--- ray/src/util/rfluxmtx.c	2020/03/02 22:00:05	2.51
+++ ray/src/util/rfluxmtx.c	2021/12/15 01:38:50	2.54
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: rfluxmtx.c,v 2.51 2020/03/02 22:00:05 greg Exp $";
+static const char RCSid[] = "$Id: rfluxmtx.c,v 2.54 2021/12/15 01:38:50 greg Exp $";
 #endif
 /*
  * Calculate flux transfer matrix or matrices using rcontrib
@@ -720,9 +720,9 @@ sample_origin(PARAMS *p, FVECT orig, const FVECT rdir,
 					/* compute projected areas */
 	for (i = 0, sp = p->slist; sp != NULL; i++, sp = sp->next) {
 		projsa[i] = -DOT(sp->snrm, rdir) * sp->area;
-		tarea += projsa[i] *= (double)(projsa[i] > FTINY);
+		tarea += projsa[i] *= (double)(projsa[i] > 0);
 	}
-	if (tarea < 0) {		/* wrong side of sender? */
+	if (tarea < FTINY*FTINY) {	/* wrong side of sender? */
 		fputs(progname, stderr);
 		fputs(": internal - sample behind all sender elements!\n",
 				stderr);
@@ -740,8 +740,7 @@ sample_uniform(PARAMS *p, int b, FILE *fp)
 {
 	int	n = sampcnt;
 	double	samp3[3];
-	double	duvw[3];
-	FVECT	orig_dir[2];
+	FVECT	duvw, orig_dir[2];
 	int	i;
 
 	if (fp == NULL)			/* just requesting number of bins? */
@@ -749,7 +748,7 @@ sample_uniform(PARAMS *p, int b, FILE *fp)
 
 	while (n--) {			/* stratified hemisphere sampling */
 		SDmultiSamp(samp3, 3, (n+frandom())/sampcnt);
-		SDsquare2disk(duvw, samp3[1], samp3[2]);
+		square2disk(duvw, samp3[1], samp3[2]);
 		duvw[2] = -sqrt(1. - duvw[0]*duvw[0] - duvw[1]*duvw[1]);
 		for (i = 3; i--; )
 			orig_dir[1][i] = duvw[0]*p->udir[i] +
@@ -769,8 +768,7 @@ sample_shirchiu(PARAMS *p, int b, FILE *fp)
 {
 	int	n = sampcnt;
 	double	samp3[3];
-	double	duvw[3];
-	FVECT	orig_dir[2];
+	FVECT	duvw, orig_dir[2];
 	int	i;
 
 	if (fp == NULL)			/* just requesting number of bins? */
@@ -778,7 +776,7 @@ sample_shirchiu(PARAMS *p, int b, FILE *fp)
 
 	while (n--) {			/* stratified sampling */
 		SDmultiSamp(samp3, 3, (n+frandom())/sampcnt);
-		SDsquare2disk(duvw, (b/p->hsiz + samp3[1])/curparams.hsiz,
+		square2disk(duvw, (b/p->hsiz + samp3[1])/curparams.hsiz,
 				(b%p->hsiz + samp3[2])/curparams.hsiz);
 		duvw[2] = sqrt(1. - duvw[0]*duvw[0] - duvw[1]*duvw[1]);
 		for (i = 3; i--; )
@@ -997,7 +995,7 @@ finish_polygon(SURF *p)
 		VCOPY(e1, e2);
 	}
 	p->area = normalize(p->snrm)*0.5;
-	return(p->area > FTINY);
+	return(p->area > FTINY*FTINY);
 }
 
 /* Add a surface to our current parameters */
@@ -1060,7 +1058,7 @@ add_surface(int st, const char *oname, FILE *fp)
 		snew->area *= PI*snew->area;
 		break;
 	}
-	if ((snew->area <= FTINY) & (verbose >= 0)) {
+	if ((snew->area <= FTINY*FTINY) & (verbose >= 0)) {
 		fprintf(stderr, "%s: warning - zero area for surface '%s'\n",
 				progname, oname);
 		free(snew);
@@ -1308,6 +1306,7 @@ main(int argc, char *argv[])
 		case 'n':		/* options with 1 argument */
 		case 's':
 		case 'o':
+		case 't':
 			na = 2;
 			break;
 		case 'b':		/* special case */