// Get the max fps from OpenGL ES2
    QGLFormat format = QGLFormat::defaultFormat();
    format.setSampleBuffers(false);    // disable AA.
    QGLWidget *glWidget = new QGLWidget(format);
    //### potentially faster, but causes junk to appear if top-level is Item, not Rectangle, or is transparent
    glWidget->setAutoFillBackground(false);