ubuntu18.04 OpenGL开发（显示YUV）

gcc -o triangle glad.c triangle.c -lglfw3 -lGL -lX11 -lm -lpthread -ldl

ffmpeg -i C:\Users\Administrator\Desktop\test.h264 -y -an -frames 1 -s 1920x1080 out.yuv
pause

#include<string>
#include<fstream>
#include<sstream>
#include<iostream>
#include<stdio.h>
#include "glad.h"
#include <GLFW/glfw3.h>
 
typedef unsigned char BYTE;
const unsigned int SCR_WIDTH = 500;
const unsigned int SCR_HEIGHT = 600;
const int len = 1920*1080 * 3/2;
BYTE YUVdata [len];
 
unsigned int VBO = 0;
unsigned int VAO = 0;
unsigned int EBO = 0;
unsigned int texturePIC = 0;
int shaderProgram = 0;
 
GLuint texIndexarray[3];
GLuint texUniformY = 99;
GLuint texUniformU = 99;
GLuint texUniformV = 99;
 
void LoadPicture()
{
 
    
    glGenTextures(3, texIndexarray);//生成三个纹理索引
    
    glBindTexture(GL_TEXTURE_2D, texIndexarray[0]);
    //为bind的纹理设置环绕，过滤方式
    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);
 
    glBindTexture(GL_TEXTURE_2D, texIndexarray[1]);
    //为bind的纹理设置环绕，过滤方式
    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);
    glBindTexture(GL_TEXTURE_2D, texIndexarray[2]);
    //为bind的纹理设置环绕，过滤方式
    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);
    
 
    
    //使用着色器程序，返回采样器的序号
    glUseProgram(shaderProgram);//该语句必须要有；安装 指定着色器程序
    texUniformY = glGetUniformLocation(shaderProgram, "dataY");
    texUniformU = glGetUniformLocation(shaderProgram, "dataU");
    texUniformV = glGetUniformLocation(shaderProgram, "dataV");
 
    ----------加载数据--------------------------------------------------------
    FILE* fp = fopen("./out.yuv","rb+");//I420
    int returns  =fread(YUVdata,1,len,fp);
    int w = 1920;
    int h = 1080;
    int ysize = w*h;
    int uvsize = w * h / 4;
 
    void* uptr = &YUVdata[ysize];
    void* vptr = &YUVdata[ysize * 5 / 4];
 
 
    //---------------------------------------------------------------------------
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texIndexarray[0]);// texindexarray[0] =1
    //使用GL_red表示单通道，glfw3里边没有YUV那个GL属性；
    glTexImage2D(GL_TEXTURE_2D, 0 , GL_RED, w, h ,0, GL_RED,GL_UNSIGNED_BYTE ,YUVdata);
    glUniform1i(texUniformY,0);                //通过 glUniform1i 的设置，保证每个 uniform 采样器对应着正确的纹理单元;注意这里不能用tesindexarray[0];
    
 
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, texIndexarray[1]);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, w/2, h/2, 0, GL_RED, GL_UNSIGNED_BYTE,uptr);
    
    glUniform1i(texUniformU, 1);
    
 
    glActiveTexture(GL_TEXTURE2);
    glBindTexture(GL_TEXTURE_2D, texIndexarray[2]);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, w/2, h/2, 0, GL_RED, GL_UNSIGNED_BYTE,vptr);
    glUniform1i(texUniformV,2);
    
    glUseProgram(0);
}
 
 
void render()
{
    glBindVertexArray(VAO);
    glUseProgram(shaderProgram);
    glDrawElements(GL_TRIANGLES,6,GL_UNSIGNED_INT,0);
    //glDrawArrays(GL_TRIANGLE_FAN,0,4);也可
    glUseProgram(0);
    glBindVertexArray(0);
}
 
void initmodule()
{
    //做个一模型;正方形；映射了顶点坐标和纹理坐标的对应关系
    float vertexs[] = {
        //顶点坐标-------纹理坐标(屏幕坐标翻转)
        1.0f,  1.0f, 0.0f,  1.0f, 0.0f,   
        1.0f, -1.0f, 0.0f,  1.0f, 1.0f,   
        -1.0f, -1.0f, 0.0f,  0.0f, 1.0f,   
        -1.0f,  1.0f, 0.0f,  0.0f, 0.0f    
        
        
    };
    //一个正方形是由两个三角形得来的；记录顶点的索引顺序
    unsigned int indexs[] = {
        0,1,3,
        1,2,3,
    };
    
    //做VAO
    glGenVertexArrays(1,&VAO);
    glBindVertexArray(VAO);
 
    //做VBO
 
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    //创建显存空间
    glBufferData(GL_ARRAY_BUFFER,sizeof(vertexs), vertexs, GL_STATIC_DRAW);
    
    //设置索引缓冲
    glGenBuffers(1,&EBO);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(indexs),indexs,GL_STATIC_DRAW);    //加载纹理图片,生成纹理
    LoadPicture();
    
    //设置第0个锚点,3个点，不需要归一化，跨度5个float可以读下一个点
    glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,5*sizeof(float),(void*)0);
    //打开顶点
    glEnableVertexAttribArray(0);
    //纹理属性设置,纹理在第一个锚点上（指定顶点数据）
    glVertexAttribPointer(1,2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
    //打开纹理
    glEnableVertexAttribArray(1);
 
    //解除绑定VBO
    glBindBuffer(GL_ARRAY_BUFFER,0);
 
    //解绑VAO
    glBindVertexArray(0);
 
    
 
}
 
void initshader(const char* verpath,const char* fragpath)
{
    //编译shader，并记录shaderID
    std::string VerCode("");
    std::string fregCode("");
    //读文件
    std::ifstream  vShaderFile;
    std::ifstream  fShaderFile;
 
    vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    
    try
    {
        vShaderFile.open(verpath);
        fShaderFile.open(fragpath);
 
        std::stringstream vsstream, fsstream;
        vsstream << vShaderFile.rdbuf();
        fsstream << fShaderFile.rdbuf();
        VerCode = vsstream.str();
        fregCode = fsstream.str();
        
    }
    catch (const std::exception&)
    {
        std::cout << "read file error" << std::endl;
    }
 
    const char* vshader = VerCode.c_str();
    const char* fshader = fregCode.c_str();
 
    //shader 编译连接
    unsigned int vertexID = 0, fragID = 0;
    char infoLog[512];//存储错误信息
    int  successflag = 0;
    vertexID = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexID,1,&vshader,NULL );
    glCompileShader(vertexID);
    //获取编译是否成功
    glGetShaderiv(vertexID,GL_COMPILE_STATUS,&successflag);
    if (!successflag)
    {
        glGetShaderInfoLog(vertexID,512,NULL,infoLog);
        std::string errstr(infoLog);
        std::cout << "v shader err"<<infoLog;
    }
    //frag
    fragID = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragID, 1, &fshader, NULL);
    glCompileShader(fragID);
    //获取编译是否成功
    glGetShaderiv(fragID, GL_COMPILE_STATUS, &successflag);
    if (!successflag)
    {
        glGetShaderInfoLog(fragID, 512, NULL, infoLog);
        std::string errstr(infoLog);
        std::cout << "f shader err"<<infoLog;
    }
    //链接
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram,vertexID);
    glAttachShader(shaderProgram,fragID);
    
    glBindAttribLocation(shaderProgram, 0, "aPos");
    glBindAttribLocation(shaderProgram, 1, "texCoord");
 
    glLinkProgram(shaderProgram);
    glGetProgramiv(shaderProgram,GL_LINK_STATUS,&successflag);
    if (!successflag)
    {
        glGetShaderInfoLog(shaderProgram, 512, NULL, infoLog);
        std::string errstr(infoLog);
        std::cout << "link error";
    }
 
    //编译完成后，可以把中间的步骤程序删除
    glDeleteShader(vertexID);
    glDeleteShader(fragID);
}
void processInput(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    {
        //将窗口设置为关闭，跳出循环
        glfwSetWindowShouldClose(window, true);
    }
}
 
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}
 
int main()
{
    //glfw初始化
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
    //glfw创建窗口
    GLFWwindow* window = glfwCreateWindow(500, 600, "LearnOpenGL", NULL, NULL);
    if (window == NULL)
    {
        printf("创建窗口失败");
        //终止
        glfwTerminate();
        return -1;
    }
    //显示窗口
    glfwMakeContextCurrent(window);
 
    //设置回调，当窗口大小调整后将调用该回调函数
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
    // glad初始化
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        printf("加载失败");
        return -1;
    }
    initshader("vertexShader.glsl", "fragmentShader.glsl");//先编译着色器
    initmodule();
    
    
    // 使用循环达到循环渲染效果
    while (!glfwWindowShouldClose(window))
    {
        //自定义输入事件
        processInput(window);
 
        glClearColor(0.0f,0.0f,0.0f,1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        render();
        
        //交互缓冲区，否则显示空白
        glfwSwapBuffers(window);
        //输入输出事件,否则无法对窗口进行交互
        glfwPollEvents();
    }
 
    //终止渲染 关闭并清理glfw本地资源
    glfwTerminate();
    return 0;
}

#version 330 core
layout(location = 0) in vec3 aPos;
layout(location = 1) in vec2 texCoord; 
 
out vec2 TexCoord;
void main()
{
   gl_Position = vec4(aPos.x,aPos.y,aPos.z,1.0);
   TexCoord = texCoord;
};

#version 330 core
layout(location = 0) out vec4 FragColor;
in vec2 TexCoord;
uniform sampler2D dataY;
uniform sampler2D dataU;
uniform sampler2D dataV;
vec3 yuv;
vec3 rgb;
void main()
{
   yuv.x = texture2D(dataY, TexCoord).r-0.0625;
   yuv.y = texture2D(dataU, TexCoord).r-0.5;
   yuv.z = texture2D(dataV, TexCoord).r-0.5;
 
   rgb = mat3(1,              1,      1,     
            0,       -0.18732, 1.8556,    
            1.57481, -0.46813,      0) * yuv;   
    FragColor = vec4(rgb.x, rgb.y,rgb.z,1); 
};

g++ -o yuv_show glad.c yuv_show.cpp -lglfw3 -lGL -lX11 -lm -lpthread -ldl