--- ray/src/gen/skybright.cal	1992/06/17 11:15:32	2.3
+++ ray/src/gen/skybright.cal	1993/06/07 13:08:58	2.4
@@ -8,7 +8,7 @@
      Additional arguments required for calculation of skybright:
 
 	A1			- boolean, positive for cloudy sky
-				  (A1>=2 for cloudy uniform sky)
+				  (A1>=2 for uniform sky)
 	A2			- zenith brightness
 	A3			- ground plane brightness
 	A4			- normalization factor based on sun direction
@@ -22,9 +22,7 @@ wmean(a, x, b, y) = (a*x + b*y) / (a + b);
 
 cloudysky = A2 * if(A1-1.5, 1, (1 + 2*Dz)/3);
 
-sunnysky = A2 * (.91 + 10*exp(-3*gamma) + .45*cosgamma*cosgamma)
+sunnysky = A2 * (.91 + 10*exp(-3*Acos(cosgamma)) + .45*cosgamma*cosgamma)
 	      *  if( Dz - .01, 1.0 - exp(-.32/Dz), 1.0) / A4;
-
-gamma = Acos(cosgamma);
 
 cosgamma = Dx*A5 + Dy*A6 + Dz*A7;