<!-- NEW4 — TEST 4 · THE QUILT · part 256 -->
 global audio context in the engine.
 *
 * @hideconstructor
 */
class AudioContext {

	/**
	 * Returns the global native audio context.
	 *
	 * @return {Window.AudioContext} The native audio context.
	 */
	static getContext() {

		if ( _context === undefined ) {

			_context = new ( window.AudioContext || window.webkitAudioContext )();

		}

		return _context;

	}

	/**
	 * Allows to set the global native audio context from outside.
	 *
	 * @param {Window.AudioContext} value - The native context to set.
	 */
	static setContext( value ) {

		_context = value;

	}

}

/**
 * Class for loading audio buffers. Audios are internally
 * loaded via {@link FileLoader}.
 *
 * ```js
 * const audioListener = new THREE.AudioListener();
 * const ambientSound = new THREE.Audio( audioListener );
 *
 * const loader = new THREE.AudioLoader();
 * const audioBuffer = await loader.loadAsync( 'audio/ambient_ocean.ogg' );
 *
 * ambientSound.setBuffer( audioBuffer );
 * ambientSound.play();
 * ```
 *
 * @augments Loader
 */
class AudioLoader extends Loader {

	/**
	 * Constructs a new audio loader.
	 *
	 * @param {LoadingManager} [manager] - The loading manager.
	 */
	constructor( manager ) {

		super( manager );

	}

	/**
	 * Starts loading from the given URL and passes the loaded audio buffer
	 * to the `onLoad()` callback.
	 *
	 * @param {string} url - The path/URL of the file to be loaded. This can also be a data URI.
	 * @param {function(AudioBuffer)} onLoad - Executed when the loading process has been finished.
	 * @param {onProgressCallback} onProgress - Executed while the loading is in progress.
	 * @param {onErrorCallback} onError - Executed when errors occur.
	 */
	load( url, onLoad, onProgress, onError ) {

		const scope = this;

		const loader = new FileLoader( this.manager );
		loader.setResponseType( 'arraybuffer' );
		loader.setPath( this.path );
		loader.setRequestHeader( this.requestHeader );
		loader.setWithCredentials( this.withCredentials );
		loader.load( url, function ( buffer ) {

			try {

				// Create a copy of the buffer. The `decodeAudioData` method
				// detaches the buffer when complete, preventing reuse.
				const bufferCopy = buffer.slice( 0 );

				const context = AudioContext.getContext();

				const decodeUrl = url + '#decode';
				scope.manager.itemStart( decodeUrl ); // prevent loading manager from completing too early, see #33378

				context.decodeAudioData( bufferCopy, function ( audioBuffer ) {

					onLoad( audioBuffer );
					scope.manager.itemEnd( decodeUrl );

				} ).catch( function ( e ) {

					handleError( e );
					scope.manager.itemEnd( decodeUrl );

				} );

			} catch ( e ) {

				handleError( e );

			}

		}, onProgress, onError );

		function handleError( e ) {

			if ( onError ) {

				onError( e );

			} else {

				error( e );

			}

			scope.manager.itemError( url );

		}

	}

}

const _eyeRight = /*@__PURE__*/ new Matrix4();
const _eyeLeft = /*@__PURE__*/ new Matrix4();
const _projectionMatrix = /*@__PURE__*/ new Matrix4();

/**
 * A special type of camera that uses two perspective cameras with
 * stereoscopic projection. Can be used for rendering stereo effects
 * like [3D Anaglyph](https://en.wikipedia.org/wiki/Anaglyph_3D) or
 * [Parallax Barrier](https://en.wikipedia.org/wiki/parallax_barrier).
 */
class StereoCamera {

	/**
	 * Constructs a new stereo camera.
	 */
	constructor() {

		/**
		 * The type property is used for detecting the object type
		 * in context of serialization/deserialization.
		 *
		 * @type {string}
		 * @readonly
		 */
		this.type = 'StereoCamera';

		/**
		 * The aspect.
		 *
		 * @type {number}
		 * @default 1
		 */
		this.aspect = 1;

		/**
		 * The eye separation which represents the distance
		 * between the left and right camera.
		 *
		 * @type {number}
		 * @default 0.064
		 */
		this.eyeSep = 0.064;

		/**
		 * The camera representing the left eye. This is added to layer `1` so objects to be
		 * rendered by the left camera must also be added to this layer.
		 *
		 * @type {PerspectiveCamera}
		 */
		this.cameraL = new PerspectiveCamera();
		this.cameraL.layers.enable( 1 );
		this.cameraL.matrixAutoUpdate = false;

		/**
		 * The camera representing the right eye. This is added to layer `2` so objects to be
		 * rendered by the right camera must also be added to this layer.
		 *
		 * @type {PerspectiveCamera}
		 */
		this.cameraR = new PerspectiveCamera();
		this.cameraR.layers.enable( 2 );
		this.cameraR.matrixAutoUpdate = false;

		this._cache = {
			focus: null,
			fov: null,
			aspect: null,
			near: null,
			far: null,
			zoom: null,
			eyeSep: null
		};

	}

	/**
	 * Updates the stereo camera based on the given perspective camera.
	 *
	 * @param {PerspectiveCamera} camera - The perspective camera.
	 */
	update( camera ) {

		const cache = this._cache;

		const needsUpdate = cache.focus !== camera.focus || cache.fov !== camera.fov ||
			cache.aspect !== camera.aspect * this.aspect