--- ray/src/rt/raytrace.c	1991/05/02 11:58:20	1.16
+++ ray/src/rt/raytrace.c	1991/06/14 10:34:26	1.19
@@ -1,4 +1,4 @@
-/* Copyright (c) 1990 Regents of the University of California */
+/* Copyright (c) 1991 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -121,6 +121,7 @@ int  mod;
 					/* check for infinite loop */
 	if (depth++ >= MAXLOOP)
 		objerror(r->ro, USER, "possible modifier loop");
+	r->rt = r->rot;			/* set effective ray length */
 	for ( ; mod != OVOID; mod = m->omod) {
 		m = objptr(mod);
 		/****** unnecessary test since modifier() is always called
@@ -136,7 +137,7 @@ int  mod;
 				raytrans(r);
 				return;
 			}
-			if (m->otype != MAT_ILLUM)
+			if (!islight(m->otype))
 				m = &Lamb;
 		}
 		(*ofun[m->otype].funp)(m, r);	/* execute function */
@@ -322,6 +323,8 @@ register CUBE  *scene;
 		else if (r->rdir[i] < -FTINY)
 			sflags |= 0x10 << i;
 	}
+	if (sflags == 0)
+		error(CONSISTENCY, "zero ray direction in localhit");
 	t = 0.0;
 	if (!incube(scene, curpos)) {
 					/* find distance to entry */