--- ray/src/cv/bsdfrep.c	2012/11/13 04:23:38	2.9
+++ ray/src/cv/bsdfrep.c	2013/03/24 17:22:23	2.13
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdfrep.c,v 2.9 2012/11/13 04:23:38 greg Exp $";
+static const char RCSid[] = "$Id: bsdfrep.c,v 2.13 2013/03/24 17:22:23 greg Exp $";
 #endif
 /*
  * Support BSDF representation as radial basis functions.
@@ -26,6 +26,12 @@ int			single_plane_incident = -1;
 int			input_orient = 0;
 int			output_orient = 0;
 
+				/* BSDF histogram */
+int			bsdf_hist[HISTLEN];
+
+				/* BSDF value for boundary regions */
+double			bsdf_min = 0;
+
 				/* processed incident DSF measurements */
 RBFNODE			*dsf_list = NULL;
 
@@ -82,7 +88,7 @@ new_input_direction(double new_theta, double new_phi)
 int
 use_symmetry(FVECT vec)
 {
-	double	phi = get_phi360(vec);
+	const double	phi = get_phi360(vec);
 
 	switch (inp_coverage) {
 	case INP_QUAD1|INP_QUAD2|INP_QUAD3|INP_QUAD4:
@@ -189,7 +195,7 @@ rotate_rbf(RBFNODE *rbf, const FVECT invec)
 	int			pos[2];
 	int			n;
 
-	for (n = rbf->nrbf; n-- > 0; ) {
+	for (n = ((-.01 > phi) | (phi > .01))*rbf->nrbf; n-- > 0; ) {
 		ovec_from_pos(outvec, rbf->rbfa[n].gx, rbf->rbfa[n].gy);
 		spinvector(outvec, outvec, vnorm, phi);
 		pos_from_vec(pos, outvec);
@@ -241,14 +247,18 @@ pos_from_vec(int pos[2], const FVECT vec)
 double
 eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
 {
+	double		minval = bsdf_min*output_orient*outvec[2];
 	double		res = 0;
 	const RBFVAL	*rbfp;
 	FVECT		odir;
 	double		sig2;
 	int		n;
-
-	if (rp == NULL)
-		return(.0);
+				/* use minimum if no information avail. */
+	if (rp == NULL) {
+		if (outvec[2] > 0 ^ output_orient > 0)
+			return(.0);
+		return(minval);
+	}
 	rbfp = rp->rbfa;
 	for (n = rp->nrbf; n--; rbfp++) {
 		ovec_from_pos(odir, rbfp->gx, rbfp->gy);
@@ -257,6 +267,8 @@ eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
 		if (sig2 > -19.)
 			res += rbfp->peak * exp(sig2);
 	}
+	if (res < minval)	/* never return less than minval */
+		return(minval);
 	return(res);
 }
 
@@ -390,6 +402,7 @@ save_bsdf_rep(FILE *ofp)
 	fprintf(ofp, "SYMMETRY=%d\n", !single_plane_incident * inp_coverage);
 	fprintf(ofp, "IO_SIDES= %d %d\n", input_orient, output_orient);
 	fprintf(ofp, "GRIDRES=%d\n", grid_res);
+	fprintf(ofp, "BSDFMIN=%g\n", bsdf_min);
 	fputformat(BSDFREP_FMT, ofp);
 	fputc('\n', ofp);
 					/* write each DSF */
@@ -453,6 +466,10 @@ headline(char *s, void *p)
 	}
 	if (!strncmp(s, "GRIDRES=", 8)) {
 		sscanf(s+8, "%d", &grid_res);
+		return(0);
+	}
+	if (!strncmp(s, "BSDFMIN=", 8)) {
+		sscanf(s+8, "%lf", &bsdf_min);
 		return(0);
 	}
 	if (formatval(fmt, s) && strcmp(fmt, BSDFREP_FMT))