Merge pull request #4532 from AndrewMeadows/inertia

fix crash in PhysicsEngine on shutdown

interface/src/Application.cpp

@@ -608,6 +608,7 @@ Application::~Application() {
 
     Menu::getInstance()->deleteLater();
 
+    _physicsEngine.setCharacterController(NULL);
     _myAvatar = NULL;
 
     ModelEntityItem::cleanupLoadedAnimations();

libraries/physics/src/CharacterController.cpp

@@ -241,6 +241,12 @@ CharacterController::CharacterController(AvatarData* avatarData) {
 }
 
 CharacterController::~CharacterController() {
+    delete _ghostObject;
+    _ghostObject = NULL;
+    delete _convexShape;
+    _convexShape = NULL;
+    // make sure you remove this Character from its DynamicsWorld before reaching this spot
+    assert(_dynamicsWorld == NULL);
 }
 
 btPairCachingGhostObject* CharacterController::getGhostObject() {

libraries/physics/src/PhysicsEngine.cpp

@@ -28,6 +28,9 @@ PhysicsEngine::PhysicsEngine(const glm::vec3& offset)
 }
 
 PhysicsEngine::~PhysicsEngine() {
+    if (_characterController) {
+        _characterController->setDynamicsWorld(NULL);
+    }
     // TODO: delete engine components... if we ever plan to create more than one instance
     delete _collisionConfig;
     delete _collisionDispatcher;
@@ -614,8 +617,14 @@ bool PhysicsEngine::updateObjectHard(btRigidBody* body, ObjectMotionState* motio
 }
 
 void PhysicsEngine::setCharacterController(CharacterController* character) {
-    if (!_characterController) {
+    if (_characterController != character) {
         lock();
+        if (_characterController) {
+            // remove the character from the DynamicsWorld immediately
+            _characterController->setDynamicsWorld(NULL);
+            _characterController = NULL;
+        }
+        // the character will be added to the DynamicsWorld later
         _characterController = character;
         unlock();
     }