#ifndef lint
static const char RCSid[] = "$Id: bsdf2ttree.c,v 2.39 2016/10/13 16:59:29 greg Exp $";
#endif
/*
 * Load measured BSDF interpolant and write out as XML file with tensor tree.
 *
 *	G. Ward
 */

#define _USE_MATH_DEFINES
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "random.h"
#include "platform.h"
#include "paths.h"
#include "rtio.h"
#include "calcomp.h"
#include "bsdfrep.h"
				/* global argv[0] */
char			*progname;
				/* percentage to cull (<0 to turn off) */
static double		pctcull = 90.;
				/* sampling order */
static int		samp_order = 6;
				/* super-sampling threshold */
const double		ssamp_thresh = 0.35;
				/* number of super-samples */
#ifndef NSSAMP
#define	NSSAMP		64
#endif
				/* limit on number of RBF lobes */
static int		lobe_lim = 15000;
				/* progress bar length */
static int		do_prog = 79;

#define MAXCARG		512	/* wrapBSDF command */
static char		*wrapBSDF[MAXCARG] = {"wrapBSDF", "-U"};
static int		wbsdfac = 2;

/* Add argument to wrapBSDF, allocating space if !isstatic */
static void
add_wbsdf(const char *arg, int isstatic)
{
	if (arg == NULL)
		return;
	if (wbsdfac >= MAXCARG-1) {
		fputs(progname, stderr);
		fputs(": too many command arguments to wrapBSDF\n", stderr);
		exit(1);
	}
	if (!*arg)
		arg = "";
	else if (!isstatic)
		arg = savqstr((char *)arg);

	wrapBSDF[wbsdfac++] = (char *)arg;
}

/* Create Yuv component file and add appropriate arguments */
static char *
create_component_file(int c)
{
	static const char	sname[3][6] = {"CIE-Y", "CIE-u", "CIE-v"};
	static const char	cname[4][4] = {"-rf", "-tf", "-tb", "-rb"};
	char			*tfname = mktemp(savqstr(TEMPLATE));

	add_wbsdf("-s", 1); add_wbsdf(sname[c], 1);
	add_wbsdf(cname[(input_orient>0)<<1 | (output_orient>0)], 1);
	add_wbsdf(tfname, 1);
	return(tfname);
}

/* Start new progress bar */
#define prog_start(s)	if (do_prog) fprintf(stderr, "%s: %s...\n", progname, s); else

/* Draw progress bar of the appropriate length */
static void
prog_show(double frac)
{
	static unsigned	call_cnt = 0;
	static char	lastc[] = "-\\|/";
	char		pbar[256];
	int		nchars;

	if (do_prog <= 1) return;
	if (do_prog > sizeof(pbar)-2)
		do_prog = sizeof(pbar)-2;
	if (frac < 0) frac = 0;
	else if (frac >= 1) frac = .9999;
	nchars = do_prog*frac;
	pbar[0] = '\r';
	memset(pbar+1, '*', nchars);
	pbar[nchars+1] = lastc[call_cnt++ & 3];
	memset(pbar+2+nchars, '-', do_prog-nchars-1);
	pbar[do_prog+1] = '\0';
	fputs(pbar, stderr);
}

/* Finish progress bar */
static void
prog_done(void)
{
	int	n = do_prog;

	if (n <= 1) return;
	fputc('\r', stderr);
	while (n--)
		fputc(' ', stderr);
	fputc('\r', stderr);
}

/* Compute absolute relative difference */
static double
abs_diff(double v1, double v0)
{
	if ((v0 < 0) | (v1 < 0))
		return(.0);
	v1 = (v1-v0)*2./(v0+v1+.0001);
	if (v1 < 0)
		return(-v1);
	return(v1);
}

/* Interpolate and output isotropic BSDF data */
static void
eval_isotropic(char *funame)
{
	const int	sqres = 1<<samp_order;
	FILE		*ofp, *uvfp[2];
	int		assignD = 0;
	char		cmd[128];
	int		ix, ox, oy;
	double		iovec[6];
	float		bsdf, uv[2];

	if (pctcull >= 0) {
		sprintf(cmd, "rttree_reduce -a -h -ff -r 3 -t %f -g %d > %s",
				pctcull, samp_order, create_component_file(0));
		ofp = popen(cmd, "w");
		if (ofp == NULL) {
			fprintf(stderr, "%s: cannot create pipe to rttree_reduce\n",
					progname);
			exit(1);
		}
		SET_FILE_BINARY(ofp);
#ifdef getc_unlocked				/* avoid lock/unlock overhead */
		flockfile(ofp);
#endif
		if (rbf_colorimetry == RBCtristimulus) {
			double	uvcull = 100. - (100.-pctcull)*.25;
			sprintf(cmd, "rttree_reduce -a -h -ff -r 3 -t %f -g %d > %s",
					uvcull, samp_order, create_component_file(1));
			uvfp[0] = popen(cmd, "w");
			sprintf(cmd, "rttree_reduce -a -h -ff -r 3 -t %f -g %d > %s",
					uvcull, samp_order, create_component_file(2));
			uvfp[1] = popen(cmd, "w");
			if ((uvfp[0] == NULL) | (uvfp[1] == NULL)) {
				fprintf(stderr, "%s: cannot open pipes to uv output\n",
						progname);
				exit(1);
			}
			SET_FILE_BINARY(uvfp[0]); SET_FILE_BINARY(uvfp[1]);
#ifdef getc_unlocked
			flockfile(uvfp[0]); flockfile(uvfp[1]);
#endif
		}
	} else {
		ofp = fopen(create_component_file(0), "w");
		if (ofp == NULL) {
			fprintf(stderr, "%s: cannot create Y output file\n",
					progname);
			exit(1);
		}
		fputs("{\n", ofp);
		if (rbf_colorimetry == RBCtristimulus) {
			uvfp[0] = fopen(create_component_file(1), "w");
			uvfp[1] = fopen(create_component_file(2), "w");
			if ((uvfp[0] == NULL) | (uvfp[1] == NULL)) {
				fprintf(stderr, "%s: cannot create uv output file(s)\n",
						progname);
				exit(1);
			}
			fputs("{\n", uvfp[0]);
			fputs("{\n", uvfp[1]);
		}
	}
	if (funame != NULL)			/* need to assign Dx, Dy, Dz? */
		assignD = (fundefined(funame) < 6);
						/* run through directions */
	for (ix = 0; ix < sqres/2; ix++) {
		RBFNODE	*rbf = NULL;
		iovec[0] = 2.*(ix+.5)/sqres - 1.;
		iovec[1] = .0;
		iovec[2] = input_orient * sqrt(1. - iovec[0]*iovec[0]);
		if (funame == NULL)
			rbf = advect_rbf(iovec, lobe_lim);
		for (ox = 0; ox < sqres; ox++) {
		    float	last_bsdf = -1;
		    for (oy = 0; oy < sqres; oy++) {
			SDsquare2disk(iovec+3, (ox+.5)/sqres, (oy+.5)/sqres);
			iovec[5] = output_orient *
				sqrt(1. - iovec[3]*iovec[3] - iovec[4]*iovec[4]);
			if (funame == NULL) {
			    SDValue	sdv;
			    eval_rbfcol(&sdv, rbf, iovec+3);
			    bsdf = sdv.cieY;
			    if (rbf_colorimetry == RBCtristimulus) {
				c_ccvt(&sdv.spec, C_CSXY);
				uv[0] = uv[1] = 1. /
				    (-2.*sdv.spec.cx + 12.*sdv.spec.cy + 3.);
				uv[0] *= 4.*sdv.spec.cx;
				uv[1] *= 9.*sdv.spec.cy;
			    }
			} else {
			    if (assignD) {
				varset("Dx", '=', -iovec[3]);
				varset("Dy", '=', -iovec[4]);
				varset("Dz", '=', -iovec[5]);
				++eclock;
			    }
			    bsdf = funvalue(funame, 6, iovec);
#if (NSSAMP > 0)
			    if (abs_diff(bsdf, last_bsdf) > ssamp_thresh) {
				int	ssi;
				double	ssa[3], ssvec[6], sum = 0;
						/* super-sample voxel */
				for (ssi = NSSAMP; ssi--; ) {
				    SDmultiSamp(ssa, 3, (ssi+frandom()) *
							(1./NSSAMP));
				    ssvec[0] = 2.*(ix+ssa[0])/sqres - 1.;
				    ssvec[1] = .0;
				    ssvec[2] = input_orient *
						sqrt(1. - ssvec[0]*ssvec[0]);
				    SDsquare2disk(ssvec+3, (ox+ssa[1])/sqres,
						(oy+ssa[2])/sqres);
				    ssvec[5] = output_orient *
						sqrt(1. - ssvec[3]*ssvec[3] -
							ssvec[4]*ssvec[4]);
				    if (assignD) {
					varset("Dx", '=', -ssvec[3]);
					varset("Dy", '=', -ssvec[4]);
					varset("Dz", '=', -ssvec[5]);
					++eclock;
				    }
				    sum += funvalue(funame, 6, ssvec);
				}
				bsdf = sum/NSSAMP;
			    }
#endif
			}
			if (pctcull >= 0)
				putbinary(&bsdf, sizeof(bsdf), 1, ofp);
			else
				fprintf(ofp, "\t%.3e\n", bsdf);

			if (rbf_colorimetry == RBCtristimulus) {
				if (pctcull >= 0) {
					putbinary(&uv[0], sizeof(*uv), 1, uvfp[0]);
					putbinary(&uv[1], sizeof(*uv), 1, uvfp[1]);
				} else {
					fprintf(uvfp[0], "\t%.3e\n", uv[0]);
					fprintf(uvfp[1], "\t%.3e\n", uv[1]);
				}
			}
			last_bsdf = bsdf;
		    }
		}
		if (rbf != NULL)
			free(rbf);
		prog_show((ix+1.)*(2./sqres));
	}
	prog_done();
	if (pctcull >= 0) {			/* finish output */
		if (pclose(ofp)) {
			fprintf(stderr, "%s: error running rttree_reduce on Y\n",
					progname);
			exit(1);
		}
		if (rbf_colorimetry == RBCtristimulus &&
				(pclose(uvfp[0]) || pclose(uvfp[1]))) {
			fprintf(stderr, "%s: error running rttree_reduce on uv\n",
					progname);
			exit(1);
		}
	} else {
		for (ix = sqres*sqres*sqres/2; ix--; )
			fputs("\t0\n", ofp);
		fputs("}\n", ofp);
		if (fclose(ofp)) {
			fprintf(stderr, "%s: error writing Y file\n",
					progname);
			exit(1);
		}
		if (rbf_colorimetry == RBCtristimulus) {
			for (ix = sqres*sqres*sqres/2; ix--; ) {
				fputs("\t0\n", uvfp[0]);
				fputs("\t0\n", uvfp[1]);
			}
			fputs("}\n", uvfp[0]);
			fputs("}\n", uvfp[1]);
			if (fclose(uvfp[0]) || fclose(uvfp[1])) {
				fprintf(stderr, "%s: error writing uv file(s)\n",
						progname);
				exit(1);
			}
		}
	}
}

/* Interpolate and output anisotropic BSDF data */
static void
eval_anisotropic(char *funame)
{
	const int	sqres = 1<<samp_order;
	FILE		*ofp, *uvfp[2];
	int		assignD = 0;
	char		cmd[128];
	int		ix, iy, ox, oy;
	double		iovec[6];
	float		bsdf, uv[2];

	if (pctcull >= 0) {
		const char	*avgopt = (input_orient>0 ^ output_orient>0)
						? "" : " -a";
		sprintf(cmd, "rttree_reduce%s -h -ff -r 4 -t %f -g %d > %s",
				avgopt, pctcull, samp_order,
				create_component_file(0));
		ofp = popen(cmd, "w");
		if (ofp == NULL) {
			fprintf(stderr, "%s: cannot create pipe to rttree_reduce\n",
					progname);
			exit(1);
		}
		SET_FILE_BINARY(ofp);
#ifdef getc_unlocked				/* avoid lock/unlock overhead */
		flockfile(ofp);
#endif
		if (rbf_colorimetry == RBCtristimulus) {
			double	uvcull = 100. - (100.-pctcull)*.25;
			sprintf(cmd, "rttree_reduce%s -h -ff -r 4 -t %f -g %d > %s",
					avgopt, uvcull, samp_order,
					create_component_file(1));
			uvfp[0] = popen(cmd, "w");
			sprintf(cmd, "rttree_reduce%s -h -ff -r 4 -t %f -g %d > %s",
					avgopt, uvcull, samp_order,
					create_component_file(2));
			uvfp[1] = popen(cmd, "w");
			if ((uvfp[0] == NULL) | (uvfp[1] == NULL)) {
				fprintf(stderr, "%s: cannot open pipes to uv output\n",
						progname);
				exit(1);
			}
			SET_FILE_BINARY(uvfp[0]); SET_FILE_BINARY(uvfp[1]);
#ifdef getc_unlocked
			flockfile(uvfp[0]); flockfile(uvfp[1]);
#endif
		}
	} else {
		ofp = fopen(create_component_file(0), "w");
		if (ofp == NULL) {
			fprintf(stderr, "%s: cannot create Y output file\n",
					progname);
			exit(1);
		}
		fputs("{\n", ofp);
		if (rbf_colorimetry == RBCtristimulus) {
			uvfp[0] = fopen(create_component_file(1), "w");
			uvfp[1] = fopen(create_component_file(2), "w");
			if ((uvfp[0] == NULL) | (uvfp[1] == NULL)) {
				fprintf(stderr, "%s: cannot create uv output file(s)\n",
						progname);
				exit(1);
			}
			fputs("{\n", uvfp[0]);
			fputs("{\n", uvfp[1]);
		}
	}
	if (funame != NULL)			/* need to assign Dx, Dy, Dz? */
		assignD = (fundefined(funame) < 6);
						/* run through directions */
	for (ix = 0; ix < sqres; ix++)
	    for (iy = 0; iy < sqres; iy++) {
		RBFNODE	*rbf = NULL;		/* Klems reversal */
		SDsquare2disk(iovec, 1.-(ix+.5)/sqres, 1.-(iy+.5)/sqres);
		iovec[2] = input_orient *
				sqrt(1. - iovec[0]*iovec[0] - iovec[1]*iovec[1]);
		if (funame == NULL)
			rbf = advect_rbf(iovec, lobe_lim);
		for (ox = 0; ox < sqres; ox++) {
		    float	last_bsdf = -1;
		    for (oy = 0; oy < sqres; oy++) {
			SDsquare2disk(iovec+3, (ox+.5)/sqres, (oy+.5)/sqres);
			iovec[5] = output_orient *
				sqrt(1. - iovec[3]*iovec[3] - iovec[4]*iovec[4]);
			if (funame == NULL) {
			    SDValue	sdv;
			    eval_rbfcol(&sdv, rbf, iovec+3);
			    bsdf = sdv.cieY;
			    if (rbf_colorimetry == RBCtristimulus) {
				c_ccvt(&sdv.spec, C_CSXY);
				uv[0] = uv[1] = 1. /
				    (-2.*sdv.spec.cx + 12.*sdv.spec.cy + 3.);
				uv[0] *= 4.*sdv.spec.cx;
				uv[1] *= 9.*sdv.spec.cy;
			    }
			} else {
			    if (assignD) {
				varset("Dx", '=', -iovec[3]);
				varset("Dy", '=', -iovec[4]);
				varset("Dz", '=', -iovec[5]);
				++eclock;
			    }
			    bsdf = funvalue(funame, 6, iovec);
#if (NSSAMP > 0)
			    if (abs_diff(bsdf, last_bsdf) > ssamp_thresh) {
				int	ssi;
				double	ssa[4], ssvec[6], sum = 0;
						/* super-sample voxel */
				for (ssi = NSSAMP; ssi--; ) {
				    SDmultiSamp(ssa, 4, (ssi+frandom()) *
							(1./NSSAMP));
				    SDsquare2disk(ssvec, 1.-(ix+ssa[0])/sqres,
						1.-(iy+ssa[1])/sqres);
				    ssvec[2] = input_orient *
						sqrt(1. - ssvec[0]*ssvec[0] -
							ssvec[1]*ssvec[1]);
				    SDsquare2disk(ssvec+3, (ox+ssa[2])/sqres,
						(oy+ssa[3])/sqres);
				    ssvec[5] = output_orient *
						sqrt(1. - ssvec[3]*ssvec[3] -
							ssvec[4]*ssvec[4]);
				    if (assignD) {
					varset("Dx", '=', -ssvec[3]);
					varset("Dy", '=', -ssvec[4]);
					varset("Dz", '=', -ssvec[5]);
					++eclock;
				    }
				    sum += funvalue(funame, 6, ssvec);
				}
				bsdf = sum/NSSAMP;
			    }
#endif
			}
			if (pctcull >= 0)
				putbinary(&bsdf, sizeof(bsdf), 1, ofp);
			else
				fprintf(ofp, "\t%.3e\n", bsdf);

			if (rbf_colorimetry == RBCtristimulus) {
				if (pctcull >= 0) {
					putbinary(&uv[0], sizeof(*uv), 1, uvfp[0]);
					putbinary(&uv[1], sizeof(*uv), 1, uvfp[1]);
				} else {
					fprintf(uvfp[0], "\t%.3e\n", uv[0]);
					fprintf(uvfp[1], "\t%.3e\n", uv[1]);
				}
			}
			last_bsdf = bsdf;
		    }
		}
		if (rbf != NULL)
			free(rbf);
		prog_show((ix*sqres+iy+1.)/(sqres*sqres));
	    }
	prog_done();
	if (pctcull >= 0) {			/* finish output */
		if (pclose(ofp)) {
			fprintf(stderr, "%s: error running rttree_reduce on Y\n",
					progname);
			exit(1);
		}
		if (rbf_colorimetry == RBCtristimulus &&
				(pclose(uvfp[0]) || pclose(uvfp[1]))) {
			fprintf(stderr, "%s: error running rttree_reduce on uv\n",
					progname);
			exit(1);
		}
	} else {
		fputs("}\n", ofp);
		if (fclose(ofp)) {
			fprintf(stderr, "%s: error writing Y file\n",
					progname);
			exit(1);
		}
		if (rbf_colorimetry == RBCtristimulus) {
			fputs("}\n", uvfp[0]);
			fputs("}\n", uvfp[1]);
			if (fclose(uvfp[0]) || fclose(uvfp[1])) {
				fprintf(stderr, "%s: error writing uv file(s)\n",
						progname);
				exit(1);
			}
		}
	}
}

#if defined(_WIN32) || defined(_WIN64)
/* Execute wrapBSDF command (may never return) */
static int
wrap_up(void)
{
	char	cmd[8192];

	if (bsdf_manuf[0]) {
		add_wbsdf("-f", 1);
		strcpy(cmd, "m=");
		strcpy(cmd+2, bsdf_manuf);
		add_wbsdf(cmd, 0);
	}
	if (bsdf_name[0]) {
		add_wbsdf("-f", 1);
		strcpy(cmd, "n=");
		strcpy(cmd+2, bsdf_name);
		add_wbsdf(cmd, 0);
	}
	if (!convert_commandline(cmd, sizeof(cmd), wrapBSDF)) {
		fputs(progname, stderr);
		fputs(": command line too long in wrap_up()\n", stderr);
		return(1);
	}
	return(system(cmd));
}
#else
/* Execute wrapBSDF command (may never return) */
static int
wrap_up(void)
{
	char	buf[256];
	char	*compath = getpath((char *)wrapBSDF[0], getenv("PATH"), X_OK);

	if (compath == NULL) {
		fprintf(stderr, "%s: cannot locate %s\n", progname, wrapBSDF[0]);
		return(1);
	}
	if (bsdf_manuf[0]) {
		add_wbsdf("-f", 1);
		strcpy(buf, "m=");
		strcpy(buf+2, bsdf_manuf);
		add_wbsdf(buf, 0);
	}
	if (bsdf_name[0]) {
		add_wbsdf("-f", 1);
		strcpy(buf, "n=");
		strcpy(buf+2, bsdf_name);
		add_wbsdf(buf, 0);
	}
	execv(compath, wrapBSDF);	/* successful call never returns */
	perror(compath);
	return(1);
}
#endif

/* Read in BSDF and interpolate as tensor tree representation */
int
main(int argc, char *argv[])
{
	static char	tfmt[2][4] = {"t4", "t3"};
	int	dofwd = 0, dobwd = 1;
	char	buf[2048];
	int	i, na;

	progname = argv[0];
	esupport |= E_VARIABLE|E_FUNCTION|E_RCONST;
	esupport &= ~(E_INCHAN|E_OUTCHAN);
	scompile("PI:3.14159265358979323846", NULL, 0);
	biggerlib();
	for (i = 1; i < argc-1 && (argv[i][0] == '-') | (argv[i][0] == '+'); i++)
		switch (argv[i][1]) {		/* get options */
		case 'e':
			scompile(argv[++i], NULL, 0);
			break;
		case 'f':
			if (!argv[i][2]) {
				if (strchr(argv[++i], '=') != NULL) {
					add_wbsdf("-f", 1);
					add_wbsdf(argv[i], 1);
				} else
					fcompile(argv[i]);
			} else
				dofwd = (argv[i][0] == '+');
			break;
		case 'b':
			dobwd = (argv[i][0] == '+');
			break;
		case 't':
			switch (argv[i][2]) {
			case '3':
				single_plane_incident = 1;
				break;
			case '4':
				single_plane_incident = 0;
				break;
			case '\0':
				pctcull = atof(argv[++i]);
				break;
			default:
				goto userr;
			}
			break;
		case 'g':
			samp_order = atoi(argv[++i]);
			break;
		case 'l':
			lobe_lim = atoi(argv[++i]);
			break;
		case 'p':
			do_prog = atoi(argv[i]+2);
			break;
		case 'W':
			add_wbsdf(argv[i], 1);
			break;
		case 'u':
		case 'C':
			add_wbsdf(argv[i], 1);
			add_wbsdf(argv[++i], 1);
			break;
		default:
			goto userr;
		}
	strcpy(buf, "File produced by: ");
	if (convert_commandline(buf+18, sizeof(buf)-18, argv) != NULL) {
		add_wbsdf("-C", 1); add_wbsdf(buf, 0);
	}
	if (single_plane_incident >= 0) {	/* function-based BSDF? */
		void	(*evf)(char *s) = single_plane_incident ?
				eval_isotropic : eval_anisotropic;
		if (i != argc-1 || fundefined(argv[i]) < 3) {
			fprintf(stderr,
	"%s: need single function with 6 arguments: bsdf(ix,iy,iz,ox,oy,oz)\n",
					progname);
			fprintf(stderr, "\tor 3 arguments using Dx,Dy,Dz: bsdf(ix,iy,iz)\n");
			goto userr;
		}
		++eclock;
		add_wbsdf("-a", 1);
		add_wbsdf(tfmt[single_plane_incident], 1);
		if (dofwd) {
			input_orient = -1;
			output_orient = -1;
			prog_start("Evaluating outside reflectance");
			(*evf)(argv[i]);
			output_orient = 1;
			prog_start("Evaluating outside->inside transmission");
			(*evf)(argv[i]);
		}
		if (dobwd) {
			input_orient = 1;
			output_orient = 1;
			prog_start("Evaluating inside reflectance");
			(*evf)(argv[i]);
			output_orient = -1;
			prog_start("Evaluating inside->outside transmission");
			(*evf)(argv[i]);
		}
		return(wrap_up());
	}
	if (i < argc) {				/* open input files if given */
		int	nbsdf = 0;
		for ( ; i < argc; i++) {	/* interpolate each component */
			char	pbuf[256];
			FILE	*fpin = fopen(argv[i], "rb");
			if (fpin == NULL) {
				fprintf(stderr, "%s: cannot open BSDF interpolant '%s'\n",
						progname, argv[i]);
				return(1);
			}
			if (!load_bsdf_rep(fpin))
				return(1);
			fclose(fpin);
			sprintf(pbuf, "Interpolating component '%s'", argv[i]);
			prog_start(pbuf);
			if (!nbsdf++) {
				add_wbsdf("-a", 1);
				add_wbsdf(tfmt[single_plane_incident], 1);
			}
			if (single_plane_incident)
				eval_isotropic(NULL);
			else
				eval_anisotropic(NULL);
		}
		return(wrap_up());
	}
	SET_FILE_BINARY(stdin);			/* load from stdin */
	if (!load_bsdf_rep(stdin))
		return(1);
	prog_start("Interpolating from standard input");
	add_wbsdf("-a", 1);
	add_wbsdf(tfmt[single_plane_incident], 1);
	if (single_plane_incident)		/* resample dist. */
		eval_isotropic(NULL);
	else
		eval_anisotropic(NULL);

	return(wrap_up());
userr:
	fprintf(stderr,
	"Usage: %s [-g Nlog2][-t pctcull][-l maxlobes] [bsdf.sir ..] > bsdf.xml\n",
				progname);
	fprintf(stderr,
	"   or: %s -t{3|4} [-g Nlog2][-t pctcull][{+|-}for[ward]][{+|-}b[ackward]][-e expr][-f file] bsdf_func > bsdf.xml\n",
				progname);
	return(1);
}