--- ray/src/rt/source.c	1991/06/20 13:43:29	1.35
+++ ray/src/rt/source.c	1992/10/22 09:55:16	2.7
@@ -1,4 +1,4 @@
-/* Copyright (c) 1990 Regents of the University of California */
+/* Copyright (c) 1992 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -18,32 +18,33 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "source.h"
 
-#include  "random.h"
-
 /*
  * Structures used by direct()
  */
 
 typedef struct {
+	int  sno;		/* source number */
 	FVECT  dir;		/* source direction */
 	COLOR  coef;		/* material coefficient */
 	COLOR  val;		/* contribution */
 }  CONTRIB;		/* direct contribution */
 
 typedef struct {
-	int  sno;		/* source number */
+	int  sndx;		/* source index (to CONTRIB array) */
 	float  brt;		/* brightness (for comparison) */
 }  CNTPTR;		/* contribution pointer */
 
 static CONTRIB  *srccnt;		/* source contributions in direct() */
 static CNTPTR  *cntord;			/* source ordering in direct() */
+static int  maxcntr = 0;		/* size of contribution arrays */
 
 
 marksources()			/* find and mark source objects */
 {
+	int  foundsource = 0;
 	int  i;
 	register OBJREC  *o, *m;
-	register SRCREC  *ns;
+	register int  ns;
 					/* initialize dispatch table */
 	initstypes();
 					/* find direct sources */
@@ -72,30 +73,40 @@ marksources()			/* find and mark source objects */
 				sfun[o->otype].of->setsrc == NULL)
 			objerror(o, USER, "illegal material");
 
-		if ((ns = newsource()) == NULL)
+		if ((ns = newsource()) < 0)
 			goto memerr;
 
-		(*sfun[o->otype].of->setsrc)(ns, o);
+		setsource(&source[ns], o);
 
 		if (m->otype == MAT_GLOW) {
-			ns->sflags |= SPROX;
-			ns->sl.prox = m->oargs.farg[3];
+			source[ns].sflags |= SPROX;
+			source[ns].sl.prox = m->oargs.farg[3];
 			if (o->otype == OBJ_SOURCE)
-				ns->sflags |= SSKIP;
+				source[ns].sflags |= SSKIP;
 		} else if (m->otype == MAT_SPOT) {
-			ns->sflags |= SSPOT;
-			if ((ns->sl.s = makespot(m)) == NULL)
+			source[ns].sflags |= SSPOT;
+			if ((source[ns].sl.s = makespot(m)) == NULL)
 				goto memerr;
+			if (source[ns].sflags & SFLAT &&
+				!checkspot(source[ns].sl.s,source[ns].snorm)) {
+				objerror(o, WARNING,
+					"invalid spotlight direction");
+				source[ns].sflags |= SSKIP;
+			}
 		}
+		if (!(source[ns].sflags & SSKIP))
+			foundsource++;
 	}
-	if (nsources <= 0) {
+	if (!foundsource) {
 		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)
+				/* allocate our contribution arrays */
+	maxcntr = nsources + MAXSPART;	/* start with this many */
+	srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
+	cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
+	if (srccnt == NULL | cntord == NULL)
 		goto memerr;
 	return;
 memerr:
@@ -103,90 +114,40 @@ memerr:
 }
 
 
-double
-srcray(sr, r, sn)		/* send a ray to a source, return domega */
+srcray(sr, r, si)		/* send a ray to a source, return domega */
 register RAY  *sr;		/* returned source ray */
 RAY  *r;			/* ray which hit object */
-register int  sn;		/* source number */
+SRCINDEX  *si;			/* source sample index */
 {
-	double  ddot;			/* (distance times) cosine */
-	FVECT  vd;
-	double  d;
-	register int  i;
+    double  d;				/* distance to source */
+    register SRCREC  *srcp;
 
-	if (source[sn].sflags & SSKIP)
-		return(0.0);			/* skip this source */
+    rayorigin(sr, r, SHADOW, 1.0);		/* ignore limits */
 
-	rayorigin(sr, r, SHADOW, 1.0);		/* ignore limits */
-
-	sr->rsrc = sn;				/* remember source */
-						/* get source direction */
-	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, source[sn].sloc);
-	} else {				/* compute direction */
-		for (i = 0; i < 3; i++)
-			sr->rdir[i] = source[sn].sloc[i] - sr->rorg[i];
-
-		if (source[sn].sflags & SFLAT &&
-			(ddot = -DOT(sr->rdir, source[sn].snorm)) <= FTINY)
-			return(0.0);		/* behind surface! */
+    while ((d = nextssamp(sr, si)) != 0.0) {
+	sr->rsrc = si->sn;			/* remember source */
+	srcp = source + si->sn;
+	if (srcp->sflags & SDISTANT) {
+		if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s, 1))
+			continue;
+		return(1);		/* sample OK */
 	}
-	if (dstrsrc > FTINY) {
-					/* distribute source direction */
-		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 * source[sn].snorm[i];
-		}
-		for (i = 0; i < 3; i++)		/* offset source direction */
-			sr->rdir[i] += vd[i];
-
-	} else if (source[sn].sflags & SDISTANT)
-						/* already normalized */
-		return(source[sn].ss2);
-
-	if ((d = normalize(sr->rdir)) == 0.0)
-						/* at source! */
-		return(0.0);
-	
-	if (source[sn].sflags & SDISTANT)
-						/* domega constant */
-		return(source[sn].ss2);
-
+				/* local source */
 						/* check proximity */
-	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;
+	if (srcp->sflags & SPROX && d > srcp->sl.prox)
+		continue;
 						/* check angle */
-	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 */
+	if (srcp->sflags & SSPOT) {
+		if (spotout(sr, srcp->sl.s, 0))
+			continue;
+					/* adjust solid angle */
+		si->dom *= d*d;
+		d += srcp->sl.s->flen;
+		si->dom /= d*d;
 	}
-						/* compute domega */
-	return(ddot*source[sn].ss2/(d*d));
+	return(1);			/* sample OK */
+    }
+    return(0);			/* no more samples */
 }
 
 
@@ -222,6 +183,41 @@ RAY  *r;
 }
 
 
+sourcehit(r)			/* check to see if ray hit distant source */
+register RAY  *r;
+{
+	int  first, last;
+	register int  i;
+
+	if (r->rsrc >= 0) {		/* check only one if aimed */
+		first = last = r->rsrc;
+	} else {			/* otherwise check all */
+		first = 0; last = nsources-1;
+	}
+	for (i = first; i <= last; i++)
+		if ((source[i].sflags & (SDISTANT|SVIRTUAL)) == SDISTANT)
+			/*
+			 * Check to see if ray is within
+			 * solid angle of source.
+			 */
+			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;
+			}
+
+	if (r->ro != NULL) {
+		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;
@@ -239,45 +235,52 @@ RAY  *r;			/* ray that hit surface */
 int  (*f)();			/* direct component coefficient function */
 char  *p;			/* data for f */
 {
-	extern double  pow();
+	extern int  (*trace)();
 	register int  sn;
+	register CONTRIB  *scp;
+	SRCINDEX  si;
 	int  nshadcheck, ncnts;
 	int  nhits;
-	double  dom, prob, ourthresh, hwt;
+	double  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);
+	initsrcindex(&si);
+	for (sn = 0; srcray(&sr, r, &si); sn++) {
+		if (sn >= maxcntr) {
+			maxcntr = sn + MAXSPART;
+			srccnt = (CONTRIB *)realloc((char *)srccnt,
+					maxcntr*sizeof(CONTRIB));
+			cntord = (CNTPTR *)realloc((char *)cntord,
+					maxcntr*sizeof(CNTPTR));
+			if (srccnt == NULL | cntord == NULL)
+				error(SYSTEM, "out of memory in direct");
+		}
+		cntord[sn].sndx = sn;
+		scp = srccnt + sn;
+		scp->sno = sr.rsrc;
 						/* compute coefficient */
-		(*f)(srccnt[sn].coef, p, srccnt[sn].dir, dom);
-		cntord[sn].brt = bright(srccnt[sn].coef);
+		(*f)(scp->coef, p, sr.rdir, si.dom);
+		cntord[sn].brt = bright(scp->coef);
 		if (cntord[sn].brt <= 0.0)
 			continue;
+		VCOPY(scp->dir, sr.rdir);
 						/* compute potential */
 		sr.revf = srcvalue;
 		rayvalue(&sr);
-		copycolor(srccnt[sn].val, sr.rcol);
-		multcolor(srccnt[sn].val, srccnt[sn].coef);
-		cntord[sn].brt = bright(srccnt[sn].val);
+		copycolor(scp->val, sr.rcol);
+		multcolor(scp->val, scp->coef);
+		cntord[sn].brt = bright(scp->val);
 	}
 						/* sort contributions */
-	qsort(cntord, nsources, sizeof(CNTPTR), cntcmp);
+	qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
 	{					/* find last */
 		register int  l, m;
 
-		sn = 0; ncnts = l = nsources;
+		ncnts = l = sn;
+		sn = 0;
 		while ((m = (sn + ncnts) >> 1) != l) {
 			if (cntord[m].brt > 0.0)
 				sn = m;
@@ -286,9 +289,15 @@ char  *p;			/* data for f */
 			l = m;
 		}
 	}
+	if (ncnts == 0)
+		return;		/* no contributions! */
                                                 /* accumulate tail */
         for (sn = ncnts-1; sn > 0; sn--)
                 cntord[sn-1].brt += cntord[sn].brt;
+						/* compute number to check */
+	nshadcheck = pow((double)ncnts, shadcert) + .5;
+						/* modify threshold */
+	ourthresh = shadthresh / r->rweight;
 						/* test for shadows */
 	nhits = 0;
 	for (sn = 0; sn < ncnts; sn++) {
@@ -297,27 +306,28 @@ char  *p;			/* data for f */
 				cntord[sn].brt-cntord[sn+nshadcheck].brt)
 				< ourthresh*bright(r->rcol))
 			break;
-						/* get statistics */
-		source[cntord[sn].sno].ntests++;
+		scp = srccnt + cntord[sn].sndx;
 						/* test for hit */
 		rayorigin(&sr, r, SHADOW, 1.0);
-		VCOPY(sr.rdir, srccnt[cntord[sn].sno].dir);
-		sr.rsrc = cntord[sn].sno;
+		VCOPY(sr.rdir, scp->dir);
+		sr.rsrc = scp->sno;
+		source[scp->sno].ntests++;	/* keep statistics */
 		if (localhit(&sr, &thescene) &&
-				( sr.ro != source[cntord[sn].sno].so ||
-				source[cntord[sn].sno].sflags & SFOLLOW )) {
+				( sr.ro != source[scp->sno].so ||
+				source[scp->sno].sflags & SFOLLOW )) {
 						/* follow entire path */
 			raycont(&sr);
+			if (trace != NULL)
+				(*trace)(&sr);	/* trace execution */
 			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);
+			copycolor(scp->val, sr.rcol);
+			multcolor(scp->val, scp->coef);
 		}
 						/* add contribution if hit */
-		addcolor(r->rcol, srccnt[cntord[sn].sno].val);
+		addcolor(r->rcol, scp->val);
 		nhits++;
-		source[cntord[sn].sno].nhits++;
+		source[scp->sno].nhits++;
 	}
 					/* surface hit rate */
 	if (sn > 0)
@@ -331,9 +341,121 @@ char  *p;			/* data for f */
 #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);
+		scp = srccnt + cntord[sn].sndx;
+		prob = hwt * (double)source[scp->sno].nhits /
+				(double)source[scp->sno].ntests;
+		scalecolor(scp->val, prob);
+		addcolor(r->rcol, scp->val);
 	}
+}
+
+
+/****************************************************************
+ * The following macros were separated from the m_light() routine
+ * because they are very nasty and difficult to understand.
+ */
+
+/* wrongillum *
+ *
+ * We cannot allow an illum to pass to another illum, because that
+ * would almost certainly constitute overcounting.
+ * However, we do allow an illum to pass to another illum
+ * that is actually going to relay to a virtual light source.
+ */
+
+#define  wrongillum(m, r)	(!(source[r->rsrc].sflags&SVIRTUAL) && \
+			objptr(source[r->rsrc].so->omod)->otype==MAT_ILLUM)
+
+/* wrongsource *
+ *
+ * This source is the wrong source (ie. overcounted) if we are
+ * aimed to a different source than the one we hit and the one
+ * we hit is not an illum which should be passed.
+ */
+
+#define  wrongsource(m, r)	(r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
+				(m->otype!=MAT_ILLUM || wrongillum(m,r)))
+
+/* distglow *
+ *
+ * A distant glow is an object that sometimes acts as a light source,
+ * but is too far away from the test point to be one in this case.
+ */
+
+#define  distglow(m, r)		(m->otype==MAT_GLOW && \
+				r->rot > m->oargs.farg[3])
+
+/* badcomponent *
+ *
+ * We must avoid counting light sources in the ambient calculation,
+ * since the direct component is handled separately.  Therefore, any
+ * ambient ray which hits an active light source must be discarded.
+ * The same is true for stray specular samples, since the specular
+ * contribution from light sources is calculated separately.
+ */
+
+#define  badcomponent(m, r)	(r->crtype&(AMBIENT|SPECULAR) && \
+				!(r->crtype&SHADOW || r->rod < 0.0 || \
+					distglow(m, r)))
+
+/* overcount *
+ *
+ * All overcounting possibilities are contained here.
+ */
+
+#define  overcount(m, r)	(badcomponent(m,r) || wrongsource(m,r))
+
+/* passillum *
+ *
+ * An illum passes to another material type when we didn't hit it
+ * on purpose (as part of a direct calculation), or it is relaying
+ * a virtual light source.
+ */
+
+#define  passillum(m, r)	(m->otype==MAT_ILLUM && \
+				(r->rsrc<0 || source[r->rsrc].so!=r->ro || \
+				source[r->rsrc].sflags&SVIRTUAL))
+
+/* srcignore *
+ *
+ * The -di flag renders light sources invisible, and here is the test.
+ */
+
+#define  srcignore(m, r)	(directinvis && !(r->crtype&SHADOW) && \
+				!distglow(m, r))
+
+
+m_light(m, r)			/* ray hit a light source */
+register OBJREC  *m;
+register RAY  *r;
+{
+						/* check for over-counting */
+	if (overcount(m, r))
+		return;
+						/* check for passed illum */
+	if (passillum(m, r)) {
+		if (m->oargs.nsargs < 1 || !strcmp(m->oargs.sarg[0], VOIDID))
+			raytrans(r);
+		else
+			rayshade(r, modifier(m->oargs.sarg[0]));
+		return;
+	}
+					/* otherwise treat as source */
+						/* check for behind */
+	if (r->rod < 0.0)
+		return;
+						/* check for invisibility */
+	if (srcignore(m, r))
+		return;
+						/* check for outside spot */
+	if (m->otype==MAT_SPOT && spotout(r, (SPOT *)m->os, r->rot>=FHUGE))
+		return;
+						/* get distribution pattern */
+	raytexture(r, m->omod);
+						/* get source color */
+	setcolor(r->rcol, m->oargs.farg[0],
+			  m->oargs.farg[1],
+			  m->oargs.farg[2]);
+						/* modify value */
+	multcolor(r->rcol, r->pcol);
 }