--- ray/src/rt/raytrace.c	2018/01/09 05:01:15	2.72
+++ ray/src/rt/raytrace.c	2023/11/15 18:02:53	2.88
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: raytrace.c,v 2.72 2018/01/09 05:01:15 greg Exp $";
+static const char RCSid[] = "$Id: raytrace.c,v 2.88 2023/11/15 18:02:53 greg Exp $";
 #endif
 /*
  *  raytrace.c - routines for tracing and shading rays.
@@ -41,20 +41,20 @@ rayorigin(		/* start new ray from old one */
 	RAY  *r,
 	int  rt,
 	const RAY  *ro,
-	const COLOR rc
+	const SCOLOR rc
 )
 {
 	double	rw, re;
 						/* assign coefficient/weight */
 	if (rc == NULL) {
 		rw = 1.0;
-		setcolor(r->rcoef, 1., 1., 1.);
+		setscolor(r->rcoef, 1., 1., 1.);
 	} else {
-		rw = intens(rc);
+		rw = sintens(rc);
 		if (rw > 1.0)
 			rw = 1.0;		/* avoid calculation growth */
 		if (rc != r->rcoef)
-			copycolor(r->rcoef, rc);
+			copyscolor(r->rcoef, rc);
 	}
 	if ((r->parent = ro) == NULL) {		/* primary ray */
 		r->rlvl = 0;
@@ -68,7 +68,7 @@ rayorigin(		/* start new ray from old one */
 		r->gecc = seccg;
 		r->slights = NULL;
 	} else {				/* spawned ray */
-		if (ro->rot >= FHUGE) {
+		if (ro->rot >= FHUGE*.99) {
 			memset(r, 0, sizeof(RAY));
 			return(-1);		/* illegal continuation */
 		}
@@ -116,21 +116,21 @@ rayorigin(		/* start new ray from old one */
 		if (photonMapping && rt != TRANS)
 			return(-1);
 	}
-	if (maxdepth <= 0 && rc != NULL) {	/* Russian roulette */
+	if ((maxdepth <= 0) & (rc != NULL)) {	/* Russian roulette */
 		if (minweight <= 0.0)
 			error(USER, "zero ray weight in Russian roulette");
-		if (maxdepth < 0 && r->rlvl > -maxdepth)
+		if ((maxdepth < 0) & (r->rlvl > -maxdepth))
 			return(-1);		/* upper reflection limit */
 		if (r->rweight >= minweight)
 			return(0);
 		if (frandom() > r->rweight/minweight)
 			return(-1);
 		rw = minweight/r->rweight;	/* promote survivor */
-		scalecolor(r->rcoef, rw);
+		scalescolor(r->rcoef, rw);
 		r->rweight = minweight;
 		return(0);
 	}
-	return(r->rweight >= minweight && r->rlvl <= abs(maxdepth) ? 0 : -1);
+	return((r->rweight >= minweight) & (r->rlvl <= abs(maxdepth)) ? 0 : -1);
 }
 
 
@@ -145,11 +145,16 @@ rayclear(			/* clear a ray for (re)evaluation */
 	r->robj = OVOID;
 	r->ro = NULL;
 	r->rox = NULL;
-	r->rt = r->rot = FHUGE;
+	r->rxt = r->rmt = r->rot = FHUGE;
+	VCOPY(r->rop, r->rorg);
+	r->ron[0] = -r->rdir[0]; r->ron[1] = -r->rdir[1]; r->ron[2] = -r->rdir[2];
+	r->rod = 1.0;
 	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
+	r->rflips = 0;
 	r->uv[0] = r->uv[1] = 0.0;
-	setcolor(r->pcol, 1.0, 1.0, 1.0);
-	setcolor(r->rcol, 0.0, 0.0, 0.0);
+	setscolor(r->pcol, 1.0, 1.0, 1.0);
+	scolorblack(r->mcol);
+	scolorblack(r->rcol);
 }
 
 
@@ -194,20 +199,43 @@ raytrans(			/* transmit ray as is */
 	rayorigin(&tr, TRANS, r, NULL);		/* always continue */
 	VCOPY(tr.rdir, r->rdir);
 	rayvalue(&tr);
-	copycolor(r->rcol, tr.rcol);
-	r->rt = r->rot + tr.rt;
+	copyscolor(r->mcol, tr.mcol);
+	copyscolor(r->rcol, tr.rcol);
+	r->rmt = r->rot + tr.rmt;
+	r->rxt = r->rot + tr.rxt;
 }
 
 
 int
+raytirrad(			/* irradiance hack */
+	OBJREC	*m,
+	RAY	*r
+)
+{
+	if (ofun[m->otype].flags & (T_M|T_X) && m->otype != MAT_CLIP) {
+		if (istransp(m->otype) || isBSDFproxy(m)) {
+			raytrans(r);
+			return(1);
+		}
+		if (!islight(m->otype)) {
+			setscolor(r->pcol, 1.0, 1.0, 1.0);
+			return((*ofun[Lamb.otype].funp)(&Lamb, r));
+		}
+	}
+	return(0);		/* not a qualifying surface */
+}
+
+
+int
 rayshade(		/* shade ray r with material mod */
 	RAY  *r,
 	int  mod
 )
 {
+	int	tst_irrad = do_irrad && !(r->crtype & ~(PRIMARY|TRANS));
 	OBJREC  *m;
 
-	r->rt = r->rot;			/* preset effective ray length */
+	r->rxt = r->rot;		/* preset effective ray length */
 	for ( ; mod != OVOID; mod = m->omod) {
 		m = objptr(mod);
 		/****** unnecessary test since modifier() is always called
@@ -217,16 +245,9 @@ rayshade(		/* shade ray r with material mod */
 		}
 		******/
 					/* hack for irradiance calculation */
-		if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS)) &&
-				(ofun[m->otype].flags & (T_M|T_X)) &&
-				m->otype != MAT_CLIP) {
-			if (istransp(m->otype) || isBSDFproxy(m)) {
-				raytrans(r);
-				return(1);
-			}
-			if (!islight(m->otype))
-				m = &Lamb;
-		}
+		if (tst_irrad && raytirrad(m, r))
+			return(1);
+
 		if ((*ofun[m->otype].funp)(m, r))
 			return(1);	/* materials call raytexture() */
 	}
@@ -239,7 +260,7 @@ rayparticipate(			/* compute ray medium participation 
 	RAY  *r
 )
 {
-	COLOR	ce, ca;
+	SCOLOR	ce, ca;
 	double	re, ge, be;
 
 	if (intens(r->cext) <= 1./FHUGE)
@@ -252,20 +273,20 @@ rayparticipate(			/* compute ray medium participation 
 		ge *= 1. - colval(r->albedo,GRN);
 		be *= 1. - colval(r->albedo,BLU);
 	}
-	setcolor(ce,	re<=FTINY ? 1. : re>92. ? 0. : exp(-re),
+	setscolor(ce,	re<=FTINY ? 1. : re>92. ? 0. : exp(-re),
 			ge<=FTINY ? 1. : ge>92. ? 0. : exp(-ge),
 			be<=FTINY ? 1. : be>92. ? 0. : exp(-be));
-	multcolor(r->rcol, ce);			/* path extinction */
+	smultscolor(r->rcol, ce);		/* path extinction */
 	if (r->crtype & SHADOW || intens(r->albedo) <= FTINY)
 		return;				/* no scattering */
 	
 	/* PMAP: indirect inscattering accounted for by volume photons? */
 	if (!volumePhotonMapping) {
-		setcolor(ca,
+		setscolor(ca,
 			colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)),
 			colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)),
 			colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU)));
-		addcolor(r->rcol, ca);			/* ambient in scattering */
+		saddscolor(r->rcol, ca);		/* ambient in scattering */
 	}
 	
 	srcscatter(r);				/* source in scattering */
@@ -306,6 +327,7 @@ raymixture(		/* mix modifiers */
 )
 {
 	RAY  fr, br;
+	double  mfore, mback;
 	int  foremat, backmat;
 	int  i;
 					/* bound coefficient */
@@ -319,14 +341,14 @@ raymixture(		/* mix modifiers */
 	fr = *r;
 	if (coef > FTINY) {
 		fr.rweight *= coef;
-		scalecolor(fr.rcoef, coef);
+		scalescolor(fr.rcoef, coef);
 		foremat = rayshade(&fr, fore);
 	}
 					/* background */
 	br = *r;
 	if (coef < 1.0-FTINY) {
 		br.rweight *= 1.0-coef;
-		scalecolor(br.rcoef, 1.0-coef);
+		scalescolor(br.rcoef, 1.0-coef);
 		backmat = rayshade(&br, back);
 	}
 					/* check for transparency */
@@ -340,19 +362,26 @@ raymixture(		/* mix modifiers */
 	for (i = 0; i < 3; i++)
 		r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
 					/* mix pattern colors */
-	scalecolor(fr.pcol, coef);
-	scalecolor(br.pcol, 1.0-coef);
-	copycolor(r->pcol, fr.pcol);
-	addcolor(r->pcol, br.pcol);
+	scalescolor(fr.pcol, coef);
+	scalescolor(br.pcol, 1.0-coef);
+	copyscolor(r->pcol, fr.pcol);
+	saddscolor(r->pcol, br.pcol);
 					/* return value tells if material */
 	if (!foremat & !backmat)
 		return(0);
 					/* mix returned ray values */
-	scalecolor(fr.rcol, coef);
-	scalecolor(br.rcol, 1.0-coef);
-	copycolor(r->rcol, fr.rcol);
-	addcolor(r->rcol, br.rcol);
-	r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
+	scalescolor(fr.rcol, coef);
+	scalescolor(br.rcol, 1.0-coef);
+	copyscolor(r->rcol, fr.rcol);
+	saddscolor(r->rcol, br.rcol);
+	scalescolor(fr.mcol, coef);
+	scalescolor(br.mcol, 1.0-coef);
+	copyscolor(r->mcol, fr.mcol);
+	saddscolor(r->mcol, br.mcol);
+	mfore = pbright(fr.mcol); mback = pbright(br.mcol);
+	r->rmt = mfore > mback ? fr.rmt : br.rmt;
+	r->rxt = pbright(fr.rcol)-mfore > pbright(br.rcol)-mback ?
+			fr.rxt : br.rxt;
 	return(1);
 }
 
@@ -375,27 +404,26 @@ raydist(		/* compute (cumulative) ray distance */
 
 void
 raycontrib(		/* compute (cumulative) ray contribution */
-	RREAL  rc[3],
+	SCOLOR  rc,
 	const RAY  *r,
 	int  flags
 )
 {
-	double	eext[3];
-	int	i;
+	static int	warnedPM = 0;
 
-	eext[0] = eext[1] = eext[2] = 0.;
-	rc[0] = rc[1] = rc[2] = 1.;
+	setscolor(rc, 1., 1., 1.);
 
 	while (r != NULL && r->crtype&flags) {
-		for (i = 3; i--; ) {
-			rc[i] *= colval(r->rcoef,i);
-			eext[i] += r->rot * colval(r->cext,i);
+		smultscolor(rc, r->rcoef);
+					/* check for participating medium */
+		if (!warnedPM && (bright(r->cext) > FTINY) |
+				(bright(r->albedo) > FTINY)) {
+			error(WARNING,
+	"ray contribution calculation does not support participating media");
+			warnedPM++;
 		}
 		r = r->parent;
 	}
-	for (i = 3; i--; )
-		rc[i] *= (eext[i] <= FTINY) ? 1. :
-				(eext[i] > 92.) ? 0. : exp(-eext[i]);
 }
 
 
@@ -485,8 +513,51 @@ flipsurface(			/* reverse surface orientation */
 	r->pert[0] = -r->pert[0];
 	r->pert[1] = -r->pert[1];
 	r->pert[2] = -r->pert[2];
+	r->rflips++;
 }
 
+
+int
+rayreject(		/* check if candidate hit is worse than current */
+	OBJREC *o,
+	RAY *r,
+	double t,
+	double rod
+)
+{
+	OBJREC	*mnew, *mray;
+
+	if ((t <= FTINY) | (t > r->rot + FTINY))
+		return(1);
+	if (t < r->rot - FTINY)		/* is new hit significantly closer? */
+		return(0);
+					/* coincident point, so decide... */
+	if (o == r->ro)
+		return(1);		/* shouldn't happen */
+	if (r->ro == NULL)
+		return(0);		/* ditto */
+	mnew = findmaterial(o);
+	mray = findmaterial(r->ro);	/* check material transparencies */
+	if (mnew == NULL) {
+		if (mray != NULL)
+			return(1);	/* old has material, new does not */
+	} else if (mray == NULL) {
+		return(0);		/* new has material, old does not */
+	} else if (istransp(mnew->otype)) {
+		if (!istransp(mray->otype))
+			return(1);	/* new is transparent, old is not */
+	} else if (istransp(mray->otype)) {
+		return(0);		/* old is transparent, new is not */
+	}
+	if (rod <= 0) {			/* check which side we hit */
+		if (r->rod > 0)
+			return(1);	/* old hit front, new did not */
+	} else if (r->rod <= 0) {
+		return(0);		/* new hit front, old did not */
+	}
+			/* earlier modifier definition wins tie */
+	return (r->ro->omod >= o->omod);
+}
 
 void
 rayhit(			/* standard ray hit test */