--- ray/src/cv/bsdfrep.c	2012/10/19 04:14:29	2.1
+++ ray/src/cv/bsdfrep.c	2021/12/15 01:38:50	2.37
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdfrep.c,v 2.1 2012/10/19 04:14:29 greg Exp $";
+static const char RCSid[] = "$Id: bsdfrep.c,v 2.37 2021/12/15 01:38:50 greg Exp $";
 #endif
 /*
  * Support BSDF representation as radial basis functions.
@@ -13,7 +13,14 @@ static const char RCSid[] = "$Id: bsdfrep.c,v 2.1 2012
 #include "rtio.h"
 #include "resolu.h"
 #include "bsdfrep.h"
-				/* which quadrants are represented */
+#include "random.h"
+				/* name and manufacturer if known */
+char			bsdf_name[256];
+char			bsdf_manuf[256];
+				/* active grid resolution */
+int			grid_res = GRIDRES;
+
+				/* coverage/symmetry using INP_QUAD? flags */
 int			inp_coverage = 0;
 				/* all incident angles in-plane so far? */
 int			single_plane_incident = -1;
@@ -22,6 +29,21 @@ int			single_plane_incident = -1;
 int			input_orient = 0;
 int			output_orient = 0;
 
+				/* represented color space */
+RBColor			rbf_colorimetry = RBCunknown;
+
+const char		*RBCident[] = {
+				"CIE-Y", "CIE-XYZ", "Spectral", "Unknown"
+			};
+
+				/* BSDF histogram */
+unsigned long		bsdf_hist[HISTLEN];
+
+				/* BSDF value for boundary regions */
+double			bsdf_min = 0;
+double			bsdf_spec_val = 0;
+double			bsdf_spec_rad = 0;
+
 				/* processed incident DSF measurements */
 RBFNODE			*dsf_list = NULL;
 
@@ -31,18 +53,13 @@ MIGRATION		*mig_list = NULL;
 				/* current input direction */
 double			theta_in_deg, phi_in_deg;
 
+				/* header line sharing callback */
+int			(*sir_headshare)(char *s) = NULL;
+
 /* Register new input direction */
 int
 new_input_direction(double new_theta, double new_phi)
 {
-	if (!input_orient)		/* check input orientation */
-		input_orient = 1 - 2*(new_theta > 90.);
-	else if (input_orient > 0 ^ new_theta < 90.) {
-		fprintf(stderr,
-		"%s: Cannot handle input angles on both sides of surface\n",
-				progname);
-		return(0);
-	}
 					/* normalize angle ranges */
 	while (new_theta < -180.)
 		new_theta += 360.;
@@ -56,11 +73,21 @@ new_input_direction(double new_theta, double new_phi)
 		new_phi += 360.;
 	while (new_phi >= 360.)
 		new_phi -= 360.;
+					/* check input orientation */
+	if (!input_orient)
+		input_orient = 1 - 2*(new_theta > 90.);
+	else if (input_orient > 0 ^ new_theta < 90.) {
+		fprintf(stderr,
+		"%s: Cannot handle input angles on both sides of surface\n",
+				progname);
+		return(0);
+	}
+	if ((theta_in_deg = new_theta) < 1.0)
+		return(1);		/* don't rely on phi near normal */
 	if (single_plane_incident > 0)	/* check input coverage */
 		single_plane_incident = (round(new_phi) == round(phi_in_deg));
 	else if (single_plane_incident < 0)
 		single_plane_incident = 1;
-	theta_in_deg = new_theta;	/* assume it's OK */
 	phi_in_deg = new_phi;
 	if ((1. < new_phi) & (new_phi < 89.))
 		inp_coverage |= INP_QUAD1;
@@ -78,6 +105,9 @@ int
 use_symmetry(FVECT vec)
 {
 	double	phi = get_phi360(vec);
+				/* because of -0. issue */
+	while (phi >= 360.) phi -= 360.;
+	while (phi < 0.) phi += 360.;
 
 	switch (inp_coverage) {
 	case INP_QUAD1|INP_QUAD2|INP_QUAD3|INP_QUAD4:
@@ -167,29 +197,41 @@ rev_rbf_symmetry(RBFNODE *rbf, int sym)
 	rev_symmetry(rbf->invec, sym);
 	if (sym & MIRROR_X)
 		for (n = rbf->nrbf; n-- > 0; )
-			rbf->rbfa[n].gx = GRIDRES-1 - rbf->rbfa[n].gx;
+			rbf->rbfa[n].gx = grid_res-1 - rbf->rbfa[n].gx;
 	if (sym & MIRROR_Y)
 		for (n = rbf->nrbf; n-- > 0; )
-			rbf->rbfa[n].gy = GRIDRES-1 - rbf->rbfa[n].gy;
+			rbf->rbfa[n].gy = grid_res-1 - rbf->rbfa[n].gy;
 }
 
-/* Compute volume associated with Gaussian lobe */
-double
-rbf_volume(const RBFVAL *rbfp)
+/* Rotate RBF to correspond to given incident vector */
+void
+rotate_rbf(RBFNODE *rbf, const FVECT invec)
 {
-	double	rad = R2ANG(rbfp->crad);
+	static const FVECT	vnorm = {.0, .0, 1.};
+	const double		phi = atan2(invec[1],invec[0]) -
+					atan2(rbf->invec[1],rbf->invec[0]);
+	FVECT			outvec;
+	int			pos[2];
+	int			n;
 
-	return((2.*M_PI) * rbfp->peak * rad*rad);
+	for (n = (cos(phi) < 1.-FTINY)*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);
+		rbf->rbfa[n].gx = pos[0];
+		rbf->rbfa[n].gy = pos[1];
+	}
+	VCOPY(rbf->invec, invec);
 }
 
 /* Compute outgoing vector from grid position */
 void
 ovec_from_pos(FVECT vec, int xpos, int ypos)
 {
-	double	uv[2];
+	RREAL	uv[2];
 	double	r2;
 	
-	SDsquare2disk(uv, (1./GRIDRES)*(xpos+.5), (1./GRIDRES)*(ypos+.5));
+	square2disk(uv, (xpos+.5)/grid_res, (ypos+.5)/grid_res);
 				/* uniform hemispherical projection */
 	r2 = uv[0]*uv[0] + uv[1]*uv[1];
 	vec[0] = vec[1] = sqrt(2. - r2);
@@ -202,38 +244,100 @@ ovec_from_pos(FVECT vec, int xpos, int ypos)
 void
 pos_from_vec(int pos[2], const FVECT vec)
 {
-	double	sq[2];		/* uniform hemispherical projection */
+	RREAL	sq[2];		/* uniform hemispherical projection */
 	double	norm = 1./sqrt(1. + fabs(vec[2]));
 
-	SDdisk2square(sq, vec[0]*norm, vec[1]*norm);
+	disk2square(sq, vec[0]*norm, vec[1]*norm);
 
-	pos[0] = (int)(sq[0]*GRIDRES);
-	pos[1] = (int)(sq[1]*GRIDRES);
+	pos[0] = (int)(sq[0]*grid_res);
+	pos[1] = (int)(sq[1]*grid_res);
 }
 
-/* Evaluate RBF for DSF at the given normalized outgoing direction */
+/* Compute volume associated with Gaussian lobe */
 double
-eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
+rbf_volume(const RBFVAL *rbfp)
 {
-	double		res = .0;
+	double	rad = R2ANG(rbfp->crad);
+	FVECT	odir;
+	double	elev, integ;
+				/* infinite integral approximation */
+	integ = (2.*M_PI) * rbfp->peak * rad*rad;
+				/* check if we're near horizon */
+	ovec_from_pos(odir, rbfp->gx, rbfp->gy);
+	elev = output_orient*odir[2];
+				/* apply cut-off correction if > 1% */
+	if (elev < 2.8*rad) {
+		/* elev = asin(elev);	/* this is so crude, anyway... */
+		integ *= 1. - .5*exp(-.5*elev*elev/(rad*rad));
+	}
+	return(integ);
+}
+
+/* Evaluate BSDF at the given normalized outgoing direction in color */
+SDError
+eval_rbfcol(SDValue *sv, const RBFNODE *rp, const FVECT outvec)
+{
+	const double	rfact2 = (38./M_PI/M_PI)*(grid_res*grid_res);
+	int		pos[2];
+	double		res = 0;
+	double		usum = 0, vsum = 0;
 	const RBFVAL	*rbfp;
 	FVECT		odir;
-	double		sig2;
+	double		rad2;
 	int		n;
-
-	if (rp == NULL)
-		return(.0);
+				/* assign default value */
+	sv->spec = c_dfcolor;
+	sv->cieY = bsdf_min;
+				/* check for wrong side */
+	if (outvec[2] > 0 ^ output_orient > 0) {
+		strcpy(SDerrorDetail, "Wrong-side scattering query");
+		return(SDEargument);
+	}
+	if (rp == NULL)		/* return minimum if no information avail. */
+		return(SDEnone);
+				/* optimization for fast lobe culling */
+	pos_from_vec(pos, outvec);
+				/* sum radial basis function */
 	rbfp = rp->rbfa;
 	for (n = rp->nrbf; n--; rbfp++) {
+		int	d2 = (pos[0]-rbfp->gx)*(pos[0]-rbfp->gx) +
+				(pos[1]-rbfp->gy)*(pos[1]-rbfp->gy);
+		double	val;
+		rad2 = R2ANG(rbfp->crad);
+		rad2 *= rad2;
+		if (d2 > rad2*rfact2)
+			continue;
 		ovec_from_pos(odir, rbfp->gx, rbfp->gy);
-		sig2 = R2ANG(rbfp->crad);
-		sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2);
-		if (sig2 > -19.)
-			res += rbfp->peak * exp(sig2);
+		val = rbfp->peak * exp((DOT(odir,outvec) - 1.) / rad2);
+		if (rbf_colorimetry == RBCtristimulus) {
+			usum += val * (rbfp->chroma & 0xff);
+			vsum += val * (rbfp->chroma>>8 & 0xff);
+		}
+		res += val;
 	}
-	return(res);
+	sv->cieY = res / COSF(outvec[2]);
+	if (sv->cieY < bsdf_min) {	/* never return less than bsdf_min */
+		sv->cieY = bsdf_min;
+	} else if (rbf_colorimetry == RBCtristimulus) {
+		C_CHROMA	cres = (int)(usum/res + frandom());
+		cres |= (int)(vsum/res + frandom()) << 8;
+		c_decodeChroma(&sv->spec, cres);
+	}
+	return(SDEnone);
 }
 
+/* Evaluate BSDF at the given normalized outgoing direction in Y */
+double
+eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
+{
+	SDValue	sv;
+
+	if (eval_rbfcol(&sv, rp, outvec) == SDEnone)
+		return(sv.cieY);
+
+	return(0.0);
+}
+
 /* Insert a new directional scattering function in our global list */
 int
 insert_dsf(RBFNODE *newrbf)
@@ -244,8 +348,9 @@ insert_dsf(RBFNODE *newrbf)
 	for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
 		if (DOT(rbf->invec, newrbf->invec) >= 1.-FTINY) {
 			fprintf(stderr,
-				"%s: Duplicate incident measurement (ignored)\n",
-					progname);
+		"%s: Duplicate incident measurement ignored at (%.1f,%.1f)\n",
+					progname, get_theta180(newrbf->invec),
+					get_phi360(newrbf->invec));
 			free(newrbf);
 			return(-1);
 		}
@@ -280,7 +385,7 @@ get_dsf(int ord)
 	RBFNODE		*rbf;
 
 	for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
-		if (rbf->ord == ord);
+		if (rbf->ord == ord)
 			return(rbf);
 	return(NULL);
 }
@@ -311,17 +416,17 @@ is_rev_tri(const FVECT v1, const FVECT v2, const FVECT
 int
 get_triangles(RBFNODE *rbfv[2], const MIGRATION *mig)
 {
-	const MIGRATION	*ej, *ej2;
+	const MIGRATION	*ej1, *ej2;
 	RBFNODE		*tv;
 
 	rbfv[0] = rbfv[1] = NULL;
 	if (mig == NULL)
 		return(0);
-	for (ej = mig->rbfv[0]->ejl; ej != NULL;
-				ej = nextedge(mig->rbfv[0],ej)) {
-		if (ej == mig)
+	for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
+				ej1 = nextedge(mig->rbfv[0],ej1)) {
+		if (ej1 == mig)
 			continue;
-		tv = opp_rbf(mig->rbfv[0],ej);
+		tv = opp_rbf(mig->rbfv[0],ej1);
 		for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
 			if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
 				rbfv[is_rev_tri(mig->rbfv[0]->invec,
@@ -333,6 +438,161 @@ get_triangles(RBFNODE *rbfv[2], const MIGRATION *mig)
 	return((rbfv[0] != NULL) + (rbfv[1] != NULL));
 }
 
+/* Return single-lobe specular RBF for the given incident direction */
+RBFNODE *
+def_rbf_spec(const FVECT invec)
+{
+	RBFNODE		*rbf;
+	FVECT		ovec;
+	int		pos[2];
+
+	if (input_orient > 0 ^ invec[2] > 0)	/* wrong side? */
+		return(NULL);
+	if ((bsdf_spec_val <= bsdf_min) | (bsdf_spec_rad <= 0))
+		return(NULL);			/* nothing set */
+	rbf = (RBFNODE *)malloc(sizeof(RBFNODE));
+	if (rbf == NULL)
+		return(NULL);
+	ovec[0] = -invec[0];
+	ovec[1] = -invec[1];
+	ovec[2] = invec[2]*(2*(input_orient==output_orient) - 1);
+	pos_from_vec(pos, ovec);
+	rbf->ord = 0;
+	rbf->next = NULL;
+	rbf->ejl = NULL;
+	VCOPY(rbf->invec, invec);
+	rbf->nrbf = 1;
+	rbf->rbfa[0].peak = bsdf_spec_val * COSF(ovec[2]);
+	rbf->rbfa[0].chroma = c_dfchroma;
+	rbf->rbfa[0].crad = ANG2R(bsdf_spec_rad);
+	rbf->rbfa[0].gx = pos[0];
+	rbf->rbfa[0].gy = pos[1];
+	rbf->vtotal = rbf_volume(rbf->rbfa);
+	return(rbf);
+}
+
+/* Advect and allocate new RBF along edge (internal call) */
+RBFNODE *
+e_advect_rbf(const MIGRATION *mig, const FVECT invec, int lobe_lim)
+{
+	double		cthresh = FTINY;
+	RBFNODE		*rbf;
+	int		n, i, j;
+	double		t, full_dist;
+						/* get relative position */
+	t = Acos(DOT(invec, mig->rbfv[0]->invec));
+	if (t <= .001) {			/* near first DSF */
+		n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
+		rbf = (RBFNODE *)malloc(n);
+		if (rbf == NULL)
+			goto memerr;
+		memcpy(rbf, mig->rbfv[0], n);	/* just duplicate */
+		rbf->next = NULL; rbf->ejl = NULL;
+		return(rbf);
+	}
+	full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
+	if (t >= full_dist-.001) {		/* near second DSF */
+		n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
+		rbf = (RBFNODE *)malloc(n);
+		if (rbf == NULL)
+			goto memerr;
+		memcpy(rbf, mig->rbfv[1], n);	/* just duplicate */
+		rbf->next = NULL; rbf->ejl = NULL;
+		return(rbf);
+	}
+	t /= full_dist;
+tryagain:
+	n = 0;					/* count migrating particles */
+	for (i = 0; i < mtx_nrows(mig); i++)
+	    for (j = 0; j < mtx_ncols(mig); j++)
+		n += (mtx_coef(mig,i,j) > cthresh);
+						/* are we over our limit? */
+	if ((lobe_lim > 0) & (n > lobe_lim)) {
+		cthresh = cthresh*2. + 10.*FTINY;
+		goto tryagain;
+	}
+#ifdef DEBUG
+	fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
+			mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
+#endif
+	rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
+	if (rbf == NULL)
+		goto memerr;
+	rbf->next = NULL; rbf->ejl = NULL;
+	VCOPY(rbf->invec, invec);
+	rbf->nrbf = n;
+	rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
+	n = 0;					/* advect RBF lobes */
+	for (i = 0; i < mtx_nrows(mig); i++) {
+	    const RBFVAL	*rbf0i = &mig->rbfv[0]->rbfa[i];
+	    const float		peak0 = rbf0i->peak;
+	    const double	rad0 = R2ANG(rbf0i->crad);
+	    C_COLOR		cc0;
+	    FVECT		v0;
+	    float		mv;
+	    ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
+	    c_decodeChroma(&cc0, rbf0i->chroma);
+	    for (j = 0; j < mtx_ncols(mig); j++)
+		if ((mv = mtx_coef(mig,i,j)) > cthresh) {
+			const RBFVAL	*rbf1j = &mig->rbfv[1]->rbfa[j];
+			double		rad2;
+			FVECT		v;
+			int		pos[2];
+			rad2 = R2ANG(rbf1j->crad);
+			rad2 = rad0*rad0*(1.-t) + rad2*rad2*t;
+			rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal *
+						rad0*rad0/rad2;
+			if (rbf_colorimetry == RBCtristimulus) {
+				C_COLOR	cres;
+				c_decodeChroma(&cres, rbf1j->chroma);
+				c_cmix(&cres, 1.-t, &cc0, t, &cres);
+				rbf->rbfa[n].chroma = c_encodeChroma(&cres);
+			} else
+				rbf->rbfa[n].chroma = c_dfchroma;
+			rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
+			ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
+			geodesic(v, v0, v, t, GEOD_REL);
+			pos_from_vec(pos, v);
+			rbf->rbfa[n].gx = pos[0];
+			rbf->rbfa[n].gy = pos[1];
+			++n;
+		}
+	}
+	rbf->vtotal *= mig->rbfv[0]->vtotal;	/* turn ratio into actual */
+	return(rbf);
+memerr:
+	fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
+	exit(1);
+	return(NULL);	/* pro forma return */
+}
+
+/* Clear our BSDF representation and free memory */
+void
+clear_bsdf_rep(void)
+{
+	while (mig_list != NULL) {
+		MIGRATION	*mig = mig_list;
+		mig_list = mig->next;
+		free(mig);
+	}
+	while (dsf_list != NULL) {
+		RBFNODE		*rbf = dsf_list;
+		dsf_list = rbf->next;
+		free(rbf);
+	}
+	bsdf_name[0] = '\0';
+	bsdf_manuf[0] = '\0';
+	inp_coverage = 0;
+	single_plane_incident = -1;
+	input_orient = output_orient = 0;
+	rbf_colorimetry = RBCunknown;
+	grid_res = GRIDRES;
+	memset(bsdf_hist, 0, sizeof(bsdf_hist));
+	bsdf_min = 0;
+	bsdf_spec_val = 0;
+	bsdf_spec_rad = 0;
+}
+
 /* Write our BSDF mesh interpolant out to the given binary stream */
 void
 save_bsdf_rep(FILE *ofp)
@@ -341,8 +601,20 @@ save_bsdf_rep(FILE *ofp)
 	MIGRATION	*mig;
 	int		i, n;
 					/* finish header */
+	if (bsdf_name[0])
+		fprintf(ofp, "NAME=%s\n", bsdf_name);
+	if (bsdf_manuf[0])
+		fprintf(ofp, "MANUFACT=%s\n", bsdf_manuf);
+	fprintf(ofp, "SYMMETRY=%d\n", !single_plane_incident * inp_coverage);
+	fprintf(ofp, "IO_SIDES= %d %d\n", input_orient, output_orient);
+	fprintf(ofp, "COLORIMETRY=%s\n", RBCident[rbf_colorimetry]);
+	fprintf(ofp, "GRIDRES=%d\n", grid_res);
+	fprintf(ofp, "BSDFMIN=%g\n", bsdf_min);
+	if ((bsdf_spec_val > bsdf_min) & (bsdf_spec_rad > 0))
+		fprintf(ofp, "BSDFSPEC= %f %f\n", bsdf_spec_val, bsdf_spec_rad);
 	fputformat(BSDFREP_FMT, ofp);
 	fputc('\n', ofp);
+	putint(BSDFREP_MAGIC, 2, ofp);
 					/* write each DSF */
 	for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
 		putint(rbf->ord, 4, ofp);
@@ -353,19 +625,31 @@ save_bsdf_rep(FILE *ofp)
 		putint(rbf->nrbf, 4, ofp);
 		for (i = 0; i < rbf->nrbf; i++) {
 			putflt(rbf->rbfa[i].peak, ofp);
+			putint(rbf->rbfa[i].chroma, 2, ofp);
 			putint(rbf->rbfa[i].crad, 2, ofp);
-			putint(rbf->rbfa[i].gx, 1, ofp);
-			putint(rbf->rbfa[i].gy, 1, ofp);
+			putint(rbf->rbfa[i].gx, 2, ofp);
+			putint(rbf->rbfa[i].gy, 2, ofp);
 		}
 	}
 	putint(-1, 4, ofp);		/* terminator */
 					/* write each migration matrix */
-	for (mig = mig_list; mig != NULL; mig = mig_list->next) {
+	for (mig = mig_list; mig != NULL; mig = mig->next) {
+		int	zerocnt = 0;
 		putint(mig->rbfv[0]->ord, 4, ofp);
 		putint(mig->rbfv[1]->ord, 4, ofp);
+					/* write out as sparse data */
 		n = mtx_nrows(mig) * mtx_ncols(mig);
-		for (i = 0; i < n; i++)
-			putflt(mig->mtx[i], ofp);
+		for (i = 0; i < n; i++) {
+			if (zerocnt == 0xff) {
+				putint(0xff, 1, ofp); zerocnt = 0;
+			}
+			if (mig->mtx[i] != 0) {
+				putint(zerocnt, 1, ofp); zerocnt = 0;
+				putflt(mig->mtx[i], ofp);
+			} else
+				++zerocnt;
+		}
+		putint(zerocnt, 1, ofp);
 	}
 	putint(-1, 4, ofp);		/* terminator */
 	putint(-1, 4, ofp);
@@ -376,6 +660,64 @@ save_bsdf_rep(FILE *ofp)
 	}
 }
 
+/* Check header line for critical information */
+static int
+headline(char *s, void *p)
+{
+	char	fmt[MAXFMTLEN];
+	int	i;
+
+	if (isheadid(s))
+		return(0);
+	if (!strncmp(s, "NAME=", 5)) {
+		strcpy(bsdf_name, s+5);
+		bsdf_name[strlen(bsdf_name)-1] = '\0';
+		return(1);
+	}
+	if (!strncmp(s, "MANUFACT=", 9)) {
+		strcpy(bsdf_manuf, s+9);
+		bsdf_manuf[strlen(bsdf_manuf)-1] = '\0';
+		return(1);
+	}
+	if (!strncmp(s, "SYMMETRY=", 9)) {
+		inp_coverage = atoi(s+9);
+		single_plane_incident = !inp_coverage;
+		return(1);
+	}
+	if (!strncmp(s, "IO_SIDES=", 9)) {
+		sscanf(s+9, "%d %d", &input_orient, &output_orient);
+		return(1);
+	}
+	if (!strncmp(s, "COLORIMETRY=", 12)) {
+		fmt[0] = '\0';
+		sscanf(s+12, "%s", fmt);
+		for (i = RBCunknown; i >= 0; i--)
+			if (!strcmp(fmt, RBCident[i]))
+				break;
+		if (i < 0)
+			return(-1);
+		rbf_colorimetry = i;
+		return(1);
+	}
+	if (!strncmp(s, "GRIDRES=", 8)) {
+		sscanf(s+8, "%d", &grid_res);
+		return(1);
+	}
+	if (!strncmp(s, "BSDFMIN=", 8)) {
+		sscanf(s+8, "%lf", &bsdf_min);
+		return(1);
+	}
+	if (!strncmp(s, "BSDFSPEC=", 9)) {
+		sscanf(s+9, "%lf %lf", &bsdf_spec_val, &bsdf_spec_rad);
+		return(1);
+	}
+	if (formatval(fmt, s))
+		return (strcmp(fmt, BSDFREP_FMT) ? -1 : 0);
+	if (sir_headshare != NULL)
+		return ((*sir_headshare)(s));
+	return(0);
+}
+
 /* Read a BSDF mesh interpolant from the given binary stream */
 int
 load_bsdf_rep(FILE *ifp)
@@ -383,40 +725,46 @@ load_bsdf_rep(FILE *ifp)
 	RBFNODE		rbfh;
 	int		from_ord, to_ord;
 	int		i;
-#ifdef DEBUG
-	if ((dsf_list != NULL) | (mig_list != NULL)) {
-		fprintf(stderr,
-		"%s: attempt to load BSDF interpolant over existing\n",
+
+	clear_bsdf_rep();
+	if (ifp == NULL)
+		return(0);
+	if (getheader(ifp, headline, NULL) < 0 || (single_plane_incident < 0) |
+			!input_orient | !output_orient |
+			(grid_res < 16) | (grid_res > 0xffff)) {
+		fprintf(stderr, "%s: missing/bad format for BSDF interpolant\n",
 				progname);
 		return(0);
 	}
-#endif
-	if (checkheader(ifp, BSDFREP_FMT, NULL) <= 0) {
-		fprintf(stderr, "%s: missing/bad format for BSDF interpolant\n",
+	if (getint(2, ifp) != BSDFREP_MAGIC) {
+		fprintf(stderr, "%s: bad magic number for BSDF interpolant\n",
 				progname);
 		return(0);
 	}
-	rbfh.next = NULL;		/* read each DSF */
-	rbfh.ejl = NULL;
+	memset(&rbfh, 0, sizeof(rbfh));	/* read each DSF */
 	while ((rbfh.ord = getint(4, ifp)) >= 0) {
 		RBFNODE		*newrbf;
 
 		rbfh.invec[0] = getflt(ifp);
 		rbfh.invec[1] = getflt(ifp);
 		rbfh.invec[2] = getflt(ifp);
-		rbfh.nrbf = getint(4, ifp);
-		if (!new_input_vector(rbfh.invec))
+		if (normalize(rbfh.invec) == 0) {
+			fprintf(stderr, "%s: zero incident vector\n", progname);
 			return(0);
+		}
+		rbfh.vtotal = getflt(ifp);
+		rbfh.nrbf = getint(4, ifp);
 		newrbf = (RBFNODE *)malloc(sizeof(RBFNODE) +
 					sizeof(RBFVAL)*(rbfh.nrbf-1));
 		if (newrbf == NULL)
 			goto memerr;
-		memcpy(newrbf, &rbfh, sizeof(RBFNODE));
+		*newrbf = rbfh;
 		for (i = 0; i < rbfh.nrbf; i++) {
 			newrbf->rbfa[i].peak = getflt(ifp);
+			newrbf->rbfa[i].chroma = getint(2, ifp) & 0xffff;
 			newrbf->rbfa[i].crad = getint(2, ifp) & 0xffff;
-			newrbf->rbfa[i].gx = getint(1, ifp) & 0xff;
-			newrbf->rbfa[i].gy = getint(1, ifp) & 0xff;
+			newrbf->rbfa[i].gx = getint(2, ifp) & 0xffff;
+			newrbf->rbfa[i].gy = getint(2, ifp) & 0xffff;
 		}
 		if (feof(ifp))
 			goto badEOF;
@@ -447,9 +795,15 @@ load_bsdf_rep(FILE *ifp)
 			goto memerr;
 		newmig->rbfv[0] = from_rbf;
 		newmig->rbfv[1] = to_rbf;
-					/* read matrix coefficients */
-		for (i = 0; i < n; i++)
-			newmig->mtx[i] = getflt(ifp);
+		memset(newmig->mtx, 0, sizeof(float)*n);
+		for (i = 0; ; ) {	/* read sparse data */
+			int	zc = getint(1, ifp) & 0xff;
+			if ((i += zc) >= n)
+				break;
+			if (zc == 0xff)
+				continue;
+			newmig->mtx[i++] = getflt(ifp);
+		}
 		if (feof(ifp))
 			goto badEOF;
 					/* insert in edge lists */