--- ray/src/rt/virtuals.c	2004/03/30 16:13:01	2.14
+++ ray/src/rt/virtuals.c	2010/10/28 09:38:46	2.18
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: virtuals.c,v 2.14 2004/03/30 16:13:01 schorsch Exp $";
+static const char	RCSid[] = "$Id: virtuals.c,v 2.18 2010/10/28 09:38:46 greg Exp $";
 #endif
 /*
  * Routines for simulating virtual light sources
@@ -309,7 +309,7 @@ vstestvis(		/* pretest source visibility */
 	FVECT  onorm;
 	FVECT  offsdir;
 	SRCINDEX  si;
-	double  or, d;
+	double  or, d, d1;
 	int  stestlim, ssn;
 	int  nhit, nok;
 	register int  i, n;
@@ -360,8 +360,7 @@ vstestvis(		/* pretest source visibility */
 				sr.rorg[i] = oc[i] + offsdir[i] + d*onorm[i];
 				sr.rdir[i] = -onorm[i];
 			}
-			sr.rmax = 0.0;
-			rayorigin(&sr, NULL, PRIMARY, 1.0);
+			rayorigin(&sr, PRIMARY, NULL, NULL);
 		} while (!(*ofun[o->otype].funp)(o, &sr));
 					/* check against source */
 		VCOPY(sr.rorg, sr.rop);	/* starting from intersection */
@@ -375,14 +374,21 @@ vstestvis(		/* pretest source visibility */
 		}
 		sr.revf = srcvalue;
 		rayvalue(&sr);			/* check sample validity */
-		if (bright(sr.rcol) <= FTINY)
+		if ((d = bright(sr.rcol)) <= FTINY)
 			continue;
 		nok++;			/* got sample; check obstructions */
 		rayclear(&sr);
 		sr.revf = raytrace;
 		rayvalue(&sr);
-		if (bright(sr.rcol) > FTINY)
+		if ((d1 = bright(sr.rcol)) > FTINY) {
+			if (d - d1 > FTINY) {
+#ifdef DEBUG
+				fprintf(stderr, "\tpartially shadowed\n");
+#endif
+				return(f);	/* intervening transmitter */
+			}
 			nhit++;
+		}
 		if (nhit > 0 && nhit < nok) {
 #ifdef DEBUG
 			fprintf(stderr, "\tpartially occluded\n");