--- ray/src/rt/rcontrib.c	2012/11/15 19:41:03	2.18
+++ ray/src/rt/rcontrib.c	2014/07/19 00:07:03	2.19
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: rcontrib.c,v 2.18 2012/11/15 19:41:03 greg Exp $";
+static const char RCSid[] = "$Id: rcontrib.c,v 2.19 2014/07/19 00:07:03 greg Exp $";
 #endif
 /*
  * Accumulate ray contributions for a set of materials
@@ -216,6 +216,7 @@ static void
 trace_contrib(RAY *r)
 {
 	MODCONT	*mp;
+	double	bval;
 	int	bn;
 	RREAL	contr[3];
 
@@ -231,8 +232,9 @@ trace_contrib(RAY *r)
 		return;
 
 	worldfunc(RCCONTEXT, r);		/* else get bin number */
-	bn = (int)(evalue(mp->binv) + .5);
-	if ((bn < 0) | (bn >= mp->nbins)) {
+	if ((bval = evalue(mp->binv)) <= -.5)
+		return;				/* silently ignore */
+	if ((bn = (int)(bval + .5)) >= mp->nbins) {
 		error(WARNING, "bad bin number (ignored)");
 		return;
 	}