Babylon.js/src/Audio/audioSceneComponent.ts

    // Adds the parser to the scene parsers.
    AbstractScene.AddParser(SceneComponentConstants.NAME_AUDIO, (parsedData: any, scene: Scene, container: AssetContainer, rootUrl: string) => {
        // TODO: add sound
        var loadedSounds: Sound[] = [];
        var loadedSound: Sound;
        container.sounds = container.sounds || [];
        if (parsedData.sounds !== undefined && parsedData.sounds !== null) {
            for (let index = 0, cache = parsedData.sounds.length; index < cache; index++) {
                var parsedSound = parsedData.sounds[index];
                if (Engine.audioEngine.canUseWebAudio) {
                    if (!parsedSound.url) { parsedSound.url = parsedSound.name; }
                    if (!loadedSounds[parsedSound.url]) {
                        loadedSound = Sound.Parse(parsedSound, scene, rootUrl);
                        loadedSounds[parsedSound.url] = loadedSound;
                        container.sounds.push(loadedSound);
                    }
                    else {
                        container.sounds.push(Sound.Parse(parsedSound, scene, rootUrl, loadedSounds[parsedSound.url]));
                    }
                } else {
                    container.sounds.push(new Sound(parsedSound.name, null, scene));
                }
            }
        }

        loadedSounds = [];
    });

    export interface AbstractScene {
        /**
         * The list of sounds used in the scene.
         */
        sounds: Nullable<Array<Sound>>;
    }

    export interface Scene {
        /**
         * @hidden
         * Backing field
         */
        _mainSoundTrack: SoundTrack;
        /**
         * The main sound track played by the scene.
         * It cotains your primary collection of sounds.
         */
        mainSoundTrack: SoundTrack;
        /**
         * The list of sound tracks added to the scene
         * @see http://doc.babylonjs.com/how_to/playing_sounds_and_music
         */
        soundTracks: Nullable<Array<SoundTrack>>;

        /**
         * Gets a sound using a given name
         * @param name defines the name to search for
         * @return the found sound or null if not found at all.
         */
        getSoundByName(name: string): Nullable<Sound>;

        /**
         * Gets or sets if audio support is enabled
         * @see http://doc.babylonjs.com/how_to/playing_sounds_and_music
         */
        audioEnabled: boolean;

        /**
         * Gets or sets if audio will be output to headphones
         * @see http://doc.babylonjs.com/how_to/playing_sounds_and_music
         */
        headphone: boolean;
    }

    Object.defineProperty(Scene.prototype, "mainSoundTrack", {
        get: function(this: Scene) {
            let compo = this._getComponent(SceneComponentConstants.NAME_AUDIO) as AudioSceneComponent;
            if (!compo) {
                compo = new AudioSceneComponent(this);
                this._addComponent(compo);
            }

            if (!this._mainSoundTrack) {
                this._mainSoundTrack = new SoundTrack(this, { mainTrack: true });
            }

            return this._mainSoundTrack;
        },
        enumerable: true,
        configurable: true
    });

    Scene.prototype.getSoundByName = function(name: string): Nullable<Sound> {
        var index: number;
        for (index = 0; index < this.mainSoundTrack.soundCollection.length; index++) {
            if (this.mainSoundTrack.soundCollection[index].name === name) {
                return this.mainSoundTrack.soundCollection[index];
            }
        }

        if (this.soundTracks) {
            for (var sdIndex = 0; sdIndex < this.soundTracks.length; sdIndex++) {
                for (index = 0; index < this.soundTracks[sdIndex].soundCollection.length; index++) {
                    if (this.soundTracks[sdIndex].soundCollection[index].name === name) {
                        return this.soundTracks[sdIndex].soundCollection[index];
                    }
                }
            }
        }

        return null;
    };

    Object.defineProperty(Scene.prototype, "audioEnabled", {
        get: function(this: Scene) {
            let compo = this._getComponent(SceneComponentConstants.NAME_AUDIO) as AudioSceneComponent;
            if (!compo) {
                compo = new AudioSceneComponent(this);
                this._addComponent(compo);
            }

            return compo.audioEnabled;
        },
        set: function(this: Scene, value: boolean) {
            let compo = this._getComponent(SceneComponentConstants.NAME_AUDIO) as AudioSceneComponent;
            if (!compo) {
                compo = new AudioSceneComponent(this);
                this._addComponent(compo);
            }

            if (value) {
                compo.enableAudio();
            }
            else {
                compo.disableAudio();
            }
        },
        enumerable: true,
        configurable: true
    });

    Object.defineProperty(Scene.prototype, "headphone", {
        get: function(this: Scene) {
            let compo = this._getComponent(SceneComponentConstants.NAME_AUDIO) as AudioSceneComponent;
            if (!compo) {
                compo = new AudioSceneComponent(this);
                this._addComponent(compo);
            }

            return compo.headphone;
        },
        set: function(this: Scene, value: boolean) {
            let compo = this._getComponent(SceneComponentConstants.NAME_AUDIO) as AudioSceneComponent;
            if (!compo) {
                compo = new AudioSceneComponent(this);
                this._addComponent(compo);
            }

            if (value) {
                compo.switchAudioModeForHeadphones();
            }
            else {
                compo.switchAudioModeForNormalSpeakers();
            }
        },
        enumerable: true,
        configurable: true
    });

    /**
     * Defines the sound scene component responsible to manage any sounds
     * in a given scene.
     */
    export class AudioSceneComponent implements ISceneSerializableComponent {
        /**
         * The component name helpfull to identify the component in the list of scene components.
         */
        public readonly name = SceneComponentConstants.NAME_AUDIO;

        /**
         * The scene the component belongs to.
         */
        public scene: Scene;

        private _audioEnabled = true;
        /**
         * Gets whether audio is enabled or not.
         * Please use related enable/disable method to switch state.
         */
        public get audioEnabled(): boolean {
            return this._audioEnabled;
        }

        private _headphone = false;
        /**
         * Gets whether audio is outputing to headphone or not.
         * Please use the according Switch methods to change output.
         */
        public get headphone(): boolean {
            return this._headphone;
        }

        /**
         * Creates a new instance of the component for the given scene
         * @param scene Defines the scene to register the component in
         */
        constructor(scene: Scene) {
            this.scene = scene;

            scene.soundTracks = new Array<SoundTrack>();
            scene.sounds = new Array<Sound>();
        }

        /**
         * Registers the component in a given scene
         */
        public register(): void {
            this.scene._afterRenderStage.registerStep(SceneComponentConstants.STEP_AFTERRENDER_AUDIO, this, this._afterRender);
        }

        /**
         * Rebuilds the elements related to this component in case of
         * context lost for instance.
         */
        public rebuild(): void {
            // Nothing to do here. (Not rendering related)
        }

        /**
         * Serializes the component data to the specified json object
         * @param serializationObject The object to serialize to
         */
        public serialize(serializationObject: any): void {
            serializationObject.sounds = [];

            if (this.scene.soundTracks) {
                for (var index = 0; index < this.scene.soundTracks.length; index++) {
                    var soundtrack = this.scene.soundTracks[index];

                    for (var soundId = 0; soundId < soundtrack.soundCollection.length; soundId++) {
                        serializationObject.sounds.push(soundtrack.soundCollection[soundId].serialize());
                    }
                }
            }
        }

        /**
         * Adds all the element from the container to the scene
         * @param container the container holding the elements
         */
        public addFromContainer(container: AbstractScene): void {
            if (!container.sounds) {
                return;
            }
            container.sounds.forEach((sound) => {
                sound.play();
                sound.autoplay = true;
                this.scene.mainSoundTrack.AddSound(sound);
            });
        }

        /**
         * Removes all the elements in the container from the scene
         * @param container contains the elements to remove
         */
        public removeFromContainer(container: AbstractScene): void {
            if (!container.sounds) {
                return;
            }
            container.sounds.forEach((sound) => {
                sound.stop();
                sound.autoplay = false;
                this.scene.mainSoundTrack.RemoveSound(sound);
            });
        }

        /**
         * Disposes the component and the associated ressources.
         */
        public dispose(): void {
            const scene = this.scene;
            if (scene._mainSoundTrack) {
                scene.mainSoundTrack.dispose();
            }

            if (scene.soundTracks) {
                for (var scIndex = 0; scIndex < scene.soundTracks.length; scIndex++) {
                    scene.soundTracks[scIndex].dispose();
                }
            }
        }

        /**
         * Disables audio in the associated scene.
         */
        public disableAudio() {
            const scene = this.scene;
            this._audioEnabled = false;

            let i: number;
            for (i = 0; i < scene.mainSoundTrack.soundCollection.length; i++) {
                scene.mainSoundTrack.soundCollection[i].pause();
            }
            if (scene.soundTracks) {
                for (i = 0; i < scene.soundTracks.length; i++) {
                    for (var j = 0; j < scene.soundTracks[i].soundCollection.length; j++) {
                        scene.soundTracks[i].soundCollection[j].pause();
                    }
                }
            }
        }

        /**
         * Enables audio in the associated scene.
         */
        public enableAudio() {
            const scene = this.scene;
            this._audioEnabled = true;

            let i: number;
            for (i = 0; i < scene.mainSoundTrack.soundCollection.length; i++) {
                if (scene.mainSoundTrack.soundCollection[i].isPaused) {
                    scene.mainSoundTrack.soundCollection[i].play();
                }
            }
            if (scene.soundTracks) {
                for (i = 0; i < scene.soundTracks.length; i++) {
                    for (var j = 0; j < scene.soundTracks[i].soundCollection.length; j++) {
                        if (scene.soundTracks[i].soundCollection[j].isPaused) {
                            scene.soundTracks[i].soundCollection[j].play();
                        }
                    }
                }
            }
        }

        /**
         * Switch audio to headphone output.
         */
        public switchAudioModeForHeadphones() {
            const scene = this.scene;
            this._headphone = true;

            scene.mainSoundTrack.switchPanningModelToHRTF();
            if (scene.soundTracks) {
                for (var i = 0; i < scene.soundTracks.length; i++) {
                    scene.soundTracks[i].switchPanningModelToHRTF();
                }
            }
        }

        /**
         * Switch audio to normal speakers.
         */
        public switchAudioModeForNormalSpeakers() {
            const scene = this.scene;
            this._headphone = false;

            scene.mainSoundTrack.switchPanningModelToEqualPower();

            if (scene.soundTracks) {
                for (var i = 0; i < scene.soundTracks.length; i++) {
                    scene.soundTracks[i].switchPanningModelToEqualPower();
                }
            }
        }

        private _afterRender() {
            const scene = this.scene;
            if (!this._audioEnabled || !scene._mainSoundTrack || !scene.soundTracks || (scene._mainSoundTrack.soundCollection.length === 0 && scene.soundTracks.length === 1)) {
                return;
            }

            var listeningCamera: Nullable<Camera>;
            var audioEngine = Engine.audioEngine;

            if (scene.activeCameras.length > 0) {
                listeningCamera = scene.activeCameras[0];
            } else {
                listeningCamera = scene.activeCamera;
            }

            if (listeningCamera && audioEngine.audioContext) {
                audioEngine.audioContext.listener.setPosition(listeningCamera.position.x, listeningCamera.position.y, listeningCamera.position.z);
                // for VR cameras
                if (listeningCamera.rigCameras && listeningCamera.rigCameras.length > 0) {
                    listeningCamera = listeningCamera.rigCameras[0];
                }
                var mat = Matrix.Invert(listeningCamera.getViewMatrix());
                var cameraDirection = Vector3.TransformNormal(new Vector3(0, 0, -1), mat);
                cameraDirection.normalize();
                // To avoid some errors on GearVR
                if (!isNaN(cameraDirection.x) && !isNaN(cameraDirection.y) && !isNaN(cameraDirection.z)) {
                    audioEngine.audioContext.listener.setOrientation(cameraDirection.x, cameraDirection.y, cameraDirection.z, 0, 1, 0);
                }

                var i: number;
                for (i = 0; i < scene.mainSoundTrack.soundCollection.length; i++) {
                    var sound = scene.mainSoundTrack.soundCollection[i];
                    if (sound.useCustomAttenuation) {
                        sound.updateDistanceFromListener();
                    }
                }
                if (scene.soundTracks) {
                    for (i = 0; i < scene.soundTracks.length; i++) {
                        for (var j = 0; j < scene.soundTracks[i].soundCollection.length; j++) {
                            sound = scene.soundTracks[i].soundCollection[j];
                            if (sound.useCustomAttenuation) {
                                sound.updateDistanceFromListener();
                            }
                        }
                    }
                }
            }
        }
    }