{ RCSid: $Id: rev.cal,v 2.3 2003/02/22 02:07:24 greg Exp $ } { Phong normal interpolation for surfaces of revolution about z. 11/7/88 (A1,A2) = (Mz,Bz) (A3,A4) = (Mr,Br) } rev_dr = rev_rad*A3 + A4; rev_rad = sqrt(Px*Px + Py*Py); rev_dx = rev_dr * Px/rev_rad; rev_dy = rev_dr * Py/rev_rad; rev_dz = Pz*A1 + A2;