#ifndef lint
static const char RCSid[] = "$Id: pabopto2bsdf.c,v 2.5 2013/09/12 16:09:31 greg Exp $";
#endif
/*
 * Load measured BSDF data in PAB-Opto format.
 *
 *	G. Ward
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "platform.h"
#include "bsdfrep.h"
				/* global argv[0] */
char			*progname;

typedef struct {
	const char	*fname;		/* input file path */
	double		theta, phi;	/* incident angles (in degrees) */
	int		isDSF;		/* data is DSF (rather than BSDF)? */
	long		dstart;		/* data start offset in file */
} PGINPUT;

PGINPUT		*inpfile;	/* input files sorted by incidence */
int		ninpfiles;	/* number of input files */

/* Compare incident angles */
static int
cmp_inang(const void *p1, const void *p2)
{
	const PGINPUT	*inp1 = (const PGINPUT *)p1;
	const PGINPUT	*inp2 = (const PGINPUT *)p2;
	
	if (inp1->theta > inp2->theta+FTINY)
		return(1);
	if (inp1->theta < inp2->theta-FTINY)
		return(-1);
	if (inp1->phi > inp2->phi+FTINY)
		return(1);
	if (inp1->phi < inp2->phi-FTINY)
		return(-1);
	return(0);
}

/* Prepare a PAB-Opto input file by reading its header */
static int
init_pabopto_inp(const int i, const char *fname)
{
	FILE	*fp = fopen(fname, "r");
	char	buf[2048];
	int	c;
	
	if (fp == NULL) {
		fputs(fname, stderr);
		fputs(": cannot open\n", stderr);
		return(0);
	}
	inpfile[i].fname = fname;
	inpfile[i].isDSF = -1;
	inpfile[i].theta = inpfile[i].phi = -10001.;
				/* read header information */
	while ((c = getc(fp)) == '#' || c == EOF) {
		char	typ[32];
		if (fgets(buf, sizeof(buf), fp) == NULL) {
			fputs(fname, stderr);
			fputs(": unexpected EOF\n", stderr);
			fclose(fp);
			return(0);
		}
		if (sscanf(buf, "format: theta phi %s", typ) == 1) {
			if (!strcasecmp(typ, "DSF")) {
				inpfile[i].isDSF = 1;
				continue;
			}
			if (!strcasecmp(typ, "BSDF")) {
				inpfile[i].isDSF = 0;
				continue;
			}
		}
		if (sscanf(buf, "intheta %lf", &inpfile[i].theta) == 1)
			continue;
		if (sscanf(buf, "inphi %lf", &inpfile[i].phi) == 1)
			continue;
		if (sscanf(buf, "incident_angle %lf %lf",
				&inpfile[i].theta, &inpfile[i].phi) == 2)
			continue;
	}
	inpfile[i].dstart = ftell(fp) - 1;
	fclose(fp);
	if (inpfile[i].isDSF < 0) {
		fputs(fname, stderr);
		fputs(": unknown format\n", stderr);
		return(0);
	}
	if ((inpfile[i].theta < -10000.) | (inpfile[i].phi < -10000.)) {
		fputs(fname, stderr);
		fputs(": unknown incident angle\n", stderr);
		return(0);
	}
	while (inpfile[i].phi < 0)	/* normalize phi direction */
		inpfile[i].phi += 360.;
	return(1);
}

/* Load a set of measurements corresponding to a particular incident angle */
static int
add_pabopto_inp(const int i)
{
	FILE	*fp = fopen(inpfile[i].fname, "r");
	double	theta_out, phi_out, val;
	int	n, c;
	
	if (fp == NULL || fseek(fp, inpfile[i].dstart, 0) == EOF) {
		fputs(inpfile[i].fname, stderr);
		fputs(": cannot open\n", stderr);
		return(0);
	}
					/* prepare input grid */
	if (!i || cmp_inang(&inpfile[i-1], &inpfile[i])) {
		if (i)			/* need to process previous incidence */
			make_rbfrep();
#ifdef DEBUG
		fprintf(stderr, "New incident (theta,phi)=(%f,%f)\n",
					inpfile[i].theta, inpfile[i].phi);
#endif
		new_bsdf_data(inpfile[i].theta, inpfile[i].phi);
	}
#ifdef DEBUG
	fprintf(stderr, "Loading measurements from '%s'...\n", inpfile[i].fname);
#endif
					/* read scattering data */
	while (fscanf(fp, "%lf %lf %lf\n", &theta_out, &phi_out, &val) == 3)
		add_bsdf_data(theta_out, phi_out, val, inpfile[i].isDSF);
	n = 0;
	while ((c = getc(fp)) != EOF)
		n += !isspace(c);
	if (n) 
		fprintf(stderr,
			"%s: warning: %d unexpected characters past EOD\n",
				inpfile[i].fname, n);
	fclose(fp);
	return(1);
}

/* Read in PAB-Opto BSDF files and output RBF interpolant */
int
main(int argc, char *argv[])
{
	extern int	nprocs;
	int		i;
						/* start header */
	SET_FILE_BINARY(stdout);
	newheader("RADIANCE", stdout);
	printargs(argc, argv, stdout);
	fputnow(stdout);
	progname = argv[0];			/* get options */
	while (argc > 2 && argv[1][0] == '-') {
		switch (argv[1][1]) {
		case 'n':
			nprocs = atoi(argv[2]);
			break;
		default:
			goto userr;
		}
		argv += 2; argc -= 2;
	}
						/* initialize & sort inputs */
	ninpfiles = argc - 1;
	if (ninpfiles < 2)
		goto userr;
	inpfile = (PGINPUT *)malloc(sizeof(PGINPUT)*ninpfiles);
	if (inpfile == NULL)
		return(1);
	for (i = 0; i < ninpfiles; i++)
		if (!init_pabopto_inp(i, argv[i+1]))
			return(1);
	qsort(inpfile, ninpfiles, sizeof(PGINPUT), &cmp_inang);
						/* compile measurements */
	for (i = 0; i < ninpfiles; i++)
		if (!add_pabopto_inp(i))
			return(1);
	make_rbfrep();				/* process last data set */
	build_mesh();				/* create interpolation */
	save_bsdf_rep(stdout);			/* write it out */
	return(0);
userr:
	fprintf(stderr, "Usage: %s [-n nproc] meas1.dat meas2.dat .. > bsdf.sir\n",
					progname);
	return(1);
}