12.QT-通过QOpenGLWidget显示YUV画面,通过QOpenGLTexture纹理渲染YUV

ffmpeg -i v1080.mp4 -t 10 -s 640x340 -pix_fmt yuv420p out640x340.yuv

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

#version 330 core
const char *fsrc =GET_GLSTR(
 
out vec4 FragColor;
in vec2 TexCoord;
uniform sampler2D texY;
uniform sampler2D texU;
uniform sampler2D texV;
 
void main()
{
vec3 yuv;
vec3 rgb;
 
yuv.x = texture2D(texY, TexCoord).r;
yuv.y = texture2D(texU, TexCoord).r-0.5;
yuv.z = texture2D(texV, TexCoord).r-0.5;
 
rgb = mat3(1.0, 1.0, 1.0,
0.0, -0.3455, 1.779,
1.4075, -0.7169, 0.0) * yuv;
 
FragColor = vec4(rgb, 1.0);
}
);

#include "myglwidget.h"
#include <QtDebug>
#include <QTimer>

////GLSL3.0版本后,废弃了attribute关键字（以及varying关键字），属性变量统一用in/out作为前置关键字
#define GL_VERSION  "#version 330 core\n"
#define GET_GLSTR(x) GL_VERSION#x

static int VideoWidth=640;
static int VideoHeight=340;


const char *vsrc = GET_GLSTR(

    layout (location = 0) in vec3 aPos;
    layout (location = 1) in vec2 aTexCoord;

    out vec2 TexCoord;

    void main()
    {
        gl_Position = vec4(aPos, 1.0);
        TexCoord = aTexCoord;
    }

);

const char *fsrc =GET_GLSTR(

    out vec4 FragColor;
    in vec2 TexCoord;
    uniform sampler2D texY;
    uniform sampler2D texU;
    uniform sampler2D texV;

    void main()
    {
        vec3 yuv;
        vec3 rgb;

        yuv.x = texture(texY, TexCoord).r;
        yuv.y = texture(texU, TexCoord).r-0.5;
        yuv.z = texture(texV, TexCoord).r-0.5;

        rgb = mat3(1.0, 1.0, 1.0,
            0.0, -0.3455, 1.779,
            1.4075, -0.7169, 0.0) * yuv;

        FragColor = vec4(rgb, 1.0);
    }
);

myGlWidget::myGlWidget(QWidget *parent):QOpenGLWidget(parent)
{

}


void myGlWidget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT);


    // 渲染Shader
    vao.bind();
     if (file->atEnd())
     {
        qDebug()<<"repaly!!!!!!!!";
        file->seek(0);
     }
      program->setUniformValue("texY", 0);
      program->setUniformValue("texU", 1);
      program->setUniformValue("texV", 2);

      for(int i=0;i<3;i++)
      {
          if(i==0)
          {

                  yuvArr[i] = file->read(VideoWidth*VideoHeight);
          }
          else
          {
                  yuvArr[i] = file->read(VideoWidth*VideoHeight/4);
          }



          m_textureYUV[i]->setData(QOpenGLTexture::Red,QOpenGLTexture::UInt8,yuvArr[i]);

          m_textureYUV[i]->bind(i);
      }

     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

     m_textureYUV[0]->release();
     m_textureYUV[1]->release();
     m_textureYUV[2]->release();

    vao.release();       //解绑
}

void myGlWidget::initializeGL()
{
    //为当前环境初始化OpenGL函数
    initializeOpenGLFunctions();

    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);    //设置背景色为白色


    file =new QFile("G:\\out640x340.yuv");
    if (!file->open(QIODevice::ReadOnly ))
    {
        qDebug()<<"out640x340.yuv file open failed!";
    }


     //初始化纹理对象
     for(int i=0;i<3;i++)
     {

         m_textureYUV[i]  = new QOpenGLTexture(QOpenGLTexture::Target2D);

         if(i==0)
         {
                 m_textureYUV[i]->setSize(VideoWidth,VideoHeight);
         }
         else
         {
                 m_textureYUV[i]->setSize(VideoWidth/2,VideoHeight/2);
         }

         m_textureYUV[i]->setMinMagFilters(QOpenGLTexture::LinearMipMapLinear,QOpenGLTexture::Linear);
         m_textureYUV[i]->create();
         m_textureYUV[i]->setFormat(QOpenGLTexture::R8_UNorm);
         m_textureYUV[i]->allocateStorage();        //存储配置(放大缩小过滤、格式、size)
         m_textureYUV[i]->setData(QOpenGLTexture::Red,QOpenGLTexture::UInt8,yuvArr[i]);

     }


    program = new  QOpenGLShaderProgram(this);

    program->addShaderFromSourceCode(QOpenGLShader::Fragment,fsrc);

    program->addShaderFromSourceCode(QOpenGLShader::Vertex,vsrc);

    program->link();
    program->bind();


    //初始化VBO,将顶点数据存储到buffer中,等待VAO激活后才能释放

    float vertices[] = {
         //顶点坐标               //纹理坐标的Y方向需要是反的,因为opengl中的坐标系是Y原点位于下方
        -1.0f, -1.0f, 0.0f,  0.0f, 1.0f,        //左下
        1.0f , -1.0f, 0.0f,  1.0f, 1.0f,        //右下
        -1.0f, 1.0f,  0.0f,  0.0f, 0.0f,        //左上
        1.0f,  1.0f,  0.0f,  1.0f, 0.0f         //右上

    };


    vbo.create();
    vbo.bind();
    vbo.bind();              //绑定到当前的OpenGL上下文,
    vbo.allocate(vertices, sizeof(vertices));
    vbo.setUsagePattern(QOpenGLBuffer::StaticDraw);  //设置为一次修改，多次使用(坐标不变,变得只是像素点)

    //初始化VAO,设置顶点数据状态(顶点，法线，纹理坐标等)
    vao.create();
    vao.bind();

    // void setAttributeBuffer(int location, GLenum type, int offset, int tupleSize, int stride = 0);
    program->setAttributeBuffer(0, GL_FLOAT, 0,                  3, 5 * sizeof(float));   //设置aPos顶点属性
    program->setAttributeBuffer(1, GL_FLOAT, 3 * sizeof(float),  2, 5 * sizeof(float));   //设置aColor顶点颜色

    program->enableAttributeArray(0); //使能
    program->enableAttributeArray(1);



    //解绑所有对象
    vao.release();
    vbo.release();

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


}



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