--- ray/src/rt/glass.c	1990/10/15 20:39:32	1.5
+++ ray/src/rt/glass.c	1991/05/07 17:45:51	1.6
@@ -82,7 +82,9 @@ register RAY  *r;
 	}
 						/* transmitted ray */
 	if (rayorigin(&p, r, TRANS, bright(trans)) == 0) {
-		VCOPY(p.rdir, r->rdir);
+		for (i = 0; i < 3; i++)		/* perturb direction */
+			p.rdir[i] = r->rdir[i] - r->pert[i]/RINDEX;
+		normalize(p.rdir);
 		rayvalue(&p);
 		multcolor(p.rcol, r->pcol);	/* modify */
 		multcolor(p.rcol, trans);