QCometen3 is a port of the popular KCometen3 screensaver for KDE, to Qt4.
Unfortunately, QCometen3 doesn't come with a setup dialog. However, if you used KCometen3 before, QCometen3 can read its config files. If not, you'll have to create a config file in ~/.config/QCometen3.conf manually. (See default values at the bottom of the README.)