--- ray/src/ot/wfconv.c	2014/01/24 01:26:44	2.11
+++ ray/src/ot/wfconv.c	2014/06/10 23:19:00	2.13
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: wfconv.c,v 2.11 2014/01/24 01:26:44 greg Exp $";
+static const char RCSid[] = "$Id: wfconv.c,v 2.13 2014/06/10 23:19:00 greg Exp $";
 #endif
 /*
  *  Load Wavefront .OBJ file and convert to triangles with mesh info.
@@ -32,15 +32,15 @@ static char	group[256];	/* current group name */
 static int	lineno;		/* current line number */
 static int	faceno;		/* current face number */
 
-static int getstmt(char	*av[MAXARG], FILE	*fp);
-static int cvtndx(VNDX	vi, char	*vs);
-static int putface(int	ac, char	**av);
+static int getstmt(char	*av[MAXARG], FILE *fp);
+static int cvtndx(VNDX vi, char *vs);
+static int putface(int ac, char **av);
 static OBJECT getmod(void);
-static int puttri(char	*v1, char	*v2, char	*v3);
+static int puttri(char	*v1, char *v2, char *v3);
 static void freeverts(void);
-static int newv(double	x, double	y, double	z);
-static int newvn(double	x, double	y, double	z);
-static int newvt(double	x, double	y);
+static int newv(double	x, double y, double z);
+static int newvn(double	x, double y, double z);
+static int newvt(double	x, double y);
 static void syntax(char	*er);
 
 
@@ -249,12 +249,14 @@ cvtndx(				/* convert vertex string to index */
 static int
 dominant_axis(char *v1, char *v2, char *v3)
 {
-	int	v1i = atoi(v1), v2i = atoi(v2), v3i = atoi(v3);
+	VNDX	v1i, v2i, v3i;
 	FVECT	e1, e2, vn;
 	int	i, imax;
 
-	VSUB(e1, vlist[v2i], vlist[v1i]);
-	VSUB(e2, vlist[v3i], vlist[v2i]);
+	if (!cvtndx(v1i, v1) || !cvtndx(v2i, v2) || !cvtndx(v3i, v3))
+		return(-1);
+	VSUB(e1, vlist[v2i[0]], vlist[v1i[0]]);
+	VSUB(e2, vlist[v3i[0]], vlist[v2i[0]]);
 	VCROSS(vn, e1, e2);
 	for (i = imax = 2; i--; )
 		if (vn[i]*vn[i] > vn[imax]*vn[imax])
@@ -287,7 +289,7 @@ putface(				/* put out an N-sided polygon */
 		if ((ax = dominant_axis(av[i], av[i+1], av[i+2])) >= 0)
 			break;
 	if (ax < 0)
-		return(0);
+		return(1);		/* ignore degenerate face */
 	if (++ax >= 3) ax = 0;
 	ay = ax;
 	if (++ay >= 3) ay = 0;
@@ -302,8 +304,10 @@ putface(				/* put out an N-sided polygon */
 		poly->v[i].mY = vlist[vi[0]][ay];
 	}
 					/* break into triangles & output */
-	if (!polyTriangulate(poly, &tri_out))
-		return(0);
+	if (!polyTriangulate(poly, &tri_out)) {
+		sprintf(errmsg, "self-intersecting face with %d vertices", ac);
+		error(WARNING, errmsg);
+	}
 	polyFree(poly);
 	return(1);
 }