity;
    float yOffset = (lastYPos - ypos) * sensitivity;

    lastXPos = xpos;
    lastYPos = ypos;

    yaw += xOffset;
    pitch += yOffset;

    if (pitch > 89.0f)
        pitch = 89.0f;
    if (pitch < -89.0f)
        pitch = -89.0f;

    glm::mat4 rotate = glm::mat4(1.0f);
    rotate = glm::rotate(rotate, glm::radians(pitch), glm::vec3(1.0f, 0.0f, 0.0f));
    rotate = glm::rotate(rotate, glm::radians(yaw), glm::vec3(0.0f, 1.0f, 0.0f));

    cameraFront = glm::normalize(rotate * glm::vec4(0.0f, 0.0f, -1.0f, 0.0f));
    cameraUp = glm::normalize(rotate * glm::vec4(0.0f, 1.0f, 0.0f, 0.0f));

    //std::cout << (cameraFront.x * cameraUp.x + cameraFront.y * cameraUp.y + cameraFront.z * cameraUp.z) << std::endl;
}
std::string getShaderSource(const std::string &filename)
{
    
    

    std::ifstream in;
    in.open(filename, std::ios::in);
    if (!in.is_open())
    {
    
    
        exit(-1);
    }

    std::string ans, line;
    while (!in.eof())
    {
    
    
        getline(in, line);
        ans += line;
        ans.push_back('\n');
    }

    return ans;
}

GLuint complieVertexShader(const std::string &filename)
{
    
    
    const char *charPtr = nullptr;

    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    std::string vertexShaderSource = getShaderSource(filename);
    if (vertexShaderSource.empty())
        exit(-1);

    charPtr = vertexShaderSource.c_str();
    // 把这个着色器源码附加到着色器对象上，然后编译
    glShaderSource(vertexShader, 1, &charPtr, nullptr);
    glCompileShader(vertexShader);

    // 获取顶点着色器编译信息
    int success;
    char info[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
    
    
        glGetShaderInfoLog(vertexShader, 512, nullptr, info);
        std::cout << "Complie vertex shader error: " << info << std::endl;
        exit(-1);
    }

    return vertexShader;
}

GLuint complieFragmentShader(const std::string &filename)
{
    
    
    const char *charPtr = nullptr;

    // 编译片段着色器
    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    std::string fragmentShaderSource = getShaderSource(filename);
    if (fragmentShaderSource.empty())
    {
    
    
        exit(-1);
    }
    charPtr = fragmentShaderSource.c_str();
    glShaderSource(fragmentShader, 1, &charPtr, nullptr);
    glCompileShader(fragmentShader);

    int success;
    char info[512];
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
    
    
        glGetShaderInfoLog(fragmentShader, 512, nullptr, info);
        std::cout << "Complie fragment shader error: " << info << std::endl;
        exit(-1);
    }

    return fragmentShader;
}

GLuint getShaderProgram(GLuint vertexShader, GLuint fragmentShader)
{
    
    
    // 创建着色器程序对象
    GLuint shaderProgram;
    shaderProgram = glCreateProgram();

    // 链接着色器到程序对象
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    // 删除着色器对象
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    return shaderProgram;
}

void scroll_callback(GLFWwindow *window, double xoffset, double yoffset)
{
    
    
    fov -= yoffset;
    if (fov <= 1.0f)
    {
    
    
        fov = 1.0f;
    }
    if (fov >= 45.0f)
    {
    
    
        fov = 45.0f;
    }
}