--- ray/src/rt/ambcomp.c	2005/05/28 22:27:54	2.15
+++ ray/src/rt/ambcomp.c	2014/04/11 20:31:37	2.25
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: ambcomp.c,v 2.15 2005/05/28 22:27:54 greg Exp $";
+static const char	RCSid[] = "$Id: ambcomp.c,v 2.25 2014/04/11 20:31:37 greg Exp $";
 #endif
 /*
  * Routines to compute "ambient" values using Monte Carlo
@@ -10,35 +10,39 @@ static const char	RCSid[] = "$Id: ambcomp.c,v 2.15 200
 #include "copyright.h"
 
 #include  "ray.h"
-
 #include  "ambient.h"
-
 #include  "random.h"
 
+#ifdef NEWAMB
 
+#else /* ! NEWAMB */
+
+
 void
 inithemi(			/* initialize sampling hemisphere */
-	register AMBHEMI  *hp,
+	AMBHEMI  *hp,
+	COLOR ac,
 	RAY  *r,
-	COLOR ac, 
 	double  wt
 )
 {
-	register int  i;
+	double	d;
+	int  i;
 					/* set number of divisions */
-	hp->nt = sqrt(ambdiv * wt * (1./PI/AVGREFL)) + 0.5;
+	if (ambacc <= FTINY &&
+			wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight)))
+		wt = d;			/* avoid ray termination */
+	hp->nt = sqrt(ambdiv * wt / PI) + 0.5;
 	i = ambacc > FTINY ? 3 : 1;	/* minimum number of samples */
 	if (hp->nt < i)
 		hp->nt = i;
 	hp->np = PI * hp->nt + 0.5;
 					/* set number of super-samples */
 	hp->ns = ambssamp * wt + 0.5;
-					/* assign coefficients */
+					/* assign coefficient */
 	copycolor(hp->acoef, ac);
-	if (wt >= r->rweight)
-		hp->drc = 1.;
-	else
-		hp->drc = wt / r->rweight;
+	d = 1.0/(hp->nt*hp->np);
+	scalecolor(hp->acoef, d);
 					/* make axes */
 	VCOPY(hp->uz, r->ron);
 	hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0;
@@ -56,7 +60,7 @@ inithemi(			/* initialize sampling hemisphere */
 
 int
 divsample(				/* sample a division */
-	register AMBSAMP  *dp,
+	AMBSAMP  *dp,
 	AMBHEMI  *h,
 	RAY  *r
 )
@@ -67,14 +71,18 @@ divsample(				/* sample a division */
 	double  xd, yd, zd;
 	double  b2;
 	double  phi;
-	register int  i;
+	int  i;
 					/* ambient coefficient for weight */
-	setcolor(ar.rcoef, h->drc, h->drc, h->drc);
+	if (ambacc > FTINY)
+		setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL);
+	else
+		copycolor(ar.rcoef, h->acoef);
 	if (rayorigin(&ar, AMBIENT, r, ar.rcoef) < 0)
 		return(-1);
-	copycolor(ar.rcoef, h->acoef);	/* correct coefficient for trace */
-	b2 = 1.0/(h->nt*h->np + h->ns);	/* XXX not uniform if ns > 0 */
-	scalecolor(ar.rcoef, b2);
+	if (ambacc > FTINY) {
+		multcolor(ar.rcoef, h->acoef);
+		scalecolor(ar.rcoef, 1./AVGREFL);
+	}
 	hlist[0] = r->rno;
 	hlist[1] = dp->t;
 	hlist[2] = dp->p;
@@ -88,9 +96,11 @@ divsample(				/* sample a division */
 		ar.rdir[i] =	xd*h->ux[i] +
 				yd*h->uy[i] +
 				zd*h->uz[i];
+	checknorm(ar.rdir);
 	dimlist[ndims++] = dp->t*h->np + dp->p + 90171;
 	rayvalue(&ar);
 	ndims--;
+	multcolor(ar.rcol, ar.rcoef);	/* apply coefficient */
 	addcolor(dp->v, ar.rcol);
 					/* use rt to improve gradient calc */
 	if (ar.rt > FTINY && ar.rt < FHUGE)
@@ -131,7 +141,7 @@ ambnorm(				/* standard order */
 {
 	const AMBSAMP	*d1 = (const AMBSAMP *)p1;
 	const AMBSAMP	*d2 = (const AMBSAMP *)p2;
-	register int	c;
+	int	c;
 
 	if ( (c = d1->t - d2->t) )
 		return(c);
@@ -141,67 +151,86 @@ ambnorm(				/* standard order */
 
 double
 doambient(				/* compute ambient component */
-	COLOR  acol,
+	COLOR  rcol,
 	RAY  *r,
-	COLOR  ac,
 	double  wt,
 	FVECT  pg,
 	FVECT  dg
 )
 {
-	double  b, d;
+	double  b, d=0;
 	AMBHEMI  hemi;
 	AMBSAMP  *div;
 	AMBSAMP  dnew;
-	register AMBSAMP  *dp;
+	double  acol[3];
+	AMBSAMP  *dp;
 	double  arad;
-	int  ndivs;
-	register int  i, j;
-					/* initialize color */
-	setcolor(acol, 0.0, 0.0, 0.0);
+	int  divcnt;
+	int  i, j;
 					/* initialize hemisphere */
-	inithemi(&hemi, r, ac, wt);
-	ndivs = hemi.nt * hemi.np;
-	if (ndivs == 0)
+	inithemi(&hemi, rcol, r, wt);
+	divcnt = hemi.nt * hemi.np;
+					/* initialize */
+	if (pg != NULL)
+		pg[0] = pg[1] = pg[2] = 0.0;
+	if (dg != NULL)
+		dg[0] = dg[1] = dg[2] = 0.0;
+	setcolor(rcol, 0.0, 0.0, 0.0);
+	if (divcnt == 0)
 		return(0.0);
 					/* allocate super-samples */
 	if (hemi.ns > 0 || pg != NULL || dg != NULL) {
-		div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP));
+		div = (AMBSAMP *)malloc(divcnt*sizeof(AMBSAMP));
 		if (div == NULL)
 			error(SYSTEM, "out of memory in doambient");
 	} else
 		div = NULL;
 					/* sample the divisions */
 	arad = 0.0;
+	acol[0] = acol[1] = acol[2] = 0.0;
 	if ((dp = div) == NULL)
 		dp = &dnew;
+	divcnt = 0;
 	for (i = 0; i < hemi.nt; i++)
 		for (j = 0; j < hemi.np; j++) {
 			dp->t = i; dp->p = j;
 			setcolor(dp->v, 0.0, 0.0, 0.0);
 			dp->r = 0.0;
 			dp->n = 0;
-			if (divsample(dp, &hemi, r) < 0)
-				goto oopsy;
+			if (divsample(dp, &hemi, r) < 0) {
+				if (div != NULL)
+					dp++;
+				continue;
+			}
 			arad += dp->r;
+			divcnt++;
 			if (div != NULL)
 				dp++;
 			else
 				addcolor(acol, dp->v);
 		}
-	if (hemi.ns > 0 && arad > FTINY && ndivs/arad < minarad)
+	if (!divcnt) {
+		if (div != NULL)
+			free((void *)div);
+		return(0.0);		/* no samples taken */
+	}
+	if (divcnt < hemi.nt*hemi.np) {
+		pg = dg = NULL;		/* incomplete sampling */
+		hemi.ns = 0;
+	} else if (arad > FTINY && divcnt/arad < minarad) {
 		hemi.ns = 0;		/* close enough */
-	else if (hemi.ns > 0) {		/* else perform super-sampling */
+	} else if (hemi.ns > 0) {	/* else perform super-sampling? */
 		comperrs(div, &hemi);			/* compute errors */
-		qsort(div, ndivs, sizeof(AMBSAMP), ambcmp);	/* sort divs */
+		qsort(div, divcnt, sizeof(AMBSAMP), ambcmp);	/* sort divs */
 						/* super-sample */
 		for (i = hemi.ns; i > 0; i--) {
 			dnew = *div;
-			if (divsample(&dnew, &hemi, r) < 0)
-				goto oopsy;
-							/* reinsert */
-			dp = div;
-			j = ndivs < i ? ndivs : i;
+			if (divsample(&dnew, &hemi, r) < 0) {
+				dp++;
+				continue;
+			}
+			dp = div;		/* reinsert */
+			j = divcnt < i ? divcnt : i;
 			while (--j > 0 && dnew.k < dp[1].k) {
 				*dp = *(dp+1);
 				dp++;
@@ -209,12 +238,12 @@ doambient(				/* compute ambient component */
 			*dp = dnew;
 		}
 		if (pg != NULL || dg != NULL)	/* restore order */
-			qsort(div, ndivs, sizeof(AMBSAMP), ambnorm);
+			qsort(div, divcnt, sizeof(AMBSAMP), ambnorm);
 	}
 					/* compute returned values */
 	if (div != NULL) {
-		arad = 0.0;
-		for (i = ndivs, dp = div; i-- > 0; dp++) {
+		arad = 0.0;		/* note: divcnt may be < nt*np */
+		for (i = hemi.nt*hemi.np, dp = div; i-- > 0; dp++) {
 			arad += dp->r;
 			if (dp->n > 1) {
 				b = 1.0/dp->n;
@@ -226,7 +255,7 @@ doambient(				/* compute ambient component */
 		}
 		b = bright(acol);
 		if (b > FTINY) {
-			b = ndivs/b;
+			b = 1.0/b;	/* compute & normalize gradient(s) */
 			if (pg != NULL) {
 				posgradient(pg, div, &hemi);
 				for (i = 0; i < 3; i++)
@@ -237,22 +266,14 @@ doambient(				/* compute ambient component */
 				for (i = 0; i < 3; i++)
 					dg[i] *= b;
 			}
-		} else {
-			if (pg != NULL)
-				for (i = 0; i < 3; i++)
-					pg[i] = 0.0;
-			if (dg != NULL)
-				for (i = 0; i < 3; i++)
-					dg[i] = 0.0;
 		}
 		free((void *)div);
 	}
-	b = 1.0/ndivs;
-	scalecolor(acol, b);
+	copycolor(rcol, acol);
 	if (arad <= FTINY)
 		arad = maxarad;
 	else
-		arad = (ndivs+hemi.ns)/arad;
+		arad = (divcnt+hemi.ns)/arad;
 	if (pg != NULL) {		/* reduce radius if gradient large */
 		d = DOT(pg,pg);
 		if (d*arad*arad > 1.0)
@@ -269,22 +290,18 @@ doambient(				/* compute ambient component */
 	if ((arad /= sqrt(wt)) > maxarad)
 		arad = maxarad;
 	return(arad);
-oopsy:
-	if (div != NULL)
-		free((void *)div);
-	return(0.0);
 }
 
 
 void
 comperrs(			/* compute initial error estimates */
 	AMBSAMP  *da,	/* assumes standard ordering */
-	register AMBHEMI  *hp
+	AMBHEMI  *hp
 )
 {
 	double  b, b2;
 	int  i, j;
-	register AMBSAMP  *dp;
+	AMBSAMP  *dp;
 				/* sum differences from neighbors */
 	dp = da;
 	for (i = 0; i < hp->nt; i++)
@@ -332,14 +349,14 @@ void
 posgradient(					/* compute position gradient */
 	FVECT  gv,
 	AMBSAMP  *da,			/* assumes standard ordering */
-	register AMBHEMI  *hp
+	AMBHEMI  *hp
 )
 {
-	register int  i, j;
+	int  i, j;
 	double  nextsine, lastsine, b, d;
 	double  mag0, mag1;
 	double  phi, cosp, sinp, xd, yd;
-	register AMBSAMP  *dp;
+	AMBSAMP  *dp;
 
 	xd = yd = 0.0;
 	for (j = 0; j < hp->np; j++) {
@@ -382,7 +399,7 @@ posgradient(					/* compute position gradient */
 		yd += mag0*sinp + mag1*cosp;
 	}
 	for (i = 0; i < 3; i++)
-		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/PI;
+		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*(hp->nt*hp->np)/PI;
 }
 
 
@@ -390,13 +407,13 @@ void
 dirgradient(					/* compute direction gradient */
 	FVECT  gv,
 	AMBSAMP  *da,			/* assumes standard ordering */
-	register AMBHEMI  *hp
+	AMBHEMI  *hp
 )
 {
-	register int  i, j;
+	int  i, j;
 	double  mag;
 	double  phi, xd, yd;
-	register AMBSAMP  *dp;
+	AMBSAMP  *dp;
 
 	xd = yd = 0.0;
 	for (j = 0; j < hp->np; j++) {
@@ -417,5 +434,7 @@ dirgradient(					/* compute direction gradient */
 		yd += mag * tsin(phi);
 	}
 	for (i = 0; i < 3; i++)
-		gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np);
+		gv[i] = xd*hp->ux[i] + yd*hp->uy[i];
 }
+
+#endif	/* ! NEWAMB */