QOpenGLWindow QPainter混合绘制

Question

我只是喜欢这个链接：source=tuicool

我做的链接say.But，我不能得到正确的result.Only有背景颜色。我的代码有什么问题？

我的代码：

class Render : public QOpenGLWindow
{
public:
    Render();
    ~Render();
protected:
    void initializeGL();
    void paintGL();
    void resizeGL(int  w ,int h);
     QOpenGLFunctions * f;
     QOpenGLBuffer * triangle;
     QOpenGLVertexArrayObject * vao;
     QOpenGLShaderProgram * program;
      QMatrix4x4 mv,p;
      QTimer * time;
      float rota;
     //QPainter * painter;

};

GLfloat tri[] =
{
    0.0f,1.0f,-1.0f,1.0f,
     1.0f,1.0f,-1.0f,1.0f,
     1.0f,0.0f,-1.0f,1.0f,

};
Render::Render()
{
    QSurfaceFormat format;
    format.setDepthBufferSize(24);
    format.setStencilBufferSize(8);
    format.setVersion(3,3);
    format.setProfile(QSurfaceFormat::CoreProfile);
    setFormat(format);
    time = new QTimer;
    connect(time,SIGNAL(timeout()),this,SLOT(update()));
    time->start(50);
    rota = 0;


}

Render::~Render()
{

}
void Render::initializeGL()
{
//    f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
//    f->initializeOpenGLFunctions();

    f = context()->functions();


    program =  new QOpenGLShaderProgram;
    program->addShaderFromSourceCode(QOpenGLShader::Vertex,
                                     "#version 330 core \n\
                                     layout(location = 0) in vec4 vertex;\
            uniform mat4 mvp;\
                                     void main() \
            {\
                gl_Position = mvp * vertex;\
             }");

    program->addShaderFromSourceCode(QOpenGLShader::Fragment,
                                     "#version 330 core \n\
                                     out vec4 fragColor;\
            void main() \
    { \
        fragColor = vec4(0.0f,1.0f,0.0f,1.0f);\
    }");
    program->link();

    vao = new QOpenGLVertexArrayObject;
    vao->create();
    vao->bind();
    triangle = new QOpenGLBuffer(QOpenGLBuffer::VertexBuffer);
    triangle->create();
    triangle->bind();

    triangle->setUsagePattern(QOpenGLBuffer::StaticDraw);
    triangle->allocate(tri,sizeof(tri));
    program->enableAttributeArray(0);
    program->setAttributeBuffer(0,GL_FLOAT,0,4,0);
    f->glEnable(GL_DEPTH_TEST);


}
void Render::resizeGL(int w ,int h)
{
    p.setToIdentity();
     p.perspective(35.0f,float(w)/float(h),1.0f,30.0f);
}
void Render::paintGL()
{
    program->bind();
    f->glClearColor(0.5,0.5f,0.5f,1.0f);
    f->glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    f->glViewport(0,0,width(),height());

    mv.setToIdentity();

    mv.lookAt(QVector3D(0.0f,0.0f,5.0f),QVector3D(0.0f,0.0f,0.0f),QVector3D(0.0f,1.0f,0.0f));
    mv.rotate(0.5+rota,0,1,0);
    program->setUniformValue("mvp",p*mv);
    vao->bind();
    f->glDrawArrays(GL_TRIANGLES,0,3);
    rota=rota+1.5;
    rota=rota>360.0?0:rota;


    QPainter pp(this);

    pp.drawText(10,20,"dsdsds");
    update();
}

Answer 1

当我需要这样做时，我使用了paintEvent，并使用了QPainter::beginNativePainting ();/QPainter::endNativePainting ();

void Render::paintEvent(QPaintEvent *)
{

    QPainter p(this);
    p.beginNativePainting ();
    makeCurrent ();
    //restore and save state so they don't interact
    glEnable (GL_DEPTH_TEST);
    glClear (GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
    paintGL ();
    glClear (GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
    glDisable (GL_DEPTH_TEST);
    p.endNativePainting ();

    //other painting
}

Answer 2

我也有同样的问题，在使用QPainter之前可以通过释放顶点缓冲区来解决这个问题。因此，在初始化QPainter之前，您可能需要尝试vao->release()；try >release()；program->release()；。

Answer 3

这就是在"QOpenGLWidget“中对我起作用的地方。我不需要将OpenGL代码放在"beginNativePainting()“和"beginNativePainting()”Qpainter函数调用之间。我不需要覆盖paintEvent .这与您共享的链接中的内容类似。

1)在"QOpenGLWidget“的构造函数中，将格式设置为"CompatibilityProfile”，例如：

QSurfaceFormat  format;
format.setProfile(QSurfaceFormat::CompatibilityProfile);
QSurfaceFormat::setDefaultFormat(format);
this->setFormat(format);

2)在游戏循环函数中，确保在您完成OpenGL代码之后，在调用您的Q画家并在函数的末尾使用它之前，释放程序VAO、VBO和& EBO。例：

VAO.release();
VBO->release();
EBO->release();
m_program->release();
QPainter painter(this);
painter.begin(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.drawText(10,20,"dsdsds");
painter.end();