From a16f99c74c3f9aa2ccb114d29f7e22d62282e164 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Mon, 9 Jul 2001 23:14:14 +0000
Subject: [PATCH] allow scales to zero for BoundingLines

---
 panda/src/mathutil/boundingLine.cxx | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/panda/src/mathutil/boundingLine.cxx b/panda/src/mathutil/boundingLine.cxx
index de1cc0c04a..e54de2d47e 100644
--- a/panda/src/mathutil/boundingLine.cxx
+++ b/panda/src/mathutil/boundingLine.cxx
@@ -43,7 +43,11 @@ xform(const LMatrix4f &mat) {
   if (!is_empty() && !is_infinite()) {
     _origin = _origin * mat;
     _vector = _vector * mat;
-    _vector.normalize();
+    if (!_vector.normalize()) {
+      // If we just scaled the line down to nothing, it becomes an
+      // empty volume.
+      _flags |= F_empty;
+    }
   }
 }