--- ray/src/rt/ambcomp.c	2014/05/03 05:46:19	2.47
+++ ray/src/rt/ambcomp.c	2014/05/07 20:20:24	2.51
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: ambcomp.c,v 2.47 2014/05/03 05:46:19 greg Exp $";
+static const char	RCSid[] = "$Id: ambcomp.c,v 2.51 2014/05/07 20:20:24 greg Exp $";
 #endif
 /*
  * Routines to compute "ambient" values using Monte Carlo
@@ -23,8 +23,6 @@ static const char	RCSid[] = "$Id: ambcomp.c,v 2.47 201
 
 #ifdef NEWAMB
 
-/* #define HEM_MULT	4.0	/* hem multiplier (bigger => sparser cache) */
-
 extern void		SDsquare2disk(double ds[2], double seedx, double seedy);
 
 				/* vertex direction bit positions */
@@ -274,10 +272,10 @@ static void
 ambsupersamp(double acol[3], AMBHEMI *hp, int cnt)
 {
 	float	*earr = getambdiffs(hp);
-	double	e2sum = 0;
+	double	e2sum = 0.0;
 	AMBSAMP	*ap;
 	RAY	ar;
-	COLOR	asum;
+	double	asum[3];
 	float	*ep;
 	int	i, j, n;
 
@@ -290,7 +288,7 @@ ambsupersamp(double acol[3], AMBHEMI *hp, int cnt)
 	for (ap = hp->sa, i = 0; i < hp->ns; i++)
 	    for (j = 0; j < hp->ns; j++, ap++) {
 		int	nss = *ep/e2sum*cnt + frandom();
-		setcolor(asum, 0., 0., 0.);
+		asum[0] = asum[1] = asum[2] = 0.0;
 		for (n = 1; n <= nss; n++) {
 			if (!getambsamp(&ar, hp, i, j, n)) {
 				nss = n-1;
@@ -301,7 +299,7 @@ ambsupersamp(double acol[3], AMBHEMI *hp, int cnt)
 		if (nss) {		/* update returned ambient value */
 			const double	ssf = 1./(nss + 1);
 			for (n = 3; n--; )
-				acol[n] += ssf*colval(asum,n) +
+				acol[n] += ssf*asum[n] +
 						(ssf - 1.)*colval(ap->v,n);
 		}
 		e2sum -= *ep++;		/* update remainders */
@@ -720,38 +718,43 @@ ambdirgrad(AMBHEMI *hp, FVECT uv[2], float dg[2])
 }
 
 
-/* Make sure radii don't extend beyond what we see in our periphery */
-static void
-hem_radii(AMBHEMI *hp, FVECT uv[2], float ra[2])
+/* Compute potential light leak direction flags for cache value */
+static uint32
+ambcorral(AMBHEMI *hp, FVECT uv[2], const double r0, const double r1)
 {
-#ifdef HEM_MULT
-	double		udsum = 0, vdsum = 0;
-	double		uwsum = 0, vwsum = 0;
+	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));
+	double		avg_d = 0;
+	uint32		flgs = 0;
 	int		i, j;
-					/* circle around perimeter */
+					/* check distances above us */
+	for (i = hp->ns*3/4; i-- > hp->ns>>2; )
+	    for (j = hp->ns*3/4; j-- > hp->ns>>2; )
+		avg_d += ambsam(hp,i,j).d;
+	avg_d *= 4.0/(hp->ns*hp->ns);
+	if (avg_d >= max_d)		/* too close to corral? */
+		return(0);
+					/* else circle around perimeter */
 	for (i = 0; i < hp->ns; i++)
 	    for (j = 0; j < hp->ns; j += !i|(i==hp->ns-1) ? 1 : hp->ns-1) {
 		AMBSAMP	*ap = &ambsam(hp,i,j);
 		FVECT	vec;
-		double	us2, vs2;
+		double	u, v;
+		double	ang, a1;
+		int	abp;
+		if ((ap->d <= FTINY) | (ap->d >= max_d))
+			continue;	/* too far or too near */
 		VSUB(vec, ap->p, hp->rp->rop);
-		us2 = DOT(vec, uv[0]) * ap->d;
-		us2 *= us2;
-		vs2 = DOT(vec, uv[1]) * ap->d;
-		vs2 *= vs2;
-		udsum += us2 * ap->d;
-		uwsum += us2;
-		vdsum += vs2 * ap->d;
-		vwsum += vs2;
+		u = DOT(vec, uv[0]) * ap->d;
+		v = DOT(vec, uv[1]) * ap->d;
+		if ((r0*r0*u*u + r1*r1*v*v) * ap->d*ap->d <= 1.0)
+			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)
+			flgs |= 1L<<(int)(16/PI*(a1 + 2.*PI*(a1 < 0)));
 	    }
-	uwsum *= HEM_MULT;		/* adjust effective hem size */
-	vwsum *= HEM_MULT;
-					/* cap radii (recall d=1/rt) */
-	if (ra[0]*udsum > uwsum)
-		ra[0] = uwsum/udsum;
-	if (ra[1]*vdsum > vwsum)
-		ra[1] = vwsum/vdsum;
-#endif
+	return(flgs);
 }
 
 
@@ -763,7 +766,8 @@ doambient(				/* compute ambient component */
 	FVECT	uv[2],			/* returned (optional) */
 	float	ra[2],			/* returned (optional) */
 	float	pg[2],			/* returned (optional) */
-	float	dg[2]			/* returned (optional) */
+	float	dg[2],			/* returned (optional) */
+	uint32	*crlp			/* returned (optional) */
 )
 {
 	AMBHEMI	*hp = inithemi(rcol, r, wt);
@@ -783,6 +787,8 @@ doambient(				/* compute ambient component */
 		pg[0] = pg[1] = 0.0;
 	if (dg != NULL)
 		dg[0] = dg[1] = 0.0;
+	if (crlp != NULL)
+		*crlp = 0;
 					/* sample the hemisphere */
 	acol[0] = acol[1] = acol[2] = 0.0;
 	cnt = 0;
@@ -803,7 +809,7 @@ doambient(				/* compute ambient component */
 		return(-1);		/* return value w/o Hessian */
 	}
 	cnt = ambssamp*wt + 0.5;	/* perform super-sampling? */
-	if (cnt > 0)
+	if (cnt > 8)
 		ambsupersamp(acol, hp, cnt);
 	copycolor(rcol, acol);		/* final indirect irradiance/PI */
 	if ((ra == NULL) & (pg == NULL) & (dg == NULL)) {
@@ -836,10 +842,9 @@ doambient(				/* compute ambient component */
 				ra[0] = 1.0/d;
 			if (ra[1]*(d = fabs(pg[1])) > 1.0)
 				ra[1] = 1.0/d;
+			if (ra[0] > ra[1])
+				ra[0] = ra[1];
 		}
-		hem_radii(hp, uv, ra);
-		if (ra[0] > ra[1])
-			ra[0] = ra[1];
 		if (ra[0] < minarad) {
 			ra[0] = minarad;
 			if (ra[1] < minarad)
@@ -853,6 +858,8 @@ doambient(				/* compute ambient component */
 			if (ra[0] > maxarad)
 				ra[0] = maxarad;
 		}
+		if (crlp != NULL)	/* flag encroached directions */
+			*crlp = ambcorral(hp, uv, ra[0]*ambacc, ra[1]*ambacc);
 		if (pg != NULL) {	/* cap gradient if necessary */
 			d = pg[0]*pg[0]*ra[0]*ra[0] + pg[1]*pg[1]*ra[1]*ra[1];
 			if (d > 1.0) {