--- ray/src/rt/source.c	1989/02/02 10:41:41	1.1
+++ ray/src/rt/source.c	1991/06/20 09:03:57	1.34
@@ -1,4 +1,4 @@
-/* Copyright (c) 1986 Regents of the University of California */
+/* Copyright (c) 1990 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -12,6 +12,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "ray.h"
 
+#include  "octree.h"
+
 #include  "source.h"
 
 #include  "otypes.h"
@@ -24,15 +26,21 @@ static char SCCSid[] = "$SunId$ LBL";
 
 
 extern double  dstrsrc;			/* source distribution amount */
+extern double  shadthresh;		/* relative shadow threshold */
+extern double  shadcert;		/* shadow testing certainty */
 
-SOURCE  srcval[MAXSOURCE];		/* our array of sources */
+SRCREC  *source = NULL;			/* our list of sources */
 int  nsources = 0;			/* the number of sources */
 
+static CONTRIB  *srccnt;		/* source contributions in direct() */
+static CNTPTR  *cntord;			/* source ordering in direct() */
 
+
 marksources()			/* find and mark source objects */
 {
+	int  i;
 	register OBJREC  *o, *m;
-	register int  i;
+	register SRCREC  *ns;
 
 	for (i = 0; i < nobjects; i++) {
 	
@@ -43,10 +51,7 @@ marksources()			/* find and mark source objects */
 
 		m = objptr(o->omod);
 
-		if (m->otype != MAT_LIGHT &&
-				m->otype != MAT_ILLUM &&
-				m->otype != MAT_GLOW &&
-				m->otype != MAT_SPOT)
+		if (!islight(m->otype))
 			continue;
 	
 		if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
@@ -58,27 +63,56 @@ marksources()			/* find and mark source objects */
 				m->oargs.farg[3] <= FTINY)
 			continue;			/* don't bother */
 
-		if (nsources >= MAXSOURCE)
-			error(INTERNAL, "too many sources in marksources");
+		if ((ns = newsource()) == NULL)
+			goto memerr;
 
-		newsource(&srcval[nsources], o);
+		setsource(ns, o);
 
 		if (m->otype == MAT_GLOW) {
-			srcval[nsources].sflags |= SPROX;
-			srcval[nsources].sl.prox = m->oargs.farg[3];
+			ns->sflags |= SPROX;
+			ns->sl.prox = m->oargs.farg[3];
 			if (o->otype == OBJ_SOURCE)
-				srcval[nsources].sflags |= SSKIP;
+				ns->sflags |= SSKIP;
 		} else if (m->otype == MAT_SPOT) {
-			srcval[nsources].sflags |= SSPOT;
-			srcval[nsources].sl.s = makespot(m);
+			ns->sflags |= SSPOT;
+			if ((ns->sl.s = makespot(m)) == NULL)
+				goto memerr;
 		}
-		nsources++;
 	}
+	if (nsources <= 0) {
+		error(WARNING, "no light sources found");
+		return;
+	}
+	markvirtuals();			/* find and add virtual sources */
+	srccnt = (CONTRIB *)malloc(nsources*sizeof(CONTRIB));
+	cntord = (CNTPTR *)malloc(nsources*sizeof(CNTPTR));
+	if (srccnt != NULL && cntord != NULL)
+		goto memerr;
+	return;
+memerr:
+	error(SYSTEM, "out of memory in marksources");
 }
 
 
-newsource(src, so)			/* add a source to the array */
-register SOURCE  *src;
+SRCREC *
+newsource()			/* allocate new source in our array */
+{
+	if (nsources == 0)
+		source = (SRCREC *)malloc(sizeof(SRCREC));
+	else
+		source = (SRCREC *)realloc((char *)source,
+				(unsigned)(nsources+1)*sizeof(SRCREC));
+	if (source == NULL)
+		return(NULL);
+	source[nsources].sflags = 0;
+	source[nsources].nhits = 1;
+	source[nsources].ntests = 2;	/* initial hit probability = 1/2 */
+	return(&source[nsources++]);
+}
+
+
+setsource(src, so)			/* add a source to the array */
+register SRCREC  *src;
 register OBJREC  *so;
 {
 	double  cos(), tan(), sqrt();
@@ -88,7 +122,7 @@ register OBJREC  *so;
 	int  j;
 	register int  i;
 	
-	src->sflags = 0;
+	src->sa.success = 2*AIMREQT-1;		/* bitch on second failure */
 	src->so = so;
 
 	switch (so->otype) {
@@ -118,10 +152,12 @@ register OBJREC  *so;
 			src->sloc[j] = 0.0;
 			for (i = 0; i < f->nv; i++)
 				src->sloc[j] += VERTEX(f,i)[j];
-			src->sloc[j] /= f->nv;
+			src->sloc[j] /= (double)f->nv;
 		}
 		if (!inface(src->sloc, f))
 			objerror(so, USER, "cannot hit center");
+		src->sflags |= SFLAT;
+		VCOPY(src->snorm, f->norm);
 		src->ss = sqrt(f->area / PI);
 		src->ss2 = f->area;
 		break;
@@ -131,6 +167,8 @@ register OBJREC  *so;
 		VCOPY(src->sloc, CO_P0(co));
 		if (CO_R0(co) > 0.0)
 			objerror(so, USER, "cannot hit center");
+		src->sflags |= SFLAT;
+		VCOPY(src->snorm, co->ad);
 		src->ss = CO_R1(co);
 		src->ss2 = PI * src->ss * src->ss;
 		break;
@@ -148,7 +186,7 @@ register OBJREC  *m;
 	register SPOT  *ns;
 
 	if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL)
-		error(SYSTEM, "out of memory in makespot");
+		return(NULL);
 	ns->siz = 2.0*PI * (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3]));
 	VCOPY(ns->aim, m->oargs.farg+4);
 	if ((ns->flen = normalize(ns->aim)) == 0.0)
@@ -163,79 +201,84 @@ register RAY  *sr;		/* returned source ray */
 RAY  *r;			/* ray which hit object */
 register int  sn;		/* source number */
 {
-	register double  *norm = NULL;	/* plane normal */
 	double  ddot;			/* (distance times) cosine */
 	FVECT  vd;
 	double  d;
 	register int  i;
 
-	if (srcval[sn].sflags & SSKIP)
+	if (source[sn].sflags & SSKIP)
 		return(0.0);			/* skip this source */
 
 	rayorigin(sr, r, SHADOW, 1.0);		/* ignore limits */
 
 	sr->rsrc = sn;				/* remember source */
 						/* get source direction */
-	if (srcval[sn].sflags & SDISTANT)
+	if (source[sn].sflags & SDISTANT) {
+		if (source[sn].sflags & SSPOT) {	/* check location */
+			for (i = 0; i < 3; i++)
+				vd[i] = sr->rorg[i] - source[sn].sl.s->aim[i];
+			d = DOT(source[sn].sloc,vd);
+			d = DOT(vd,vd) - d*d;
+			if (PI*d > source[sn].sl.s->siz)
+				return(0.0);
+		}
 						/* constant direction */
-		VCOPY(sr->rdir, srcval[sn].sloc);
-	else {					/* compute direction */
+		VCOPY(sr->rdir, source[sn].sloc);
+	} else {				/* compute direction */
 		for (i = 0; i < 3; i++)
-			sr->rdir[i] = srcval[sn].sloc[i] - sr->rorg[i];
+			sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];
 
-		if (srcval[sn].so->otype == OBJ_FACE)
- 			norm = getface(srcval[sn].so)->norm;
-		else if (srcval[sn].so->otype == OBJ_RING)
-			norm = getcone(srcval[sn].so,0)->ad;
-
-		if (norm != NULL && (ddot = -DOT(sr->rdir, norm)) <= 0.0)
+		if (source[sn].sflags & SFLAT &&
+			(ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
 			return(0.0);		/* behind surface! */
 	}
 	if (dstrsrc > FTINY) {
 					/* distribute source direction */
-		for (i = 0; i < 3; i++)
-			vd[i] = dstrsrc * srcval[sn].ss * (1.0 - 2.0*frandom());
-
-		if (norm != NULL) {		/* project offset */
-			d = DOT(vd, norm);
+		dimlist[ndims++] = sn;
+		for (i = 0; i < 3; i++) {
+			dimlist[ndims] = i + 8831;
+			vd[i] = dstrsrc * source[sn].ss *
+		(1.0 - 2.0*urand(ilhash(dimlist,ndims+1)+samplendx));
+		}
+		ndims--;
+		if (source[sn].sflags & SFLAT) {	/* project offset */
+			d = DOT(vd, source[sn].snorm);
 			for (i = 0; i < 3; i++)
-				vd[i] -= d * norm[i];
+				vd[i] -= d * source[sn].snorm[i];
 		}
 		for (i = 0; i < 3; i++)		/* offset source direction */
 			sr->rdir[i] += vd[i];
 
-	} else if (srcval[sn].sflags & SDISTANT)
+	} else if (source[sn].sflags & SDISTANT)
 						/* already normalized */
-		return(srcval[sn].ss2);
+		return(source[sn].ss2);
 
 	if ((d = normalize(sr->rdir)) == 0.0)
 						/* at source! */
 		return(0.0);
 	
-	if (srcval[sn].sflags & SDISTANT)
+	if (source[sn].sflags & SDISTANT)
 						/* domega constant */
-		return(srcval[sn].ss2);
+		return(source[sn].ss2);
 
-	else {
 						/* check proximity */
-		if (srcval[sn].sflags & SPROX &&
-				d > srcval[sn].sl.prox)
-			return(0.0);
-
-		if (norm != NULL)
-			ddot /= d;
-		else
-			ddot = 1.0;
+	if (source[sn].sflags & SPROX &&
+			d > source[sn].sl.prox)
+		return(0.0);
+						/* compute dot product */
+	if (source[sn].sflags & SFLAT)
+		ddot /= d;
+	else
+		ddot = 1.0;
 						/* check angle */
-		if (srcval[sn].sflags & SSPOT) {
-			if (srcval[sn].sl.s->siz < 2.0*PI *
-				(1.0 + DOT(srcval[sn].sl.s->aim,sr->rdir)))
-				return(0.0);
-			d += srcval[sn].sl.s->flen;
-		}
-						/* return domega */
-		return(ddot*srcval[sn].ss2/(d*d));
+	if (source[sn].sflags & SSPOT) {
+		if (source[sn].sl.s->siz < 2.0*PI *
+				(1.0 + DOT(source[sn].sl.s->aim,sr->rdir)))
+			return(0.0);
+		d += source[sn].sl.s->flen;	/* adjust length */
 	}
+						/* compute domega */
+	return(ddot*source[sn].ss2/(d*d));
 }
 
 
@@ -251,15 +294,15 @@ register RAY  *r;
 		first = 0; last = nsources-1;
 	}
 	for (i = first; i <= last; i++)
-		if (srcval[i].sflags & SDISTANT)
+		if (source[i].sflags & SDISTANT)
 			/*
 			 * Check to see if ray is within
 			 * solid angle of source.
 			 */
-			if (2.0*PI * (1.0 - DOT(srcval[i].sloc,r->rdir))
-					<= srcval[i].ss2) {
-				r->ro = srcval[i].so;
-				if (!(srcval[i].sflags & SSKIP))
+			if (2.0*PI * (1.0 - DOT(source[i].sloc,r->rdir))
+					<= source[i].ss2) {
+				r->ro = source[i].so;
+				if (!(source[i].sflags & SSKIP))
 					break;
 			}
 
@@ -267,31 +310,179 @@ register RAY  *r;
 		for (i = 0; i < 3; i++)
 			r->ron[i] = -r->rdir[i];
 		r->rod = 1.0;
+		r->rox = NULL;
 		return(1);
 	}
 	return(0);
 }
 
 
+static int
+cntcmp(sc1, sc2)			/* contribution compare (descending) */
+register CNTPTR  *sc1, *sc2;
+{
+	if (sc1->brt > sc2->brt)
+		return(-1);
+	if (sc1->brt < sc2->brt)
+		return(1);
+	return(0);
+}
+
+
+direct(r, f, p)				/* add direct component */
+RAY  *r;			/* ray that hit surface */
+int  (*f)();			/* direct component coefficient function */
+char  *p;			/* data for f */
+{
+	extern double  pow();
+	register int  sn;
+	int  nshadcheck, ncnts;
+	int  nhits;
+	double  dom, prob, ourthresh, hwt;
+	RAY  sr;
+			/* NOTE: srccnt and cntord global so no recursion */
+	if (nsources <= 0)
+		return;		/* no sources?! */
+						/* compute number to check */
+	nshadcheck = pow((double)nsources, shadcert) + .5;
+						/* modify threshold */
+	ourthresh = shadthresh / r->rweight;
+						/* potential contributions */
+	for (sn = 0; sn < nsources; sn++) {
+		cntord[sn].sno = sn;
+		cntord[sn].brt = 0.0;
+						/* get source ray */
+		if ((dom = srcray(&sr, r, sn)) == 0.0)
+			continue;
+		VCOPY(srccnt[sn].dir, sr.rdir);
+						/* compute coefficient */
+		(*f)(srccnt[sn].coef, p, srccnt[sn].dir, dom);
+		cntord[sn].brt = bright(srccnt[sn].coef);
+		if (cntord[sn].brt <= 0.0)
+			continue;
+						/* compute contribution */
+		srcvalue(&sr);
+		copycolor(srccnt[sn].val, sr.rcol);
+		multcolor(srccnt[sn].val, srccnt[sn].coef);
+		cntord[sn].brt = bright(srccnt[sn].val);
+	}
+						/* sort contributions */
+	qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
+	{					/* find last */
+		register int  l, m;
+
+		sn = 0; ncnts = l = nsources;
+		while ((m = (sn + ncnts) >> 1) != l) {
+			if (cntord[m].brt > 0.0)
+				sn = m;
+			else
+				ncnts = m;
+			l = m;
+		}
+	}
+                                                /* accumulate tail */
+        for (sn = ncnts-1; sn > 0; sn--)
+                cntord[sn-1].brt += cntord[sn].brt;
+						/* test for shadows */
+	nhits = 0;
+	for (sn = 0; sn < ncnts; sn++) {
+						/* check threshold */
+		if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
+				cntord[sn].brt-cntord[sn+nshadcheck].brt)
+				< ourthresh*bright(r->rcol))
+			break;
+						/* get statistics */
+		source[cntord[sn].sno].ntests++;
+						/* test for hit */
+		rayorigin(&sr, r, SHADOW, 1.0);
+		VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
+		sr.rsrc = cntord[sn].sno;
+		if (localhit(&sr, &thescene) &&
+				( sr.ro != source[cntord[sn].sno].so ||
+				source[cntord[sn].sno].sflags & SFOLLOW )) {
+						/* follow entire path */
+			raycont(&sr);
+			if (bright(sr.rcol) <= FTINY)
+				continue;	/* missed! */
+			copycolor(srccnt[cntord[sn].sno].val, sr.rcol);
+			multcolor(srccnt[cntord[sn].sno].val,
+					srccnt[cntord[sn].sno].coef);
+		}
+						/* add contribution if hit */
+		addcolor(r->rcol, srccnt[cntord[sn].sno].val);
+		nhits++;
+		source[cntord[sn].sno].nhits++;
+	}
+					/* surface hit rate */
+	if (sn > 0)
+		hwt = (double)nhits / (double)sn;
+	else
+		hwt = 0.5;
+#ifdef DEBUG
+	sprintf(errmsg, "%d tested, %d untested, %f hit rate\n",
+			sn, ncnts-sn, hwt);
+	eputs(errmsg);
+#endif
+					/* add in untested sources */
+	for ( ; sn < ncnts; sn++) {
+		prob = hwt * (double)source[cntord[sn].sno].nhits /
+				(double)source[cntord[sn].sno].ntests;
+		scalecolor(srccnt[cntord[sn].sno].val, prob);
+		addcolor(r->rcol, srccnt[cntord[sn].sno].val);
+	}
+}
+
+
+srcvalue(r)			/* punch ray to source and compute value */
+RAY  *r;
+{
+	register SRCREC  *sp;
+
+	sp = &source[r->rsrc];
+	if (sp->sflags & SVIRTUAL) {		/* virtual source */
+		RAY  nr;
+					/* check intersection */
+		if (!(*ofun[sp->so->otype].funp)(sp->so, r))
+			return;
+					/* relay ray to source */
+		vsrcrelay(&nr, r);
+		srcvalue(&nr);
+		return;
+	}
+					/* compute intersection */
+	if (sp->sflags & SDISTANT ? sourcehit(r) :
+			(*ofun[sp->so->otype].funp)(sp->so, r)) {
+		if (sp->sa.success >= 0)
+			sp->sa.success++;
+		raycont(r);		/* compute contribution */
+		return;
+	}
+	if (sp->sa.success < 0)
+		return;			/* bitched already */
+	sp->sa.success -= AIMREQT;
+	if (sp->sa.success >= 0)
+		return;			/* leniency */
+	sprintf(errmsg, "aiming failure for light source \"%s\"",
+			sp->so->oname);
+	error(WARNING, errmsg);		/* issue warning */
+}
+
+
 #define  wrongsource(m, r)	(m->otype!=MAT_ILLUM && \
 				r->rsrc>=0 && \
-				srcval[r->rsrc].so!=r->ro)
+				source[r->rsrc].so!=r->ro)
 
 #define  badambient(m, r)	((r->crtype&(AMBIENT|SHADOW))==AMBIENT && \
-				!(r->rtype&REFLECTED) && 	/* hack! */\
 				!(m->otype==MAT_GLOW&&r->rot>m->oargs.farg[3]))
 
 #define  passillum(m, r)	(m->otype==MAT_ILLUM && \
-				!(r->rsrc>=0&&srcval[r->rsrc].so==r->ro))
+				!(r->rsrc>=0&&source[r->rsrc].so==r->ro))
 
 
 m_light(m, r)			/* ray hit a light source */
 register OBJREC  *m;
 register RAY  *r;
 {
-						/* check for behind */
-	if (r->rod < 0.0)
-		return;
 						/* check for over-counting */
 	if (wrongsource(m, r) || badambient(m, r))
 		return;
@@ -305,6 +496,9 @@ register RAY  *r;
 
 						/* otherwise treat as source */
 	} else {
+						/* check for behind */
+		if (r->rod < 0.0)
+			return;
 						/* get distribution pattern */
 		raytexture(r, m->omod);
 						/* get source color */
@@ -315,6 +509,3 @@ register RAY  *r;
 		multcolor(r->rcol, r->pcol);
 	}
 }
-
-
-o_source() {}		/* intersection with a source is done elsewhere */