////  FaceTracker.cpp//  interface/src/devices////  Created by Andrzej Kapolka on 4/9/14.//  Copyright 2014 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 <QTimer> #include <GLMHelpers.h> #include "FaceTracker.h"#include "InterfaceLogging.h"#include "Menu.h" const int FPS_TIMER_DELAY = 2000;  // msconst int FPS_TIMER_DURATION = 2000;  // ms void FaceTracker::init() {    _isMuted = Menu::getInstance()->isOptionChecked(MenuOption::MuteFaceTracking);    _isInitialized = true;  // FaceTracker can be used now} inline float FaceTracker::getBlendshapeCoefficient(int index) const {    return isValidBlendshapeIndex(index) ? glm::mix(0.0f, _blendshapeCoefficients[index], getFadeCoefficient())                                         : 0.0f;} const QVector<float>& FaceTracker::getBlendshapeCoefficients() const {    static QVector<float> blendshapes;    float fadeCoefficient = getFadeCoefficient();    if (fadeCoefficient == 1.0f) {        return _blendshapeCoefficients;    } else {        blendshapes.resize(_blendshapeCoefficients.size());        for (int i = 0; i < _blendshapeCoefficients.size(); i++) {            blendshapes[i] = glm::mix(0.0f, _blendshapeCoefficients[i], fadeCoefficient);        }        return blendshapes;    }} float FaceTracker::getFadeCoefficient() const {    return _fadeCoefficient;} const glm::vec3 FaceTracker::getHeadTranslation() const {    return glm::mix(glm::vec3(0.0f), _headTranslation, getFadeCoefficient());} const glm::quat FaceTracker::getHeadRotation() const {    return safeMix(glm::quat(), _headRotation, getFadeCoefficient());} void FaceTracker::update(float deltaTime) {    // Based on exponential distributions: http://en.wikipedia.org/wiki/Exponential_distribution    static const float EPSILON = 0.02f; // MUST BE < 1.0f    static const float INVERSE_AT_EPSILON = -std::log(EPSILON); // So that f(1.0f) = EPSILON ~ 0.0f    static const float RELAXATION_TIME = 0.8f; // sec        if (isTracking()) {        if (_relaxationStatus == 1.0f) {            _fadeCoefficient = 1.0f;            return;        }        _relaxationStatus = glm::clamp(_relaxationStatus + deltaTime / RELAXATION_TIME, 0.0f, 1.0f);        _fadeCoefficient = 1.0f - std::exp(-_relaxationStatus * INVERSE_AT_EPSILON);    } else {        if (_relaxationStatus == 0.0f) {            _fadeCoefficient = 0.0f;            return;        }        _relaxationStatus = glm::clamp(_relaxationStatus - deltaTime / RELAXATION_TIME, 0.0f, 1.0f);        _fadeCoefficient = std::exp(-(1.0f - _relaxationStatus) * INVERSE_AT_EPSILON);    }} void FaceTracker::reset() {    if (isActive() && !_isCalculatingFPS) {        QTimer::singleShot(FPS_TIMER_DELAY, this, SLOT(startFPSTimer()));        _isCalculatingFPS = true;    }} void FaceTracker::startFPSTimer() {    _frameCount = 0;    QTimer::singleShot(FPS_TIMER_DURATION, this, SLOT(finishFPSTimer()));} void FaceTracker::countFrame() {    if (_isCalculatingFPS) {        _frameCount++;    }} void FaceTracker::finishFPSTimer() {    qCDebug(interfaceapp) << "Face tracker FPS =" << (float)_frameCount / ((float)FPS_TIMER_DURATION / 1000.0f);    _isCalculatingFPS = false;} void FaceTracker::toggleMute() {    _isMuted = !_isMuted;    emit muteToggled();}