--- ray/src/util/cmbsdf.c	2014/01/20 22:18:29	2.2
+++ ray/src/util/cmbsdf.c	2021/01/19 23:32:00	2.9
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: cmbsdf.c,v 2.2 2014/01/20 22:18:29 greg Exp $";
+static const char RCSid[] = "$Id: cmbsdf.c,v 2.9 2021/01/19 23:32:00 greg Exp $";
 #endif
 /*
  * Load and convert BSDF into color coefficient matrix representation.
@@ -15,7 +15,7 @@ static const char RCSid[] = "$Id: cmbsdf.c,v 2.2 2014/
 
 /* Convert a BSDF to our matrix representation */
 static CMATRIX *
-cm_bsdf(const COLOR diffBSDF, const COLOR specCol, const SDMat *bsdf)
+cm_bsdf(const COLOR diffBSDF, const SDMat *bsdf)
 {
 	CMATRIX	*cm = cm_alloc(bsdf->nout, bsdf->ninc);
 	int	nbadohm = 0;
@@ -28,15 +28,18 @@ cm_bsdf(const COLOR diffBSDF, const COLOR specCol, con
 		nbadohm += (dom <= 0);
 
 		for (r = 0; r < cm->nrows; r++) {
-			float	f = mBSDF_value(bsdf,c,r);
+			float	f = mBSDF_value(bsdf,r,c);
 			COLORV	*mp = cm_lval(cm,r,c);
 					/* check BSDF value */
 			if ((f <= 0) | (dom <= 0)) {
 				nneg += (f < -FTINY);
-				f = .0f;
-			}
-			copycolor(mp, specCol);
-			scalecolor(mp, f);
+				setcolor(mp, .0f, .0f, .0f);
+			} else if (bsdf->chroma != NULL) {
+				C_COLOR	cxy;
+				c_decodeChroma(&cxy, mBSDF_chroma(bsdf,r,c));
+				ccy2rgb(&cxy, f, mp);
+			} else
+				setcolor(mp, f, f, f);
 			addcolor(mp, diffBSDF);
 			scalecolor(mp, dom);
 		}
@@ -76,7 +79,7 @@ recip_in_from_out(const SDMat *bsdf, int out_recip)
 
 /* Convert a BSDF to our matrix representation, applying reciprocity */
 static CMATRIX *
-cm_bsdf_recip(const COLOR diffBSDF, const COLOR specCol, const SDMat *bsdf)
+cm_bsdf_recip(const COLOR diffBSDF, const SDMat *bsdf)
 {
 	CMATRIX	*cm = cm_alloc(bsdf->ninc, bsdf->nout);
 	int	nbadohm = 0;
@@ -91,15 +94,18 @@ cm_bsdf_recip(const COLOR diffBSDF, const COLOR specCo
 
 		for (r = 0; r < cm->nrows; r++) {
 			const int	ri = recip_in_from_out(bsdf,r);
-			float		f = mBSDF_value(bsdf,ri,ro);
+			float		f = mBSDF_value(bsdf,ro,ri);
 			COLORV		*mp = cm_lval(cm,r,c);
 					/* check BSDF value */
 			if ((f <= 0) | (dom <= 0)) {
 				nneg += (f < -FTINY);
-				f = .0f;
-			}
-			copycolor(mp, specCol);
-			scalecolor(mp, f);
+				setcolor(mp, .0f, .0f, .0f);
+			} else if (bsdf->chroma != NULL) {
+				C_COLOR	cxy;
+				c_decodeChroma(&cxy, mBSDF_chroma(bsdf,ro,ri));
+				ccy2rgb(&cxy, f, mp);
+			} else
+				setcolor(mp, f, f, f);
 			addcolor(mp, diffBSDF);
 			scalecolor(mp, dom);
 		}
@@ -117,54 +123,91 @@ cm_bsdf_recip(const COLOR diffBSDF, const COLOR specCo
 static CMATRIX *
 cm_bsdf_Lamb(const COLOR diffBSDF)
 {
-	CMATRIX	*cm = cm_alloc(145, 145);	/* this is a hack */
-	int	r, c;
+	CMATRIX		*cm = cm_alloc(145, 145);	/* this is a hack */
+	ANGLE_BASIS	*abase = abase_list;
+	int		r, c;
 
-	for (c = 0; c < cm->ncols; c++)
+	while (abase->nangles != cm->nrows)
+		if (++abase >= abase_list+nabases)
+			error(INTERNAL, "Code error in cm_bsdf_Lamb()");
+
+	for (c = 0; c < cm->ncols; c++) {
+		const double	dom = io_getohm(c,abase);
 		for (r = 0; r < cm->nrows; r++) {
 			COLORV	*mp = cm_lval(cm,r,c);
 			copycolor(mp, diffBSDF);
+			scalecolor(mp, dom);
 		}
+	}
 	return(cm);
 }
 
 /* Load and convert a matrix BTDF from the given XML file */
 CMATRIX *
-cm_loadBTDF(char *fname)
+cm_loadBTDF(const char *fname)
 {
 	CMATRIX		*Tmat;
-	char		*fpath;
 	int		recip;
 	SDError		ec;
 	SDData		myBSDF;
 	SDSpectralDF	*tdf;
-	COLOR		diffBSDF, specCol;
-					/* find path to BSDF file */
-	fpath = getpath(fname, getrlibpath(), R_OK);
-	if (fpath == NULL) {
-		sprintf(errmsg, "cannot find BSDF file '%s'", fname);
-		error(USER, errmsg);
-	}
+	COLOR		diffBTDF;
+
 	SDclearBSDF(&myBSDF, fname);	/* load XML and check type */
-	ec = SDloadFile(&myBSDF, fpath);
+	ec = SDloadFile(&myBSDF, fname);
 	if (ec)
 		error(USER, transSDError(ec));
-	ccy2rgb(&myBSDF.tLamb.spec, myBSDF.tLamb.cieY/PI, diffBSDF);
+	ccy2rgb(&myBSDF.tLamb.spec, myBSDF.tLamb.cieY/PI, diffBTDF);
 	recip = (myBSDF.tb == NULL);
 	tdf = recip ? myBSDF.tf : myBSDF.tb;
 	if (tdf == NULL) {		/* no non-Lambertian transmission? */
 		SDfreeBSDF(&myBSDF);
-		return(cm_bsdf_Lamb(diffBSDF));
+		return(cm_bsdf_Lamb(diffBTDF));
 	}
 	if (tdf->ncomp != 1 || tdf->comp[0].func != &SDhandleMtx) {
-		sprintf(errmsg, "unsupported BSDF '%s'", fpath);
+		sprintf(errmsg, "unsupported BSDF '%s'", fname);
 		error(USER, errmsg);
 	}
 					/* convert BTDF to matrix */
-	ccy2rgb(&tdf->comp[0].cspec[0], 1., specCol);
-	Tmat = recip ? cm_bsdf_recip(diffBSDF, specCol, (SDMat *)tdf->comp[0].dist)
-			: cm_bsdf(diffBSDF, specCol, (SDMat *)tdf->comp[0].dist);
+	Tmat = recip ? cm_bsdf_recip(diffBTDF, (SDMat *)tdf->comp[0].dist)
+			: cm_bsdf(diffBTDF, (SDMat *)tdf->comp[0].dist);
 					/* free BSDF and return */
 	SDfreeBSDF(&myBSDF);
 	return(Tmat);
+}
+
+/* Load and convert a matrix BRDF from the given XML file */
+CMATRIX *
+cm_loadBRDF(const char *fname, int backside)
+{
+	CMATRIX		*Rmat;
+	SDError		ec;
+	SDData		myBSDF;
+	SDSpectralDF	*rdf;
+	COLOR		diffBRDF;
+
+	SDclearBSDF(&myBSDF, fname);	/* load XML and check type */
+	ec = SDloadFile(&myBSDF, fname);
+	if (ec)
+		error(USER, transSDError(ec));
+	if (backside) {
+		ccy2rgb(&myBSDF.rLambBack.spec, myBSDF.rLambBack.cieY/PI, diffBRDF);
+		rdf = myBSDF.rb;
+	} else {
+		ccy2rgb(&myBSDF.rLambFront.spec, myBSDF.rLambFront.cieY/PI, diffBRDF);
+		rdf = myBSDF.rf;
+	}
+	if (rdf == NULL) {		/* no non-Lambertian reflection? */
+		SDfreeBSDF(&myBSDF);
+		return(cm_bsdf_Lamb(diffBRDF));
+	}
+	if (rdf->ncomp != 1 || rdf->comp[0].func != &SDhandleMtx) {
+		sprintf(errmsg, "unsupported BSDF '%s'", fname);
+		error(USER, errmsg);
+	}
+					/* convert BRDF to matrix */
+	Rmat = cm_bsdf(diffBRDF, (SDMat *)rdf->comp[0].dist);
+					/* free BSDF and return */
+	SDfreeBSDF(&myBSDF);
+	return(Rmat);
 }