--- ray/src/rt/rayinit.cal	1991/10/09 11:36:45	1.3
+++ ray/src/rt/rayinit.cal	1991/11/25 09:51:57	2.2
@@ -66,7 +66,7 @@ noise3d(i,x,y,z) = select(i, noise3a(x,y,z), noise3b(x
 bound(a,x,b) : if(a-x, a, if(x-b, b, x));
 Acos(x) : acos(bound(-1,x,1));
 Asin(x) : asin(bound(-1,x,1));
-Exp(x) : if(-x-60, 0, exp(x));
+Exp(x) : if(-x-100, 0, exp(x));
 Sqrt(x) : if(x, sqrt(x), 0);
 
 			{ Useful constants }
@@ -91,10 +91,10 @@ linterp(t,p0,p1) : (1-t)*p0 + t*p1;
 
 noop(v) = v;
 clip(v) = bound(0,v,1);
-noneg(v) = max(0,v);
-red(r,g,b) = r;
-green(r,g,b) = g;
-blue(r,g,b) = b;
+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;
 clip_r(r,g,b) = bound(0,r,1);
 clip_g(r,g,b) = bound(0,g,1);
@@ -135,7 +135,7 @@ turbulencec(x,y,z,s) = if( s-1.01, 0,
 
 un2`private(t) : t - (2.515517+t*(.802853+t*.010328))/
 		(1+t*(1.432788+t*(.189269+t*.001308))) ;
-un1`private(p) : un2`private(sqrt(log(1/p/p))) ;
+un1`private(p) : un2`private(sqrt(-2*log(p))) ;
 
 unif2norm(p) : if( .5-p, un1`private(p), -un1`private(1-p) ) ;