--- ray/src/rt/m_wgmdf.c	2024/12/10 03:16:13	2.2
+++ ray/src/rt/m_wgmdf.c	2024/12/19 23:25:28	2.8
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: m_wgmdf.c,v 2.2 2024/12/10 03:16:13 greg Exp $";
+static const char RCSid[] = "$Id: m_wgmdf.c,v 2.8 2024/12/19 23:25:28 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)
@@ -190,50 +213,45 @@ 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 */
-	errno = 0;
-	coef = evalue(wp->mf->ep[eoff]);
-	if ((errno == EDOM) | (errno == ERANGE)) {
-		objerror(wp->mtp, WARNING, "specular compute error");
-		scolorblack(sp->scol);
-		return;
-	}
-	if (coef <= FTINY) {		/* negligible value? */
-		scolorblack(sp->scol);
-		return;
-	}				/* else get modifier */
+	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)
+		goto blackout;
+					/* 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);
 	}
+	if (sintens(sp->mo.pcol) <= FTINY)
+		goto blackout;		/* got black pattern */
+	setWGMDfunc(&sp->mo, wp);	/* else compute coefficient */
+	errno = 0;
+	coef = evalue(exa[0]);
+	if ((errno == EDOM) | (errno == ERANGE)) {
+		objerror(wp->mtp, WARNING, "specular compute error");
+		goto blackout;
+	}
+	if (coef <= FTINY)		/* negligible value? */
+		goto blackout;
 	copyscolor(sp->scol, sp->mo.pcol);
 	scalescolor(sp->scol, coef);
-	if (sintens(sp->scol) <= FTINY) {
-		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);
-		return;
+		goto blackout;
 	}				/* we have something... */
 	wp->specfl |= trans ? SP_TRAN : SP_REFL;
 	if (sp->v_alpha <= FTINY) {	/* is it pure specular? */
 		wp->specfl |= trans ? SP_TPURE : SP_RPURE;
 		sp->u_alpha = sp->v_alpha = 0.0;
 		return;
-	}
-					/* get anisotropic coordinates */
+	}				/* else get aniso coordinates */
 	fcross(sp->v, sp->mo.pnorm, wp->ulocal);
 	if (normalize(sp->v) == 0.0) {	/* orientation vector==normal? */
 		if (fabs(sp->u_alpha - sp->v_alpha) > 0.001)
@@ -244,6 +262,9 @@ set_scomp(WGMDDAT *wp, int trans)
 			(sp->u_alpha*sp->u_alpha + sp->v_alpha*sp->v_alpha) );
 	} else
 		fcross(sp->u, sp->v, sp->mo.pnorm);
+	return;
+blackout:
+	scolorblack(sp->scol);		/* zero out component */
 }
 
 /* sample anisotropic Gaussian specular */
@@ -517,8 +538,8 @@ m_wgmdf(OBJREC *m, RAY *r)
 	wd.rp = r;
 	wd.mtp = m;
 	wd.mf = getfunc(m, 12, 0xEEE, 1);
-	set_dcomp(&wd, 0);		/* calls main modifier */
-	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]);
@@ -532,12 +553,14 @@ m_wgmdf(OBJREC *m, RAY *r)
 		return(1);		/* second shadow test */
 	set_dcomp(&wd, 1);
 	set_scomp(&wd, 0);
-	wd.specfl |= SP_FLAT*(r->ro != NULL && isflat(r->ro->otype));
+	wd.specfl |= SP_FLAT*(!wd.rs.mo.hastexture &&
+				r->ro != NULL && isflat(r->ro->otype));
 					/* apply Fresnel adjustments? */
 	if (wd.specfl & SP_RPURE && pbright(wd.rs.scol) >= FRESTHRESH) {
 		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);
 	}
@@ -590,8 +613,7 @@ m_wgmdf(OBJREC *m, RAY *r)
 		copyscolor(r->mcol, lr.rcol);
 		saddscolor(r->rcol, lr.rcol);
 		r->rmt = r->rot;
-		if (wd.specfl & SP_FLAT &&
-				!wd.rs.mo.hastexture | (r->crtype & AMBIENT))
+		if (wd.specfl & SP_FLAT && r->crtype & AMBIENT)
 			r->rmt += raydistance(&lr);
 	}
 	if (wd.specfl & (SP_REFL|SP_TRAN))	/* specularly scattered rays */