--- ray/src/rt/ambcomp.c	1991/06/13 10:54:00	1.6
+++ ray/src/rt/ambcomp.c	1991/07/24 10:36:13	1.10
@@ -72,9 +72,9 @@ RAY  *r;
 	hlist[1] = dp->t;
 	hlist[2] = dp->p;
 	hlist[3] = 0;
-	zd = sqrt((dp->t+urand(ilhash(hlist,4)+dp->n))/h->nt);
+	zd = sqrt((dp->t+urand(urind(ilhash(hlist,4),dp->n)))/h->nt);
 	hlist[3] = 1;
-	phi = 2.0*PI * (dp->p+urand(ilhash(hlist,4)+dp->n))/h->np;
+	phi = 2.0*PI * (dp->p+urand(urind(ilhash(hlist,4),dp->n)))/h->np;
 	xd = cos(phi) * zd;
 	yd = sin(phi) * zd;
 	zd = sqrt(1.0 - zd*zd);
@@ -86,7 +86,7 @@ RAY  *r;
 	rayvalue(&ar);
 	ndims--;
 	addcolor(dp->v, ar.rcol);
-	if (ar.rt < FHUGE)
+	if (ar.rt > FTINY && ar.rt < FHUGE)
 		dp->r += 1.0/ar.rt;
 					/* (re)initialize error */
 	if (dp->n++) {
@@ -213,6 +213,14 @@ FVECT  pg, dg;
 	else if (arad < minarad)
 		arad = minarad;
 	arad /= sqrt(r->rweight);
+	if (pg != NULL) {		/* clip pos. gradient if too large */
+		d = 4.0*DOT(pg,pg)*arad*arad;
+		if (d > 1.0) {
+			d = 1.0/sqrt(d);
+			for (i = 0; i < 3; i++)
+				pg[i] *= d;
+		}
+	}
 	return(arad);
 oopsy:
 	if (div != NULL)
@@ -227,8 +235,8 @@ RAY  *r;
 {
 	register int  i;
 					/* set number of divisions */
-	hp->nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5;
-	hp->np = 2 * hp->nt;
+	hp->nt = sqrt(ambdiv * r->rweight / PI) + 0.5;
+	hp->np = PI * hp->nt;
 					/* make axes */
 	VCOPY(hp->uz, r->ron);
 	hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0;