--- ray/src/rt/virtuals.c	1991/06/25 13:29:22	1.10
+++ ray/src/rt/virtuals.c	1995/11/07 12:40:25	2.5
@@ -1,4 +1,4 @@
-/* Copyright (c) 1991 Regents of the University of California */
+/* Copyright (c) 1995 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -19,7 +19,10 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "random.h"
 
+#define  MINSAMPLES	16		/* minimum number of pretest samples */
+#define  STESTMAX	32		/* maximum seeks per sample */
 
+
 double  getdisk();
 
 static OBJECT  *vobject;		/* virtual source objects */
@@ -38,11 +41,13 @@ markvirtuals()			/* find and mark virtual sources */
 		o = objptr(i);
 		if (!issurface(o->otype) || o->omod == OVOID)
 			continue;
-		if (!isvlight(objptr(o->omod)->otype))
+		if (!isvlight(vsmaterial(o)->otype))
 			continue;
 		if (sfun[o->otype].of == NULL ||
-				sfun[o->otype].of->getpleq == NULL)
-			objerror(o, USER, "illegal material");
+				sfun[o->otype].of->getpleq == NULL) {
+			objerror(o,WARNING,"secondary sources not supported");
+			continue;
+		}
 		if (nvobjects == 0)
 			vobject = (OBJECT *)malloc(sizeof(OBJECT));
 		else
@@ -96,11 +101,12 @@ int  n;
 	if (o == source[sn].so)	/* objects cannot project themselves */
 		return;
 				/* get virtual source material */
-	vsmat = sfun[objptr(o->omod)->otype].mf;
+	vsmat = sfun[vsmaterial(o)->otype].mf;
 				/* project virtual sources */
 	for (i = 0; i < vsmat->nproj; i++)
 		if ((*vsmat->vproj)(proj, o, &source[sn], i))
 			if ((ns = makevsrc(o, sn, proj)) >= 0) {
+				source[ns].sa.sv.pn = i;
 #ifdef DEBUG
 				virtverb(ns, stderr);
 #endif
@@ -109,6 +115,23 @@ int  n;
 }
 
 
+OBJREC *
+vsmaterial(o)			/* get virtual source material pointer */
+OBJREC  *o;
+{
+	register int  i;
+	register OBJREC  *m;
+
+	i = o->omod;
+	m = objptr(i);
+	if (m->otype != MAT_ILLUM || m->oargs.nsargs < 1 ||
+			!strcmp(m->oargs.sarg[0], VOIDID) ||
+			(i = modifier(m->oargs.sarg[0])) == OVOID)
+		return(m);		/* direct modifier */
+	return(objptr(i));		/* illum alternate */
+}
+
+
 int
 makevsrc(op, sn, pm)		/* make virtual source if reasonable */
 OBJREC  *op;
@@ -131,12 +154,17 @@ MAT4  pm;
 		if (source[sn].sflags & SPROX)
 			return(-1);		/* should never get here! */
 		multv3(nsloc, source[sn].sloc, pm);
+		normalize(nsloc);
 		VCOPY(ourspot.aim, ocent);
 		ourspot.siz = PI*maxrad2;
-		ourspot.flen = 0.;
+		ourspot.flen = -1.;
 		if (source[sn].sflags & SSPOT) {
-			copystruct(&theirspot, source[sn].sl.s);
 			multp3(theirspot.aim, source[sn].sl.s->aim, pm);
+						/* adjust for source size */
+			d = sqrt(dist2(ourspot.aim, theirspot.aim));
+			d = sqrt(source[sn].sl.s->siz/PI) + d*source[sn].srad;
+			theirspot.siz = PI*d*d;
+			ourspot.flen = theirspot.flen = source[sn].sl.s->flen;
 			d = ourspot.siz;
 			if (!commonbeam(&ourspot, &theirspot, nsloc))
 				return(-1);	/* no overlap */
@@ -158,14 +186,27 @@ MAT4  pm;
 			return(-1);		/* at source!! */
 		if (source[sn].sflags & SPROX && d > source[sn].sl.prox)
 			return(-1);		/* too far away */
-		ourspot.siz = 2.*PI*(1. - d/sqrt(d*d+maxrad2));
 		ourspot.flen = 0.;
+						/* adjust for source size */
+		d = (sqrt(maxrad2) + source[sn].srad) / d;
+		if (d < 1.-FTINY)
+			ourspot.siz = 2.*PI*(1. - sqrt(1.-d*d));
+		else
+			nsflags &= ~SSPOT;
 		if (source[sn].sflags & SSPOT) {
 			copystruct(&theirspot, source[sn].sl.s);
 			multv3(theirspot.aim, source[sn].sl.s->aim, pm);
-			d = ourspot.siz;
-			if (!commonspot(&ourspot, &theirspot, nsloc))
-				return(-1);	/* no overlap */
+			normalize(theirspot.aim);
+			if (nsflags & SSPOT) {
+				ourspot.flen = theirspot.flen;
+				d = ourspot.siz;
+				if (!commonspot(&ourspot, &theirspot, nsloc))
+					return(-1);	/* no overlap */
+			} else {
+				nsflags |= SSPOT;
+				copystruct(&ourspot, &theirspot);
+				d = 2.*ourspot.siz;
+			}
 			if (ourspot.siz < d-FTINY) {	/* it shrunk */
 				d = spotdisk(v, op, &ourspot, nsloc);
 				if (d <= FTINY)
@@ -175,11 +216,11 @@ MAT4  pm;
 					VCOPY(ocent, v);
 				}
 			}
-			ourspot.flen = theirspot.flen;
 		}
 		if (source[sn].sflags & SFLAT) {	/* behind source? */
 			multv3(nsnorm, source[sn].snorm, pm);
-			if (checkspot(&ourspot, nsnorm) < 0)
+			normalize(nsnorm);
+			if (nsflags & SSPOT && !checkspot(&ourspot, nsnorm))
 				return(-1);
 		}
 	}
@@ -192,15 +233,22 @@ MAT4  pm;
 		goto memerr;
 	source[i].sflags = nsflags;
 	VCOPY(source[i].sloc, nsloc);
+	multv3(source[i].ss[SU], source[sn].ss[SU], pm);
+	multv3(source[i].ss[SV], source[sn].ss[SV], pm);
 	if (nsflags & SFLAT)
 		VCOPY(source[i].snorm, nsnorm);
-	source[i].ss = source[sn].ss; source[i].ss2 = source[sn].ss2;
-	if ((source[i].sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
-		goto memerr;
-	copystruct(source[i].sl.s, &ourspot);
+	else
+		multv3(source[i].ss[SW], source[sn].ss[SW], pm);
+	source[i].srad = source[sn].srad;
+	source[i].ss2 = source[sn].ss2;
+	if (nsflags & SSPOT) {
+		if ((source[i].sl.s = (SPOT *)malloc(sizeof(SPOT))) == NULL)
+			goto memerr;
+		copystruct(source[i].sl.s, &ourspot);
+	}
 	if (nsflags & SPROX)
 		source[i].sl.prox = source[sn].sl.prox;
-	source[i].sa.svnext = sn;
+	source[i].sa.sv.sn = sn;
 	source[i].so = op;
 	return(i);
 memerr:
@@ -251,10 +299,10 @@ register int  sn;	/* target source number */
 	RAY  sr;
 	FVECT  onorm;
 	FVECT  offsdir;
+	SRCINDEX  si;
 	double  or, d;
-	int  infront;
-	int  ssn;
-	int  nhit;
+	int  stestlim, ssn;
+	int  nhit, nok;
 	register int  i, n;
 				/* return if pretesting disabled */
 	if (vspretest <= 0)
@@ -263,71 +311,75 @@ register int  sn;	/* target source number */
 	getplaneq(onorm, o);
 				/* set number of rays to sample */
 	if (source[sn].sflags & SDISTANT) {
-		n = (2./3.*PI*PI)*or2/(thescene.cusize*thescene.cusize)*
-				vspretest + .5;
-		infront = DOT(onorm, source[sn].sloc) > 0.;
+					/* 32. == heuristic constant */
+		n = 32.*or2/(thescene.cusize*thescene.cusize)*vspretest + .5;
 	} else {
 		for (i = 0; i < 3; i++)
 			offsdir[i] = source[sn].sloc[i] - oc[i];
-		n = or2/DOT(offsdir,offsdir)*vspretest + .5;
-		infront = DOT(onorm, offsdir) > 0.;
+		d = DOT(offsdir,offsdir);
+		if (d <= FTINY)
+			n = 2.*PI * vspretest + .5;
+		else
+			n = 2.*PI * (1.-sqrt(1./(1.+or2/d)))*vspretest + .5;
 	}
-	if (n < 1) n = 1;
+	if (n < MINSAMPLES) n = MINSAMPLES;
 #ifdef DEBUG
 	fprintf(stderr, "pretesting source %d in object %s with %d rays\n",
 			sn, o->oname, n);
 #endif
 				/* sample */
 	or = sqrt(or2);
-	ssn = 25*n;
-	nhit = 0;
+	stestlim = n*STESTMAX;
+	ssn = 0;
+	nhit = nok = 0;
+	initsrcindex(&si);
 	while (n-- > 0) {
 					/* get sample point */
 		do {
-			if (--ssn < 0) {
+			if (ssn >= stestlim) {
 #ifdef DEBUG
 				fprintf(stderr, "\ttoo hard to hit\n");
 #endif
 				return(f);	/* too small a target! */
 			}
+			multisamp(offsdir, 3, urand(sn*931+5827+ssn));
 			for (i = 0; i < 3; i++)
-				offsdir[i] = or*(1. -
-						2.*urand(931*i+5827+ssn));
-			for (i = 0; i < 3; i++)
-				sr.rorg[i] = oc[i] + offsdir[i];
-			d = DOT(offsdir,onorm);
-			if (infront)
-				for (i = 0; i < 3; i++) {
-					sr.rorg[i] -= (d-.0001)*onorm[i];
-					sr.rdir[i] = -onorm[i];
-				}
-			else
-				for (i = 0; i < 3; i++) {
-					sr.rorg[i] -= (d+.0001)*onorm[i];
-					sr.rdir[i] = onorm[i];
-				}
+				offsdir[i] = or*(1. - 2.*offsdir[i]);
+			ssn++;
+			d = 1. - DOT(offsdir, onorm);
+			for (i = 0; i < 3; i++) {
+				sr.rorg[i] = oc[i] + offsdir[i] + d*onorm[i];
+				sr.rdir[i] = -onorm[i];
+			}
+			sr.rmax = 0.0;
 			rayorigin(&sr, NULL, PRIMARY, 1.0);
 		} while (!(*ofun[o->otype].funp)(o, &sr));
 					/* check against source */
+		VCOPY(sr.rorg, sr.rop);	/* starting from intersection */
 		samplendx++;
-		if (srcray(&sr, NULL, sn) == 0.)
-			continue;
+		if (si.sp >= si.np-1 ||
+				!srcray(&sr, NULL, &si) || sr.rsrc != sn) {
+			si.sn = sn-1;		/* reset index to our source */
+			si.np = 0;
+			if (!srcray(&sr, NULL, &si) || sr.rsrc != sn)
+				continue;	/* can't get there from here */
+		}
 		sr.revf = srcvalue;
-		rayvalue(&sr);
+		rayvalue(&sr);			/* check sample validity */
 		if (bright(sr.rcol) <= FTINY)
 			continue;
-					/* check against obstructions */
-		srcray(&sr, NULL, sn);
+		nok++;			/* got sample; check obstructions */
+		rayclear(&sr);
+		sr.revf = raytrace;
 		rayvalue(&sr);
-		if (bright(sr.rcol) <= FTINY) {
-			if (nhit > 0) {
+		if (bright(sr.rcol) > FTINY)
+			nhit++;
+		if (nhit > 0 && nhit < nok) {
 #ifdef DEBUG
-				fprintf(stderr, "\tpartially occluded\n");
+			fprintf(stderr, "\tpartially occluded\n");
 #endif
-				return(f);	/* need to shadow test */
-			}
-		} else
-			nhit++;
+			return(f);		/* need to shadow test */
+		}
 	}
 	if (nhit == 0) {
 #ifdef DEBUG
@@ -356,7 +408,7 @@ FILE  *fp;
 	fprintf(fp, "\tat (%f,%f,%f)\n",
 		source[sn].sloc[0], source[sn].sloc[1], source[sn].sloc[2]);
 	fprintf(fp, "\tlinked to source %d (%s)\n",
-		source[sn].sa.svnext, source[source[sn].sa.svnext].so->oname);
+		source[sn].sa.sv.sn, source[source[sn].sa.sv.sn].so->oname);
 	if (source[sn].sflags & SFOLLOW)
 		fprintf(fp, "\talways followed\n");
 	else