drawing a triangle a circle or just a polygon

I have recently started to play with SDL::*. I went throught the tutorials
coming with the distro and that could be also found on http://sdl.perl.org/
but I think I have not found a way yet how to draw a circle or a triangle or
just any polygon, well excetp a rectangular.

Also I could not so far use SDL::OpenGL. Can you point me to a
working example?

The little search I did did not bring me closer,
I'd appreciate any pointers.

  Gabor