From e30dfb13d3bb1771ebd5b963e1d07fa6ee27a503 Mon Sep 17 00:00:00 2001
From: Aussiemon <mattrohrlach+git@gmail.com>
Date: Wed, 14 Dec 2016 19:05:30 -0700
Subject: [PATCH 1/3] Added check before attempting to remove actor's collision
 object from world

---
 apps/openmw/mwphysics/actor.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/apps/openmw/mwphysics/actor.cpp b/apps/openmw/mwphysics/actor.cpp
index 61022da28..dacffe22c 100644
--- a/apps/openmw/mwphysics/actor.cpp
+++ b/apps/openmw/mwphysics/actor.cpp
@@ -72,7 +72,10 @@ void Actor::enableCollisionBody(bool collision)
 
 void Actor::updateCollisionMask()
 {
-    mCollisionWorld->removeCollisionObject(mCollisionObject.get());
+    if (mCollisionObject.get()->getWorldArrayIndex() >= 0)
+    {
+        mCollisionWorld->removeCollisionObject(mCollisionObject.get());
+    }
     int collisionMask = CollisionType_World | CollisionType_HeightMap;
     if (mExternalCollisionMode)
         collisionMask |= CollisionType_Actor | CollisionType_Projectile | CollisionType_Door;

From 7c2a088b34cf9acff43586d1c6d303f57bb82927 Mon Sep 17 00:00:00 2001
From: Aussiemon <mattrohrlach+github@gmail.com>
Date: Wed, 14 Dec 2016 20:13:23 -0700
Subject: [PATCH 2/3] Added check before removing water collision object from
 world

---
 apps/openmw/mwphysics/physicssystem.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/apps/openmw/mwphysics/physicssystem.cpp b/apps/openmw/mwphysics/physicssystem.cpp
index 1a97fc6ff..1985dba18 100644
--- a/apps/openmw/mwphysics/physicssystem.cpp
+++ b/apps/openmw/mwphysics/physicssystem.cpp
@@ -1463,7 +1463,10 @@ namespace MWPhysics
     {
         if (mWaterCollisionObject.get())
         {
-            mCollisionWorld->removeCollisionObject(mWaterCollisionObject.get());
+            if (mWaterCollisionObject.get()->getWorldArrayIndex() >= 0)
+            {
+                mCollisionWorld->removeCollisionObject(mWaterCollisionObject.get());
+            }
         }
 
         if (!mWaterEnabled)

From b794aa7c2f3c0621c8e3de7029efe4dcc1750909 Mon Sep 17 00:00:00 2001
From: Aussiemon <mattrohrlach+github@gmail.com>
Date: Fri, 16 Dec 2016 12:22:07 -0700
Subject: [PATCH 3/3] Helper methods for updateCollisionMask(), prevent water
 collision being removed twice, remove Bullet 2.8.5 methods

---
 apps/openmw/mwphysics/actor.cpp         | 20 ++++++++++++++------
 apps/openmw/mwphysics/actor.hpp         |  2 ++
 apps/openmw/mwphysics/physicssystem.cpp |  8 ++++----
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/apps/openmw/mwphysics/actor.cpp b/apps/openmw/mwphysics/actor.cpp
index dacffe22c..9be34495e 100644
--- a/apps/openmw/mwphysics/actor.cpp
+++ b/apps/openmw/mwphysics/actor.cpp
@@ -47,7 +47,7 @@ Actor::Actor(const MWWorld::Ptr& ptr, osg::ref_ptr<const Resource::BulletShape>
     updateScale();
     updatePosition();
 
-    updateCollisionMask();
+    addCollisionMask(getCollisionMask());
 }
 
 Actor::~Actor()
@@ -70,18 +70,26 @@ void Actor::enableCollisionBody(bool collision)
     }
 }
 
+void Actor::addCollisionMask(int collisionMask)
+{
+    mCollisionWorld->addCollisionObject(mCollisionObject.get(), CollisionType_Actor, collisionMask);
+}
+
 void Actor::updateCollisionMask()
 {
-    if (mCollisionObject.get()->getWorldArrayIndex() >= 0)
-    {
-        mCollisionWorld->removeCollisionObject(mCollisionObject.get());
-    }
+    mCollisionWorld->removeCollisionObject(mCollisionObject.get());
+    addCollisionMask(getCollisionMask());
+}
+
+int Actor::getCollisionMask()
+{
     int collisionMask = CollisionType_World | CollisionType_HeightMap;
     if (mExternalCollisionMode)
         collisionMask |= CollisionType_Actor | CollisionType_Projectile | CollisionType_Door;
     if (mCanWaterWalk)
         collisionMask |= CollisionType_Water;
-    mCollisionWorld->addCollisionObject(mCollisionObject.get(), CollisionType_Actor, collisionMask);
+    return collisionMask;
+    
 }
 
 void Actor::updatePosition()
diff --git a/apps/openmw/mwphysics/actor.hpp b/apps/openmw/mwphysics/actor.hpp
index b238547e1..a0bf5bfc0 100644
--- a/apps/openmw/mwphysics/actor.hpp
+++ b/apps/openmw/mwphysics/actor.hpp
@@ -139,6 +139,8 @@ namespace MWPhysics
     private:
         /// Removes then re-adds the collision object to the dynamics world
         void updateCollisionMask();
+        void addCollisionMask(int collisionMask);
+        int getCollisionMask();
 
         bool mCanWaterWalk;
         bool mWalkingOnWater;
diff --git a/apps/openmw/mwphysics/physicssystem.cpp b/apps/openmw/mwphysics/physicssystem.cpp
index 1985dba18..f94ee14b6 100644
--- a/apps/openmw/mwphysics/physicssystem.cpp
+++ b/apps/openmw/mwphysics/physicssystem.cpp
@@ -1463,14 +1463,14 @@ namespace MWPhysics
     {
         if (mWaterCollisionObject.get())
         {
-            if (mWaterCollisionObject.get()->getWorldArrayIndex() >= 0)
-            {
-                mCollisionWorld->removeCollisionObject(mWaterCollisionObject.get());
-            }
+            mCollisionWorld->removeCollisionObject(mWaterCollisionObject.get());
         }
 
         if (!mWaterEnabled)
+        {
+            mWaterCollisionObject.reset();
             return;
+        }
 
         mWaterCollisionObject.reset(new btCollisionObject());
         mWaterCollisionShape.reset(new btStaticPlaneShape(btVector3(0,0,1), mWaterHeight));