--- ray/src/rt/m_wgmdf.c	2024/12/09 00:44:29	2.1
+++ ray/src/rt/m_wgmdf.c	2024/12/18 17:57:06	2.6
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: m_wgmdf.c,v 2.1 2024/12/09 00:44:29 greg Exp $";
+static const char RCSid[] = "$Id: m_wgmdf.c,v 2.6 2024/12/18 17:57:06 greg Exp $";
 #endif
 /*
  *  Shading function for programmable Ward-Geisler-Moroder-Duer material.
@@ -158,6 +158,29 @@ fill_modval(MODVAL *mp, const WGMDDAT *wp)
 	return(set_modval(mp, lastmod(objndx(wp->mtp), mp->nam), wp->rp));
 }
 
+/* set calculation context for given component of MAT_WGMDF */
+static int
+setWGMDfunc(MODVAL *mp, const WGMDDAT *wp)
+{
+	static char	lastMod[MAXSTR];
+	double		sf;
+	FVECT		vec;
+
+	if (setfunc(wp->mtp, wp->rp) == 0 &&
+			!strcmp(mp->nam, lastMod))
+		return(0);	/* already set */
+	strcpy(lastMod, mp->nam);
+				/* else (re)assign special variables */
+	sf = 1 - 2*(wp->rp->rod < 0);
+	varset("RdotP`", '=', mp->pdot*sf);
+	multv3(vec, mp->pnorm, funcxf.xfm);
+	sf /= funcxf.sca;
+	varset("NxP`", '=', vec[0]*sf);
+	varset("NyP`", '=', vec[1]*sf);
+	varset("NzP`", '=', vec[2]*sf);
+	return(1);
+}
+
 /* assign indicated diffuse component (do !trans first) */
 static void
 set_dcomp(WGMDDAT *wp, int trans)
@@ -190,13 +213,23 @@ set_dcomp(WGMDDAT *wp, int trans)
 static void
 set_scomp(WGMDDAT *wp, int trans)
 {
-	SCOMP		*sp = trans ? &wp->ts : &wp->rs;
-	const int	eoff = 3*(trans != 0);
-	double		coef;
-
-	setfunc(wp->mtp, wp->rp);	/* get coefficient, first */
+	SCOMP	*sp = trans ? &wp->ts : &wp->rs;
+	EPNODE  **exa = wp->mf->ep + 3*(trans != 0);
+	double	coef;
+					/* constant zero check */
+	if (exa[0]->type == NUM && exa[0]->v.num <= FTINY) {
+		scolorblack(sp->scol);
+		return;
+	}				/* need modifier */
+	sp->mo.nam = wp->mtp->oargs.sarg[4*(trans != 0)];
+	if (!fill_modval(&sp->mo, wp)) {
+		sprintf(errmsg, "unknown specular %s modifier '%s'",
+			trans ? "transmission" : "reflection", sp->mo.nam);
+		objerror(wp->mtp, USER, errmsg);
+	}
+	setWGMDfunc(&sp->mo, wp);
 	errno = 0;
-	coef = evalue(wp->mf->ep[eoff]);
+	coef = evalue(exa[0]);
 	if ((errno == EDOM) | (errno == ERANGE)) {
 		objerror(wp->mtp, WARNING, "specular compute error");
 		scolorblack(sp->scol);
@@ -205,12 +238,6 @@ set_scomp(WGMDDAT *wp, int trans)
 	if (coef <= FTINY) {		/* negligible value? */
 		scolorblack(sp->scol);
 		return;
-	}				/* else get modifier */
-	sp->mo.nam = wp->mtp->oargs.sarg[4*(trans != 0)];
-	if (!fill_modval(&sp->mo, wp)) {
-		sprintf(errmsg, "unknown specular %s modifier '%s'",
-			trans ? "transmission" : "reflection", sp->mo.nam);
-		objerror(wp->mtp, USER, errmsg);
 	}
 	copyscolor(sp->scol, sp->mo.pcol);
 	scalescolor(sp->scol, coef);
@@ -218,10 +245,9 @@ set_scomp(WGMDDAT *wp, int trans)
 		scolorblack(sp->scol);
 		return;			/* got black pattern */
 	}
-	setfunc(wp->mtp, wp->rp);	/* else get roughness */
-	errno = 0;
-	sp->u_alpha = evalue(wp->mf->ep[eoff+1]);
-	sp->v_alpha = (sp->u_alpha > FTINY) ? evalue(wp->mf->ep[eoff+2]) : 0.0;
+	errno = 0;			/* else get roughness */
+	sp->u_alpha = evalue(exa[1]);
+	sp->v_alpha = (sp->u_alpha > FTINY) ? evalue(exa[2]) : 0.0;
 	if ((errno == EDOM) | (errno == ERANGE)) {
 		objerror(wp->mtp, WARNING, "roughness compute error");
 		scolorblack(sp->scol);
@@ -510,11 +536,15 @@ m_wgmdf(OBJREC *m, RAY *r)
 	}
 	if ((m->oargs.nsargs < 13) | (m->oargs.nfargs < 9))
 		objerror(m, USER, "bad number of arguments");
+
+	if (r->crtype & SHADOW && !strcmp(m->oargs.sarg[5], "0"))
+		return(1);		/* first shadow test */
 	clr_comps(&wd);
 	wd.rp = r;
 	wd.mtp = m;
 	wd.mf = getfunc(m, 12, 0xEEE, 1);
-	setfunc(m, r);			/* get local u vector */
+	set_dcomp(&wd, 0);		/* gets main modifier */
+	setWGMDfunc(&wd.rd.mo, &wd);	/* get local u vector */
 	errno = 0;
 	for (i = 0; i < 3; i++)
 		wd.ulocal[i] = evalue(wd.mf->ep[6+i]);
@@ -523,11 +553,10 @@ m_wgmdf(OBJREC *m, RAY *r)
 	else if (wd.mf->fxp != &unitxf)
 		multv3(wd.ulocal, wd.ulocal, wd.mf->fxp->xfm);
 
-	set_dcomp(&wd, 0);		/* call this first */
-	set_dcomp(&wd, 1);		/* call this second */
 	set_scomp(&wd, 1);		/* sets SP_TPURE */
 	if (r->crtype & SHADOW && !(wd.specfl & SP_TPURE))
-		return(1);		/* early shadow test */
+		return(1);		/* second shadow test */
+	set_dcomp(&wd, 1);
 	set_scomp(&wd, 0);
 	wd.specfl |= SP_FLAT*(r->ro != NULL && isflat(r->ro->otype));
 					/* apply Fresnel adjustments? */
@@ -535,6 +564,7 @@ m_wgmdf(OBJREC *m, RAY *r)
 		const double	fest = FRESNE(fabs(wd.rs.mo.pdot));
 		for (i = NCSAMP; i--; )
 			wd.rs.scol[i] += fest*(1. - wd.rs.scol[i]);
+		scalescolor(wd.rd.scol, 1.-fest);
 		scalescolor(wd.ts.scol, 1.-fest);
 		scalescolor(wd.td.scol, 1.-fest);
 	}