Qt 使用openGL 渲染NV12格式的视频

Posted 2021-02-01 nanqiang

直接上代码

Nv12Render.h

#ifndef NV12RENDER_H
#define NV12RENDER_H
#include <QOpenGLFunctions>
#include <QOpenGLShaderProgram>
#include <QOpenGLBuffer>

class Nv12Render : public QOpenGLFunctions
{
public:
    Nv12Render() = default;
    Nv12Render(const Nv12Render&) = delete;
    ~Nv12Render();

    void initialize();
    void render(uchar* m_py,uchar* m_pu,int width,int height);
    void render(uchar *nv12Ptr, int w, int h);

private:
    QOpenGLShaderProgram program;
    GLuint idY,idUV;
    QOpenGLBuffer vbo;
};

#endif // NV12RENDER_H

Nv12Render.cpp

#include "NV12_Render.h"
#include <QOpenGLTexture>
#include <QDebug>

Nv12Render::~Nv12Render()
{

}

void Nv12Render::initialize()
{
    initializeOpenGLFunctions();
    const char *vsrc =
            "attribute vec4 vertexIn; 
             attribute vec4 textureIn;              varying vec4 textureOut;               void main(void)                        {                                          gl_Position = vertexIn;                  textureOut = textureIn;              }";

    const char *fsrc =
            "varying mediump vec4 textureOut;
"
            "uniform sampler2D textureY;
"
            "uniform sampler2D textureUV;
"
            "void main(void)
"
            "{
"
            "vec3 yuv; 
"
            "vec3 rgb; 
"
            "yuv.x = texture2D(textureY, textureOut.st).r - 0.0625; 
"
            "yuv.y = texture2D(textureUV, textureOut.st).r - 0.5; 
"
            "yuv.z = texture2D(textureUV, textureOut.st).g - 0.5; 
"
            "rgb = mat3( 1,       1,         1, 
"
                        "0,       -0.39465,  2.03211, 
"
                        "1.13983, -0.58060,  0) * yuv; 
"
            "gl_FragColor = vec4(rgb, 1); 
"
            "}
";
    program.addShaderFromSourceCode(QOpenGLShader::Vertex,vsrc);
    program.addShaderFromSourceCode(QOpenGLShader::Fragment,fsrc);
    program.link();

    GLfloat points[]{
        -1.0f, 1.0f,
         1.0f, 1.0f,
         1.0f, -1.0f,
        -1.0f, -1.0f,

        0.0f,0.0f,
        1.0f,0.0f,
        1.0f,1.0f,
        0.0f,1.0f
    };
    vbo.create();
    vbo.bind();
    vbo.allocate(points,sizeof(points));

    GLuint ids[2];
    glGenTextures(2,ids);
    idY = ids[0];
    idUV = ids[1];
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
}

void Nv12Render::render(uchar* py,uchar* puv, int w, int h)
{
     glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glDisable(GL_DEPTH_TEST);

    program.bind();
    vbo.bind();
    program.enableAttributeArray("vertexIn");
    program.enableAttributeArray("textureIn");
    program.setAttributeBuffer("vertexIn",GL_FLOAT, 0, 2, 2*sizeof(GLfloat));
    program.setAttributeBuffer("textureIn",GL_FLOAT,2 * 4 * sizeof(GLfloat),2,2*sizeof(GLfloat));

    glActiveTexture(GL_TEXTURE0 + 1);
    glBindTexture(GL_TEXTURE_2D,idY);
    glTexImage2D(GL_TEXTURE_2D,0,GL_RED,w,h,0,GL_RED,GL_UNSIGNED_BYTE,py);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glActiveTexture(GL_TEXTURE0 + 0);
    glBindTexture(GL_TEXTURE_2D,idUV);
    glTexImage2D(GL_TEXTURE_2D,0,GL_RG,w >> 1,h >> 1,0,GL_RG,GL_UNSIGNED_BYTE,puv);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    program.setUniformValue("textureUV",0);
    program.setUniformValue("textureY",1);
    glDrawArrays(GL_QUADS,0,4);
    program.disableAttributeArray("vertexIn");
    program.disableAttributeArray("textureIn");
    program.release();
}


void Nv12Render::render(uchar *nv12Ptr, int w, int h)
{
    if(!nv12Ptr)return;

     glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glDisable(GL_DEPTH_TEST);

    program.bind();
    vbo.bind();
    program.enableAttributeArray("vertexIn");
    program.enableAttributeArray("textureIn");
    program.setAttributeBuffer("vertexIn",GL_FLOAT, 0, 2, 2*sizeof(GLfloat));
    program.setAttributeBuffer("textureIn",GL_FLOAT,2 * 4 * sizeof(GLfloat),2,2*sizeof(GLfloat));

    glActiveTexture(GL_TEXTURE0 + 1);
    glBindTexture(GL_TEXTURE_2D,idY);
    glTexImage2D(GL_TEXTURE_2D,0,GL_RED,w,h,0,GL_RED,GL_UNSIGNED_BYTE,nv12Ptr);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glActiveTexture(GL_TEXTURE0 + 0);
    glBindTexture(GL_TEXTURE_2D,idUV);
    glTexImage2D(GL_TEXTURE_2D,0,GL_RG,w >> 1,h >> 1,0,GL_RG,GL_UNSIGNED_BYTE,nv12Ptr + w*h);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    program.setUniformValue("textureUV",0);
    program.setUniformValue("textureY",1);
    glDrawArrays(GL_QUADS,0,4);
    program.disableAttributeArray("vertexIn");
    program.disableAttributeArray("textureIn");
    program.release();
}

最后写一个窗口类继承 QOpenGLWidget

重写两个函数
void initializeGL(); //调用上面渲染类的初始化函数

void paintGL();//调用上面渲染类的渲染函数