QGL::setPreferredPaintEngine( QPaintEngine::OpenGL2 );
    QGLFormat glFmt = QGLFormat::defaultFormat();
    glFmt.setSwapInterval( 0 ); // 1= vsync on
    glFmt.setAlpha( false );
    glFmt.setRgba( true );
    glFmt.setDoubleBuffer( true ); // default
    glFmt.setOverlay( false );
    QGLFormat::setDefaultFormat( glFmt );
    glFmt.setSampleBuffers( true ); // must true for anti-aliasing
    QGLWidget *glWidget = new QGLWidget( glFmt );
    //### potentially faster, but causes junk to appear if top-level is Item, not Rectangle
    glWidget->setAutoFillBackground( false );

    viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qml/shotMe/main.qml"));
    viewer.setViewportUpdateMode( QGraphicsView::FullViewportUpdate );
    viewer.setViewport( glWidget );
    viewer.showFullScreen();