--- ray/src/rt/rayinit.cal	1998/10/19 15:45:30	2.12
+++ ray/src/rt/rayinit.cal	2013/03/25 16:10:00	2.15
@@ -1,5 +1,4 @@
-{ SCCSid "$SunId$ LBL" }
-
+{ RCSid $Id: rayinit.cal,v 2.15 2013/03/25 16:10:00 greg Exp $ }
 {
 	Initialization file for Radiance.
 
@@ -18,8 +17,12 @@
 	Kx, Ky, Kz			- world k unit vector
 	arg(n)				- real arguments, arg(0) is count
 
-	For brdf functions, the following are also available:
+	For mesh objects, the following are available:
 
+	Lu, Lv				- local (u,v) coordinates
+
+	For *func & *data materials, the following are also available:
+
  	NxP, NyP, NzP			- perturbed surface normal
  	RdotP				- perturbed ray dot product
  	CrP, CgP, CbP			- perturbed material color
@@ -38,7 +41,7 @@
 
 	sin(x), cos(x), tan(x),
 	asin(x), acos(x),
-	atan(x), atan2(y,x)		- standard trig functions
+	atan(x), atan2(y,x)		- standard trig functions (radians)
 
 	floor(x), ceil(x)		- g.l.b. & l.u.b.
 
@@ -88,6 +91,7 @@ FTINY : 1e-7;
 and(a,b) : if( a, b, a );
 or(a,b) : if( a, a, b );
 not(a) : if( a, -1, 1 );
+xor(a,b) : if( a, not(b), b );
 abs(x) : if( x, x, -x );
 sgn(x) : if( x, 1, if(-x, -1, 0) );
 sq(x) : x*x;