From 5fee00c7df737898ee82e51665078709cc864159 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Fri, 27 Jun 2003 23:08:21 +0000
Subject: [PATCH] tolerate billboards under a singular transform

---
 panda/src/pgraph/billboardEffect.cxx | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/panda/src/pgraph/billboardEffect.cxx b/panda/src/pgraph/billboardEffect.cxx
index b76d5731d6..cc41fa2121 100644
--- a/panda/src/pgraph/billboardEffect.cxx
+++ b/panda/src/pgraph/billboardEffect.cxx
@@ -110,6 +110,11 @@ do_billboard(const TransformState *net_transform,
     camera_transform = _look_at.get_net_transform();
   }
 
+  if (net_transform->is_singular()) {
+    // If we're under a singular transform, never mind.
+    return TransformState::make_identity();
+  }
+
   CPT(TransformState) rel_transform =
     net_transform->invert_compose(camera_transform);
   const LMatrix4f &rel_mat = rel_transform->get_mat();