--- ray/src/rt/m_brdf.c	1991/05/08 08:27:50	1.7
+++ ray/src/rt/m_brdf.c	1991/08/12 08:20:53	1.16
@@ -122,7 +122,7 @@ double  omega;			/* light source size */
 	if (ldot > 0.0 ? np->rspec <= FTINY : np->tspec <= FTINY)
 		return;		/* no specular component */
 					/* set up function */
-	setfunc(np->mp, np->pr);
+	setbrdfunc(np);
 	sa = np->mp->oargs.sarg;
 	errno = 0;
 					/* transform light vector */
@@ -191,8 +191,7 @@ register RAY  *r;
 	BRDFDAT  nd;
 	double  transtest, transdist;
 	COLOR  ctmp;
-	double  dtmp;
-	FVECT  vec;
+	double  dtmp, tspect, rspecr;
 	register int  i;
 						/* check arguments */
 	switch (m->otype) {
@@ -237,7 +236,6 @@ register RAY  *r;
 	raytexture(r, m->omod);
 	nd.pdot = raynormal(nd.pnorm, r);	/* perturb normal */
 	multcolor(nd.mcolor, r->pcol);		/* modify material color */
-	r->rt = r->rot;				/* default ray length */
 	transtest = 0;
 						/* load auxiliary files */
 	if (m->otype == MAT_PDATA || m->otype == MAT_MDATA
@@ -248,46 +246,39 @@ register RAY  *r;
 				break;
 		if (i-3 != nd.dp->nd)
 			objerror(m, USER, "dimension error");
-		if (!fundefined(m->oargs.sarg[3]))
-			loadfunc(m->oargs.sarg[2]);
+		funcfile(m->oargs.sarg[2]);
 	} else if (m->otype == MAT_BRTDF) {
 		nd.dp = NULL;
-		if (!fundefined(m->oargs.sarg[7]))
-			loadfunc(m->oargs.sarg[9]);
+		funcfile(m->oargs.sarg[9]);
 	} else {
 		nd.dp = NULL;
-		if (!fundefined(m->oargs.sarg[0]))
-			loadfunc(m->oargs.sarg[1]);
+		funcfile(m->oargs.sarg[1]);
 	}
 						/* set special variables */
-	setfunc(m, r);
-	multv3(vec, nd.pnorm, funcxf.xfm);
-	varset("NxP", '=', vec[0]/funcxf.sca);
-	varset("NyP", '=', vec[1]/funcxf.sca);
-	varset("NzP", '=', vec[2]/funcxf.sca);
-	varset("RdotP", '=', nd.pdot);
-	varset("CrP", '=', colval(nd.mcolor,RED));
-	varset("CgP", '=', colval(nd.mcolor,GRN));
-	varset("CbP", '=', colval(nd.mcolor,BLU));
+	setbrdfunc(&nd);
 						/* compute transmitted ray */
+	tspect = 0.;
 	if (m->otype == MAT_BRTDF && nd.tspec > FTINY) {
 		RAY  sr;
 		errno = 0;
-		setcolor(ctmp, varvalue(m->oargs.sarg[0]),
-				varvalue(m->oargs.sarg[1]),
-				varvalue(m->oargs.sarg[2]));
-		scalecolor(ctmp, nd.tspec);
+		setcolor(ctmp, varvalue(m->oargs.sarg[3]),
+				varvalue(m->oargs.sarg[4]),
+				varvalue(m->oargs.sarg[5]));
+		scalecolor(ctmp, nd.trans);
 		if (errno)
 			objerror(m, WARNING, "compute error");
-		else if ((dtmp = bright(ctmp)) > FTINY &&
-				rayorigin(&sr, r, TRANS, dtmp) == 0) {
-			if (DOT(r->pert,r->pert) > FTINY*FTINY) {
+		else if ((tspect = bright(ctmp)) > FTINY &&
+				rayorigin(&sr, r, TRANS, tspect) == 0) {
+			if (!(r->crtype & SHADOW) &&
+					DOT(r->pert,r->pert) > FTINY*FTINY) {
 				for (i = 0; i < 3; i++)	/* perturb direction */
 					sr.rdir[i] = r->rdir[i] -
 							.75*r->pert[i];
 				normalize(sr.rdir);
-			} else
+			} else {
+				VCOPY(sr.rdir, r->rdir);
 				transtest = 2;
+			}
 			rayvalue(&sr);
 			multcolor(sr.rcol, ctmp);
 			addcolor(r->rcol, sr.rcol);
@@ -298,17 +289,17 @@ register RAY  *r;
 	if (r->crtype & SHADOW)			/* the rest is shadow */
 		return;
 						/* compute reflected ray */
+	rspecr = 0.;
 	if (m->otype == MAT_BRTDF && nd.rspec > FTINY) {
 		RAY  sr;
 		errno = 0;
-		setcolor(ctmp, varvalue(m->oargs.sarg[3]),
-				varvalue(m->oargs.sarg[4]),
-				varvalue(m->oargs.sarg[5]));
-		scalecolor(ctmp, nd.rspec);
+		setcolor(ctmp, varvalue(m->oargs.sarg[0]),
+				varvalue(m->oargs.sarg[1]),
+				varvalue(m->oargs.sarg[2]));
 		if (errno)
 			objerror(m, WARNING, "compute error");
-		else if ((dtmp = bright(ctmp)) > FTINY &&
-				rayorigin(&sr, r, REFLECTED, dtmp) == 0) {
+		else if ((rspecr = bright(ctmp)) > FTINY &&
+				rayorigin(&sr, r, REFLECTED, rspecr) == 0) {
 			for (i = 0; i < 3; i++)
 				sr.rdir[i] = r->rdir[i] +
 						2.0*nd.pdot*nd.pnorm[i];
@@ -318,22 +309,16 @@ register RAY  *r;
 		}
 	}
 						/* compute ambient */
-	if (nd.rdiff > FTINY) {
+	if ((dtmp = 1.0-nd.trans-rspecr) > FTINY) {
 		ambient(ctmp, r);
-		if (m->otype == MAT_BRTDF)
-			scalecolor(ctmp, nd.rdiff);
-		else
-			scalecolor(ctmp, 1.0-nd.trans);
+		scalecolor(ctmp, dtmp);
 		multcolor(ctmp, nd.mcolor);	/* modified by material color */
 		addcolor(r->rcol, ctmp);	/* add to returned color */
 	}
-	if (nd.tdiff > FTINY) {			/* from other side */
+	if ((dtmp = nd.trans-tspect) > FTINY) {	/* from other side */
 		flipsurface(r);
 		ambient(ctmp, r);
-		if (m->otype == MAT_BRTDF)
-			scalecolor(ctmp, nd.tdiff);
-		else
-			scalecolor(ctmp, nd.trans);
+		scalecolor(ctmp, dtmp);
 		multcolor(ctmp, nd.mcolor);
 		addcolor(r->rcol, ctmp);
 		flipsurface(r);
@@ -343,4 +328,25 @@ register RAY  *r;
 						/* check distance */
 	if (transtest > bright(r->rcol))
 		r->rt = transdist;
+}
+
+
+setbrdfunc(np)			/* set up brdf function and variables */
+register BRDFDAT  *np;
+{
+	FVECT  vec;
+
+	if (setfunc(np->mp, np->pr) == 0)
+		return(0);	/* it's OK, setfunc says we're done */
+				/* else (re)assign special variables */
+	multv3(vec, np->pnorm, funcxf.xfm);
+	varset("NxP", '=', vec[0]/funcxf.sca);
+	varset("NyP", '=', vec[1]/funcxf.sca);
+	varset("NzP", '=', vec[2]/funcxf.sca);
+	varset("RdotP", '=', np->pdot <= -1.0 ? -1.0 :
+			np->pdot >= 1.0 ? 1.0 : np->pdot);
+	varset("CrP", '=', colval(np->mcolor,RED));
+	varset("CgP", '=', colval(np->mcolor,GRN));
+	varset("CbP", '=', colval(np->mcolor,BLU));
+	return(1);
 }