--- ray/src/util/glaresrc.c	1991/03/19 09:10:58	1.4
+++ ray/src/util/glaresrc.c	2003/02/22 02:07:30	2.4
@@ -1,14 +1,12 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: glaresrc.c,v 2.4 2003/02/22 02:07:30 greg Exp $";
 #endif
-
 /*
  * Gather samples and compute glare sources.
  */
 
 #include "glare.h"
+#include "linregr.h"
 
 #define vcont(vd,vu)	((vu)-(vd)<=SEPS)
 #define hcont(s1,s2)	((s1)->r-(s2)->l>=-SEPS&&(s2)->r-(s1)->l>=-SEPS)
@@ -16,9 +14,7 @@ static char SCCSid[] = "$SunId$ LBL";
 struct source	*curlist = NULL;	/* current source list */
 struct source	*donelist = NULL;	/* finished sources */
 
-double	threshold;			/* glare threshold */
 
-
 struct srcspan *
 newspan(l, r, v, sb)		/* allocate a new source span */
 int	l, r, v;
@@ -50,6 +46,14 @@ analyze()			/* analyze our scene */
 	if (spanbr == NULL)
 		memerr("view span brightness buffer");
 	for (v = vsize; v >= -vsize; v--) {
+		close_sources(v);
+#ifndef DEBUG
+		if (verbose) {
+			fprintf(stderr, "%s: analyzing... %3ld%%\r",
+				progname, 100L*(vsize-v)/(2*vsize));
+			fflush(stderr);
+		}
+#endif
 		getviewspan(v, spanbr);
 		left = hsize + 1;
 		for (h = -hsize; h <= hsize; h++) {
@@ -68,59 +72,60 @@ analyze()			/* analyze our scene */
 					addsrcspan(newspan(left,h,v,spanbr));
 					left = hsize + 1;
 				}
-				addindirect(h, spanbr[h+hsize]);
+				addindirect(h, v, spanbr[h+hsize]);
 			}
 		}
 		if (left < h)
 			addsrcspan(newspan(left,h,v,spanbr));
-		close_sources(v);
 	}
+	free((void *)spanbr);
 	close_allsrcs();
-	free((char *)spanbr);
 }
 
 
-addindirect(h, br)		/* add brightness to indirect illuminances */
-int	h;
+addindirect(h, v, br)		/* add brightness to indirect illuminances */
+int	h, v;
 double	br;
 {
 	double	tanb, d;
+	int	hl;
 	register int	i;
 
-	if (h <= -hlim) {			/* left region */
-		d = (double)(h+hlim)/sampdens;
-		if (d <= -1.0+FTINY)
+	hl = hlim(v);
+	if (h <= -hl) {			/* left region */
+		d = (double)(-h-hl)/sampdens;
+		if (d >= 1.0-FTINY)
 			return;
 		tanb = d/sqrt(1.0-d*d);
 		for (i = 0; i < nglardirs; i++) {
 			d = indirect[i].lcos - tanb*indirect[i].lsin;
 			if (d > 0.0) {
 				indirect[i].sum += d * br;
-				indirect[i].n++;
+				indirect[i].n += d;
 			}
 		}
 		return;
 	}
-	if (h >= hlim) {			/* right region */
-		d = (double)(h-hlim)/sampdens;
-		if (d >= 1.0-FTINY)
+	if (h >= hl) {			/* right region */
+		d = (double)(-h+hl)/sampdens;
+		if (d <= -1.0+FTINY)
 			return;
 		tanb = d/sqrt(1.0-d*d);
 		for (i = 0; i < nglardirs; i++) {
 			d = indirect[i].rcos - tanb*indirect[i].rsin;
 			if (d > 0.0) {
 				indirect[i].sum += d * br;
-				indirect[i].n++;
+				indirect[i].n += d;
 			}
 		}
 		return;
 	}
 					/* central region */
 	for (i = 0; i < nglardirs; i++) {
-		d = cos(h_theta(h) - indirect[i].theta);
+		d = cos(h_theta(h,v) - indirect[i].theta);
 		if (d > 0.0) {
 			indirect[i].sum += d * br;
-			indirect[i].n++;
+			indirect[i].n += d;
 		}
 	}
 }
@@ -137,13 +142,14 @@ comp_thresh()			/* compute glare threshold */
 				progname);
 	brsum = 0.0;
 	nsamps = 0;
-	for (v = vsize; v >= -vsize; v -= TSAMPSTEP)
+	for (v = vsize; v >= -vsize; v -= TSAMPSTEP) {
 		for (h = -hsize; h <= hsize; h += TSAMPSTEP) {
 			if ((br = getviewpix(h, v)) < 0.0)
 				continue;
 			brsum += br;
 			nsamps++;
 		}
+	}
 	if (nsamps == 0) {
 		fprintf(stderr, "%s: no viewable scene!\n", progname);
 		exit(1);
@@ -154,7 +160,9 @@ comp_thresh()			/* compute glare threshold */
 		exit(1);
 	}
 	if (verbose) {
+#ifdef DEBUG
 		pict_stats();
+#endif
 		fprintf(stderr,
 			"%s: threshold set to %f cd/m2 from %d samples\n",
 				progname, threshold, nsamps);
@@ -167,7 +175,6 @@ struct srcspan	*nss;
 {
 	struct source	*last, *cs, *this;
 	register struct srcspan	*ss;
-	register int	res;
 
 	cs = NULL;
 	for (this = curlist; this != NULL; this = this->next) {
@@ -178,9 +185,9 @@ struct srcspan	*nss;
 				if (cs == NULL)
 					cs = this;
 				else {
-					mergesource(cs, this);
 					last->next = this->next;
-					free((char *)this);
+					mergesource(cs, this);
+					this = last;
 				}
 				break;
 			}
@@ -191,6 +198,7 @@ struct srcspan	*nss;
 		cs = (struct source *)malloc(sizeof(struct source));
 		if (cs == NULL)
 			memerr("source records");
+		cs->dom = 0.0;
 		cs->first = NULL;
 		cs->next = curlist;
 		curlist = cs;
@@ -221,7 +229,16 @@ struct source	*sp, *ap;
 	if (prev->next == NULL)
 		prev->next = alp;
 	sp->first = head.next;
-	ap->first = NULL;
+	if (ap->dom > 0.0 && sp->dom > 0.0) {		/* sources are done */
+		sp->dir[0] *= sp->dom;
+		sp->dir[1] *= sp->dom;
+		sp->dir[2] *= sp->dom;
+		fvsum(sp->dir, sp->dir, ap->dir, ap->dom);
+		normalize(sp->dir);
+		sp->brt = (sp->brt*sp->dom + ap->brt*ap->dom)
+				/ (sp->dom + ap->dom);
+	}
+	free((void *)ap);
 }
 
 
@@ -246,51 +263,209 @@ int	v;
 
 close_allsrcs()			/* done with everything */
 {
-	register struct source	*this, *nsrc;
+	register struct source	*this, *next;
 
-	for (this = curlist; this != NULL; this = nsrc) {
-		nsrc = this->next;
+	this = curlist;
+	while (this != NULL) {
+		next = this->next;
 		donesource(this);
+		this = next;
 	}
 	curlist = NULL;
 }
 
 
+struct srcspan *
+splitspan(sso, h, v, m)		/* divide source span at point */
+register struct srcspan	*sso;
+double	h, v, m;
+{
+	register struct srcspan	*ssn;
+	double	d;
+	int	hs;
+
+	d = h - m*(sso->v - v);
+	hs = d < 0. ? d-.5 : d+.5;
+	if (sso->l >= hs)
+		return(NULL);
+	if (sso->r <= hs)
+		return(sso);
+				/* need to split it */
+	ssn = (struct srcspan *)malloc(sizeof(struct srcspan));
+	if (ssn == NULL)
+		memerr("source spans in splitspan");
+	ssn->brsum = (double)(hs - sso->l)/(sso->r - sso->l) * sso->brsum;
+	sso->brsum -= ssn->brsum;
+	ssn->v = sso->v;
+	ssn->l = sso->l;
+	ssn->r = sso->l = hs;
+	return(ssn);
+}
+
+
+struct source *
+splitsource(so)			/* divide source in two if it's big and long */
+struct source	*so;
+{
+	LRSUM	lr;
+	LRLIN	fit;
+	register struct srcspan	*ss, *ssn;
+	struct srcspan	*ssl, *ssnl, head;
+	int	h;
+	double	mh, mv;
+	struct source	*sn;
+
+	lrclear(&lr);
+	for (ss = so->first; ss != NULL; ss = ss->next)
+		for (h = ss->l; h < ss->r; h++)
+			lrpoint(h, ss->v, &lr);
+	if ((double)lr.n/(sampdens*sampdens) < SABIG)
+		return(NULL);			/* too small */
+	if (lrfit(&fit, &lr) < 0)
+		return(NULL);			/* can't fit a line */
+	if (fit.correlation < LCORR && fit.correlation > -LCORR)
+		return(NULL);
+	if (verbose)
+		fprintf(stderr, "%s: splitting large source\n", progname);
+	mh = lrxavg(&lr);
+	mv = lryavg(&lr);
+	sn = (struct source *)malloc(sizeof(struct source));
+	if (sn == NULL)
+		memerr("source records in splitsource");
+	sn->dom = 0.0;
+	sn->first = NULL;
+	ssnl = NULL;
+	head.next = so->first;
+	ssl = &head;
+	for (ss = so->first; ss != NULL; ssl = ss, ss = ss->next)
+		if ((ssn = splitspan(ss, mh, mv, fit.slope)) != NULL) {
+			if (ssn == ss) {	/* remove from old */
+				ssl->next = ss->next;
+				ss = ssl;
+			}
+			if (ssnl == NULL)	/* add to new */
+				sn->first = ssn;
+			else
+				ssnl->next = ssn;
+			ssn->next = NULL;
+			ssnl = ssn;
+		}
+	so->first = head.next;
+	return(sn);
+}
+
+
 donesource(sp)			/* finished with this source */
 register struct source	*sp;
 {
-	FVECT	dthis, dright;
+	struct source	*newsrc;
 	register struct srcspan	*ss;
 	int	h, n;
-	double	d;
+	double	hsum, vsum, d;
 
+	while ((newsrc = splitsource(sp)) != NULL)	/* split it? */
+		donesource(newsrc);
 	sp->dom = 0.0;
-	sp->dir[0] = sp->dir[1] = sp->dir[1] = 0.0;
+	hsum = vsum = 0.0;
 	sp->brt = 0.0;
 	n = 0;
 	for (ss = sp->first; ss != NULL; ss = ss->next) {
 		sp->brt += ss->brsum;
 		n += ss->r - ss->l;
-		compdir(dright, ss->r, ss->v);
-		for (h = ss->r-1; h >= ss->l; h--) {
-			compdir(dthis, h, ss->v);
-			d = dist2(dthis, dright);
-			fvsum(sp->dir, sp->dir, dthis, d);
+		for (h = ss->l; h < ss->r; h++) {
+			d = pixsize(h, ss->v);
+			hsum += d*h;
+			vsum += d*ss->v;
 			sp->dom += d;
-			VCOPY(dright, dthis);
 		}
-		free((char *)ss);
 	}
-	sp->first = NULL;
+	freespans(sp);
+	if (sp->dom <= FTINY) {		/* must be right at edge of image */
+		free((void *)sp);
+		return;
+	}
 	sp->brt /= (double)n;
-	sp->dir[0] /= sp->dom;
-	sp->dir[1] /= sp->dom;
-	sp->dir[2] /= sp->dom;
+	compdir(sp->dir, (int)(hsum/sp->dom), (int)(vsum/sp->dom));
 	sp->next = donelist;
 	donelist = sp;
 	if (verbose)
 		fprintf(stderr,
-	"%s: found source at (%f,%f,%f), dw %f, br %f\n",
+	"%s: source at [%.3f,%.3f,%.3f], dw %.5f, br %.1f (%d samps)\n",
 			progname, sp->dir[0], sp->dir[1], sp->dir[2], 
-			sp->dom, sp->brt);
+			sp->dom, sp->brt, n);
+}
+
+
+struct source *
+findbuddy(s, l)			/* find close enough source to s in l*/
+register struct source	*s, *l;
+{
+	struct source	*bestbuddy = NULL;
+	double	d, r, mindist = MAXBUDDY;
+
+	r = sqrt(s->dom/PI);
+	for ( ; l != NULL; l = l->next) {
+		d = sqrt(dist2(l->dir, s->dir)) - sqrt(l->dom/PI) - r;
+		if (d < mindist) {
+			bestbuddy = l;
+			mindist = d;
+		}
+	}
+	return(bestbuddy);
+}
+
+
+absorb_specks()			/* eliminate too-small sources */
+{
+	struct source	head, *buddy;
+	register struct source	*last, *this;
+
+	if (verbose)
+		fprintf(stderr, "%s: absorbing small sources...\n", progname);
+	head.next = donelist;
+	last = &head;
+	for (this = head.next; this != NULL; this = this->next)
+		if (TOOSMALL(this)) {
+			last->next = this->next;
+			buddy = findbuddy(this, head.next);
+			if (buddy != NULL)
+				mergesource(buddy, this);
+			else
+				absorb(this);
+			this = last;
+		} else
+			last = this;
+	donelist = head.next;
+}
+
+
+absorb(s)			/* absorb a source into indirect */
+register struct source	*s;
+{
+	FVECT	dir;
+	double	d;
+	register int	i;
+
+	for (i = 0; i < nglardirs; i++) {
+		spinvector(dir, ourview.vdir, ourview.vup, indirect[i].theta);
+		d = DOT(dir,s->dir)*s->dom*(sampdens*sampdens);
+		if (d <= 0.0)
+			continue;
+		indirect[i].sum += d * s->brt;
+		indirect[i].n += d;
+	}
+	freespans(s);
+	free((void *)s);
+}
+
+
+freespans(sp)			/* free spans associated with source */
+struct source	*sp;
+{
+	register struct srcspan	*ss;
+
+	while ((ss = sp->first) != NULL) {
+		sp->first = ss->next;
+		free((void *)ss);
+	}
 }