--- ray/src/rt/m_brdf.c	1991/05/07 17:19:52	1.5
+++ ray/src/rt/m_brdf.c	1991/11/25 09:51:03	2.2
@@ -1,4 +1,4 @@
-/* Copyright (c) 1990 Regents of the University of California */
+/* Copyright (c) 1991 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -14,6 +14,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "otypes.h"
 
+#include  "func.h"
+
 /*
  *	Arguments to this material include the color and specularity.
  *  String arguments include the reflection function and files.
@@ -58,15 +60,11 @@ static char SCCSid[] = "$SunId$ LBL";
  *		CrP, CgP, CbP -		perturbed material color
  */
 
-extern double	funvalue(), varvalue();
-extern XF  funcxf;
-
 typedef struct {
 	OBJREC  *mp;		/* material pointer */
 	RAY  *pr;		/* intersected ray */
 	DATARRAY  *dp;		/* data array for PDATA, MDATA or TDATA */
 	COLOR  mcolor;		/* color of this material */
-	COLOR  scolor;		/* color of specular reflection */
 	double  rspec;		/* specular reflection */
 	double	rdiff;		/* diffuse reflection */
 	double  trans;		/* transmissivity */
@@ -123,7 +121,7 @@ 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 */
@@ -133,13 +131,13 @@ double  omega;			/* light source size */
 					/* compute BRTDF */
 	if (np->mp->otype == MAT_BRTDF) {
 		colval(ctmp,RED) = funvalue(sa[6], 3, ldx);
-		if (sa[7] == sa[6])
+		if (!strcmp(sa[7],sa[6]))
 			colval(ctmp,GRN) = colval(ctmp,RED);
 		else
 			colval(ctmp,GRN) = funvalue(sa[7], 3, ldx);
-		if (sa[8] == sa[6])
+		if (!strcmp(sa[8],sa[6]))
 			colval(ctmp,BLU) = colval(ctmp,RED);
-		else if (sa[8] == sa[7])
+		else if (!strcmp(sa[8],sa[7]))
 			colval(ctmp,BLU) = colval(ctmp,GRN);
 		else
 			colval(ctmp,BLU) = funvalue(sa[8], 3, ldx);
@@ -154,30 +152,31 @@ double  omega;			/* light source size */
 		dtmp = funvalue(sa[0], 1, &dtmp);
 		setcolor(ctmp, dtmp, dtmp, dtmp);
 	}
-	if (errno)
-		goto computerr;
+	if (errno) {
+		objerror(np->mp, WARNING, "compute error");
+		return;
+	}
 	if (dtmp <= FTINY)
 		return;
 	if (ldot > 0.0) {
 		/*
 		 *  Compute reflected non-diffuse component.
 		 */
-		multcolor(ctmp, np->scolor);
-		dtmp = ldot * omega;
+		if (np->mp->otype == MAT_MFUNC || np->mp->otype == MAT_MDATA)
+			multcolor(ctmp, np->mcolor);
+		dtmp = ldot * omega * np->rspec;
 		scalecolor(ctmp, dtmp);
 		addcolor(cval, ctmp);
 	} else {
 		/*
 		 *  Compute transmitted non-diffuse component.
 		 */
+		if (np->mp->otype == MAT_TFUNC || np->mp->otype == MAT_TDATA)
+			multcolor(ctmp, np->mcolor);
 		dtmp = -ldot * omega * np->tspec;
 		scalecolor(ctmp, dtmp);
 		addcolor(cval, ctmp);
 	}
-	return;
-computerr:
-	objerror(np->mp, WARNING, "compute error");
-	return;
 }
 
 
@@ -187,9 +186,10 @@ register RAY  *r;
 {
 	int  minsa, minfa;
 	BRDFDAT  nd;
+	double  transtest, transdist;
 	COLOR  ctmp;
-	double  dtmp;
-	FVECT  vec;
+	double  dtmp, tspect, rspecr;
+	MFUNC  *mf;
 	register int  i;
 						/* check arguments */
 	switch (m->otype) {
@@ -234,108 +234,112 @@ 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
-			|| m->otype == MAT_TDATA) {
+	if (hasdata(m->otype)) {
 		nd.dp = getdata(m->oargs.sarg[1]);
-		for (i = 3; i < m->oargs.nsargs; i++)
-			if (m->oargs.sarg[i][0] == '-')
-				break;
-		if (i-3 != nd.dp->nd)
-			objerror(m, USER, "dimension error");
-		if (!fundefined(m->oargs.sarg[3]))
-			loadfunc(m->oargs.sarg[2]);
+		i = (1 << nd.dp->nd) - 1;
+		mf = getfunc(m, 2, i<<3, 0);
 	} else if (m->otype == MAT_BRTDF) {
 		nd.dp = NULL;
-		if (!fundefined(m->oargs.sarg[7]))
-			loadfunc(m->oargs.sarg[9]);
+		mf = getfunc(m, 9, 0x3f, 0);
 	} else {
 		nd.dp = NULL;
-		if (!fundefined(m->oargs.sarg[0]))
-			loadfunc(m->oargs.sarg[1]);
+		mf = getfunc(m, 1, 0, 0);
 	}
 						/* 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, evalue(mf->ep[3]),
+				evalue(mf->ep[4]),
+				evalue(mf->ep[5]));
+		scalecolor(ctmp, nd.trans);
 		if (errno)
 			objerror(m, WARNING, "compute error");
-		else if ((dtmp = bright(ctmp)) > FTINY &&
-				rayorigin(&sr, r, TRANS, dtmp) == 0) {
-			VCOPY(sr.rdir, r->rdir);
+		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 {
+				VCOPY(sr.rdir, r->rdir);
+				transtest = 2;
+			}
 			rayvalue(&sr);
 			multcolor(sr.rcol, ctmp);
 			addcolor(r->rcol, sr.rcol);
-			if (dtmp > .5)
-				r->rt = r->rot + sr.rt;
+			transtest *= bright(sr.rcol);
+			transdist = r->rot + sr.rt;
 		}
 	}
 	if (r->crtype & SHADOW)			/* the rest is shadow */
 		return;
-	if (nd.rspec > FTINY) {			/* has specular component */
-						/* compute specular color */
-		if (m->otype == MAT_MFUNC || m->otype == MAT_MDATA)
-			copycolor(nd.scolor, nd.mcolor);
-		else
-			setcolor(nd.scolor, 1.0, 1.0, 1.0);
-		scalecolor(nd.scolor, nd.rspec);
 						/* compute reflected ray */
-		if (m->otype == MAT_BRTDF) {
-			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);
-			if (errno)
-				objerror(m, WARNING, "compute error");
-			else if ((dtmp = bright(ctmp)) > FTINY &&
-				rayorigin(&sr, r, REFLECTED, dtmp) == 0) {
-				for (i = 0; i < 3; i++)
-					sr.rdir[i] = r->rdir[i] +
+	rspecr = 0.;
+	if (m->otype == MAT_BRTDF && nd.rspec > FTINY) {
+		RAY  sr;
+		errno = 0;
+		setcolor(ctmp, evalue(mf->ep[0]),
+				evalue(mf->ep[1]),
+				evalue(mf->ep[2]));
+		if (errno)
+			objerror(m, WARNING, "compute error");
+		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];
-				rayvalue(&sr);
-				multcolor(sr.rcol, ctmp);
-				addcolor(r->rcol, sr.rcol);
-			}
+			rayvalue(&sr);
+			multcolor(sr.rcol, ctmp);
+			addcolor(r->rcol, sr.rcol);
 		}
 	}
 						/* 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);
 	}
 						/* add direct component */
 	direct(r, dirbrdf, &nd);
+						/* 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);
 }