Simple scene graph engine in OpenGL

Hi,

Continuing my GL hackathon, I've been scribbling together a scene graph
engine during the past few days using ruby-opengl, glut and ruby-imlib2
for texture loading.

It can handle around 200 (moving) objects per frame on my AthlonXP
1733MHz, and gulps a lot of cpu for that. Haven't tested the amount of
geometry and textures.

Now if I could stop playing with sinewave animations and implement some
useful things instead, like an input handler, a model importer and a
scene editor, life would be just perfect...

It's not really even at 0.1 yet but feel free to take a look:
http://dark.fhtr.org/repos/gl/

Here's a screenshot of iso/iso.rb:
http://dark.fhtr.org/trees2.jpg

- Ilmari

P.S. my 3D-fu is weak so there's more than likely a good amount of
crack-rock in the design.. feel free to offer comments and critique