使用glfw缩放纹理并显示的例子-DPDK中文网

下面是一个使用GLFW缩放纹理并显示的简单示例代码：

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
// 回调函数：窗口大小变化时触发，用于调整视口
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}
int main()
{
    // 初始化GLFW
    if (!glfwInit())
    {
        std::cout << "Failed to initialize GLFW" << std::endl;
        return -1;
    }
    // 创建窗口和OpenGL上下文
    GLFWwindow* window = glfwCreateWindow(800, 600, "Texture Scaling Example", nullptr, nullptr);
    if (window == nullptr)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    
    // 设置当前窗口为当前线程的主上下文
    glfwMakeContextCurrent(window);
    // 设置视口大小回调函数
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    // 初始化GLEW
    if (glewInit() != GLEW_OK)
    {
        std::cout << "Failed to initialize GLEW" << std::endl;
        glfwTerminate();
        return -1;
    }
   // 纹理坐标数组
   float textureCoordinates[] = {
       0.0f, 0.0f,
       1.0f, 0.0f,
       1.0f, 1.0f,
       0.0f, 1.0f
   };
   // 顶点数组
   float vertices[] = {
       // 位置             // 纹理坐标
       -0.5f, -0.5f, 0.0f, 0.0f,
        0.5f, -0.5f, 1.0f, 0.0f,
        0.5f,  0.5f, 1.0f, 1.0f,
       -0.5f,  0.5f, 0.0f, 1.0f
   };
   // 索引数组
   unsigned int indices[] = {
       0, 1, 2,
       2, 3 ,0
   };
   // 创建并绑定顶点数组对象（VAO）
   unsigned int VAO;
   glGenVertexArrays(1, &VAO);
   glBindVertexArray(VAO);
   // 创建并绑定顶点缓冲对象（VBO）
   unsigned int 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(0,2,GL_FLOAT,GL_FALSE,sizeof(float)*4,(void*)nullptr); 
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1,2,GL_FLOAT,GL_FALSE,sizeof(float)*4,(void*)(sizeof(float)*2)); 
    glEnableVertexAttribArray(1);
    // 创建并绑定索引缓冲对象（EBO）
    unsigned int EBO;
    glGenBuffers(1,&EBO);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(indices),indices,GL_STATIC_DRAW);
    // 解绑VAO、VBO和EBO
    glBindVertexArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
   // 加载纹理
   unsigned int texture;
   glGenTextures(1, &texture);
   glBindTexture(GL_TEXTURE_2D, texture);
   // 设置纹理参数
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   // 加载图片并生成纹理
   int width, height, nrChannels;
   stbi_set_flip_vertically_on_load(true); // 翻转加载图片的Y轴，因为OpenGL坐标系的Y轴方向与大部分图片格式相反
   unsigned char* data = stbi_load("texture.jpg", &width,&height,&nrChannels, 0);
   if (data)
   {
       glTexImage2D(GL_TEXTURE_2D, 0,GL_RGB,width,height ,0,GL_RGB,GL_UNSIGNED_BYTE,data);
       glGenerateMipmap(GL_TEXTURE_2D); 
    }
    else
    {
        std::cout << "Failed to load texture" << std::endl;
        glfwTerminate();
        return -1;
    }
   
    stbi_image_free(data); 
    while(!glfwWindowShouldClose(window))
    {
        // 清除颜色缓冲区
        glClear(GL_COLOR_BUFFER_BIT);
        // 绑定纹理
        glBindTexture(GL_TEXTURE_2D, texture);
        // 使用着色器程序、VAO和EBO绘制矩形
        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        // 交换前后缓冲区
        glfwSwapBuffers(window);
        // 处理事件
        glfwPollEvents();
    }
    // 清理资源
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1,&VBO); 
    glDeleteBuffers(1,&EBO);
    glDeleteTextures(1,&texture); 
   // 终止GLFW
   glfwTerminate();
   return 0;
}