问如何在QT中实现updateGL()的实时性

EN

class MyGLWidget: public QGLWidget
{
    // ...
private:
    QTimer timer;
}

QGLFormat desiredFormat()
{
    QGLFormat fmt;
    fmt.setSwapInterval(1);
    return fmt;
}

MyGLWidget::MyGLWidget() :
    QGLWidget(desiredFormat())
{
    // Configure the timer
    connect(&timer, SIGNAL(timeout()), this, SLOT(updateGL()));
    if(format().swapInterval() == -1)
    {
        // V_blank synchronization not available (tearing likely to happen)
        qDebug("Swap Buffers at v_blank not available: refresh at approx 60fps.");
        timer.setInterval(17);
    }
    else
    {
        // V_blank synchronization available
        timer.setInterval(0);
    }
    timer.start();
}