--- ray/src/rt/m_brdf.c	1993/11/18 09:43:04	2.9
+++ ray/src/rt/m_brdf.c	2004/03/30 16:13:01	2.21
@@ -1,19 +1,18 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: m_brdf.c,v 2.21 2004/03/30 16:13:01 schorsch Exp $";
 #endif
-
 /*
  *  Shading for materials with arbitrary BRDF's
  */
 
-#include  "ray.h"
+#include "copyright.h"
 
+#include  "ray.h"
+#include  "ambient.h"
 #include  "data.h"
-
+#include  "source.h"
 #include  "otypes.h"
-
+#include  "rtotypes.h"
 #include  "func.h"
 
 /*
@@ -78,20 +77,27 @@ typedef struct {
 }  BRDFDAT;		/* BRDF material data */
 
 
-dirbrdf(cval, np, ldir, omega)		/* compute source contribution */
-COLOR  cval;			/* returned coefficient */
-register BRDFDAT  *np;		/* material data */
-FVECT  ldir;			/* light source direction */
-double  omega;			/* light source size */
+static srcdirf_t dirbrdf;
+static int setbrdfunc(BRDFDAT  *np);
+
+
+static void
+dirbrdf(		/* compute source contribution */
+	COLOR  cval,			/* returned coefficient */
+	void  *nnp,		/* material data */
+	FVECT  ldir,			/* light source direction */
+	double  omega			/* light source size */
+)
 {
+	register BRDFDAT *np = nnp;
 	double  ldot;
 	double  dtmp;
 	COLOR  ctmp;
 	FVECT  ldx;
-	double  lddx[3], pt[MAXDIM];
-	double  vldx[4];
+	static double  vldx[5], pt[MAXDIM];
 	register char	**sa;
 	register int	i;
+#define lddx (vldx+1)
 
 	setcolor(cval, 0.0, 0.0, 0.0);
 	
@@ -132,35 +138,35 @@ double  omega;			/* light source size */
 	multv3(ldx, ldir, funcxf.xfm);
 	for (i = 0; i < 3; i++)
 		lddx[i] = ldx[i]/funcxf.sca;
+	lddx[3] = omega;
 					/* compute BRTDF */
 	if (np->mp->otype == MAT_BRTDF) {
 		if (sa[6][0] == '0')		/* special case */
 			colval(ctmp,RED) = 0.0;
 		else
-			colval(ctmp,RED) = funvalue(sa[6], 3, lddx);
+			colval(ctmp,RED) = funvalue(sa[6], 4, lddx);
 		if (!strcmp(sa[7],sa[6]))
 			colval(ctmp,GRN) = colval(ctmp,RED);
 		else
-			colval(ctmp,GRN) = funvalue(sa[7], 3, lddx);
+			colval(ctmp,GRN) = funvalue(sa[7], 4, lddx);
 		if (!strcmp(sa[8],sa[6]))
 			colval(ctmp,BLU) = colval(ctmp,RED);
 		else if (!strcmp(sa[8],sa[7]))
 			colval(ctmp,BLU) = colval(ctmp,GRN);
 		else
-			colval(ctmp,BLU) = funvalue(sa[8], 3, lddx);
+			colval(ctmp,BLU) = funvalue(sa[8], 4, lddx);
 		dtmp = bright(ctmp);
 	} else if (np->dp == NULL) {
-		dtmp = funvalue(sa[0], 3, lddx);
+		dtmp = funvalue(sa[0], 4, lddx);
 		setcolor(ctmp, dtmp, dtmp, dtmp);
 	} else {
 		for (i = 0; i < np->dp->nd; i++)
-			pt[i] = funvalue(sa[3+i], 3, lddx);
+			pt[i] = funvalue(sa[3+i], 4, lddx);
 		vldx[0] = datavalue(np->dp, pt);
-		vldx[1] = lddx[0]; vldx[2] = lddx[1]; vldx[3] = lddx[2];
-		dtmp = funvalue(sa[0], 4, vldx);
+		dtmp = funvalue(sa[0], 5, vldx);
 		setcolor(ctmp, dtmp, dtmp, dtmp);
 	}
-	if (errno) {
+	if (errno == EDOM || errno == ERANGE) {
 		objerror(np->mp, WARNING, "compute error");
 		return;
 	}
@@ -170,7 +176,7 @@ double  omega;			/* light source size */
 		/*
 		 *  Compute reflected non-diffuse component.
 		 */
-		if (np->mp->otype == MAT_MFUNC | np->mp->otype == MAT_MDATA)
+		if ((np->mp->otype == MAT_MFUNC) | (np->mp->otype == MAT_MDATA))
 			multcolor(ctmp, np->mcolor);
 		dtmp = ldot * omega * np->rspec;
 		scalecolor(ctmp, dtmp);
@@ -179,28 +185,33 @@ double  omega;			/* light source size */
 		/*
 		 *  Compute transmitted non-diffuse component.
 		 */
-		if (np->mp->otype == MAT_TFUNC | np->mp->otype == MAT_TDATA)
+		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);
 	}
+#undef lddx
 }
 
 
-m_brdf(m, r)			/* color a ray which hit a BRDTF material */
-register OBJREC  *m;
-register RAY  *r;
+extern int
+m_brdf(			/* color a ray that hit a BRDTfunc material */
+	register OBJREC  *m,
+	register RAY  *r
+)
 {
+	int  hitfront = 1;
 	BRDFDAT  nd;
 	RAY  sr;
 	double  transtest, transdist;
 	int  hasrefl, hastrans;
 	COLOR  ctmp;
+	FVECT  vtmp;
 	register MFUNC  *mf;
 	register int  i;
 						/* check arguments */
-	if (m->oargs.nsargs < 10 | m->oargs.nfargs < 9)
+	if ((m->oargs.nsargs < 10) | (m->oargs.nfargs < 9))
 		objerror(m, USER, "bad # arguments");
 	nd.mp = m;
 	nd.pr = r;
@@ -220,7 +231,7 @@ register RAY  *r;
 	setcolor(nd.tdiff, m->oargs.farg[6],
 			m->oargs.farg[7],
 			m->oargs.farg[8]);
-					/* get modifiers */
+						/* get modifiers */
 	raytexture(r, m->omod);
 	nd.pdot = raynormal(nd.pnorm, r);	/* perturb normal */
 	if (r->rod < 0.0) {			/* orient perturbed values */
@@ -229,6 +240,7 @@ register RAY  *r;
 			nd.pnorm[i] = -nd.pnorm[i];
 			r->pert[i] = -r->pert[i];
 		}
+		hitfront = 0;
 	}
 	copycolor(nd.mcolor, r->pcol);		/* get pattern color */
 	multcolor(nd.rdiff, nd.mcolor);		/* modify diffuse values */
@@ -246,7 +258,7 @@ register RAY  *r;
 	setcolor(ctmp, evalue(mf->ep[3]),
 			evalue(mf->ep[4]),
 			evalue(mf->ep[5]));
-	if (errno)
+	if (errno == EDOM || errno == ERANGE)
 		objerror(m, WARNING, "compute error");
 	else if (rayorigin(&sr, r, TRANS, bright(ctmp)) == 0) {
 		if (!(r->crtype & SHADOW) &&
@@ -268,14 +280,14 @@ register RAY  *r;
 		transdist = r->rot + sr.rt;
 	}
 	if (r->crtype & SHADOW)			/* the rest is shadow */
-		return;
+		return(1);
 						/* compute reflected ray */
 	setbrdfunc(&nd);
 	errno = 0;
 	setcolor(ctmp, evalue(mf->ep[0]),
 			evalue(mf->ep[1]),
 			evalue(mf->ep[2]));
-	if (errno)
+	if (errno == EDOM || errno == ERANGE)
 		objerror(m, WARNING, "compute error");
 	else if (rayorigin(&sr, r, REFLECTED, bright(ctmp)) == 0) {
 		for (i = 0; i < 3; i++)
@@ -286,21 +298,24 @@ register RAY  *r;
 	}
 						/* compute ambient */
 	if (hasrefl) {
-		if (nd.pdot < 0.0)
+		if (!hitfront)
 			flipsurface(r);
-		ambient(ctmp, r);
+		ambient(ctmp, r, nd.pnorm);
 		multcolor(ctmp, nd.rdiff);
 		addcolor(r->rcol, ctmp);	/* add to returned color */
-		if (nd.pdot < 0.0)
+		if (!hitfront)
 			flipsurface(r);
 	}
 	if (hastrans) {				/* from other side */
-		if (nd.pdot > 0.0)
+		if (hitfront)
 			flipsurface(r);
-		ambient(ctmp, r);
+		vtmp[0] = -nd.pnorm[0];
+		vtmp[1] = -nd.pnorm[1];
+		vtmp[2] = -nd.pnorm[2];
+		ambient(ctmp, r, vtmp);
 		multcolor(ctmp, nd.tdiff);
 		addcolor(r->rcol, ctmp);
-		if (nd.pdot > 0.0)
+		if (hitfront)
 			flipsurface(r);
 	}
 	if (hasrefl | hastrans || m->oargs.sarg[6][0] != '0')
@@ -308,24 +323,41 @@ register RAY  *r;
 						/* check distance */
 	if (transtest > bright(r->rcol))
 		r->rt = transdist;
+
+	return(1);
 }
 
 
 
-m_brdf2(m, r)			/* color a ray which hit a BRDF material */
-register OBJREC  *m;
-register RAY  *r;
+extern int
+m_brdf2(			/* color a ray that hit a BRDF material */
+	register OBJREC  *m,
+	register RAY  *r
+)
 {
 	BRDFDAT  nd;
 	COLOR  ctmp;
+	FVECT  vtmp;
 	double  dtmp;
 						/* always a shadow */
 	if (r->crtype & SHADOW)
-		return;
+		return(1);
 						/* check arguments */
-	if (m->oargs.nsargs < (hasdata(m->otype)?4:2) | m->oargs.nfargs <
-			(m->otype==MAT_TFUNC|m->otype==MAT_TDATA?6:4))
+	if ((m->oargs.nsargs < (hasdata(m->otype)?4:2)) | (m->oargs.nfargs <
+			((m->otype==MAT_TFUNC)|(m->otype==MAT_TDATA)?6:4)))
 		objerror(m, USER, "bad # arguments");
+						/* check for back side */
+	if (r->rod < 0.0) {
+		if (!backvis && m->otype != MAT_TFUNC
+				&& m->otype != MAT_TDATA) {
+			raytrans(r);
+			return(1);
+		}
+		raytexture(r, m->omod);
+		flipsurface(r);			/* reorient if backvis */
+	} else
+		raytexture(r, m->omod);
+
 	nd.mp = m;
 	nd.pr = r;
 						/* get material color */
@@ -335,7 +367,7 @@ register RAY  *r;
 						/* get specular component */
 	nd.rspec = m->oargs.farg[3];
 						/* compute transmittance */
-	if (m->otype == MAT_TFUNC | m->otype == MAT_TDATA) {
+	if ((m->otype == MAT_TFUNC) | (m->otype == MAT_TDATA)) {
 		nd.trans = m->oargs.farg[4]*(1.0 - nd.rspec);
 		nd.tspec = nd.trans * m->oargs.farg[5];
 		dtmp = nd.trans - nd.tspec;
@@ -347,11 +379,6 @@ register RAY  *r;
 						/* compute reflectance */
 	dtmp = 1.0 - nd.trans - nd.rspec;
 	setcolor(nd.rdiff, dtmp, dtmp, dtmp);
-						/* fix orientation */
-	if (r->rod < 0.0)
-		flipsurface(r);
-						/* get modifiers */
-	raytexture(r, m->omod);
 	nd.pdot = raynormal(nd.pnorm, r);	/* perturb normal */
 	multcolor(nd.mcolor, r->pcol);		/* modify material color */
 	multcolor(nd.rdiff, nd.mcolor);
@@ -366,14 +393,17 @@ register RAY  *r;
 	}
 						/* compute ambient */
 	if (nd.trans < 1.0-FTINY) {
-		ambient(ctmp, r);
+		ambient(ctmp, r, nd.pnorm);
 		scalecolor(ctmp, 1.0-nd.trans);
 		multcolor(ctmp, nd.mcolor);	/* modified by material color */
 		addcolor(r->rcol, ctmp);	/* add to returned color */
 	}
 	if (nd.trans > FTINY) {		/* from other side */
 		flipsurface(r);
-		ambient(ctmp, r);
+		vtmp[0] = -nd.pnorm[0];
+		vtmp[1] = -nd.pnorm[1];
+		vtmp[2] = -nd.pnorm[2];
+		ambient(ctmp, r, vtmp);
 		scalecolor(ctmp, nd.trans);
 		multcolor(ctmp, nd.mcolor);
 		addcolor(r->rcol, ctmp);
@@ -381,11 +411,15 @@ register RAY  *r;
 	}
 						/* add direct component */
 	direct(r, dirbrdf, &nd);
+
+	return(1);
 }
 
 
-setbrdfunc(np)			/* set up brdf function and variables */
-register BRDFDAT  *np;
+static int
+setbrdfunc(			/* set up brdf function and variables */
+	register BRDFDAT  *np
+)
 {
 	FVECT  vec;