--- ray/src/rt/raycalls.c	2005/04/19 01:15:06	2.11
+++ ray/src/rt/raycalls.c	2005/06/14 02:46:30	2.13
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: raycalls.c,v 2.11 2005/04/19 01:15:06 greg Exp $";
+static const char	RCSid[] = "$Id: raycalls.c,v 2.13 2005/06/14 02:46:30 greg Exp $";
 #endif
 /*
  *  raycalls.c - interface for running Radiance rendering as a library
@@ -118,6 +118,8 @@ void	(*addobjnotify[8])() = {ambnotify, NULL};
 
 int	do_irrad = 0;			/* compute irradiance? */
 
+int	rand_samp = 0;			/* pure Monte Carlo sampling? */
+
 double	dstrsrc = 0.0;			/* square source distribution */
 double	shadthresh = .03;		/* shadow threshold */
 double	shadcert = .75;			/* shadow certainty */
@@ -179,7 +181,7 @@ ray_trace(			/* trace a primary ray */
 )
 {
 	rayorigin(r, PRIMARY, NULL, NULL);
-	samplendx++;
+	samplendx = rand_samp ? random() : samplendx+1;
 	rayvalue(r);		/* assumes origin and direction are set */
 }