--- ray/src/gen/surf.cal	1991/11/12 17:05:16	2.1
+++ ray/src/gen/surf.cal	2003/02/22 02:07:24	2.3
@@ -1,5 +1,4 @@
-{ SCCSid "$SunId$ LBL" }
-
+{ RCSid: $Id: surf.cal,v 2.3 2003/02/22 02:07:24 greg Exp $ }
 {
 	surf.cal - calculation of interpolated surface normal
 
@@ -10,9 +9,9 @@
 	A11 A12 A13	/
 }
 
+surf_u = select(arg(1)+1, Py, Pz, Px);
+surf_v = select(arg(1)+1, Pz, Px, Py);
+
 surf_dx = surf_u*surf_v*arg(2) + surf_u*arg(5) + surf_v*arg(8) + arg(11);
 surf_dy = surf_u*surf_v*arg(3) + surf_u*arg(6) + surf_v*arg(9) + arg(12);
 surf_dz = surf_u*surf_v*arg(4) + surf_u*arg(7) + surf_v*arg(10) + arg(13);
-
-surf_u = select(arg(1)+1, Py, Pz, Px);
-surf_v = select(arg(1)+1, Pz, Px, Py);