virtual architecture

HI !
i am working on a moving projection in a room. i build the room with the excat measures of the real room in openGL and moving around camera (lookat) is moving around projector in realroom. but how can i get rid of the perspective problems. actually i should map the whole scenery on a ball i guess, to not get problems in the corners !
but this seems little complicated, i am sure there is an easier way.
i had a look at jasch