text: import {
  	Color,
  	DefaultLoadingManager,
  	FileLoader,
  	FrontSide,
  	Loader,
  	LoaderUtils,
  	MeshPhongMaterial,
  	RepeatWrapping,
  	TextureLoader,
  	Vector2
  } from '../../build/three.module.js';
  
  /**
   * Loads a Wavefront .mtl file specifying materials
   */
  
  var MTLLoader = function ( manager ) {
  
  	Loader.call( this, manager );
  
  };
  
  MTLLoader.prototype = Object.assign( Object.create( Loader.prototype ), {
  
  	constructor: MTLLoader,
  
  	/**
  	 * Loads and parses a MTL asset from a URL.
  	 *
  	 * @param {String} url - URL to the MTL file.
  	 * @param {Function} [onLoad] - Callback invoked with the loaded object.
  	 * @param {Function} [onProgress] - Callback for download progress.
  	 * @param {Function} [onError] - Callback for download errors.
  	 *
  	 * @see setPath setResourcePath
  	 *
  	 * @note In order for relative texture references to resolve correctly
  	 * you must call setResourcePath() explicitly prior to load.
  	 */
  	load: function ( url, onLoad, onProgress, onError ) {
  
  		var scope = this;
  
  		var path = ( this.path === '' ) ? LoaderUtils.extractUrlBase( url ) : this.path;
  
  		var loader = new FileLoader( this.manager );
  		loader.setPath( this.path );
  		loader.setRequestHeader( this.requestHeader );
  		loader.setWithCredentials( this.withCredentials );
  		loader.load( url, function ( text ) {
  
  			try {
  
  				onLoad( scope.parse( text, path ) );
  
  			} catch ( e ) {
  
  				if ( onError ) {
  
  					onError( e );
  
  				} else {
  
  					console.error( e );
  
  				}
  
  				scope.manager.itemError( url );
  
  			}
  
  		}, onProgress, onError );
  
  	},
  
  	setMaterialOptions: function ( value ) {
  
  		this.materialOptions = value;
  		return this;
  
  	},
  
  	/**
  	 * Parses a MTL file.
  	 *
  	 * @param {String} text - Content of MTL file
  	 * @return {MTLLoader.MaterialCreator}
  	 *
  	 * @see setPath setResourcePath
  	 *
  	 * @note In order for relative texture references to resolve correctly
  	 * you must call setResourcePath() explicitly prior to parse.
  	 */
  	parse: function ( text, path ) {
  
  		var lines = text.split( '\n' );
  		var info = {};
  		var delimiter_pattern = /\s+/;
  		var materialsInfo = {};
  
  		for ( var i = 0; i < lines.length; i ++ ) {
  
  			var line = lines[ i ];
  			line = line.trim();
  
  			if ( line.length === 0 || line.charAt( 0 ) === '#' ) {
  
  				// Blank line or comment ignore
  				continue;
  
  			}
  
  			var pos = line.indexOf( ' ' );
  
  			var key = ( pos >= 0 ) ? line.substring( 0, pos ) : line;
  			key = key.toLowerCase();
  
  			var value = ( pos >= 0 ) ? line.substring( pos + 1 ) : '';
  			value = value.trim();
  
  			if ( key === 'newmtl' ) {
  
  				// New material
  
  				info = { name: value };
  				materialsInfo[ value ] = info;
  
  			} else {
  
  				if ( key === 'ka' || key === 'kd' || key === 'ks' || key === 'ke' ) {
  
  					var ss = value.split( delimiter_pattern, 3 );
  					info[ key ] = [ parseFloat( ss[ 0 ] ), parseFloat( ss[ 1 ] ), parseFloat( ss[ 2 ] ) ];
  
  				} else {
  
  					info[ key ] = value;
  
  				}
  
  			}
  
  		}
  
  		var materialCreator = new MTLLoader.MaterialCreator( this.resourcePath || path, this.materialOptions );
  		materialCreator.setCrossOrigin( this.crossOrigin );
  		materialCreator.setManager( this.manager );
  		materialCreator.setMaterials( materialsInfo );
  		return materialCreator;
  
  	}
  
  } );
  
  /**
   * Create a new MTLLoader.MaterialCreator
   * @param baseUrl - Url relative to which textures are loaded
   * @param options - Set of options on how to construct the materials
   *                  side: Which side to apply the material
   *                        FrontSide (default), THREE.BackSide, THREE.DoubleSide
   *                  wrap: What type of wrapping to apply for textures
   *                        RepeatWrapping (default), THREE.ClampToEdgeWrapping, THREE.MirroredRepeatWrapping
   *                  normalizeRGB: RGBs need to be normalized to 0-1 from 0-255
   *                                Default: false, assumed to be already normalized
   *                  ignoreZeroRGBs: Ignore values of RGBs (Ka,Kd,Ks) that are all 0's
   *                                  Default: false
   * @constructor
   */
  
  MTLLoader.MaterialCreator = function ( baseUrl, options ) {
  
  	this.baseUrl = baseUrl || '';
  	this.options = options;
  	this.materialsInfo = {};
  	this.materials = {};
  	this.materialsArray = [];
  	this.nameLookup = {};
  
  	this.side = ( this.options && this.options.side ) ? this.options.side : FrontSide;
  	this.wrap = ( this.options && this.options.wrap ) ? this.options.wrap : RepeatWrapping;
  
  };
  
  MTLLoader.MaterialCreator.prototype = {
  
  	constructor: MTLLoader.MaterialCreator,
  
  	crossOrigin: 'anonymous',
  
  	setCrossOrigin: function ( value ) {
  
  		this.crossOrigin = value;
  		return this;
  
  	},
  
  	setManager: function ( value ) {
  
  		this.manager = value;
  
  	},
  
  	setMaterials: function ( materialsInfo ) {
  
  		this.materialsInfo = this.convert( materialsInfo );
  		this.materials = {};
  		this.materialsArray = [];
  		this.nameLookup = {};
  
  	},
  
  	convert: function ( materialsInfo ) {
  
  		if ( ! this.options ) return materialsInfo;
  
  		var converted = {};
  
  		for ( var mn in materialsInfo ) {
  
  			// Convert materials info into normalized form based on options
  
  			var mat = materialsInfo[ mn ];
  
  			var covmat = {};
  
  			converted[ mn ] = covmat;
  
  			for ( var prop in mat ) {
  
  				var save = true;
  				var value = mat[ prop ];
  				var lprop = prop.toLowerCase();
  
  				switch ( lprop ) {
  
  					case 'kd':
  					case 'ka':
  					case 'ks':
  
  						// Diffuse color (color under white light) using RGB values
  
  						if ( this.options && this.options.normalizeRGB ) {
  
  							value = [ value[ 0 ] / 255, value[ 1 ] / 255, value[ 2 ] / 255 ];
  
  						}
  
  						if ( this.options && this.options.ignoreZeroRGBs ) {
  
  							if ( value[ 0 ] === 0 && value[ 1 ] === 0 && value[ 2 ] === 0 ) {
  
  								// ignore
  
  								save = false;
  
  							}
  
  						}
  
  						break;
  
  					default:
  
  						break;
  
  				}
  
  				if ( save ) {
  
  					covmat[ lprop ] = value;
  
  				}
  
  			}
  
  		}
  
  		return converted;
  
  	},
  
  	preload: function () {
  
  		for ( var mn in this.materialsInfo ) {
  
  			this.create( mn );
  
  		}
  
  	},
  
  	getIndex: function ( materialName ) {
  
  		return this.nameLookup[ materialName ];
  
  	},
  
  	getAsArray: function () {
  
  		var index = 0;
  
  		for ( var mn in this.materialsInfo ) {
  
  			this.materialsArray[ index ] = this.create( mn );
  			this.nameLookup[ mn ] = index;
  			index ++;
  
  		}
  
  		return this.materialsArray;
  
  	},
  
  	create: function ( materialName ) {
  
  		if ( this.materials[ materialName ] === undefined ) {
  
  			this.createMaterial_( materialName );
  
  		}
  
  		return this.materials[ materialName ];
  
  	},
  
  	createMaterial_: function ( materialName ) {
  
  		// Create material
  
  		var scope = this;
  		var mat = this.materialsInfo[ materialName ];
  		var params = {
  
  			name: materialName,
  			side: this.side
  
  		};
  
  		function resolveURL( baseUrl, url ) {
  
  			if ( typeof url !== 'string' || url === '' )
  				return '';
  
  			// Absolute URL
  			if ( /^https?:\/\//i.test( url ) ) return url;
  
  			return baseUrl + url;
  
  		}
  
  		function setMapForType( mapType, value ) {
  
  			if ( params[ mapType ] ) return; // Keep the first encountered texture
  
  			var texParams = scope.getTextureParams( value, params );
  			var map = scope.loadTexture( resolveURL( scope.baseUrl, texParams.url ) );
  
  			map.repeat.copy( texParams.scale );
  			map.offset.copy( texParams.offset );
  
  			map.wrapS = scope.wrap;
  			map.wrapT = scope.wrap;
  
  			params[ mapType ] = map;
  
  		}
  
  		for ( var prop in mat ) {
  
  			var value = mat[ prop ];
  			var n;
  
  			if ( value === '' ) continue;
  
  			switch ( prop.toLowerCase() ) {
  
  				// Ns is material specular exponent
  
  				case 'kd':
  
  					// Diffuse color (color under white light) using RGB values
  
  					params.color = new Color().fromArray( value );
  
  					break;
  
  				case 'ks':
  
  					// Specular color (color when light is reflected from shiny surface) using RGB values
  					params.specular = new Color().fromArray( value );
  
  					break;
  
  				case 'ke':
  
  					// Emissive using RGB values
  					params.emissive = new Color().fromArray( value );
  
  					break;
  
  				case 'map_kd':
  
  					// Diffuse texture map
  
  					setMapForType( 'map', value );
  
  					break;
  
  				case 'map_ks':
  
  					// Specular map
  
  					setMapForType( 'specularMap', value );
  
  					break;
  
  				case 'map_ke':
  
  					// Emissive map
  
  					setMapForType( 'emissiveMap', value );
  
  					break;
  
  				case 'norm':
  
  					setMapForType( 'normalMap', value );
  
  					break;
  
  				case 'map_bump':
  				case 'bump':
  
  					// Bump texture map
  
  					setMapForType( 'bumpMap', value );
  
  					break;
  
  				case 'map_d':
  
  					// Alpha map
  
  					setMapForType( 'alphaMap', value );
  					params.transparent = true;
  
  					break;
  
  				case 'ns':
  
  					// The specular exponent (defines the focus of the specular highlight)
  					// A high exponent results in a tight, concentrated highlight. Ns values normally range from 0 to 1000.
  
  					params.shininess = parseFloat( value );
  
  					break;
  
  				case 'd':
  					n = parseFloat( value );
  
  					if ( n < 1 ) {
  
  						params.opacity = n;
  						params.transparent = true;
  
  					}
  
  					break;
  
  				case 'tr':
  					n = parseFloat( value );
  
  					if ( this.options && this.options.invertTrProperty ) n = 1 - n;
  
  					if ( n > 0 ) {
  
  						params.opacity = 1 - n;
  						params.transparent = true;
  
  					}
  
  					break;
  
  				default:
  					break;
  
  			}
  
  		}
  
  		this.materials[ materialName ] = new MeshPhongMaterial( params );
  		return this.materials[ materialName ];
  
  	},
  
  	getTextureParams: function ( value, matParams ) {
  
  		var texParams = {
  
  			scale: new Vector2( 1, 1 ),
  			offset: new Vector2( 0, 0 )
  
  		 };
  
  		var items = value.split( /\s+/ );
  		var pos;
  
  		pos = items.indexOf( '-bm' );
  
  		if ( pos >= 0 ) {
  
  			matParams.bumpScale = parseFloat( items[ pos + 1 ] );
  			items.splice( pos, 2 );
  
  		}
  
  		pos = items.indexOf( '-s' );
  
  		if ( pos >= 0 ) {
  
  			texParams.scale.set( parseFloat( items[ pos + 1 ] ), parseFloat( items[ pos + 2 ] ) );
  			items.splice( pos, 4 ); // we expect 3 parameters here!
  
  		}
  
  		pos = items.indexOf( '-o' );
  
  		if ( pos >= 0 ) {
  
  			texParams.offset.set( parseFloat( items[ pos + 1 ] ), parseFloat( items[ pos + 2 ] ) );
  			items.splice( pos, 4 ); // we expect 3 parameters here!
  
  		}
  
  		texParams.url = items.join( ' ' ).trim();
  		return texParams;
  
  	},
  
  	loadTexture: function ( url, mapping, onLoad, onProgress, onError ) {
  
  		var texture;
  		var manager = ( this.manager !== undefined ) ? this.manager : DefaultLoadingManager;
  		var loader = manager.getHandler( url );
  
  		if ( loader === null ) {
  
  			loader = new TextureLoader( manager );
  
  		}
  
  		if ( loader.setCrossOrigin ) loader.setCrossOrigin( this.crossOrigin );
  		texture = loader.load( url, onLoad, onProgress, onError );
  
  		if ( mapping !== undefined ) texture.mapping = mapping;
  
  		return texture;
  
  	}
  
  };
  
  export { MTLLoader };
  