XVideoWidget.cpp

#include "XVideoWidget.h"
#include <QDebug>
#include <QTimer>
//自动加双引号
#define GET_STR(x) #x
#define A_VER 3
#define T_VER 4

FILE *fp = NULL;

//顶点shader
const char *vString = GET_STR(
    attribute vec4 vertexIn;
    attribute vec2 textureIn;
    varying vec2 textureOut;
    void main(void)
    {
        gl_Position = vertexIn;
        textureOut = textureIn;
    }
);


//片元shader
const char *tString = GET_STR(
    varying vec2 textureOut;
    uniform sampler2D tex_y;
    uniform sampler2D tex_u;
    uniform sampler2D tex_v;
    void main(void)
    {
        vec3 yuv;
        vec3 rgb;
        yuv.x = texture2D(tex_y, textureOut).r;
        yuv.y = texture2D(tex_u, textureOut).r - 0.5;
        yuv.z = texture2D(tex_v, textureOut).r - 0.5;
        rgb = mat3(1.0, 1.0, 1.0,
            0.0, -0.39465, 2.03211,
            1.13983, -0.58060, 0.0) * yuv;
        gl_FragColor = vec4(rgb, 1.0);
    }

);



//准备yuv数据
// ffmpeg -i v1080.mp4 -t 10 -s 240x128 -pix_fmt yuv420p  out240x128.yuv
XVideoWidget::XVideoWidget(QWidget *parent)
    : QOpenGLWidget(parent)
{
}

XVideoWidget::~XVideoWidget()
{
}

//初始化opengl
void XVideoWidget::initializeGL()
{
    qDebug() << "initializeGL";

    //初始化opengl （QOpenGLFunctions继承）函数
    initializeOpenGLFunctions();

    //program加载shader（顶点和片元）脚本
    //片元（像素）
    qDebug()<<program.addShaderFromSourceCode(QGLShader::Fragment, tString);
    //顶点shader
    qDebug() << program.addShaderFromSourceCode(QGLShader::Vertex, vString);

    //设置顶点坐标的变量
    program.bindAttributeLocation("vertexIn",A_VER);

    //设置材质坐标
    program.bindAttributeLocation("textureIn",T_VER);

    //编译shader
    qDebug() << "program.link() = " << program.link();

    qDebug() << "program.bind() = " << program.bind();

    //传递顶点和材质坐标
    //顶点
    static const GLfloat ver[] = {
        -1.0f,-1.0f,
        1.0f,-1.0f,
        -1.0f, 1.0f,
        1.0f,1.0f
    };

    //材质
    static const GLfloat tex[] = {
        0.0f, 1.0f,
        1.0f, 1.0f,
        0.0f, 0.0f,
        1.0f, 0.0f
    };

    //顶点
    glVertexAttribPointer(A_VER, 2, GL_FLOAT, 0, 0, ver);
    glEnableVertexAttribArray(A_VER);

    //材质
    glVertexAttribPointer(T_VER, 2, GL_FLOAT, 0, 0, tex);
    glEnableVertexAttribArray(T_VER);


    //从shader获取材质
    unis[0] = program.uniformLocation("tex_y");
    unis[1] = program.uniformLocation("tex_u");
    unis[2] = program.uniformLocation("tex_v");

    //创建材质
    glGenTextures(3, texs);

    //Y
    glBindTexture(GL_TEXTURE_2D, texs[0]);
    //放大过滤，线性插值   GL_NEAREST(效率高，但马赛克严重)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    //创建材质显卡空间
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, 0);

    //U
    glBindTexture(GL_TEXTURE_2D, texs[1]);
    //放大过滤，线性插值
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    //创建材质显卡空间
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width/2, height / 2, 0, GL_RED, GL_UNSIGNED_BYTE, 0);

    //V
    glBindTexture(GL_TEXTURE_2D, texs[2]);
    //放大过滤，线性插值
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    //创建材质显卡空间
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width / 2, height / 2, 0, GL_RED, GL_UNSIGNED_BYTE, 0);

    ///分配材质内存空间
    datas[0] = new unsigned char[width*height];		//Y
    datas[1] = new unsigned char[width*height/4];	//U
    datas[2] = new unsigned char[width*height/4];	//V

    fp = fopen("out240x128.yuv","rb");
    if (!fp)
    {
        qDebug() << "out240x128.yuv file open failed!";
    }


    //启动定时器
    QTimer *ti = new QTimer(this);
    connect(ti, SIGNAL(timeout()), this, SLOT(update()));
    ti->start(40);
}

//刷新显示
void XVideoWidget::paintGL()
{
    if (feof(fp))
    {
        fseek(fp, 0, SEEK_SET);
    }
    fread(datas[0], 1, width*height, fp);
    fread(datas[1], 1, width*height/4, fp);
    fread(datas[2], 1, width*height/4, fp);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texs[0]); //0层绑定到Y材质
    //修改材质内容(复制内存内容)
    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, datas[0]);
    //与shader uni遍历关联
    glUniform1i(unis[0], 0);


    glActiveTexture(GL_TEXTURE0+1);
    glBindTexture(GL_TEXTURE_2D, texs[1]); //1层绑定到U材质
                                           //修改材质内容(复制内存内容)
    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width/2, height / 2, GL_RED, GL_UNSIGNED_BYTE, datas[1]);
    //与shader uni遍历关联
    glUniform1i(unis[1],1);


    glActiveTexture(GL_TEXTURE0+2);
    glBindTexture(GL_TEXTURE_2D, texs[2]); //2层绑定到V材质
                                           //修改材质内容(复制内存内容)
    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width / 2, height / 2, GL_RED, GL_UNSIGNED_BYTE, datas[2]);
    //与shader uni遍历关联
    glUniform1i(unis[2], 2);

    glDrawArrays(GL_TRIANGLE_STRIP,0,4);
    qDebug() << "paintGL";
}


// 窗口尺寸变化
void XVideoWidget::resizeGL(int width, int height)
{
    qDebug() << "resizeGL "<<width<<":"<<height;
}

XVideoWidget.h

#ifndef XVIDEOWIDGET_H
#define XVIDEOWIDGET_H

#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QGLShaderProgram>

class XVideoWidget : public QOpenGLWidget,protected QOpenGLFunctions
{
    Q_OBJECT
public:
    XVideoWidget(QWidget *parent);
    ~XVideoWidget();
protected:
    //刷新显示
    void paintGL();

    //初始化gl
    void initializeGL();

    // 窗口尺寸变化
    void resizeGL(int width, int height);
private:
    //shader程序
    QGLShaderProgram program;

    //shader中yuv变量地址
    GLuint unis[3] = {0};
    //openg的 texture地址
    GLuint texs[3] = { 0 };

    //材质内存空间
    unsigned char *datas[3] = { 0 };

    int width = 240;
    int height = 128;
};

#endif // XVIDEOWIDGET_H