Smooth triangle with QGuiApplication::setAttribute(Qt::AA_UseSoftwareOpenGL, true)

[unclebenedict]

Im use QSGNode and QQuickItem for paint my item on qml scene. If user have weak graphics card, then item can not paint. In low graphics card im use QGuiApplication::setAttribute(Qt::AA_UseSoftwareOpenGL, true) for softfare opengl, all item paint, but not smooth. Example http://joxi.ru/wRmzQXSW65N6rO?d=1

Im try

QQuickView view;
QSurfaceFormat format = view.format();
format.setSamples(8);
view.setFormat(format);

but this not work on software opengl. How i can smoot triangle on software opengl ?