--- ray/src/rt/ambient.c	2014/04/16 20:32:00	2.73
+++ ray/src/rt/ambient.c	2014/05/09 16:40:01	2.87
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: ambient.c,v 2.73 2014/04/16 20:32:00 greg Exp $";
+static const char	RCSid[] = "$Id: ambient.c,v 2.87 2014/05/09 16:40:01 greg Exp $";
 #endif
 /*
  *  ambient.c - routines dealing with ambient (inter-reflected) component.
@@ -51,6 +51,7 @@ static int  nunflshed = 0;	/* number of unflushed ambi
 #define MAX_SORT_INTVL	(SORT_INTVL<<6)
 #endif
 
+
 static double  avsum = 0.;		/* computed ambient value sum (log) */
 static unsigned int  navsum = 0;	/* number of values in avsum */
 static unsigned int  nambvals = 0;	/* total number of indirect values */
@@ -108,17 +109,17 @@ setambres(				/* set ambient resolution */
 						/* set min & max radii */
 	if (ar <= 0) {
 		minarad = 0;
-		maxarad = thescene.cusize / 2.0;
+		maxarad = thescene.cusize*0.5;
 	} else {
 		minarad = thescene.cusize / ar;
-		maxarad = 64 * minarad;			/* heuristic */
-		if (maxarad > thescene.cusize / 2.0)
-			maxarad = thescene.cusize / 2.0;
+		maxarad = 64.0 * minarad;		/* heuristic */
+		if (maxarad > thescene.cusize*0.5)
+			maxarad = thescene.cusize*0.5;
 	}
 	if (minarad <= FTINY)
-		minarad = 10*FTINY;
+		minarad = 10.0*FTINY;
 	if (maxarad <= minarad)
-		maxarad = 64 * minarad;
+		maxarad = 64.0 * minarad;
 }
 
 
@@ -127,13 +128,14 @@ setambacc(				/* set ambient accuracy */
 	double  newa
 )
 {
-	double  ambdiff;
-
-	if (newa < 0.0)
-		newa = 0.0;
-	ambdiff = fabs(newa - ambacc);
-	if (ambdiff >= .01 && (ambacc = newa) > FTINY && nambvals > 0)
-		sortambvals(1);			/* rebuild tree */
+	static double	olda;		/* remember previous setting here */
+	
+	newa *= (newa > 0);
+	if (fabs(newa - olda) >= .05*(newa + olda)) {
+		ambacc = newa;
+		if (nambvals > 0)
+			sortambvals(1);		/* rebuild tree */
+	}
 }
 
 
@@ -265,6 +267,7 @@ ambnotify(			/* record new modifier */
 
 #define tfunc(lwr, x, upr)	(((x)-(lwr))/((upr)-(lwr)))
 
+static int	plugaleak(RAY *r, AMBVAL *ap, FVECT anorm, double ang);
 static double	sumambient(COLOR acol, RAY *r, FVECT rn, int al,
 				AMBTREE *at, FVECT c0, double s);
 static int	makeambient(COLOR acol, RAY *r, FVECT rn, int al);
@@ -296,7 +299,8 @@ multambient(		/* compute ambient component & multiply 
 	if (ambacc <= FTINY) {			/* no ambient storage */
 		copycolor(acol, aval);
 		rdepth++;
-		ok = doambient(acol, r, r->rweight, NULL, NULL, NULL, NULL);
+		ok = doambient(acol, r, r->rweight,
+				NULL, NULL, NULL, NULL, NULL);
 		rdepth--;
 		if (!ok)
 			goto dumbamb;
@@ -342,7 +346,52 @@ dumbamb:					/* return global value */
 }
 
 
-double
+/* Plug a potential leak where ambient cache value is occluded */
+static int
+plugaleak(RAY *r, AMBVAL *ap, FVECT anorm, double ang)
+{
+	const double	cost70sq = 0.1169778;	/* cos(70deg)^2 */
+	RAY		rtst;
+	FVECT		vdif;
+	double		normdot, ndotd, nadotd;
+	double		a, b, c, t[2];
+
+	ang += 2.*PI*(ang < 0);			/* check direction flags */
+	if ( !(ap->corral>>(int)(ang*(16./PI)) & 1) )
+		return(0);
+	/*
+	 * Generate test ray, targeting 20 degrees above sample point plane
+	 * along surface normal from cache position.  This should be high
+	 * enough to miss local geometry we don't really care about.
+	 */
+	VSUB(vdif, ap->pos, r->rop);
+	normdot = DOT(anorm, r->ron);
+	ndotd = DOT(vdif, r->ron);
+	nadotd = DOT(vdif, anorm);
+	a = normdot*normdot - cost70sq;
+	b = 2.0*(normdot*ndotd - nadotd*cost70sq);
+	c = ndotd*ndotd - DOT(vdif,vdif)*cost70sq;
+	if (quadratic(t, a, b, c) != 2)
+		return(1);			/* should rarely happen */
+	if (t[1] <= FTINY)
+		return(0);			/* should fail behind test */
+	rayorigin(&rtst, SHADOW, r, NULL);
+	VSUM(rtst.rdir, vdif, anorm, t[1]);	/* further dist. > plane */
+	rtst.rmax = normalize(rtst.rdir);	/* short ray test */
+	while (localhit(&rtst, &thescene)) {	/* check for occluder */
+		if (rtst.ro->omod != OVOID &&
+				(rtst.clipset == NULL ||
+					!inset(rtst.clipset, rtst.ro->omod)))
+			return(1);		/* plug light leak */
+		VCOPY(rtst.rorg, rtst.rop);	/* skip invisible surface */
+		rtst.rmax -= rtst.rot;
+		rayclear(&rtst);
+	}
+	return(0);				/* seems we're OK */
+}
+
+
+static double
 sumambient(		/* get interpolated ambient value */
 	COLOR  acol,
 	RAY  *r,
@@ -352,15 +401,40 @@ sumambient(		/* get interpolated ambient value */
 	FVECT  c0,
 	double	s
 )
-{					/* initial limit is ambacc radians */
-	const double	maxangle = (ambacc-PI/2.)*pow(r->rweight,0.13) + PI/2.;
+{			/* initial limit is 10 degrees plus ambacc radians */
+	const double	minangle = 10.0 * PI/180.;
+	double		maxangle = minangle + ambacc;
 	double		wsum = 0.0;
 	FVECT		ck0;
 	int		i, j;
 	AMBVAL		*av;
+
+	if (at->kid != NULL) {		/* sum children first */				
+		s *= 0.5;
+		for (i = 0; i < 8; i++) {
+			for (j = 0; j < 3; j++) {
+				ck0[j] = c0[j];
+				if (1<<j & i)
+					ck0[j] += s;
+				if (r->rop[j] < ck0[j] - OCTSCALE*s)
+					break;
+				if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
+					break;
+			}
+			if (j == 3)
+				wsum += sumambient(acol, r, rn, al,
+							at->kid+i, ck0, s);
+		}
+					/* good enough? */
+		if (wsum >= 0.05 && s > minarad*10.0)
+			return(wsum);
+	}
+					/* adjust maximum angle */
+	if (at->alist != NULL && (at->alist->lvl <= al) & (r->rweight < 0.6))
+		maxangle = (maxangle - PI/2.)*pow(r->rweight,0.13) + PI/2.;
 					/* sum this node */
 	for (av = at->alist; av != NULL; av = av->next) {
-		double	d, delta_r2, delta_t2;
+		double	u, v, d, delta_r2, delta_t2;
 		COLOR	ct;
 		FVECT	uvw[3];
 					/* record access */
@@ -369,10 +443,9 @@ sumambient(		/* get interpolated ambient value */
 		/*
 		 *  Ambient level test
 		 */
-		if (av->lvl > al)	/* list sorted, so this works */
+		if (av->lvl > al ||	/* list sorted, so this works */
+				(av->lvl == al) & (av->weight < 0.9*r->rweight))
 			break;
-		if (av->weight < 0.9*r->rweight)
-			continue;
 		/*
 		 *  Direction test using unperturbed normal
 		 */
@@ -384,24 +457,31 @@ sumambient(		/* get interpolated ambient value */
 		if (delta_r2 >= maxangle*maxangle)
 			continue;
 		/*
+		 *  Modified ray behind test
+		 */
+		VSUB(ck0, r->rop, av->pos);
+		d = DOT(ck0, uvw[2]);
+		if (d < -minarad*ambacc-.001)
+			continue;
+		d /= av->rad[0];
+		delta_t2 = d*d;
+		if (delta_t2 >= ambacc*ambacc)
+			continue;
+		/*
 		 *  Elliptical radii test based on Hessian
 		 */
 		decodedir(uvw[0], av->udir);
 		VCROSS(uvw[1], uvw[2], uvw[0]);
-		VSUB(ck0, av->pos, r->rop);
-		d = DOT(ck0, uvw[0]) / av->rad[0];
-		delta_t2 = d*d;
-		d = DOT(ck0, uvw[1]) / av->rad[1];
+		d = (u = DOT(ck0, uvw[0])) / av->rad[0];
 		delta_t2 += d*d;
+		d = (v = DOT(ck0, uvw[1])) / av->rad[1];
+		delta_t2 += d*d;
 		if (delta_t2 >= ambacc*ambacc)
 			continue;
 		/*
-		 *  Intersection behind test
+		 *  Test for potential light leak
 		 */
-		d = 0.0;
-		for (j = 0; j < 3; j++)
-			d += (r->rop[j] - av->pos[j])*(uvw[2][j] + r->ron[j]);
-		if (d*0.5 < -minarad*ambacc-.001)
+		if (av->corral && plugaleak(r, av, uvw[2], atan2a(v,u)))
 			continue;
 		/*
 		 *  Extrapolate value and compute final weight (hat function)
@@ -413,29 +493,11 @@ sumambient(		/* get interpolated ambient value */
 		addcolor(acol, ct);
 		wsum += d;
 	}
-	if (at->kid == NULL)
-		return(wsum);
-					/* sum children */
-	s *= 0.5;
-	for (i = 0; i < 8; i++) {
-		for (j = 0; j < 3; j++) {
-			ck0[j] = c0[j];
-			if (1<<j & i)
-				ck0[j] += s;
-			if (r->rop[j] < ck0[j] - OCTSCALE*s)
-				break;
-			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
-				break;
-		}
-		if (j == 3)
-			wsum += sumambient(acol, r, rn, al,
-						at->kid+i, ck0, s);
-	}
 	return(wsum);
 }
 
 
-int
+static int
 makeambient(		/* make a new ambient value for storage */
 	COLOR  acol,
 	RAY  *r,
@@ -454,9 +516,10 @@ makeambient(		/* make a new ambient value for storage 
 		amb.weight = 1.25*r->rweight;
 	setcolor(acol, AVGREFL, AVGREFL, AVGREFL);
 						/* compute ambient */
-	i = doambient(acol, r, amb.weight, uvw, amb.rad, amb.gpos, amb.gdir);
+	i = doambient(acol, r, amb.weight,
+			uvw, amb.rad, amb.gpos, amb.gdir, &amb.corral);
 	scalecolor(acol, 1./AVGREFL);		/* undo assumed reflectance */
-	if (i <= 0)				/* no Hessian => no storage */
+	if (i <= 0 || amb.rad[0] <= FTINY)	/* no Hessian or zero radius */
 		return(i);
 						/* store value */
 	VCOPY(amb.pos, r->rop);
@@ -474,7 +537,7 @@ makeambient(		/* make a new ambient value for storage 
 }
 
 
-void
+static void
 extambient(		/* extrapolate value at pv, nv */
 	COLOR  cr,
 	AMBVAL	 *ap,
@@ -544,7 +607,9 @@ avinsert(				/* insert ambient value in our tree */
 	}
 	avh.next = at->alist;		/* order by increasing level */
 	for (ap = &avh; ap->next != NULL; ap = ap->next)
-		if (ap->next->lvl >= av->lvl)
+		if ( ap->next->lvl > av->lvl ||
+				(ap->next->lvl == av->lvl) &
+				(ap->next->weight <= av->weight) )
 			break;
 	av->next = ap->next;
 	ap->next = (AMBVAL*)av;
@@ -657,10 +722,9 @@ sumambient(	/* get interpolated ambient value */
 		/*
 		 *  Ambient level test.
 		 */
-		if (av->lvl > al)	/* list sorted, so this works */
+		if (av->lvl > al ||	/* list sorted, so this works */
+				(av->lvl == al) & (av->weight < 0.9*r->rweight))
 			break;
-		if (av->weight < 0.9*r->rweight)
-			continue;
 		/*
 		 *  Ambient radius test.
 		 */
@@ -842,7 +906,9 @@ avinsert(				/* insert ambient value in our tree */
 	}
 	avh.next = at->alist;		/* order by increasing level */
 	for (ap = &avh; ap->next != NULL; ap = ap->next)
-		if (ap->next->lvl >= av->lvl)
+		if ( ap->next->lvl > av->lvl ||
+				(ap->next->lvl == av->lvl) &
+				(ap->next->weight <= av->weight) )
 			break;
 	av->next = ap->next;
 	ap->next = (AMBVAL*)av;