--- ray/src/rt/rayinit.cal	1991/11/25 09:51:57	2.2
+++ ray/src/rt/rayinit.cal	1993/03/18 12:36:03	2.6
@@ -9,6 +9,7 @@
 	Nx, Ny, Nz			- surface normal
 	Px, Py, Pz			- intersection point
 	T				- distance from start
+	Ts				- single ray (shadow) distance
 	Rdot				- ray dot product
 	S				- world scale
 	Tx, Ty, Tz			- world origin
@@ -95,11 +96,11 @@ noneg(v) = if(v,v,0);
 red(r,g,b) = if(r,r,0);
 green(r,g,b) = if(g,g,0);
 blue(r,g,b) = if(b,b,0);
-grey(r,g,b) = .3*r + .59*g + .11*b;
+grey(r,g,b) = noneg(.263*r + .655*g + .082*b);
 clip_r(r,g,b) = bound(0,r,1);
 clip_g(r,g,b) = bound(0,g,1);
 clip_b(r,g,b) = bound(0,b,1);
-clipgrey(r,g,b) = bound(0,grey(r,g,b),1);
+clipgrey(r,g,b) = min(grey(r,g,b),1);
 
 dot(v1,v2) : v1(1)*v2(1) + v1(2)*v2(2) + v1(3)*v2(3);
 cross(i,v1,v2) : select(i,	v1(2)*v2(3) - v1(3)*v2(2),
@@ -137,7 +138,7 @@ un2`private(t) : t - (2.515517+t*(.802853+t*.010328))/
 		(1+t*(1.432788+t*(.189269+t*.001308))) ;
 un1`private(p) : un2`private(sqrt(-2*log(p))) ;
 
-unif2norm(p) : if( .5-p, un1`private(p), -un1`private(1-p) ) ;
+unif2norm(p) : if( .5-p, -un1`private(p), un1`private(1-p) ) ;
 
 nrand(x) = unif2norm(rand(x));