Qt 使用openGL 渲染YUV420P格式的视频

#ifndef YUV420P_RENDER_H
#define YUV420P_RENDER_H

#include <QObject>
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLShaderProgram>
class YUV420P_Render: protected QOpenGLFunctions
{

public:
    YUV420P_Render();
    ~YUV420P_Render();

    //初始化gl
    void initialize();
    //刷新显示
    void render(uchar* py,uchar* pu,uchar* pv,int width,int height,int type);
    void render(uchar* ptr,int width,int height,int type);

private:
    //shader程序
    QOpenGLShaderProgram m_program;
    //shader中yuv变量地址
    GLuint m_textureUniformY, m_textureUniformU , m_textureUniformV;
    //创建纹理
    GLuint m_idy , m_idu , m_idv;

};

#endif // YUV420P_RENDER_H

#include "YUV420P_Render.h"
#include <QDebug>
#include <QTimer>

#define ATTRIB_VERTEX 0
#define ATTRIB_TEXTURE 1

YUV420P_Render::YUV420P_Render()
{
}

YUV420P_Render::~YUV420P_Render()
{
}

    //初始化gl
void YUV420P_Render::initialize()
{
    qDebug() << "initializeGL";

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

    //顶点shader
    const char *vString =
       "attribute vec4 vertexPosition;
        attribute vec2 textureCoordinate;
        varying vec2 texture_Out;
        void main(void)
        {
            gl_Position = vertexPosition;
            texture_Out = textureCoordinate;
        }";
    //片元shader
    const char *tString =
        "varying vec2 texture_Out;
        uniform sampler2D tex_y;
        uniform sampler2D tex_u;
        uniform sampler2D tex_v;
        void main(void)
        {
            vec3 YUV;
            vec3 RGB;
            YUV.x = texture2D(tex_y, texture_Out).r;
            YUV.y = texture2D(tex_u, texture_Out).r - 0.5;
            YUV.z = texture2D(tex_v, texture_Out).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);
        }";

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

    //设置顶点位置
    m_program.bindAttributeLocation("vertexPosition",ATTRIB_VERTEX);
    //设置纹理位置
    m_program.bindAttributeLocation("textureCoordinate",ATTRIB_TEXTURE);

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

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

    //传递顶点和纹理坐标
    //顶点
    static const GLfloat ver[] = {
        -1.0f,-1.0f,
        1.0f,-1.0f,
        -1.0f, 1.0f,
        1.0f,1.0f
//        -1.0f,-1.0f,
//        0.9f,-1.0f,
//        -1.0f, 1.0f,
//        0.9f,1.0f
    };
    //纹理
    static const GLfloat tex[] = {
        0.0f, 1.0f,
        1.0f, 1.0f,
        0.0f, 0.0f,
        1.0f, 0.0f
    };

    //设置顶点,纹理数组并启用
    glVertexAttribPointer(ATTRIB_VERTEX, 2, GL_FLOAT, 0, 0, ver);
    glEnableVertexAttribArray(ATTRIB_VERTEX);
    glVertexAttribPointer(ATTRIB_TEXTURE, 2, GL_FLOAT, 0, 0, tex);
    glEnableVertexAttribArray(ATTRIB_TEXTURE);

    //从shader获取地址
    m_textureUniformY = m_program.uniformLocation("tex_y");
    m_textureUniformU = m_program.uniformLocation("tex_u");
    m_textureUniformV = m_program.uniformLocation("tex_v");

    //创建纹理
    glGenTextures(1, &m_idy);
    //Y
    glBindTexture(GL_TEXTURE_2D, m_idy);
    //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);

    //U
    glGenTextures(1, &m_idu);
    glBindTexture(GL_TEXTURE_2D, m_idu);
    //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);

    //V
    glGenTextures(1, &m_idv);
    glBindTexture(GL_TEXTURE_2D, m_idv);
    //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);

    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT);

}

//刷新显示
void YUV420P_Render::render(uchar* py,uchar* pu,uchar* pv,int width,int height,int type)
{
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, m_idy);
    //修改纹理内容(复制内存内容)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE,py);
    //与shader 关联
    glUniform1i(m_textureUniformY, 0);

    glActiveTexture(GL_TEXTURE0+1);
    glBindTexture(GL_TEXTURE_2D, m_idu);
    //修改纹理内容(复制内存内容)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width/2, height/2, 0, GL_RED, GL_UNSIGNED_BYTE, pu);
    //与shader 关联
    glUniform1i(m_textureUniformU,1);

    glActiveTexture(GL_TEXTURE0+2);
    glBindTexture(GL_TEXTURE_2D, m_idv);
     //修改纹理内容(复制内存内容)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width/2, height/2, 0, GL_RED, GL_UNSIGNED_BYTE, pv);
    //与shader 关联
    glUniform1i(m_textureUniformV, 2);

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

void YUV420P_Render::render(uchar* ptr,int width,int height,int type)
{
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, m_idy);
    //修改纹理内容(复制内存内容)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE,ptr);
    //与shader 关联
    glUniform1i(m_textureUniformY, 0);

    glActiveTexture(GL_TEXTURE0+1);
    glBindTexture(GL_TEXTURE_2D, m_idu);
    //修改纹理内容(复制内存内容)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width/2, height/2, 0, GL_RED, GL_UNSIGNED_BYTE, ptr+width*height);
    //与shader 关联
    glUniform1i(m_textureUniformU,1);

    glActiveTexture(GL_TEXTURE0+2);
    glBindTexture(GL_TEXTURE_2D, m_idv);
     //修改纹理内容(复制内存内容)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width/2, height/2, 0, GL_RED, GL_UNSIGNED_BYTE, ptr+width*height*5/4);
    //与shader 关联
    glUniform1i(m_textureUniformV, 2);

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