////  RotationAccumulator.cpp////  Copyright 2015 High Fidelity, Inc.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html// #include "RotationAccumulator.h" #include <glm/gtx/quaternion.hpp> void RotationAccumulator::add(const glm::quat& rotation, float weight) {    // make sure both quaternions are on the same hyper-hemisphere before we add them linearly (lerp)    _rotationSum += copysignf(weight, glm::dot(_rotationSum, rotation)) * rotation;    ++_numRotations;    _isDirty = true;} glm::quat RotationAccumulator::getAverage() {    return (_numRotations > 0) ?  glm::normalize(_rotationSum) : glm::quat();} void RotationAccumulator::clear() {    _rotationSum *= 0.0f;    _numRotations = 0;} void RotationAccumulator::clearAndClean() {    clear();    _isDirty = false;}