VectorOfMotionStates& PhysicalEntitySimulation::getObjectsToAdd() {
    _tempVector.clear();
    SetOfEntities::iterator entityItr = _pendingAdds.begin();
    while (entityItr != _pendingAdds.end()) {
        EntityItemPointer entity = *entityItr;
        assert(!entity->getPhysicsInfo());
        if (!entity->shouldBePhysical()) {
            // this entity should no longer be on the internal _pendingAdds
            entityItr = _pendingAdds.erase(entityItr);
            if (entity->isMoving()) {
                _simpleKinematicEntities.insert(entity);
            }
        } else if (entity->isReadyToComputeShape()) {
            ShapeInfo shapeInfo;
            entity->computeShapeInfo(shapeInfo);
            btCollisionShape* shape = ObjectMotionState::getShapeManager()->getShape(shapeInfo);
            if (shape) {
                EntityMotionState* motionState = new EntityMotionState(shape, entity);
                entity->setPhysicsInfo(static_cast<void*>(motionState));
                _physicalObjects.insert(motionState);
                _tempVector.push_back(motionState);
                entityItr = _pendingAdds.erase(entityItr);
            } else {
                //qDebug() << "Warning!  Failed to generate new shape for entity." << entity->getName();
                ++entityItr;
            }
        } else {
            ++entityItr;
        }
    }
    return _tempVector;
}
void PhysicalEntitySimulation::getObjectsToAddToPhysics(VectorOfMotionStates& result) {
    result.clear();
    QMutexLocker lock(&_mutex);
    SetOfEntities::iterator entityItr = _entitiesToAddToPhysics.begin();
    while (entityItr != _entitiesToAddToPhysics.end()) {
        EntityItemPointer entity = (*entityItr);
        assert(!entity->getPhysicsInfo());
        if (entity->isDead()) {
            prepareEntityForDelete(entity);
        } else if (!entity->shouldBePhysical()) {
            // this entity should no longer be on the internal _entitiesToAddToPhysics
            entityItr = _entitiesToAddToPhysics.erase(entityItr);
            if (entity->isMoving()) {
                _simpleKinematicEntities.insert(entity);
            }
        } else if (entity->isReadyToComputeShape()) {
            ShapeInfo shapeInfo;
            entity->computeShapeInfo(shapeInfo);
            btCollisionShape* shape = ObjectMotionState::getShapeManager()->getShape(shapeInfo);
            if (shape) {
                EntityMotionState* motionState = new EntityMotionState(shape, entity);
                entity->setPhysicsInfo(static_cast<void*>(motionState));
                _physicalObjects.insert(motionState);
                result.push_back(motionState);
                entityItr = _entitiesToAddToPhysics.erase(entityItr);
            } else {
                //qDebug() << "Warning!  Failed to generate new shape for entity." << entity->getName();
                ++entityItr;
            }
        } else {
            ++entityItr;
        }
    }
}