bool GLWidget::event( QEvent* event ){    // QEvent::Hide    //    // workaround "Qt-workaround" that does glFinish before hiding the widget    // (the Qt workaround was seen at least in Qt 4.6.3 and 4.7.0)    //    // Qt makes the context current, performs glFinish, and releases the context.    // This makes the problem in OSG multithreaded environment as the context    // is active in another thread, thus it can not be made current for the purpose    // of glFinish in this thread.    // QEvent::ParentChange    //    // Reparenting GLWidget may create a new underlying window and a new GL context.    // Qt will then call doneCurrent on the GL context about to be deleted. The thread    // where old GL context was current has no longer current context to render to and    // we cannot make new GL context current in this thread.    // We workaround above problems by deferring execution of problematic event requests.    // These events has to be enqueue and executed later in a main GUI thread (GUI operations    // outside the main thread are not allowed) just before makeCurrent is called from the    // right thread. The good place for doing that is right after swap in a swapBuffersImplementation.    if (event->type() == QEvent::Hide)    {        // enqueue only the last of QEvent::Hide and QEvent::Show        enqueueDeferredEvent(QEvent::Hide, QEvent::Show);        return true;    }    else if (event->type() == QEvent::Show)    {        // enqueue only the last of QEvent::Show or QEvent::Hide        enqueueDeferredEvent(QEvent::Show, QEvent::Hide);        return true;    }    else if (event->type() == QEvent::ParentChange)    {        // enqueue only the last QEvent::ParentChange        enqueueDeferredEvent(QEvent::ParentChange);        return true;    }    //wyh    else if(event->type() == QEvent::TouchBegin ||event->type() == QEvent::TouchUpdate || event->type() == QEvent::TouchEnd)    {        QList<QTouchEvent::TouchPoint> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints();        if(touchPoints.count() >= 2)        {            //test            //std::cout << "touch multiViewer" << std::endl;                //std::cout << std::endl;            osg::ref_ptr<osgGA::GUIEventAdapter> osg_event(NULL);            foreach (const QTouchEvent::TouchPoint &touchPoint, touchPoints)            {                QPointF touchPos = touchPoint.pos();                ////test                //std::cout << "x:" << touchPos.x() << "\t" << "y:" << touchPos.y() << "\t";                if(touchPoint.state() == Qt::TouchPointPressed)                {                    if (!osg_event) {                        osg_event =  _gw->getEventQueue()->touchBegan( touchPoint.id(), osgGA::GUIEventAdapter::TOUCH_BEGAN, touchPos.x()  , touchPos.y());                    } else {                        osg_event->addTouchPoint( touchPoint.id(), osgGA::GUIEventAdapter::TOUCH_BEGAN, touchPos.x() , touchPos.y());                    }                }                else if(touchPoint.state() == Qt::TouchPointMoved)                {                    if (!osg_event) {                        osg_event =  _gw->getEventQueue()->touchMoved( touchPoint.id(), osgGA::GUIEventAdapter::TOUCH_MOVED, touchPos.x(), touchPos.y());                    } else {                        osg_event->addTouchPoint( touchPoint.id(), osgGA::GUIEventAdapter::TOUCH_MOVED, touchPos.x() , touchPos.y());                    }                }                else if(touchPoint.state() == Qt::TouchPointReleased)                {                    // No double tap detection with RAW TOUCH Events, sorry.                    if (!osg_event) {                        osg_event =  _gw->getEventQueue()->touchEnded( touchPoint.id(), osgGA::GUIEventAdapter::TOUCH_ENDED, touchPos.x(), touchPos.y(), 1);                    } else {                        osg_event->addTouchPoint( touchPoint.id(), osgGA::GUIEventAdapter::TOUCH_ENDED, touchPos.x() , touchPos.y());                    }                }            }            return true;        }    }    // perform regular event handling    return QGLWidget::event( event );}