--- ray/src/common/rglsurf.c	2003/04/23 02:28:06	3.7
+++ ray/src/common/rglsurf.c	2003/05/25 15:41:31	3.9
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: rglsurf.c,v 3.7 2003/04/23 02:28:06 greg Exp $";
+static const char RCSid[] = "$Id: rglsurf.c,v 3.9 2003/05/25 15:41:31 greg Exp $";
 #endif
 /*
  * Convert Radiance -> OpenGL surfaces.
@@ -259,6 +259,9 @@ register OBJREC *o;
 		if (o->oargs.farg[7] < 0.)
 			o->oargs.farg[7] = 0.;
 	}
+	h = sqrt(dist2(o->oargs.farg,o->oargs.farg+3));
+	if (h <= FTINY)
+		return;
 	cent[0] = .5*(o->oargs.farg[0] + o->oargs.farg[3]);
 	cent[1] = .5*(o->oargs.farg[1] + o->oargs.farg[4]);
 	cent[2] = .5*(o->oargs.farg[2] + o->oargs.farg[5]);
@@ -274,13 +277,14 @@ register OBJREC *o;
 	glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
 			(GLdouble)o->oargs.farg[2]);
 					/* compute height & rotation angle */
-	h = sqrt(dist2(o->oargs.farg,o->oargs.farg+3));
-	if (h <= FTINY)
-		return;
 	x1 = o->oargs.farg[1] - o->oargs.farg[4];
 	y1 = o->oargs.farg[3] - o->oargs.farg[0];
 	/* z1 = 0; */
-	d = 180./PI * asin(sqrt(x1*x1 + y1*y1) / h);
+	d = x1*x1 + y1*y1;
+	if (d <= FTINY*FTINY)
+		x1 = 1.;
+	else
+		d = 180./PI * asin(sqrt(d) / h);
 	if (o->oargs.farg[5] < o->oargs.farg[2])
 		d = 180. - d;
 	if (d > FTINY)
@@ -296,7 +300,7 @@ int
 o_ring(o)			/* convert a ring */
 register OBJREC	*o;
 {
-	double	x1, y1, d;
+	double	x1, y1, d, h;
 
 	if (o->oargs.nfargs != 8)
 		objerror(o, USER, "bad # real arguments");
@@ -311,6 +315,9 @@ register OBJREC	*o;
 		o->oargs.farg[6] = 0.;
 	if (o->oargs.farg[7] - o->oargs.farg[6] <= FTINY)
 		return;
+	h = VLEN(o->oargs.farg+3);
+	if (h <= FTINY)
+		return;
 	if (dolights)
 		doflatsrc((MATREC *)o->os, o->oargs.farg, o->oargs.farg+3, 
 				PI*(o->oargs.farg[7]*o->oargs.farg[7] -
@@ -325,13 +332,14 @@ register OBJREC	*o;
 	glTranslated((GLdouble)o->oargs.farg[0], (GLdouble)o->oargs.farg[1],
 			(GLdouble)o->oargs.farg[2]);
 					/* compute rotation angle */
-	d = VLEN(o->oargs.farg+3);
-	if (d <= FTINY)
-		return;
 	x1 = -o->oargs.farg[4];
 	y1 = o->oargs.farg[3];
 	/* z1 = 0; */
-	d = 180./PI * asin(sqrt(x1*x1 + y1*y1) / d);
+	d = x1*x1 + y1*y1;
+	if (d <= FTINY*FTINY)
+		x1 = 1.;
+	else
+		d = 180./PI * asin(sqrt(d) / h);
 	if (o->oargs.farg[5] < 0.)
 		d = 180. - d;
 	if (d > FTINY)