--- ray/src/rt/ambcomp.c	1992/10/02 16:14:38	2.4
+++ ray/src/rt/ambcomp.c	1998/12/16 18:14:57	2.8
@@ -1,7 +1,7 @@
-/* Copyright (c) 1991 Regents of the University of California */
+/* Copyright (c) 1998 Silicon Graphics, Inc. */
 
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static char SCCSid[] = "$SunId$ SGI";
 #endif
 
 /*
@@ -73,8 +73,8 @@ RAY  *r;
 	multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n));
 	zd = sqrt((dp->t + spt[0])/h->nt);
 	phi = 2.0*PI * (dp->p + spt[1])/h->np;
-	xd = cos(phi) * zd;
-	yd = sin(phi) * zd;
+	xd = tcos(phi) * zd;
+	yd = tsin(phi) * zd;
 	zd = sqrt(1.0 - zd*zd);
 	for (i = 0; i < 3; i++)
 		ar.rdir[i] =	xd*h->ux[i] +
@@ -84,8 +84,9 @@ RAY  *r;
 	rayvalue(&ar);
 	ndims--;
 	addcolor(dp->v, ar.rcol);
-	if (ar.rt > FTINY && ar.rt < FHUGE)
-		dp->r += 1.0/ar.rt;
+					/* be conservative and use rot */
+	if (ar.rot > FTINY && ar.rot < FHUGE)
+		dp->r += 1.0/ar.rot;
 					/* (re)initialize error */
 	if (dp->n++) {
 		b2 = bright(dp->v)/dp->n - bright(ar.rcol);
@@ -139,14 +140,15 @@ FVECT  pg, dg;
 			dp->n = 0;
 			if (divsample(dp, &hemi, r) < 0)
 				goto oopsy;
+			arad += dp->r;
 			if (div != NULL)
 				dp++;
-			else {
+			else
 				addcolor(acol, dp->v);
-				arad += dp->r;
-			}
 		}
-	if (ns > 0) {			/* perform super-sampling */
+	if (ns > 0 && arad > FTINY && ndivs/arad < minarad)
+		ns = 0;			/* close enough */
+	else if (ns > 0) {		/* else perform super-sampling */
 		comperrs(div, &hemi);			/* compute errors */
 		qsort(div, ndivs, sizeof(AMBSAMP), ambcmp);	/* sort divs */
 						/* super-sample */
@@ -168,6 +170,7 @@ FVECT  pg, dg;
 	}
 					/* compute returned values */
 	if (div != NULL) {
+		arad = 0.0;
 		for (i = ndivs, dp = div; i-- > 0; dp++) {
 			arad += dp->r;
 			if (dp->n > 1) {
@@ -355,7 +358,7 @@ register AMBHEMI  *hp;
 		}
 		mag0 *= 2.0*PI / hp->np;
 		phi = 2.0*PI * (double)j/hp->np;
-		cosp = cos(phi); sinp = sin(phi);
+		cosp = tcos(phi); sinp = tsin(phi);
 		xd += mag0*cosp - mag1*sinp;
 		yd += mag0*sinp + mag1*cosp;
 	}
@@ -389,8 +392,8 @@ register AMBHEMI  *hp;
 			dp += hp->np;
 		}
 		phi = 2.0*PI * (j+.5)/hp->np + PI/2.0;
-		xd += mag * cos(phi);
-		yd += mag * sin(phi);
+		xd += mag * tcos(phi);
+		yd += mag * tsin(phi);
 	}
 	for (i = 0; i < 3; i++)
 		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np);