--- ray/src/rt/virtuals.c	1991/07/30 18:23:45	1.19
+++ ray/src/rt/virtuals.c	1991/08/05 09:02:42	1.21
@@ -44,8 +44,10 @@ markvirtuals()			/* find and mark virtual sources */
 		if (!isvlight(objptr(o->omod)->otype))
 			continue;
 		if (sfun[o->otype].of == NULL ||
-				sfun[o->otype].of->getpleq == NULL)
-			objerror(o, USER, "illegal material");
+				sfun[o->otype].of->getpleq == NULL) {
+			objerror(o,WARNING,"secondary sources not supported");
+			continue;
+		}
 		if (nvobjects == 0)
 			vobject = (OBJECT *)malloc(sizeof(OBJECT));
 		else
@@ -199,7 +201,7 @@ MAT4  pm;
 		if (source[sn].sflags & SFLAT) {	/* behind source? */
 			multv3(nsnorm, source[sn].snorm, pm);
 			normalize(nsnorm);
-			if (!checkspot(&ourspot, nsnorm))
+			if (nsflags & SSPOT && !checkspot(&ourspot, nsnorm))
 				return(-1);
 		}
 	}
@@ -291,7 +293,11 @@ register int  sn;	/* target source number */
 	} else {
 		for (i = 0; i < 3; i++)
 			offsdir[i] = source[sn].sloc[i] - oc[i];
-		n = or2/DOT(offsdir,offsdir)*vspretest + .5;
+		d = DOT(offsdir,offsdir);
+		if (d <= FTINY)
+			n = 2.*PI * vspretest + .5;
+		else
+			n = 2.*PI * (1.-sqrt(1./(1.+or2/d)))*vspretest + .5;
 		infront = DOT(onorm, offsdir) > 0.;
 	}
 	if (n < MINSAMPLES) n = MINSAMPLES;