--- ray/src/util/radcompare.c	2020/06/30 22:53:05	2.24
+++ ray/src/util/radcompare.c	2022/05/24 22:34:18	2.30
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: radcompare.c,v 2.24 2020/06/30 22:53:05 greg Exp $";
+static const char RCSid[] = "$Id: radcompare.c,v 2.30 2022/05/24 22:34:18 greg Exp $";
 #endif
 /*
  * Compare Radiance files for significant differences
@@ -27,6 +27,8 @@ int	report = REP_WARN;	/* reporting level */
 
 int	ign_header = 0;		/* ignore header differences? */
 
+int	escape_newlines = 0;	/* allow backslash to skip newlines */
+
 double	rel_min = 1e-5;		/* positive for relative comparisons */
 
 double	rms_lim = 0.01;		/* RMS difference limit */
@@ -35,6 +37,8 @@ double	max_lim = 0.25;		/* difference limit if non-neg
 
 int	lin1cnt=0, lin2cnt=0;	/* file line position */
 
+int	comment_c = '\0';	/* comment delimiter for text files */
+
 const char	nsuffix[10][3] = {		/* 1st, 2nd, 3rd, etc. */
 			"th","st","nd","rd","th","th","th","th","th","th"
 		};
@@ -70,6 +74,7 @@ enum {TYP_UNKNOWN, TYP_TEXT, TYP_ASCII, TYP_RGBE, TYP_
 
 				/* header variables to always ignore */
 const char	*hdr_ignkey[] = {
+			"FORMAT",
 			"SOFTWARE",
 			"CAPDATE",
 			"GMT",
@@ -111,7 +116,7 @@ usage()
 {
 	fputs("Usage: ", stderr);
 	fputs(progname, stderr);
-	fputs(" [-h][-s|-w|-v][-rel min_test][-rms epsilon][-max epsilon] reference test\n",
+	fputs(" [-h][-c#][-s|-w|-v][-rel min_test][-rms epsilon][-max epsilon] reference test\n",
 			stderr);
 	exit(2);
 }
@@ -130,8 +135,19 @@ read_line(LINEBUF *bp, FILE *fp)
 	}
 	while (fgets(bp->str + bp->len, bp->siz - bp->len, fp)) {
 		bp->len += strlen(bp->str + bp->len);
-		if (bp->str[bp->len-1] == '\n')
+		if (bp->str[bp->len-1] == '\n') {
+			if (bp->len > 1 && bp->str[bp->len-2] == '\r') {
+				bp->str[--bp->len] = '\0';
+				bp->str[bp->len-1] = '\n';
+			}
+			if (escape_newlines && bp->len > 1 &&
+					bp->str[bp->len-2] == '\\') {
+				bp->str[--bp->len] = '\0';
+				bp->str[bp->len-1] = ' ';
+				continue;
+			}
 			break;		/* found EOL */
+		}
 		if (bp->len < bp->siz - 4)
 			continue;	/* at EOF? */
 		if (bp->siz >= MAXBUF) {
@@ -149,6 +165,14 @@ read_line(LINEBUF *bp, FILE *fp)
 		if (!bp->str)
 			goto memerr;
 	}
+	if (comment_c) {		/* elide comment? */
+		char	*cp = sskip2(bp->str,0);
+		if (*cp == comment_c) {
+			*cp++ = '\n';
+			*cp = '\0';
+			bp->len = cp - bp->str;
+		}
+	}
 	return(bp->len);
 memerr:
 	fprintf(stderr,
@@ -187,8 +211,9 @@ real_check(double r1, double r2)
 
 	if (rel_min > 0) {	/* doing relative differences? */
 		double	av2 = .25*(r1*r1 + 2.*fabs(r1*r2) + r2*r2);
-		if (av2 > rel_min*rel_min)
-			diff2 /= av2;
+		if (av2 < rel_min*rel_min)
+			av2 = rel_min*rel_min;
+		diff2 /= av2;
 	}
 	if (max_lim >= 0 && diff2 > max_lim*max_lim) {
 		if (report != REP_QUIET)
@@ -362,7 +387,7 @@ setheadvar(char *val, void *p)
 		tep->key = strcpy(malloc(kln+1), key);
 	if (tep->data) {	/* check for special cases */
 		if (!strcmp(key, "EXPOSURE")) {
-			sprintf(newval, "%f", atof(tep->data)*atof(val));
+			sprintf(newval, "%.6e", atof(tep->data)*atof(val));
 			vln = strlen(val = newval);
 		}
 		free(tep->data);
@@ -475,7 +500,6 @@ identify_type(const char *name, FILE *fin, LUTAB *htp)
 	}
 	if (c)
 		return(TYP_BINARY);
-	SET_FILE_TEXT(fin);			/* originally set to binary */
 	return(TYP_TEXT);
 badeof:
 	if (report != REP_QUIET) {
@@ -558,8 +582,18 @@ compare_text()
 
 	if (report >= REP_VERBOSE) {
 		fputs(progname, stdout);
-		fputs(": comparing inputs as ASCII text\n", stdout);
+		fputs(": comparing inputs as ASCII text", stdout);
+		if (escape_newlines)
+			fputs(", allowing escaped newlines", stdout);
+		if (comment_c) {
+			fputs(", ignoring comments starting with '", stdout);
+			fputc(comment_c, stdout);
+			fputc('\'', stdout);
+		}
+		fputc('\n', stdout);
 	}
+	SET_FILE_TEXT(f1in);			/* originally set to binary */
+	SET_FILE_TEXT(f2in);
 	init_line(&l1buf); init_line(&l2buf);	/* compare a line at a time */
 	while (read_line(&l1buf, f1in)) {
 		lin1cnt++;
@@ -898,6 +932,12 @@ main(int argc, char *argv[])
 		switch (argv[a][1]) {
 		case 'h':			/* ignore header info. */
 			ign_header = !ign_header;
+			continue;
+		case 'n':			/* allow newline escapes */
+			escape_newlines = !escape_newlines;
+			continue;
+		case 'c':			/* ignore comments */
+			comment_c = argv[a][2];
 			continue;
 		case 's':			/* silent operation */
 			report = REP_QUIET;