From 1e600848e774a10c1094571484c5b3f3f85ddf67 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Tue, 1 Jul 2003 16:49:49 +0000
Subject: [PATCH] some collisions don't have surface normals

---
 direct/src/directtools/DirectSelection.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/direct/src/directtools/DirectSelection.py b/direct/src/directtools/DirectSelection.py
index 737a929945..94dcb2471d 100644
--- a/direct/src/directtools/DirectSelection.py
+++ b/direct/src/directtools/DirectSelection.py
@@ -476,6 +476,10 @@ class SelectionQueue(CollisionHandlerQueue):
         # If dot product of collision point surface normal and
         # ray from camera to collision point is positive, we are
         # looking at the backface of the polygon
+        if not entry.hasFromSurfaceNormal():
+            # Well, no way to tell.  Assume we're not backfacing.
+            return 0
+        
         v = Vec3(entry.getFromIntersectionPoint())
         n = entry.getFromSurfaceNormal()
         # Convert to camera space for backfacing test