--- ray/src/rt/ambcomp.c	2014/08/21 10:33:49	2.65
+++ ray/src/rt/ambcomp.c	2014/10/23 18:19:14	2.68
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: ambcomp.c,v 2.65 2014/08/21 10:33:49 greg Exp $";
+static const char	RCSid[] = "$Id: ambcomp.c,v 2.68 2014/10/23 18:19:14 greg Exp $";
 #endif
 /*
  * Routines to compute "ambient" values using Monte Carlo
@@ -180,7 +180,6 @@ ambsupersamp(AMBHEMI *hp, int cnt)
 	float	*earr = getambdiffs(hp);
 	double	e2rem = 0;
 	AMBSAMP	*ap;
-	RAY	ar;
 	float	*ep;
 	int	i, j, n, nss;
 
@@ -219,7 +218,7 @@ samp_hemi(				/* sample indirect hemisphere */
 			wt > (d = 0.8*intens(rcol)*r->rweight/(ambdiv*minweight)))
 		wt = d;			/* avoid ray termination */
 	n = sqrt(ambdiv * wt) + 0.5;
-	i = 1 + 8*(ambacc > FTINY);	/* minimum number of samples */
+	i = 1 + 5*(ambacc > FTINY);	/* minimum number of samples */
 	if (n < i)
 		n = i;
 					/* allocate sampling array */
@@ -610,8 +609,8 @@ static uint32
 ambcorral(AMBHEMI *hp, FVECT uv[2], const double r0, const double r1)
 {
 	const double	max_d = 1.0/(minarad*ambacc + 0.001);
-	const double	ang_res = 0.5*PI/(hp->ns-1);
-	const double	ang_step = ang_res/((int)(16/PI*ang_res) + (1+FTINY));
+	const double	ang_res = 0.5*PI/hp->ns;
+	const double	ang_step = ang_res/((int)(16/PI*ang_res) + 1.01);
 	double		avg_d = 0;
 	uint32		flgs = 0;
 	FVECT		vec;
@@ -642,7 +641,7 @@ ambcorral(AMBHEMI *hp, FVECT uv[2], const double r0, c
 		if ((r0*r0*u*u + r1*r1*v*v) * ap->d*ap->d <= u*u + v*v)
 			continue;	/* occluder outside ellipse */
 		ang = atan2a(v, u);	/* else set direction flags */
-		for (a1 = ang-.5*ang_res; a1 <= ang+.5*ang_res; a1 += ang_step)
+		for (a1 = ang-ang_res; a1 <= ang+ang_res; a1 += ang_step)
 			flgs |= 1L<<(int)(16/PI*(a1 + 2.*PI*(a1 < 0)));
 	    }
 					/* add low-angle incident (< 20deg) */
@@ -695,7 +694,7 @@ doambient(				/* compute ambient component */
 		return(0);
 
 	if ((ra == NULL) & (pg == NULL) & (dg == NULL) ||
-			(hp->sampOK < 0) | (hp->ns < 9)) {
+			(hp->sampOK < 0) | (hp->ns < 6)) {
 		free(hp);		/* Hessian not requested/possible */
 		return(-1);		/* value-only return value */
 	}