moving projector

hi forum.

i am trying to wrap my mind around the best way on how to implement a moving projector.
i have the chance to work with a DL1 pan/tilt/zoom light fixture. http://www.highend.com/products/digital-lighting/dl-1.asp

i would like the projected image to always point north, have the same size and undo the keystone.

i could map a curve for the change in size, rotation and quad warp in accordance to the position of the DL1.
but i was hoping the is a way to model this in a virtual 3D space, i.e. build the room in openGL or something like that.

thanks for any advice,
stephan.

I think some mathematics to calculate the curves would be the easiest bet (if I correctly understand what you want to do). Also more easily adjustable than building a room in a 3D package or opengl, i think.