From c0efe069c58bdc12089a9edc31e565725b24305d Mon Sep 17 00:00:00 2001
From: Andrea Catania <info@andreacatania.com>
Date: Mon, 26 Apr 2021 11:04:39 +0200
Subject: [PATCH]  Fixes assertion caused by a 0len vector normalization

fixes #3194
---
 src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp b/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
index 7cc6b8ab0e..f74dcabc54 100644
--- a/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
+++ b/src/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
@@ -1037,7 +1037,7 @@ struct btSingleSweepCallback : public btBroadphaseRayCallback
 		  m_castShape(castShape)
 	{
 		btVector3 unnormalizedRayDir = (m_convexToTrans.getOrigin() - m_convexFromTrans.getOrigin());
-		btVector3 rayDir = unnormalizedRayDir.normalized();
+		btVector3 rayDir = unnormalizedRayDir.fuzzyZero() ? btVector3(btScalar(0.0), btScalar(0.0), btScalar(0.0)) : unnormalizedRayDir.normalized();
 		///what about division by zero? --> just set rayDirection[i] to INF/BT_LARGE_FLOAT
 		m_rayDirectionInverse[0] = rayDir[0] == btScalar(0.0) ? btScalar(BT_LARGE_FLOAT) : btScalar(1.0) / rayDir[0];
 		m_rayDirectionInverse[1] = rayDir[1] == btScalar(0.0) ? btScalar(BT_LARGE_FLOAT) : btScalar(1.0) / rayDir[1];