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QGraphicsView over existing QGLWidget



  • Hi,
    I have an object which extends QGLWidgets and renders a 3d-scene.

    I need to add some buttons to the 3D view and some animation effects, like button opacity change.
    I found out that a simple way to do that would be render the 3D scene using a QGraphicsView as explained in this example
    http://doc.trolltech.com/qq/qq26-openglcanvas.html.

    The problem is that they don't use an already existing QGLWidget.
    They do their GL-rendering from QGraphicsView::drawBackground(...).

    Is there any way to render the QGraphicsScene scene using the QGLWidget rendering functions?
    I tried to call paintGL from the drawBackground function, but it is not working.
    This is the code

    @...
    //This is how the viewport is initialized
    QGraphicsView *oglGraphicsView = new QGraphicsView();
    oglGraphicsView->setViewport(new MyQGLWidget(QGLFormat(QGL::SampleBuffers)));
    oglGraphicsView->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
    oglGraphicsView->setScene(new MyGraphicsScene());
    ...
    @

    @
    // implementation of the drawBackground
    void MyGraphicsScene::drawBackground(QPainter *painter, const QRectF &rect)
    {
    painter->beginNativePainting();

    glClearColor( 0.0, 0.0, 0.0, 1.0 );
    QList<QGraphicsView *> viewsList = views();
    if( viewsList.isEmpty() )
    return;
    MyQGLWidget *myGlViewport = static_cast<MyQGLWidget *>(viewsList[0]->viewport());
    // paint using MyQGLWidget rendering function
    myGlViewport ->paintGL();

    painter->endNativePainting();
    }
    @

    I know that the correct way to do it is to move the gl rendering in the drawbackground function, but to do that I will lose all high level rendering functions provided by QGlWidget.

    I would be very glad if you could give me some more hints.

    I'm using Qt 4.7

    Thanks,
    Calogero


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