--- ray/src/rt/rtrace.c	1989/06/07 21:00:59	1.4
+++ ray/src/rt/rtrace.c	1989/06/13 10:57:43	1.5
@@ -36,6 +36,7 @@ int  vresolu = 0;			/* vertical resolution */
 
 double  dstrsrc = 0.0;			/* square source distribution */
 double  shadthresh = .05;		/* shadow threshold */
+double  shadcert = .5;			/* shadow certainty */
 
 int  maxdepth = 6;			/* maximum recursion depth */
 double  minweight = 4e-3;		/* minimum ray weight */