LWOLoader.js

( function () {

	/**
 * @version 1.1.1
 *
 * @desc Load files in LWO3 and LWO2 format on Three.js
 *
 * LWO3 format specification:
 *  https://static.lightwave3d.com/sdk/2019/html/filefmts/lwo3.html
 *
 * LWO2 format specification:
 *  https://static.lightwave3d.com/sdk/2019/html/filefmts/lwo2.html
 *
 **/

	let _lwoTree;

	class LWOLoader extends THREE.Loader {

		constructor( manager, parameters = {} ) {

			super( manager );
			this.resourcePath = parameters.resourcePath !== undefined ? parameters.resourcePath : '';

		}

		load( url, onLoad, onProgress, onError ) {

			const scope = this;
			const path = scope.path === '' ? extractParentUrl( url, 'Objects' ) : scope.path; // give the mesh a default name based on the filename

			const modelName = url.split( path ).pop().split( '.' )[ 0 ];
			const loader = new THREE.FileLoader( this.manager );
			loader.setPath( scope.path );
			loader.setResponseType( 'arraybuffer' );
			loader.load( url, function ( buffer ) {

				// console.time( 'Total parsing: ' );
				try {

					onLoad( scope.parse( buffer, path, modelName ) );

				} catch ( e ) {

					if ( onError ) {

						onError( e );

					} else {

						console.error( e );

					}

					scope.manager.itemError( url );

				} // console.timeEnd( 'Total parsing: ' );

			}, onProgress, onError );

		}

		parse( iffBuffer, path, modelName ) {

			_lwoTree = new THREE.IFFParser().parse( iffBuffer ); // console.log( 'lwoTree', lwoTree );

			const textureLoader = new THREE.TextureLoader( this.manager ).setPath( this.resourcePath || path ).setCrossOrigin( this.crossOrigin );
			return new LWOTreeParser( textureLoader ).parse( modelName );

		}

	} // Parse the lwoTree object


	class LWOTreeParser {

		constructor( textureLoader ) {

			this.textureLoader = textureLoader;

		}

		parse( modelName ) {

			this.materials = new MaterialParser( this.textureLoader ).parse();
			this.defaultLayerName = modelName;
			this.meshes = this.parseLayers();
			return {
				materials: this.materials,
				meshes: this.meshes
			};

		}

		parseLayers() {

			// array of all meshes for building hierarchy
			const meshes = []; // final array containing meshes with scene graph hierarchy set up

			const finalMeshes = [];
			const geometryParser = new GeometryParser();
			const scope = this;

			_lwoTree.layers.forEach( function ( layer ) {

				const geometry = geometryParser.parse( layer.geometry, layer );
				const mesh = scope.parseMesh( geometry, layer );
				meshes[ layer.number ] = mesh;
				if ( layer.parent === - 1 ) finalMeshes.push( mesh ); else meshes[ layer.parent ].add( mesh );

			} );

			this.applyPivots( finalMeshes );
			return finalMeshes;

		}

		parseMesh( geometry, layer ) {

			let mesh;
			const materials = this.getMaterials( geometry.userData.matNames, layer.geometry.type );
			this.duplicateUVs( geometry, materials );
			if ( layer.geometry.type === 'points' ) mesh = new THREE.Points( geometry, materials ); else if ( layer.geometry.type === 'lines' ) mesh = new THREE.LineSegments( geometry, materials ); else mesh = new THREE.Mesh( geometry, materials );
			if ( layer.name ) mesh.name = layer.name; else mesh.name = this.defaultLayerName + '_layer_' + layer.number;
			mesh.userData.pivot = layer.pivot;
			return mesh;

		} // TODO: may need to be reversed in z to convert LWO to three.js coordinates


		applyPivots( meshes ) {

			meshes.forEach( function ( mesh ) {

				mesh.traverse( function ( child ) {

					const pivot = child.userData.pivot;
					child.position.x += pivot[ 0 ];
					child.position.y += pivot[ 1 ];
					child.position.z += pivot[ 2 ];

					if ( child.parent ) {

						const parentPivot = child.parent.userData.pivot;
						child.position.x -= parentPivot[ 0 ];
						child.position.y -= parentPivot[ 1 ];
						child.position.z -= parentPivot[ 2 ];

					}

				} );

			} );

		}

		getMaterials( namesArray, type ) {

			const materials = [];
			const scope = this;
			namesArray.forEach( function ( name, i ) {

				materials[ i ] = scope.getMaterialByName( name );

			} ); // convert materials to line or point mats if required

			if ( type === 'points' || type === 'lines' ) {

				materials.forEach( function ( mat, i ) {

					const spec = {
						color: mat.color
					};

					if ( type === 'points' ) {

						spec.size = 0.1;
						spec.map = mat.map;
						materials[ i ] = new THREE.PointsMaterial( spec );

					} else if ( type === 'lines' ) {

						materials[ i ] = new THREE.LineBasicMaterial( spec );

					}

				} );

			} // if there is only one material, return that directly instead of array


			const filtered = materials.filter( Boolean );
			if ( filtered.length === 1 ) return filtered[ 0 ];
			return materials;

		}

		getMaterialByName( name ) {

			return this.materials.filter( function ( m ) {

				return m.name === name;

			} )[ 0 ];

		} // If the material has an aoMap, duplicate UVs


		duplicateUVs( geometry, materials ) {

			let duplicateUVs = false;

			if ( ! Array.isArray( materials ) ) {

				if ( materials.aoMap ) duplicateUVs = true;

			} else {

				materials.forEach( function ( material ) {

					if ( material.aoMap ) duplicateUVs = true;

				} );

			}

			if ( ! duplicateUVs ) return;
			geometry.setAttribute( 'uv2', new THREE.BufferAttribute( geometry.attributes.uv.array, 2 ) );

		}

	}

	class MaterialParser {

		constructor( textureLoader ) {

			this.textureLoader = textureLoader;

		}

		parse() {

			const materials = [];
			this.textures = {};

			for ( const name in _lwoTree.materials ) {

				if ( _lwoTree.format === 'LWO3' ) {

					materials.push( this.parseMaterial( _lwoTree.materials[ name ], name, _lwoTree.textures ) );

				} else if ( _lwoTree.format === 'LWO2' ) {

					materials.push( this.parseMaterialLwo2( _lwoTree.materials[ name ], name, _lwoTree.textures ) );

				}

			}

			return materials;

		}

		parseMaterial( materialData, name, textures ) {

			let params = {
				name: name,
				side: this.getSide( materialData.attributes ),
				flatShading: this.getSmooth( materialData.attributes )
			};
			const connections = this.parseConnections( materialData.connections, materialData.nodes );
			const maps = this.parseTextureNodes( connections.maps );
			this.parseAttributeImageMaps( connections.attributes, textures, maps, materialData.maps );
			const attributes = this.parseAttributes( connections.attributes, maps );
			this.parseEnvMap( connections, maps, attributes );
			params = Object.assign( maps, params );
			params = Object.assign( params, attributes );
			const materialType = this.getMaterialType( connections.attributes );
			if ( materialType !== THREE.MeshPhongMaterial ) delete params.refractionRatio; // PBR materials do not support "refractionRatio"

			return new materialType( params );

		}

		parseMaterialLwo2( materialData, name
			/*, textures*/
		) {

			let params = {
				name: name,
				side: this.getSide( materialData.attributes ),
				flatShading: this.getSmooth( materialData.attributes )
			};
			const attributes = this.parseAttributes( materialData.attributes, {} );
			params = Object.assign( params, attributes );
			return new THREE.MeshPhongMaterial( params );

		} // Note: converting from left to right handed coords by switching x -> -x in vertices, and
		// then switching mat THREE.FrontSide -> THREE.BackSide
		// NB: this means that THREE.FrontSide and THREE.BackSide have been switched!


		getSide( attributes ) {

			if ( ! attributes.side ) return THREE.BackSide;

			switch ( attributes.side ) {

				case 0:
				case 1:
					return THREE.BackSide;

				case 2:
					return THREE.FrontSide;

				case 3:
					return THREE.DoubleSide;

			}

		}

		getSmooth( attributes ) {

			if ( ! attributes.smooth ) return true;
			return ! attributes.smooth;

		}

		parseConnections( connections, nodes ) {

			const materialConnections = {
				maps: {}
			};
			const inputName = connections.inputName;
			const inputNodeName = connections.inputNodeName;
			const nodeName = connections.nodeName;
			const scope = this;
			inputName.forEach( function ( name, index ) {

				if ( name === 'Material' ) {

					const matNode = scope.getNodeByRefName( inputNodeName[ index ], nodes );
					materialConnections.attributes = matNode.attributes;
					materialConnections.envMap = matNode.fileName;
					materialConnections.name = inputNodeName[ index ];

				}

			} );
			nodeName.forEach( function ( name, index ) {

				if ( name === materialConnections.name ) {

					materialConnections.maps[ inputName[ index ] ] = scope.getNodeByRefName( inputNodeName[ index ], nodes );

				}

			} );
			return materialConnections;

		}

		getNodeByRefName( refName, nodes ) {

			for ( const name in nodes ) {

				if ( nodes[ name ].refName === refName ) return nodes[ name ];

			}

		}

		parseTextureNodes( textureNodes ) {

			const maps = {};

			for ( const name in textureNodes ) {

				const node = textureNodes[ name ];
				const path = node.fileName;
				if ( ! path ) return;
				const texture = this.loadTexture( path );
				if ( node.widthWrappingMode !== undefined ) texture.wrapS = this.getWrappingType( node.widthWrappingMode );
				if ( node.heightWrappingMode !== undefined ) texture.wrapT = this.getWrappingType( node.heightWrappingMode );

				switch ( name ) {

					case 'Color':
						maps.map = texture;
						break;

					case 'Roughness':
						maps.roughnessMap = texture;
						maps.roughness = 1;
						break;

					case 'Specular':
						maps.specularMap = texture;
						maps.specular = 0xffffff;
						break;

					case 'Luminous':
						maps.emissiveMap = texture;
						maps.emissive = 0x808080;
						break;

					case 'Luminous THREE.Color':
						maps.emissive = 0x808080;
						break;

					case 'Metallic':
						maps.metalnessMap = texture;
						maps.metalness = 1;
						break;

					case 'Transparency':
					case 'Alpha':
						maps.alphaMap = texture;
						maps.transparent = true;
						break;

					case 'Normal':
						maps.normalMap = texture;
						if ( node.amplitude !== undefined ) maps.normalScale = new THREE.Vector2( node.amplitude, node.amplitude );
						break;

					case 'Bump':
						maps.bumpMap = texture;
						break;

				}

			} // LWO BSDF materials can have both spec and rough, but this is not valid in three


			if ( maps.roughnessMap && maps.specularMap ) delete maps.specularMap;
			return maps;

		} // maps can also be defined on individual material attributes, parse those here
		// This occurs on Standard (Phong) surfaces


		parseAttributeImageMaps( attributes, textures, maps ) {

			for ( const name in attributes ) {

				const attribute = attributes[ name ];

				if ( attribute.maps ) {

					const mapData = attribute.maps[ 0 ];
					const path = this.getTexturePathByIndex( mapData.imageIndex, textures );
					if ( ! path ) return;
					const texture = this.loadTexture( path );
					if ( mapData.wrap !== undefined ) texture.wrapS = this.getWrappingType( mapData.wrap.w );
					if ( mapData.wrap !== undefined ) texture.wrapT = this.getWrappingType( mapData.wrap.h );

					switch ( name ) {

						case 'Color':
							maps.map = texture;
							break;

						case 'Diffuse':
							maps.aoMap = texture;
							break;

						case 'Roughness':
							maps.roughnessMap = texture;
							maps.roughness = 1;
							break;

						case 'Specular':
							maps.specularMap = texture;
							maps.specular = 0xffffff;
							break;

						case 'Luminosity':
							maps.emissiveMap = texture;
							maps.emissive = 0x808080;
							break;

						case 'Metallic':
							maps.metalnessMap = texture;
							maps.metalness = 1;
							break;

						case 'Transparency':
						case 'Alpha':
							maps.alphaMap = texture;
							maps.transparent = true;
							break;

						case 'Normal':
							maps.normalMap = texture;
							break;

						case 'Bump':
							maps.bumpMap = texture;
							break;

					}

				}

			}

		}

		parseAttributes( attributes, maps ) {

			const params = {}; // don't use color data if color map is present

			if ( attributes.Color && ! maps.map ) {

				params.color = new THREE.Color().fromArray( attributes.Color.value );

			} else params.color = new THREE.Color();

			if ( attributes.Transparency && attributes.Transparency.value !== 0 ) {

				params.opacity = 1 - attributes.Transparency.value;
				params.transparent = true;

			}

			if ( attributes[ 'Bump Height' ] ) params.bumpScale = attributes[ 'Bump Height' ].value * 0.1;
			this.parsePhysicalAttributes( params, attributes, maps );
			this.parseStandardAttributes( params, attributes, maps );
			this.parsePhongAttributes( params, attributes, maps );
			return params;

		}

		parsePhysicalAttributes( params, attributes
			/*, maps*/
		) {

			if ( attributes.Clearcoat && attributes.Clearcoat.value > 0 ) {

				params.clearcoat = attributes.Clearcoat.value;

				if ( attributes[ 'Clearcoat Gloss' ] ) {

					params.clearcoatRoughness = 0.5 * ( 1 - attributes[ 'Clearcoat Gloss' ].value );

				}

			}

		}

		parseStandardAttributes( params, attributes, maps ) {

			if ( attributes.Luminous ) {

				params.emissiveIntensity = attributes.Luminous.value;

				if ( attributes[ 'Luminous THREE.Color' ] && ! maps.emissive ) {

					params.emissive = new THREE.Color().fromArray( attributes[ 'Luminous THREE.Color' ].value );

				} else {

					params.emissive = new THREE.Color( 0x808080 );

				}

			}

			if ( attributes.Roughness && ! maps.roughnessMap ) params.roughness = attributes.Roughness.value;
			if ( attributes.Metallic && ! maps.metalnessMap ) params.metalness = attributes.Metallic.value;

		}

		parsePhongAttributes( params, attributes, maps ) {

			if ( attributes[ 'Refraction Index' ] ) params.refractionRatio = 0.98 / attributes[ 'Refraction Index' ].value;
			if ( attributes.Diffuse ) params.color.multiplyScalar( attributes.Diffuse.value );

			if ( attributes.Reflection ) {

				params.reflectivity = attributes.Reflection.value;
				params.combine = THREE.AddOperation;

			}

			if ( attributes.Luminosity ) {

				params.emissiveIntensity = attributes.Luminosity.value;

				if ( ! maps.emissiveMap && ! maps.map ) {

					params.emissive = params.color;

				} else {

					params.emissive = new THREE.Color( 0x808080 );

				}

			} // parse specular if there is no roughness - we will interpret the material as 'Phong' in this case


			if ( ! attributes.Roughness && attributes.Specular && ! maps.specularMap ) {

				if ( attributes[ 'Color Highlight' ] ) {

					params.specular = new THREE.Color().setScalar( attributes.Specular.value ).lerp( params.color.clone().multiplyScalar( attributes.Specular.value ), attributes[ 'Color Highlight' ].value );

				} else {

					params.specular = new THREE.Color().setScalar( attributes.Specular.value );

				}

			}

			if ( params.specular && attributes.Glossiness ) params.shininess = 7 + Math.pow( 2, attributes.Glossiness.value * 12 + 2 );

		}

		parseEnvMap( connections, maps, attributes ) {

			if ( connections.envMap ) {

				const envMap = this.loadTexture( connections.envMap );

				if ( attributes.transparent && attributes.opacity < 0.999 ) {

					envMap.mapping = THREE.EquirectangularRefractionMapping; // Reflectivity and refraction mapping don't work well together in Phong materials

					if ( attributes.reflectivity !== undefined ) {

						delete attributes.reflectivity;
						delete attributes.combine;

					}

					if ( attributes.metalness !== undefined ) {

						attributes.metalness = 1; // For most transparent materials metalness should be set to 1 if not otherwise defined. If set to 0 no refraction will be visible

					}

					attributes.opacity = 1; // transparency fades out refraction, forcing opacity to 1 ensures a closer visual match to the material in Lightwave.

				} else envMap.mapping = THREE.EquirectangularReflectionMapping;

				maps.envMap = envMap;

			}

		} // get texture defined at top level by its index


		getTexturePathByIndex( index ) {

			let fileName = '';
			if ( ! _lwoTree.textures ) return fileName;

			_lwoTree.textures.forEach( function ( texture ) {

				if ( texture.index === index ) fileName = texture.fileName;

			} );

			return fileName;

		}

		loadTexture( path ) {

			if ( ! path ) return null;
			const texture = this.textureLoader.load( path, undefined, undefined, function () {

				console.warn( 'LWOLoader: non-standard resource hierarchy. Use \`resourcePath\` parameter to specify root content directory.' );

			} );
			return texture;

		} // 0 = Reset, 1 = Repeat, 2 = Mirror, 3 = Edge


		getWrappingType( num ) {

			switch ( num ) {

				case 0:
					console.warn( 'LWOLoader: "Reset" texture wrapping type is not supported in three.js' );
					return THREE.ClampToEdgeWrapping;

				case 1:
					return THREE.RepeatWrapping;

				case 2:
					return THREE.MirroredRepeatWrapping;

				case 3:
					return THREE.ClampToEdgeWrapping;

			}

		}

		getMaterialType( nodeData ) {

			if ( nodeData.Clearcoat && nodeData.Clearcoat.value > 0 ) return THREE.MeshPhysicalMaterial;
			if ( nodeData.Roughness ) return THREE.MeshStandardMaterial;
			return THREE.MeshPhongMaterial;

		}

	}

	class GeometryParser {

		parse( geoData, layer ) {

			const geometry = new THREE.BufferGeometry();
			geometry.setAttribute( 'position', new THREE.Float32BufferAttribute( geoData.points, 3 ) );
			const indices = this.splitIndices( geoData.vertexIndices, geoData.polygonDimensions );
			geometry.setIndex( indices );
			this.parseGroups( geometry, geoData );
			geometry.computeVertexNormals();
			this.parseUVs( geometry, layer, indices );
			this.parseMorphTargets( geometry, layer, indices ); // TODO: z may need to be reversed to account for coordinate system change

			geometry.translate( - layer.pivot[ 0 ], - layer.pivot[ 1 ], - layer.pivot[ 2 ] ); // let userData = geometry.userData;
			// geometry = geometry.toNonIndexed()
			// geometry.userData = userData;

			return geometry;

		} // split quads into tris


		splitIndices( indices, polygonDimensions ) {

			const remappedIndices = [];
			let i = 0;
			polygonDimensions.forEach( function ( dim ) {

				if ( dim < 4 ) {

					for ( let k = 0; k < dim; k ++ ) remappedIndices.push( indices[ i + k ] );

				} else if ( dim === 4 ) {

					remappedIndices.push( indices[ i ], indices[ i + 1 ], indices[ i + 2 ], indices[ i ], indices[ i + 2 ], indices[ i + 3 ] );

				} else if ( dim > 4 ) {

					for ( let k = 1; k < dim - 1; k ++ ) {

						remappedIndices.push( indices[ i ], indices[ i + k ], indices[ i + k + 1 ] );

					}

					console.warn( 'LWOLoader: polygons with greater than 4 sides are not supported' );

				}

				i += dim;

			} );
			return remappedIndices;

		} // NOTE: currently ignoring poly indices and assuming that they are intelligently ordered


		parseGroups( geometry, geoData ) {

			const tags = _lwoTree.tags;
			const matNames = [];
			let elemSize = 3;
			if ( geoData.type === 'lines' ) elemSize = 2;
			if ( geoData.type === 'points' ) elemSize = 1;
			const remappedIndices = this.splitMaterialIndices( geoData.polygonDimensions, geoData.materialIndices );
			let indexNum = 0; // create new indices in numerical order

			const indexPairs = {}; // original indices mapped to numerical indices

			let prevMaterialIndex;
			let materialIndex;
			let prevStart = 0;
			let currentCount = 0;

			for ( let i = 0; i < remappedIndices.length; i += 2 ) {

				materialIndex = remappedIndices[ i + 1 ];
				if ( i === 0 ) matNames[ indexNum ] = tags[ materialIndex ];
				if ( prevMaterialIndex === undefined ) prevMaterialIndex = materialIndex;

				if ( materialIndex !== prevMaterialIndex ) {

					let currentIndex;

					if ( indexPairs[ tags[ prevMaterialIndex ] ] ) {

						currentIndex = indexPairs[ tags[ prevMaterialIndex ] ];

					} else {

						currentIndex = indexNum;
						indexPairs[ tags[ prevMaterialIndex ] ] = indexNum;
						matNames[ indexNum ] = tags[ prevMaterialIndex ];
						indexNum ++;

					}

					geometry.addGroup( prevStart, currentCount, currentIndex );
					prevStart += currentCount;
					prevMaterialIndex = materialIndex;
					currentCount = 0;

				}

				currentCount += elemSize;

			} // the loop above doesn't add the last group, do that here.


			if ( geometry.groups.length > 0 ) {

				let currentIndex;

				if ( indexPairs[ tags[ materialIndex ] ] ) {

					currentIndex = indexPairs[ tags[ materialIndex ] ];

				} else {

					currentIndex = indexNum;
					indexPairs[ tags[ materialIndex ] ] = indexNum;
					matNames[ indexNum ] = tags[ materialIndex ];

				}

				geometry.addGroup( prevStart, currentCount, currentIndex );

			} // Mat names from TAGS chunk, used to build up an array of materials for this geometry


			geometry.userData.matNames = matNames;

		}

		splitMaterialIndices( polygonDimensions, indices ) {

			const remappedIndices = [];
			polygonDimensions.forEach( function ( dim, i ) {

				if ( dim <= 3 ) {

					remappedIndices.push( indices[ i * 2 ], indices[ i * 2 + 1 ] );

				} else if ( dim === 4 ) {

					remappedIndices.push( indices[ i * 2 ], indices[ i * 2 + 1 ], indices[ i * 2 ], indices[ i * 2 + 1 ] );

				} else {

					// ignore > 4 for now
					for ( let k = 0; k < dim - 2; k ++ ) {

						remappedIndices.push( indices[ i * 2 ], indices[ i * 2 + 1 ] );

					}

				}

			} );
			return remappedIndices;

		} // UV maps:
		// 1: are defined via index into an array of points, not into a geometry
		// - the geometry is also defined by an index into this array, but the indexes may not match
		// 2: there can be any number of UV maps for a single geometry. Here these are combined,
		// 	with preference given to the first map encountered
		// 3: UV maps can be partial - that is, defined for only a part of the geometry
		// 4: UV maps can be VMAP or VMAD (discontinuous, to allow for seams). In practice, most
		// UV maps are defined as partially VMAP and partially VMAD
		// VMADs are currently not supported


		parseUVs( geometry, layer ) {

			// start by creating a UV map set to zero for the whole geometry
			const remappedUVs = Array.from( Array( geometry.attributes.position.count * 2 ), function () {

				return 0;

			} );

			for ( const name in layer.uvs ) {

				const uvs = layer.uvs[ name ].uvs;
				const uvIndices = layer.uvs[ name ].uvIndices;
				uvIndices.forEach( function ( i, j ) {

					remappedUVs[ i * 2 ] = uvs[ j * 2 ];
					remappedUVs[ i * 2 + 1 ] = uvs[ j * 2 + 1 ];

				} );

			}

			geometry.setAttribute( 'uv', new THREE.Float32BufferAttribute( remappedUVs, 2 ) );

		}

		parseMorphTargets( geometry, layer ) {

			let num = 0;

			for ( const name in layer.morphTargets ) {

				const remappedPoints = geometry.attributes.position.array.slice();
				if ( ! geometry.morphAttributes.position ) geometry.morphAttributes.position = [];
				const morphPoints = layer.morphTargets[ name ].points;
				const morphIndices = layer.morphTargets[ name ].indices;
				const type = layer.morphTargets[ name ].type;
				morphIndices.forEach( function ( i, j ) {

					if ( type === 'relative' ) {

						remappedPoints[ i * 3 ] += morphPoints[ j * 3 ];
						remappedPoints[ i * 3 + 1 ] += morphPoints[ j * 3 + 1 ];
						remappedPoints[ i * 3 + 2 ] += morphPoints[ j * 3 + 2 ];

					} else {

						remappedPoints[ i * 3 ] = morphPoints[ j * 3 ];
						remappedPoints[ i * 3 + 1 ] = morphPoints[ j * 3 + 1 ];
						remappedPoints[ i * 3 + 2 ] = morphPoints[ j * 3 + 2 ];

					}

				} );
				geometry.morphAttributes.position[ num ] = new THREE.Float32BufferAttribute( remappedPoints, 3 );
				geometry.morphAttributes.position[ num ].name = name;
				num ++;

			}

			geometry.morphTargetsRelative = false;

		}

	} // ************** UTILITY FUNCTIONS **************


	function extractParentUrl( url, dir ) {

		const index = url.indexOf( dir );
		if ( index === - 1 ) return './';
		return url.slice( 0, index );

	}

	THREE.LWOLoader = LWOLoader;

} )();