--- ray/src/rt/func.c	1991/05/24 13:52:10	1.15
+++ ray/src/rt/func.c	1991/06/18 08:59:52	1.18
@@ -36,6 +36,10 @@ XF  *bx;
 	extern double  l_arg();
 	extern long  eclock;
 	static char  *initfile = "rayinit.cal";
+	static long  lastrno = -1;
+					/* check to see if already set */
+	if (m == fobj && r->rno == lastrno)
+		return(0);
 					/* initialize if first call */
 	if (initfile != NULL) {
 		loadfunc(initfile);
@@ -61,7 +65,9 @@ XF  *bx;
 			copystruct(&funcxf, &r->rox->b);
 	else
 		copystruct(&funcxf, bx);
+	lastrno = r->rno;
 	eclock++;		/* notify expression evaluator */
+	return(1);
 }
 
 
@@ -91,8 +97,7 @@ RAY  *r;
 		}
 		m->os = (char *)mxf;
 	}
-	setmap(m, r, mxf);
-	return;
+	return(setmap(m, r, mxf));
 memerr:
 	error(SYSTEM, "out of memory in setfunc");
 }
@@ -170,8 +175,10 @@ register int  n;
 		return(sum * funcxf.sca);
 
 	}
-	if (n == 10)			/* dot product */
-		return(fray->rod);
+	if (n == 10)			/* dot product (range [-1,1]) */
+		return(	fray->rod <= -1.0 ? -1.0 :
+			fray->rod >= 1.0 ? 1.0 :
+			fray->rod );
 
 	if (n == 11)			/* scale */
 		return(funcxf.sca);