cmode lighting

["Ronald D. Anderson", IBD]

am using a 4D/70G system, and want to use a lighting model while in
color-map mode.  anyone out there have a (preferably simple) example?

i will be drawing a 3-d surface of many polygons, and will be rotating
this surface about at least two axes.  the lighting model can be at
infinite distance, or may be local.

send to e-mail "andy at ibd.brl.mil" (128.63.11.2) or to info-iris if the
example is fairly short and of general interest.

						thanks,
							andy