From e46c15401aec77c88d746923787bd709394ef85e Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Wed, 5 Oct 2016 15:00:22 -0700
Subject: [PATCH] take care for division by zero when normalizing

---
 libraries/physics/src/CollisionRenderMeshCache.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libraries/physics/src/CollisionRenderMeshCache.cpp b/libraries/physics/src/CollisionRenderMeshCache.cpp
index 517e25e1c4..3a1c4d0ea4 100644
--- a/libraries/physics/src/CollisionRenderMeshCache.cpp
+++ b/libraries/physics/src/CollisionRenderMeshCache.cpp
@@ -90,7 +90,11 @@ bool copyShapeToMesh(const btTransform& transform, const btConvexShape* shape,
         avgVertex = transform * (avgVertex * (1.0f / (float)numHullVertices));
 
         for (int i = 0; i < numHullVertices; ++i) {
-            btVector3 norm = (transform * hullVertices[i] - avgVertex).normalize();
+            btVector3 norm = transform * hullVertices[i] - avgVertex;
+            btScalar normLength = norm.length();
+            if (normLength > FLT_EPSILON) {
+                norm /= normLength;
+            }
             memcpy(tempVertices + 3 * i, norm.m_floats, SIZE_OF_VEC3);
         }
         gpu::BufferView::Size numBytes = sizeof(float) * (3 * numHullVertices);