--- ray/src/util/dctimestep.c	2009/06/17 20:41:47	2.1
+++ ray/src/util/dctimestep.c	2013/01/11 17:21:39	2.25
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: dctimestep.c,v 2.1 2009/06/17 20:41:47 greg Exp $";
+static const char RCSid[] = "$Id: dctimestep.c,v 2.25 2013/01/11 17:21:39 greg Exp $";
 #endif
 /*
  * Compute time-step result using Daylight Coefficient method.
@@ -10,13 +10,15 @@ static const char RCSid[] = "$Id: dctimestep.c,v 2.1 2
 #include <ctype.h>
 #include "standard.h"
 #include "platform.h"
+#include "paths.h"
 #include "color.h"
 #include "resolu.h"
 #include "bsdf.h"
+#include "bsdf_m.h"
 
 char	*progname;			/* global argv[0] */
 
-/* Data types for matrix loading */
+/* Data types for file loading */
 enum {DTfromHeader, DTascii, DTfloat, DTdouble, DTrgbe, DTxyze};
 
 /* A color coefficient matrix -- vectors have ncols==1 */
@@ -38,7 +40,7 @@ cm_alloc(int nrows, int ncols)
 	CMATRIX	*cm;
 
 	if ((nrows <= 0) | (ncols <= 0))
-		return(NULL);
+		error(USER, "attempt to create empty matrix");
 	cm = (CMATRIX *)malloc(sizeof(CMATRIX) +
 				3*sizeof(COLORV)*(nrows*ncols - 1));
 	if (cm == NULL)
@@ -105,15 +107,20 @@ getDTfromHeader(FILE *fp)
 static CMATRIX *
 cm_load(const char *fname, int nrows, int ncols, int dtype)
 {
-	CMATRIX	*cm;
 	FILE	*fp = stdin;
+	CMATRIX	*cm;
 
+	if (ncols <= 0)
+		error(USER, "Non-positive number of columns");
 	if (fname == NULL)
 		fname = "<stdin>";
 	else if ((fp = fopen(fname, "r")) == NULL) {
 		sprintf(errmsg, "cannot open file '%s'", fname);
 		error(SYSTEM, errmsg);
 	}
+#ifdef getc_unlocked
+	flockfile(fp);
+#endif
 	if (dtype != DTascii)
 		SET_FILE_BINARY(fp);
 	if (dtype == DTfromHeader)
@@ -125,7 +132,6 @@ cm_load(const char *fname, int nrows, int ncols, int d
 		break;
 	default:
 		error(USER, "unexpected data type in cm_load()");
-		return(NULL);
 	}
 	if (nrows <= 0) {			/* don't know length? */
 		int	guessrows = 147;	/* usually big enough */
@@ -135,32 +141,38 @@ cm_load(const char *fname, int nrows, int ncols, int d
 				long	endpos = ftell(fp);
 				long	elemsiz = 3*(dtype==DTfloat ?
 					    sizeof(float) : sizeof(double));
-				guessrows = (endpos - startpos)/elemsiz;
+
+				if ((endpos - startpos) % (ncols*elemsiz)) {
+					sprintf(errmsg,
+					"improper length for binary file '%s'",
+							fname);
+					error(USER, errmsg);
+				}
+				guessrows = (endpos - startpos)/(ncols*elemsiz);
 				if (fseek(fp, startpos, SEEK_SET) < 0) {
 					sprintf(errmsg,
 						"fseek() error on file '%s'",
 							fname);
 					error(SYSTEM, errmsg);
 				}
-				if ((endpos - startpos) % elemsiz == 0)
-					nrows = guessrows;	/* confident */
+				nrows = guessrows;	/* we're confident */
 			}
 		}
 		cm = cm_alloc(guessrows, ncols);
 	} else
 		cm = cm_alloc(nrows, ncols);
-	if (cm == NULL)
+	if (cm == NULL)					/* XXX never happens */
 		return(NULL);
 	if (dtype == DTascii) {				/* read text file */
 		int	maxrow = (nrows > 0 ? nrows : 32000);
 		int	r, c;
 		for (r = 0; r < maxrow; r++) {
-		    if (r >= cm->nrows)		/* need more space? */
+		    if (r >= cm->nrows)			/* need more space? */
 			cm = cm_resize(cm, 2*cm->nrows);
 		    for (c = 0; c < ncols; c++) {
 		        COLORV	*cv = cm_lval(cm,r,c);
 			if (fscanf(fp, COLSPEC, cv, cv+1, cv+2) != 3)
-				if ((nrows <= 0) & (r > 0) & (c == 0)) {
+				if ((nrows <= 0) & (r > 0) & !c) {
 					cm = cm_resize(cm, maxrow=r);
 					break;
 				} else
@@ -188,7 +200,7 @@ cm_load(const char *fname, int nrows, int ncols, int d
 					if (nread == cm->nrows*cm->ncols)
 							/* need more space? */
 						cm = cm_resize(cm, 2*cm->nrows);
-					else if (nread % cm->ncols == 0)
+					else if (nread && !(nread % cm->ncols))
 							/* seem to be  done */
 						cm = cm_resize(cm, nread/cm->ncols);
 					else		/* ended mid-row */
@@ -210,7 +222,6 @@ cm_load(const char *fname, int nrows, int ncols, int d
 				copycolor(cvp, dc);
 				cvp += 3;
 			}
-
 		} else /* dtype == DTfloat */ {
 			float	fc[3];			/* load from float */
 			COLORV	*cvp = cm->cmem;
@@ -225,7 +236,7 @@ cm_load(const char *fname, int nrows, int ncols, int d
 				cvp += 3;
 			}
 		}
-		if (getc(fp) != EOF) {
+		if (fgetc(fp) != EOF) {
 				sprintf(errmsg,
 				"unexpected data at end of binary file %s",
 						fname);
@@ -234,18 +245,64 @@ cm_load(const char *fname, int nrows, int ncols, int d
 	}
 	if (fp != stdin)
 		fclose(fp);
+#ifdef getc_unlocked
+	else
+		funlockfile(fp);
+#endif
 	return(cm);
 EOFerror:
-	sprintf(errmsg, "unexpected EOF reading %s",
-			fname);
+	sprintf(errmsg, "unexpected EOF reading %s", fname);
 	error(USER, errmsg);
 not_handled:
 	error(INTERNAL, "unhandled data size or length in cm_load()");
 	return(NULL);	/* gratis return */
 }
 
-/* Multiply two matrices (or a matrix and a vector) and allocate the result*/
+/* Extract a column vector from a matrix */
 static CMATRIX *
+cm_column(const CMATRIX *cm, int c)
+{
+	CMATRIX	*cvr;
+	int	dr;
+
+	if ((c < 0) | (c >= cm->ncols))
+		return(NULL);
+	cvr = cm_alloc(cm->nrows, 1);
+	if (cvr == NULL)
+		return(NULL);
+	for (dr = 0; dr < cm->nrows; dr++) {
+		const COLORV	*sp = cm_lval(cm,dr,c);
+		COLORV		*dp = cv_lval(cvr,dr);
+		dp[0] = sp[0];
+		dp[1] = sp[1];
+		dp[2] = sp[2];
+	}
+	return(cvr);
+}
+
+/* Scale a matrix by a single value */
+static CMATRIX *
+cm_scale(const CMATRIX *cm1, const COLOR sca)
+{
+	CMATRIX	*cmr;
+	int	dr, dc;
+
+	cmr = cm_alloc(cm1->nrows, cm1->ncols);
+	if (cmr == NULL)
+		return(NULL);
+	for (dr = 0; dr < cmr->nrows; dr++)
+	    for (dc = 0; dc < cmr->ncols; dc++) {
+	        const COLORV	*sp = cm_lval(cm1,dr,dc);
+		COLORV		*dp = cm_lval(cmr,dr,dc);
+		dp[0] = sp[0] * sca[0];
+		dp[1] = sp[1] * sca[1];
+		dp[2] = sp[2] * sca[2];
+	    }
+	return(cmr);
+}
+
+/* Multiply two matrices (or a matrix and a vector) and allocate the result */
+static CMATRIX *
 cm_multiply(const CMATRIX *cm1, const CMATRIX *cm2)
 {
 	CMATRIX	*cmr;
@@ -285,28 +342,159 @@ cm_print(const CMATRIX *cm, FILE *fp)
 	}
 }
 
-/* convert a BSDF to our matrix representation */
+/* Convert a BSDF to our matrix representation */
 static CMATRIX *
-cm_bsdf(const struct BSDF_data *bsdf)
+cm_bsdf(const COLOR bsdfLamb, const COLOR specCol, const SDMat *bsdf)
 {
 	CMATRIX	*cm = cm_alloc(bsdf->nout, bsdf->ninc);
-	COLORV	*mp = cm->cmem;
+	int	nbadohm = 0;
+	int	nneg = 0;
 	int	r, c;
-	
-	for (r = 0; r < cm->nrows; r++)
-		for (c = 0; c < cm->ncols; c++, mp += 3)
-			mp[0] = mp[1] = mp[2] = BSDF_value(bsdf,c,r);
+					/* loop over incident angles */
+	for (c = 0; c < cm->ncols; c++) {
+		const double	dom = mBSDF_incohm(bsdf,c);
+					/* projected solid angle */
+		nbadohm += (dom <= 0);
+
+		for (r = 0; r < cm->nrows; r++) {
+			float	f = mBSDF_value(bsdf,c,r);
+			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);
+			addcolor(mp, bsdfLamb);
+			scalecolor(mp, dom);
+		}
+	}
+	if (nneg | nbadohm) {
+		sprintf(errmsg,
+		    "BTDF has %d negatives and %d bad incoming solid angles",
+				nneg, nbadohm);
+		error(WARNING, errmsg);
+	}
 	return(cm);
 }
 
-/* Sum together a set of images and write result to stdout */
+/* Convert between input and output indices for reciprocity */
 static int
-sum_images(const char *fspec, const CMATRIX *cv)
+recip_out_from_in(const SDMat *bsdf, int in_recip)
 {
+	FVECT	v;
+
+	if (!mBSDF_incvec(v, bsdf, in_recip+.5))
+		return(in_recip);		/* XXX should be error! */
+	v[2] = -v[2];
+	return(mBSDF_outndx(bsdf, v));
+}
+
+/* Convert between output and input indices for reciprocity */
+static int
+recip_in_from_out(const SDMat *bsdf, int out_recip)
+{
+	FVECT	v;
+
+	if (!mBSDF_outvec(v, bsdf, out_recip+.5))
+		return(out_recip);		/* XXX should be error! */
+	v[2] = -v[2];
+	return(mBSDF_incndx(bsdf, v));
+}
+
+/* Convert a BSDF to our matrix representation, applying reciprocity */
+static CMATRIX *
+cm_bsdf_recip(const COLOR bsdfLamb, const COLOR specCol, const SDMat *bsdf)
+{
+	CMATRIX	*cm = cm_alloc(bsdf->ninc, bsdf->nout);
+	int	nbadohm = 0;
+	int	nneg = 0;
+	int	r, c;
+					/* loop over incident angles */
+	for (c = 0; c < cm->ncols; c++) {
+		const int	ro = recip_out_from_in(bsdf,c);
+		const double	dom = mBSDF_outohm(bsdf,ro);
+					/* projected solid angle */
+		nbadohm += (dom <= 0);
+
+		for (r = 0; r < cm->nrows; r++) {
+			const int	ri = recip_in_from_out(bsdf,r);
+			float		f = mBSDF_value(bsdf,ri,ro);
+			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);
+			addcolor(mp, bsdfLamb);
+			scalecolor(mp, dom);
+		}
+	}
+	if (nneg | nbadohm) {
+		sprintf(errmsg,
+		    "BTDF has %d negatives and %d bad incoming solid angles",
+				nneg, nbadohm);
+		error(WARNING, errmsg);
+	}
+	return(cm);
+}
+
+/* Load and convert a matrix BSDF from the given XML file */
+static CMATRIX *
+cm_loadBSDF(char *fname, COLOR cLamb)
+{
+	CMATRIX		*Tmat;
+	char		*fpath;
+	int		recip;
+	SDError		ec;
+	SDData		myBSDF;
+	SDSpectralDF	*tdf;
+	COLOR		bsdfLamb, 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);
+	}
+	SDclearBSDF(&myBSDF, fname);	/* load XML and check type */
+	ec = SDloadFile(&myBSDF, fpath);
+	if (ec)
+		error(USER, transSDError(ec));
+	ccy2rgb(&myBSDF.tLamb.spec, myBSDF.tLamb.cieY/PI, bsdfLamb);
+	recip = (myBSDF.tb == NULL);
+	tdf = recip ? myBSDF.tf : myBSDF.tb;
+	if (tdf == NULL) {		/* no non-Lambertian transmission? */
+		if (cLamb != NULL)
+			copycolor(cLamb, bsdfLamb);
+		SDfreeBSDF(&myBSDF);
+		return(NULL);
+	}
+	if (tdf->ncomp != 1 || tdf->comp[0].func != &SDhandleMtx) {
+		sprintf(errmsg, "unsupported BSDF '%s'", fpath);
+		error(USER, errmsg);
+	}
+					/* convert BTDF to matrix */
+	ccy2rgb(&tdf->comp[0].cspec[0], 1., specCol);
+	Tmat = recip ? cm_bsdf_recip(bsdfLamb, specCol, (SDMat *)tdf->comp[0].dist)
+			: cm_bsdf(bsdfLamb, specCol, (SDMat *)tdf->comp[0].dist);
+	if (cLamb != NULL)		/* Lambertian is included */
+		setcolor(cLamb, .0, .0, .0);
+					/* free BSDF and return */
+	SDfreeBSDF(&myBSDF);
+	return(Tmat);
+}
+
+/* Sum together a set of images and write result to fout */
+static int
+sum_images(const char *fspec, const CMATRIX *cv, FILE *fout)
+{
 	int	myDT = DTfromHeader;
-	CMATRIX	*pmat;
-	COLOR	*scanline;
-	int	myXR, myYR;
+	COLOR	*scanline = NULL;
+	CMATRIX	*pmat = NULL;
+	int	myXR=0, myYR=0;
 	int	i, y;
 
 	if (cv->ncols != 1)
@@ -317,6 +505,10 @@ sum_images(const char *fspec, const CMATRIX *cv)
 		FILE		*fp;
 		int		dt, xr, yr;
 		COLORV		*psp;
+							/* check for zero */
+		if ((scv[RED] == 0) & (scv[GRN] == 0) & (scv[BLU] == 0) &&
+				(myDT != DTfromHeader) | (i < cv->nrows-1))
+			continue;
 							/* open next picture */
 		sprintf(fname, fspec, i);
 		if ((fp = fopen(fname, "r")) == NULL) {
@@ -338,6 +530,11 @@ sum_images(const char *fspec, const CMATRIX *cv)
 				error(SYSTEM, "out of memory in sum_images()");
 			pmat = cm_alloc(myYR, myXR);
 			memset(pmat->cmem, 0, sizeof(COLOR)*myXR*myYR);
+							/* finish header */
+			fputformat(myDT==DTrgbe ? COLRFMT : CIEFMT, fout);
+			fputc('\n', fout);
+			fprtresolu(myXR, myYR, fout);
+			fflush(fout);
 		} else if ((dt != myDT) | (xr != myXR) | (yr != myYR)) {
 			sprintf(errmsg, "picture '%s' format/size mismatch",
 					fname);
@@ -360,77 +557,195 @@ sum_images(const char *fspec, const CMATRIX *cv)
 		fclose(fp);				/* done this picture */
 	}
 	free(scanline);
-							/* finish header */
-	fputformat(myDT==DTrgbe ? COLRFMT : CIEFMT, stdout);
-	fputc('\n', stdout);
-	fprtresolu(myXR, myYR, stdout);
 							/* write scanlines */
 	for (y = 0; y < myYR; y++)
-		if (fwritescan((COLOR *)cm_lval(pmat, y, 0), myXR, stdout) < 0)
+		if (fwritescan((COLOR *)cm_lval(pmat, y, 0), myXR, fout) < 0)
 			return(0);
 	cm_free(pmat);					/* all done */
-	return(fflush(stdout) == 0);
+	return(fflush(fout) == 0);
 }
 
-/* check to see if a string contains a %d specification */
-int
-hasDecimalSpec(const char *s)
+/* check to see if a string contains a %d or %o specification */
+static int
+hasNumberFormat(const char *s)
 {
-	while (*s && *s != '%')
-		s++;
-	if (!*s)
+	if (s == NULL)
 		return(0);
-	do
-		++s;
-	while (isdigit(*s));
 
-	return(*s == 'd');
+	while (*s) {
+		while (*s != '%')
+			if (!*s++)
+				return(0);
+		if (*++s == '%') {		/* ignore "%%" */
+			++s;
+			continue;
+		}
+		while (isdigit(*s))		/* field length */
+			++s;
+						/* field we'll use? */
+		if ((*s == 'd') | (*s == 'i') | (*s == 'o') |
+					(*s == 'x') | (*s == 'X'))
+			return(1);
+	}
+	return(0);				/* didn't find one */
 }
 
 int
 main(int argc, char *argv[])
 {
-	CMATRIX			*tvec, *Dmat, *Tmat, *vtmp, *cvec;
-	struct BSDF_data	*btdf;
+	int		skyfmt = DTascii;
+	int		nsteps = 1;
+	char		*ofspec = NULL;
+	FILE		*ofp = stdout;
+	CMATRIX		*cmtx;		/* component vector/matrix result */
+	char		fnbuf[256];
+	int		a, i;
 
 	progname = argv[0];
+					/* get options */
+	for (a = 1; a < argc && argv[a][0] == '-'; a++)
+		switch (argv[a][1]) {
+		case 'n':
+			nsteps = atoi(argv[++a]);
+			if (nsteps <= 0)
+				goto userr;
+			break;
+		case 'o':
+			ofspec = argv[++a];
+			break;
+		case 'i':
+			switch (argv[a][2]) {
+			case 'f':
+				skyfmt = DTfloat;
+				break;
+			case 'd':
+				skyfmt = DTdouble;
+				break;
+			case 'a':
+				skyfmt = DTascii;
+				break;
+			default:
+				goto userr;
+			}
+			break;
+		default:
+			goto userr;
+		}
+	if ((argc-a < 1) | (argc-a > 4))
+		goto userr;
 
-	if ((argc < 4) | (argc > 5)) {
-		fprintf(stderr, "Usage: %s Vspec Tbsdf.xml Dmat.dat [tregvec]\n",
-				progname);
-		return(1);
+	if (argc-a > 2) {			/* VTDs expression */
+		CMATRIX	*smtx, *Dmat, *Tmat, *imtx;
+		COLOR	tLamb;
+						/* get sky vector/matrix */
+		smtx = cm_load(argv[a+3], 0, nsteps, skyfmt);
+						/* load BSDF */
+		Tmat = cm_loadBSDF(argv[a+1], tLamb);
+						/* load Daylight matrix */
+		Dmat = cm_load(argv[a+2], Tmat==NULL ? 0 : Tmat->ncols,
+					smtx->nrows, DTfromHeader);
+						/* multiply vector through */
+		imtx = cm_multiply(Dmat, smtx);
+		cm_free(Dmat); cm_free(smtx);
+		if (Tmat == NULL) {		/* diffuse only */
+			cmtx = cm_scale(imtx, tLamb);
+		} else {			/* else apply BTDF matrix */
+			cmtx = cm_multiply(Tmat, imtx);
+			cm_free(Tmat); 
+		}
+		cm_free(imtx);
+	} else {				/* sky vector/matrix only */
+		cmtx = cm_load(argv[a+1], 0, nsteps, skyfmt);
 	}
-	tvec = cm_load(argv[4], 0, 1, DTascii);	/* argv[4]==NULL iff argc==4 */
-	Dmat = cm_load(argv[3], 0, tvec->nrows, DTfromHeader);
-	btdf = load_BSDF(argv[2]);
-	if (btdf == NULL)
-		return(1);
-	if (btdf->ninc != Dmat->nrows) {
-		sprintf(errmsg, "Incoming BTDF dir (%d) mismatch to D (%d)",
-				btdf->ninc, Dmat->nrows);
-		error(USER, errmsg);
+						/* prepare output stream */
+	if ((ofspec != NULL) & (nsteps == 1) && hasNumberFormat(ofspec)) {
+		sprintf(fnbuf, ofspec, 1);
+		ofspec = fnbuf;
 	}
-						/* multiply vector through */
-	vtmp = cm_multiply(Dmat, tvec);
-	cm_free(Dmat); cm_free(tvec);
-	Tmat = cm_bsdf(btdf);			/* convert BTDF to matrix */
-	free_BSDF(btdf);
-	cvec = cm_multiply(Tmat, vtmp);		/* cvec = component vector */
-	cm_free(Tmat); cm_free(vtmp);
-	if (hasDecimalSpec(argv[1])) {		/* generating image */
-		SET_FILE_BINARY(stdout);
-		newheader("RADIANCE", stdout);
-		printargs(argc, argv, stdout);
-		fputnow(stdout);
-		if (!sum_images(argv[1], cvec))
+	if (ofspec != NULL && !hasNumberFormat(ofspec)) {
+		if ((ofp = fopen(ofspec, "w")) == NULL) {
+			fprintf(stderr, "%s: cannot open '%s' for output\n",
+					progname, ofspec);
 			return(1);
-	} else {				/* generating vector */
-		CMATRIX	*Vmat = cm_load(argv[1], 0, cvec->nrows, DTfromHeader);
-		CMATRIX	*rvec = cm_multiply(Vmat, cvec);
+		}
+		ofspec = NULL;			/* only need to open once */
+	}
+	if (hasNumberFormat(argv[a])) {		/* generating image(s) */
+		if (ofspec == NULL) {
+			SET_FILE_BINARY(ofp);
+			newheader("RADIANCE", ofp);
+			printargs(argc, argv, ofp);
+			fputnow(ofp);
+		}
+		if (nsteps > 1)			/* multiple output frames? */
+			for (i = 0; i < nsteps; i++) {
+				CMATRIX	*cvec = cm_column(cmtx, i);
+				if (ofspec != NULL) {
+					sprintf(fnbuf, ofspec, i+1);
+					if ((ofp = fopen(fnbuf, "wb")) == NULL) {
+						fprintf(stderr,
+					"%s: cannot open '%s' for output\n",
+							progname, fnbuf);
+						return(1);
+					}
+					newheader("RADIANCE", ofp);
+					printargs(argc, argv, ofp);
+					fputnow(ofp);
+				}
+				fprintf(ofp, "FRAME=%d\n", i+1);
+				if (!sum_images(argv[a], cvec, ofp))
+					return(1);
+				if (ofspec != NULL) {
+					if (fclose(ofp) == EOF) {
+						fprintf(stderr,
+						"%s: error writing to '%s'\n",
+							progname, fnbuf);
+						return(1);
+					}
+					ofp = stdout;
+				}
+				cm_free(cvec);
+			}
+		else if (!sum_images(argv[a], cmtx, ofp))
+			return(1);
+	} else {				/* generating vector/matrix */
+		CMATRIX	*Vmat = cm_load(argv[a], 0, cmtx->nrows, DTfromHeader);
+		CMATRIX	*rmtx = cm_multiply(Vmat, cmtx);
 		cm_free(Vmat);
-		cm_print(rvec, stdout);
-		cm_free(rvec);
+		if (ofspec != NULL)		/* multiple vector files? */
+			for (i = 0; i < nsteps; i++) {
+				CMATRIX	*rvec = cm_column(rmtx, i);
+				sprintf(fnbuf, ofspec, i+1);
+				if ((ofp = fopen(fnbuf, "w")) == NULL) {
+					fprintf(stderr,
+					"%s: cannot open '%s' for output\n",
+							progname, fnbuf);
+					return(1);
+				}
+				cm_print(rvec, ofp);
+				if (fclose(ofp) == EOF) {
+					fprintf(stderr,
+						"%s: error writing to '%s'\n",
+							progname, fnbuf);
+					return(1);
+				}
+				ofp = stdout;
+				cm_free(rvec);
+			}
+		else
+			cm_print(rmtx, ofp);
+		cm_free(rmtx);
 	}
-	cm_free(cvec);				/* final clean-up */
+	if (fflush(ofp) == EOF) {		/* final clean-up */
+		fprintf(stderr, "%s: write error on output\n", progname);
+		return(1);
+	}
+	cm_free(cmtx);
 	return(0);
+userr:
+	fprintf(stderr, "Usage: %s [-n nsteps][-o ospec][-i{f|d}] DCspec [skyf]\n",
+				progname);
+	fprintf(stderr, "   or: %s [-n nsteps][-o ospec][-i{f|d}] Vspec Tbsdf.xml Dmat.dat [skyf]\n",
+				progname);
+	return(1);
 }