three.js/examples/js/loaders/LDrawLoader.js

( function () {

	// Special surface finish tag types.
	// Note: "MATERIAL" tag (e.g. GLITTER, SPECKLE) is not implemented
	const FINISH_TYPE_DEFAULT = 0;
	const FINISH_TYPE_CHROME = 1;
	const FINISH_TYPE_PEARLESCENT = 2;
	const FINISH_TYPE_RUBBER = 3;
	const FINISH_TYPE_MATTE_METALLIC = 4;
	const FINISH_TYPE_METAL = 5;

	// State machine to search a subobject path.
	// The LDraw standard establishes these various possible subfolders.
	const FILE_LOCATION_TRY_PARTS = 0;
	const FILE_LOCATION_TRY_P = 1;
	const FILE_LOCATION_TRY_MODELS = 2;
	const FILE_LOCATION_AS_IS = 3;
	const FILE_LOCATION_TRY_RELATIVE = 4;
	const FILE_LOCATION_TRY_ABSOLUTE = 5;
	const FILE_LOCATION_NOT_FOUND = 6;
	const MAIN_COLOUR_CODE = '16';
	const MAIN_EDGE_COLOUR_CODE = '24';
	const _tempVec0 = new THREE.Vector3();
	const _tempVec1 = new THREE.Vector3();
	class LDrawConditionalLineMaterial extends THREE.ShaderMaterial {

		constructor( parameters ) {

			super( {
				uniforms: THREE.UniformsUtils.merge( [ THREE.UniformsLib.fog, {
					diffuse: {
						value: new THREE.Color()
					},
					opacity: {
						value: 1.0
					}
				} ] ),
				vertexShader: /* glsl */`
				attribute vec3 control0;
				attribute vec3 control1;
				attribute vec3 direction;
				varying float discardFlag;

				#include <common>
				#include <color_pars_vertex>
				#include <fog_pars_vertex>
				#include <logdepthbuf_pars_vertex>
				#include <clipping_planes_pars_vertex>
				void main() {
					#include <color_vertex>

					vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );
					gl_Position = projectionMatrix * mvPosition;

					// Transform the line segment ends and control points into camera clip space
					vec4 c0 = projectionMatrix * modelViewMatrix * vec4( control0, 1.0 );
					vec4 c1 = projectionMatrix * modelViewMatrix * vec4( control1, 1.0 );
					vec4 p0 = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
					vec4 p1 = projectionMatrix * modelViewMatrix * vec4( position + direction, 1.0 );

					c0.xy /= c0.w;
					c1.xy /= c1.w;
					p0.xy /= p0.w;
					p1.xy /= p1.w;

					// Get the direction of the segment and an orthogonal vector
					vec2 dir = p1.xy - p0.xy;
					vec2 norm = vec2( -dir.y, dir.x );

					// Get control point directions from the line
					vec2 c0dir = c0.xy - p1.xy;
					vec2 c1dir = c1.xy - p1.xy;

					// If the vectors to the controls points are pointed in different directions away
					// from the line segment then the line should not be drawn.
					float d0 = dot( normalize( norm ), normalize( c0dir ) );
					float d1 = dot( normalize( norm ), normalize( c1dir ) );
					discardFlag = float( sign( d0 ) != sign( d1 ) );

					#include <logdepthbuf_vertex>
					#include <clipping_planes_vertex>
					#include <fog_vertex>
				}
			`,
				fragmentShader: /* glsl */`
			uniform vec3 diffuse;
			uniform float opacity;
			varying float discardFlag;

			#include <common>
			#include <color_pars_fragment>
			#include <fog_pars_fragment>
			#include <logdepthbuf_pars_fragment>
			#include <clipping_planes_pars_fragment>
			void main() {

				if ( discardFlag > 0.5 ) discard;

				#include <clipping_planes_fragment>
				vec3 outgoingLight = vec3( 0.0 );
				vec4 diffuseColor = vec4( diffuse, opacity );
				#include <logdepthbuf_fragment>
				#include <color_fragment>
				outgoingLight = diffuseColor.rgb; // simple shader
				gl_FragColor = vec4( outgoingLight, diffuseColor.a );
				#include <tonemapping_fragment>
				#include <encodings_fragment>
				#include <fog_fragment>
				#include <premultiplied_alpha_fragment>
			}
			`
			} );
			Object.defineProperties( this, {
				opacity: {
					get: function () {

						return this.uniforms.opacity.value;

					},
					set: function ( value ) {

						this.uniforms.opacity.value = value;

					}
				},
				color: {
					get: function () {

						return this.uniforms.diffuse.value;

					}
				}
			} );
			this.setValues( parameters );
			this.isLDrawConditionalLineMaterial = true;

		}

	}
	class ConditionalLineSegments extends THREE.LineSegments {

		constructor( geometry, material ) {

			super( geometry, material );
			this.isConditionalLine = true;

		}

	}
	function generateFaceNormals( faces ) {

		for ( let i = 0, l = faces.length; i < l; i ++ ) {

			const face = faces[ i ];
			const vertices = face.vertices;
			const v0 = vertices[ 0 ];
			const v1 = vertices[ 1 ];
			const v2 = vertices[ 2 ];
			_tempVec0.subVectors( v1, v0 );
			_tempVec1.subVectors( v2, v1 );
			face.faceNormal = new THREE.Vector3().crossVectors( _tempVec0, _tempVec1 ).normalize();

		}

	}

	const _ray = new THREE.Ray();
	function smoothNormals( faces, lineSegments, checkSubSegments = false ) {

		// NOTE: 1e2 is pretty coarse but was chosen to quantize the resulting value because
		// it allows edges to be smoothed as expected (see minifig arms).
		// --
		// And the vector values are initialize multiplied by 1 + 1e-10 to account for floating
		// point errors on vertices along quantization boundaries. Ie after matrix multiplication
		// vertices that should be merged might be set to "1.7" and "1.6999..." meaning they won't
		// get merged. This added epsilon attempts to push these error values to the same quantized
		// value for the sake of hashing. See "AT-ST mini" dishes. See mrdoob/three#23169.

		const hashMultiplier = ( 1 + 1e-10 ) * 1e2;
		function hashVertex( v ) {

			const x = ~ ~ ( v.x * hashMultiplier );
			const y = ~ ~ ( v.y * hashMultiplier );
			const z = ~ ~ ( v.z * hashMultiplier );
			return `${x},${y},${z}`;

		}

		function hashEdge( v0, v1 ) {

			return `${hashVertex( v0 )}_${hashVertex( v1 )}`;

		}

		// converts the two vertices to a ray with a normalized direction and origin of 0, 0, 0 projected
		// onto the original line.
		function toNormalizedRay( v0, v1, targetRay ) {

			targetRay.direction.subVectors( v1, v0 ).normalize();
			const scalar = v0.dot( targetRay.direction );
			targetRay.origin.copy( v0 ).addScaledVector( targetRay.direction, - scalar );
			return targetRay;

		}

		function hashRay( ray ) {

			return hashEdge( ray.origin, ray.direction );

		}

		const hardEdges = new Set();
		const hardEdgeRays = new Map();
		const halfEdgeList = {};
		const normals = [];

		// Save the list of hard edges by hash
		for ( let i = 0, l = lineSegments.length; i < l; i ++ ) {

			const ls = lineSegments[ i ];
			const vertices = ls.vertices;
			const v0 = vertices[ 0 ];
			const v1 = vertices[ 1 ];
			hardEdges.add( hashEdge( v0, v1 ) );
			hardEdges.add( hashEdge( v1, v0 ) );

			// only generate the hard edge ray map if we're checking subsegments because it's more expensive to check
			// and requires more memory.
			if ( checkSubSegments ) {

				// add both ray directions to the map
				const ray = toNormalizedRay( v0, v1, new THREE.Ray() );
				const rh1 = hashRay( ray );
				if ( ! hardEdgeRays.has( rh1 ) ) {

					toNormalizedRay( v1, v0, ray );
					const rh2 = hashRay( ray );
					const info = {
						ray,
						distances: []
					};
					hardEdgeRays.set( rh1, info );
					hardEdgeRays.set( rh2, info );

				}

				// store both segments ends in min, max order in the distances array to check if a face edge is a
				// subsegment later.
				const info = hardEdgeRays.get( rh1 );
				let d0 = info.ray.direction.dot( v0 );
				let d1 = info.ray.direction.dot( v1 );
				if ( d0 > d1 ) {

					[ d0, d1 ] = [ d1, d0 ];

				}

				info.distances.push( d0, d1 );

			}

		}

		// track the half edges associated with each triangle
		for ( let i = 0, l = faces.length; i < l; i ++ ) {

			const tri = faces[ i ];
			const vertices = tri.vertices;
			const vertCount = vertices.length;
			for ( let i2 = 0; i2 < vertCount; i2 ++ ) {

				const index = i2;
				const next = ( i2 + 1 ) % vertCount;
				const v0 = vertices[ index ];
				const v1 = vertices[ next ];
				const hash = hashEdge( v0, v1 );

				// don't add the triangle if the edge is supposed to be hard
				if ( hardEdges.has( hash ) ) {

					continue;

				}

				// if checking subsegments then check to see if this edge lies on a hard edge ray and whether its within any ray bounds
				if ( checkSubSegments ) {

					toNormalizedRay( v0, v1, _ray );
					const rayHash = hashRay( _ray );
					if ( hardEdgeRays.has( rayHash ) ) {

						const info = hardEdgeRays.get( rayHash );
						const {
							ray,
							distances
						} = info;
						let d0 = ray.direction.dot( v0 );
						let d1 = ray.direction.dot( v1 );
						if ( d0 > d1 ) {

							[ d0, d1 ] = [ d1, d0 ];

						}

						// return early if the face edge is found to be a subsegment of a line edge meaning the edge will have "hard" normals
						let found = false;
						for ( let i = 0, l = distances.length; i < l; i += 2 ) {

							if ( d0 >= distances[ i ] && d1 <= distances[ i + 1 ] ) {

								found = true;
								break;

							}

						}

						if ( found ) {

							continue;

						}

					}

				}

				const info = {
					index: index,
					tri: tri
				};
				halfEdgeList[ hash ] = info;

			}

		}

		// Iterate until we've tried to connect all faces to share normals
		while ( true ) {

			// Stop if there are no more faces left
			let halfEdge = null;
			for ( const key in halfEdgeList ) {

				halfEdge = halfEdgeList[ key ];
				break;

			}

			if ( halfEdge === null ) {

				break;

			}

			// Exhaustively find all connected faces
			const queue = [ halfEdge ];
			while ( queue.length > 0 ) {

				// initialize all vertex normals in this triangle
				const tri = queue.pop().tri;
				const vertices = tri.vertices;
				const vertNormals = tri.normals;
				const faceNormal = tri.faceNormal;

				// Check if any edge is connected to another triangle edge
				const vertCount = vertices.length;
				for ( let i2 = 0; i2 < vertCount; i2 ++ ) {

					const index = i2;
					const next = ( i2 + 1 ) % vertCount;
					const v0 = vertices[ index ];
					const v1 = vertices[ next ];

					// delete this triangle from the list so it won't be found again
					const hash = hashEdge( v0, v1 );
					delete halfEdgeList[ hash ];
					const reverseHash = hashEdge( v1, v0 );
					const otherInfo = halfEdgeList[ reverseHash ];
					if ( otherInfo ) {

						const otherTri = otherInfo.tri;
						const otherIndex = otherInfo.index;
						const otherNormals = otherTri.normals;
						const otherVertCount = otherNormals.length;
						const otherFaceNormal = otherTri.faceNormal;

						// NOTE: If the angle between faces is > 67.5 degrees then assume it's
						// hard edge. There are some cases where the line segments do not line up exactly
						// with or span multiple triangle edges (see Lunar Vehicle wheels).
						if ( Math.abs( otherTri.faceNormal.dot( tri.faceNormal ) ) < 0.25 ) {

							continue;

						}

						// if this triangle has already been traversed then it won't be in
						// the halfEdgeList. If it has not then add it to the queue and delete
						// it so it won't be found again.
						if ( reverseHash in halfEdgeList ) {

							queue.push( otherInfo );
							delete halfEdgeList[ reverseHash ];

						}

						// share the first normal
						const otherNext = ( otherIndex + 1 ) % otherVertCount;
						if ( vertNormals[ index ] && otherNormals[ otherNext ] && vertNormals[ index ] !== otherNormals[ otherNext ] ) {

							otherNormals[ otherNext ].norm.add( vertNormals[ index ].norm );
							vertNormals[ index ].norm = otherNormals[ otherNext ].norm;

						}

						let sharedNormal1 = vertNormals[ index ] || otherNormals[ otherNext ];
						if ( sharedNormal1 === null ) {

							// it's possible to encounter an edge of a triangle that has already been traversed meaning
							// both edges already have different normals defined and shared. To work around this we create
							// a wrapper object so when those edges are merged the normals can be updated everywhere.
							sharedNormal1 = {
								norm: new THREE.Vector3()
							};
							normals.push( sharedNormal1.norm );

						}

						if ( vertNormals[ index ] === null ) {

							vertNormals[ index ] = sharedNormal1;
							sharedNormal1.norm.add( faceNormal );

						}

						if ( otherNormals[ otherNext ] === null ) {

							otherNormals[ otherNext ] = sharedNormal1;
							sharedNormal1.norm.add( otherFaceNormal );

						}

						// share the second normal
						if ( vertNormals[ next ] && otherNormals[ otherIndex ] && vertNormals[ next ] !== otherNormals[ otherIndex ] ) {

							otherNormals[ otherIndex ].norm.add( vertNormals[ next ].norm );
							vertNormals[ next ].norm = otherNormals[ otherIndex ].norm;

						}

						let sharedNormal2 = vertNormals[ next ] || otherNormals[ otherIndex ];
						if ( sharedNormal2 === null ) {

							sharedNormal2 = {
								norm: new THREE.Vector3()
							};
							normals.push( sharedNormal2.norm );

						}

						if ( vertNormals[ next ] === null ) {

							vertNormals[ next ] = sharedNormal2;
							sharedNormal2.norm.add( faceNormal );

						}

						if ( otherNormals[ otherIndex ] === null ) {

							otherNormals[ otherIndex ] = sharedNormal2;
							sharedNormal2.norm.add( otherFaceNormal );

						}

					}

				}

			}

		}

		// The normals of each face have been added up so now we average them by normalizing the vector.
		for ( let i = 0, l = normals.length; i < l; i ++ ) {

			normals[ i ].normalize();

		}

	}

	function isPartType( type ) {

		return type === 'Part' || type === 'Unofficial_Part';

	}

	function isPrimitiveType( type ) {

		return /primitive/i.test( type ) || type === 'Subpart';

	}

	class LineParser {

		constructor( line, lineNumber ) {

			this.line = line;
			this.lineLength = line.length;
			this.currentCharIndex = 0;
			this.currentChar = ' ';
			this.lineNumber = lineNumber;

		}
		seekNonSpace() {

			while ( this.currentCharIndex < this.lineLength ) {

				this.currentChar = this.line.charAt( this.currentCharIndex );
				if ( this.currentChar !== ' ' && this.currentChar !== '\t' ) {

					return;

				}

				this.currentCharIndex ++;

			}

		}
		getToken() {

			const pos0 = this.currentCharIndex ++;

			// Seek space
			while ( this.currentCharIndex < this.lineLength ) {

				this.currentChar = this.line.charAt( this.currentCharIndex );
				if ( this.currentChar === ' ' || this.currentChar === '\t' ) {

					break;

				}

				this.currentCharIndex ++;

			}

			const pos1 = this.currentCharIndex;
			this.seekNonSpace();
			return this.line.substring( pos0, pos1 );

		}
		getVector() {

			return new THREE.Vector3( parseFloat( this.getToken() ), parseFloat( this.getToken() ), parseFloat( this.getToken() ) );

		}
		getRemainingString() {

			return this.line.substring( this.currentCharIndex, this.lineLength );

		}
		isAtTheEnd() {

			return this.currentCharIndex >= this.lineLength;

		}
		setToEnd() {

			this.currentCharIndex = this.lineLength;

		}
		getLineNumberString() {

			return this.lineNumber >= 0 ? ' at line ' + this.lineNumber : '';

		}

	}

	// Fetches and parses an intermediate representation of LDraw parts files.
	class LDrawParsedCache {

		constructor( loader ) {

			this.loader = loader;
			this._cache = {};

		}
		cloneResult( original ) {

			const result = {};

			// vertices are transformed and normals computed before being converted to geometry
			// so these pieces must be cloned.
			result.faces = original.faces.map( face => {

				return {
					colorCode: face.colorCode,
					material: face.material,
					vertices: face.vertices.map( v => v.clone() ),
					normals: face.normals.map( () => null ),
					faceNormal: null
				};

			} );
			result.conditionalSegments = original.conditionalSegments.map( face => {

				return {
					colorCode: face.colorCode,
					material: face.material,
					vertices: face.vertices.map( v => v.clone() ),
					controlPoints: face.controlPoints.map( v => v.clone() )
				};

			} );
			result.lineSegments = original.lineSegments.map( face => {

				return {
					colorCode: face.colorCode,
					material: face.material,
					vertices: face.vertices.map( v => v.clone() )
				};

			} );

			// none if this is subsequently modified
			result.type = original.type;
			result.category = original.category;
			result.keywords = original.keywords;
			result.author = original.author;
			result.subobjects = original.subobjects;
			result.fileName = original.fileName;
			result.totalFaces = original.totalFaces;
			result.startingConstructionStep = original.startingConstructionStep;
			result.materials = original.materials;
			result.group = null;
			return result;

		}
		async fetchData( fileName ) {

			let triedLowerCase = false;
			let locationState = FILE_LOCATION_TRY_PARTS;
			while ( locationState !== FILE_LOCATION_NOT_FOUND ) {

				let subobjectURL = fileName;
				switch ( locationState ) {

					case FILE_LOCATION_AS_IS:
						locationState = locationState + 1;
						break;
					case FILE_LOCATION_TRY_PARTS:
						subobjectURL = 'parts/' + subobjectURL;
						locationState = locationState + 1;
						break;
					case FILE_LOCATION_TRY_P:
						subobjectURL = 'p/' + subobjectURL;
						locationState = locationState + 1;
						break;
					case FILE_LOCATION_TRY_MODELS:
						subobjectURL = 'models/' + subobjectURL;
						locationState = locationState + 1;
						break;
					case FILE_LOCATION_TRY_RELATIVE:
						subobjectURL = fileName.substring( 0, fileName.lastIndexOf( '/' ) + 1 ) + subobjectURL;
						locationState = locationState + 1;
						break;
					case FILE_LOCATION_TRY_ABSOLUTE:
						if ( triedLowerCase ) {

							// Try absolute path
							locationState = FILE_LOCATION_NOT_FOUND;

						} else {

							// Next attempt is lower case
							fileName = fileName.toLowerCase();
							subobjectURL = fileName;
							triedLowerCase = true;
							locationState = FILE_LOCATION_TRY_PARTS;

						}

						break;

				}

				const loader = this.loader;
				const fileLoader = new THREE.FileLoader( loader.manager );
				fileLoader.setPath( loader.partsLibraryPath );
				fileLoader.setRequestHeader( loader.requestHeader );
				fileLoader.setWithCredentials( loader.withCredentials );
				try {

					const text = await fileLoader.loadAsync( subobjectURL );
					return text;

				} catch {

					continue;

				}

			}

			throw new Error( 'LDrawLoader: Subobject "' + fileName + '" could not be loaded.' );

		}
		parse( text, fileName = null ) {

			const loader = this.loader;

			// final results
			const faces = [];
			const lineSegments = [];
			const conditionalSegments = [];
			const subobjects = [];
			const materials = {};
			const getLocalMaterial = colorCode => {

				return materials[ colorCode ] || null;

			};

			let type = 'Model';
			let category = null;
			let keywords = null;
			let author = null;
			let totalFaces = 0;

			// split into lines
			if ( text.indexOf( '\r\n' ) !== - 1 ) {

				// This is faster than String.split with regex that splits on both
				text = text.replace( /\r\n/g, '\n' );

			}

			const lines = text.split( '\n' );
			const numLines = lines.length;
			let parsingEmbeddedFiles = false;
			let currentEmbeddedFileName = null;
			let currentEmbeddedText = null;
			let bfcCertified = false;
			let bfcCCW = true;
			let bfcInverted = false;
			let bfcCull = true;
			let startingConstructionStep = false;

			// Parse all line commands
			for ( let lineIndex = 0; lineIndex < numLines; lineIndex ++ ) {

				const line = lines[ lineIndex ];
				if ( line.length === 0 ) continue;
				if ( parsingEmbeddedFiles ) {

					if ( line.startsWith( '0 FILE ' ) ) {

						// Save previous embedded file in the cache
						this.setData( currentEmbeddedFileName, currentEmbeddedText );

						// New embedded text file
						currentEmbeddedFileName = line.substring( 7 );
						currentEmbeddedText = '';

					} else {

						currentEmbeddedText += line + '\n';

					}

					continue;

				}

				const lp = new LineParser( line, lineIndex + 1 );
				lp.seekNonSpace();
				if ( lp.isAtTheEnd() ) {

					// Empty line
					continue;

				}

				// Parse the line type
				const lineType = lp.getToken();
				let material;
				let colorCode;
				let segment;
				let ccw;
				let doubleSided;
				let v0, v1, v2, v3, c0, c1;
				switch ( lineType ) {

					// Line type 0: Comment or META
					case '0':
						// Parse meta directive
						const meta = lp.getToken();
						if ( meta ) {

							switch ( meta ) {

								case '!LDRAW_ORG':
									type = lp.getToken();
									break;
								case '!COLOUR':
									material = loader.parseColorMetaDirective( lp );
									if ( material ) {

										materials[ material.userData.code ] = material;

									} else {

										console.warn( 'LDrawLoader: Error parsing material' + lp.getLineNumberString() );

									}

									break;
								case '!CATEGORY':
									category = lp.getToken();
									break;
								case '!KEYWORDS':
									const newKeywords = lp.getRemainingString().split( ',' );
									if ( newKeywords.length > 0 ) {

										if ( ! keywords ) {

											keywords = [];

										}

										newKeywords.forEach( function ( keyword ) {

											keywords.push( keyword.trim() );

										} );

									}

									break;
								case 'FILE':
									if ( lineIndex > 0 ) {

										// Start embedded text files parsing
										parsingEmbeddedFiles = true;
										currentEmbeddedFileName = lp.getRemainingString();
										currentEmbeddedText = '';
										bfcCertified = false;
										bfcCCW = true;

									}

									break;
								case 'BFC':
									// Changes to the backface culling state
									while ( ! lp.isAtTheEnd() ) {

										const token = lp.getToken();
										switch ( token ) {

											case 'CERTIFY':
											case 'NOCERTIFY':
												bfcCertified = token === 'CERTIFY';
												bfcCCW = true;
												break;
											case 'CW':
											case 'CCW':
												bfcCCW = token === 'CCW';
												break;
											case 'INVERTNEXT':
												bfcInverted = true;
												break;
											case 'CLIP':
											case 'NOCLIP':
												bfcCull = token === 'CLIP';
												break;
											default:
												console.warn( 'THREE.LDrawLoader: BFC directive "' + token + '" is unknown.' );
												break;

										}

									}

									break;
								case 'STEP':
									startingConstructionStep = true;
									break;
								case 'Author:':
									author = lp.getToken();
									break;
								default:
									// Other meta directives are not implemented
									break;

							}

						}

						break;

						// Line type 1: Sub-object file
					case '1':
						colorCode = lp.getToken();
						material = getLocalMaterial( colorCode );
						const posX = parseFloat( lp.getToken() );
						const posY = parseFloat( lp.getToken() );
						const posZ = parseFloat( lp.getToken() );
						const m0 = parseFloat( lp.getToken() );
						const m1 = parseFloat( lp.getToken() );
						const m2 = parseFloat( lp.getToken() );
						const m3 = parseFloat( lp.getToken() );
						const m4 = parseFloat( lp.getToken() );
						const m5 = parseFloat( lp.getToken() );
						const m6 = parseFloat( lp.getToken() );
						const m7 = parseFloat( lp.getToken() );
						const m8 = parseFloat( lp.getToken() );
						const matrix = new THREE.Matrix4().set( m0, m1, m2, posX, m3, m4, m5, posY, m6, m7, m8, posZ, 0, 0, 0, 1 );
						let fileName = lp.getRemainingString().trim().replace( /\\/g, '/' );
						if ( loader.fileMap[ fileName ] ) {

							// Found the subobject path in the preloaded file path map
							fileName = loader.fileMap[ fileName ];

						} else {

							// Standardized subfolders
							if ( fileName.startsWith( 's/' ) ) {

								fileName = 'parts/' + fileName;

							} else if ( fileName.startsWith( '48/' ) ) {

								fileName = 'p/' + fileName;

							}

						}

						subobjects.push( {
							material: material,
							colorCode: colorCode,
							matrix: matrix,
							fileName: fileName,
							inverted: bfcInverted,
							startingConstructionStep: startingConstructionStep
						} );
						bfcInverted = false;
						break;

						// Line type 2: Line segment
					case '2':
						colorCode = lp.getToken();
						material = getLocalMaterial( colorCode );
						v0 = lp.getVector();
						v1 = lp.getVector();
						segment = {
							material: material,
							colorCode: colorCode,
							vertices: [ v0, v1 ]
						};
						lineSegments.push( segment );
						break;

						// Line type 5: Conditional Line segment
					case '5':
						colorCode = lp.getToken();
						material = getLocalMaterial( colorCode );
						v0 = lp.getVector();
						v1 = lp.getVector();
						c0 = lp.getVector();
						c1 = lp.getVector();
						segment = {
							material: material,
							colorCode: colorCode,
							vertices: [ v0, v1 ],
							controlPoints: [ c0, c1 ]
						};
						conditionalSegments.push( segment );
						break;

						// Line type 3: Triangle
					case '3':
						colorCode = lp.getToken();
						material = getLocalMaterial( colorCode );
						ccw = bfcCCW;
						doubleSided = ! bfcCertified || ! bfcCull;
						if ( ccw === true ) {

							v0 = lp.getVector();
							v1 = lp.getVector();
							v2 = lp.getVector();

						} else {

							v2 = lp.getVector();
							v1 = lp.getVector();
							v0 = lp.getVector();

						}

						faces.push( {
							material: material,
							colorCode: colorCode,
							faceNormal: null,
							vertices: [ v0, v1, v2 ],
							normals: [ null, null, null ]
						} );
						totalFaces ++;
						if ( doubleSided === true ) {

							faces.push( {
								material: material,
								colorCode: colorCode,
								faceNormal: null,
								vertices: [ v2, v1, v0 ],
								normals: [ null, null, null ]
							} );
							totalFaces ++;

						}

						break;

						// Line type 4: Quadrilateral
					case '4':
						colorCode = lp.getToken();
						material = getLocalMaterial( colorCode );
						ccw = bfcCCW;
						doubleSided = ! bfcCertified || ! bfcCull;
						if ( ccw === true ) {

							v0 = lp.getVector();
							v1 = lp.getVector();
							v2 = lp.getVector();
							v3 = lp.getVector();

						} else {

							v3 = lp.getVector();
							v2 = lp.getVector();
							v1 = lp.getVector();
							v0 = lp.getVector();

						}

						// specifically place the triangle diagonal in the v0 and v1 slots so we can
						// account for the doubling of vertices later when smoothing normals.
						faces.push( {
							material: material,
							colorCode: colorCode,
							faceNormal: null,
							vertices: [ v0, v1, v2, v3 ],
							normals: [ null, null, null, null ]
						} );
						totalFaces += 2;
						if ( doubleSided === true ) {

							faces.push( {
								material: material,
								colorCode: colorCode,
								faceNormal: null,
								vertices: [ v3, v2, v1, v0 ],
								normals: [ null, null, null, null ]
							} );
							totalFaces += 2;

						}

						break;
					default:
						throw new Error( 'LDrawLoader: Unknown line type "' + lineType + '"' + lp.getLineNumberString() + '.' );

				}

			}

			if ( parsingEmbeddedFiles ) {

				this.setData( currentEmbeddedFileName, currentEmbeddedText );

			}

			return {
				faces,
				conditionalSegments,
				lineSegments,
				type,
				category,
				keywords,
				author,
				subobjects,
				totalFaces,
				startingConstructionStep,
				materials,
				fileName,
				group: null
			};

		}

		// returns an (optionally cloned) instance of the data
		getData( fileName, clone = true ) {

			const key = fileName.toLowerCase();
			const result = this._cache[ key ];
			if ( result === null || result instanceof Promise ) {

				return null;

			}

			if ( clone ) {

				return this.cloneResult( result );

			} else {

				return result;

			}

		}

		// kicks off a fetch and parse of the requested data if it hasn't already been loaded. Returns when
		// the data is ready to use and can be retrieved synchronously with "getData".
		async ensureDataLoaded( fileName ) {

			const key = fileName.toLowerCase();
			if ( ! ( key in this._cache ) ) {

				// replace the promise with a copy of the parsed data for immediate processing
				this._cache[ key ] = this.fetchData( fileName ).then( text => {

					const info = this.parse( text, fileName );
					this._cache[ key ] = info;
					return info;

				} );

			}

			await this._cache[ key ];

		}

		// sets the data in the cache from parsed data
		setData( fileName, text ) {

			const key = fileName.toLowerCase();
			this._cache[ key ] = this.parse( text, fileName );

		}

	}

	// returns the material for an associated color code. If the color code is 16 for a face or 24 for
	// an edge then the passthroughColorCode is used.
	function getMaterialFromCode( colorCode, parentColorCode, materialHierarchy, forEdge ) {

		const isPassthrough = ! forEdge && colorCode === MAIN_COLOUR_CODE || forEdge && colorCode === MAIN_EDGE_COLOUR_CODE;
		if ( isPassthrough ) {

			colorCode = parentColorCode;

		}

		return materialHierarchy[ colorCode ] || null;

	}

	// Class used to parse and build LDraw parts as three.js objects and cache them if they're a "Part" type.
	class LDrawPartsGeometryCache {

		constructor( loader ) {

			this.loader = loader;
			this.parseCache = new LDrawParsedCache( loader );
			this._cache = {};

		}

		// Convert the given file information into a mesh by processing subobjects.
		async processIntoMesh( info ) {

			const loader = this.loader;
			const parseCache = this.parseCache;
			const faceMaterials = new Set();

			// Processes the part subobject information to load child parts and merge geometry onto part
			// piece object.
			const processInfoSubobjects = async ( info, subobject = null ) => {

				const subobjects = info.subobjects;
				const promises = [];

				// Trigger load of all subobjects. If a subobject isn't a primitive then load it as a separate
				// group which lets instruction steps apply correctly.
				for ( let i = 0, l = subobjects.length; i < l; i ++ ) {

					const subobject = subobjects[ i ];
					const promise = parseCache.ensureDataLoaded( subobject.fileName ).then( () => {

						const subobjectInfo = parseCache.getData( subobject.fileName, false );
						if ( ! isPrimitiveType( subobjectInfo.type ) ) {

							return this.loadModel( subobject.fileName ).catch( error => {

								console.warn( error );
								return null;

							} );

						}

						return processInfoSubobjects( parseCache.getData( subobject.fileName ), subobject );

					} );
					promises.push( promise );

				}

				const group = new THREE.Group();
				group.userData.category = info.category;
				group.userData.keywords = info.keywords;
				group.userData.author = info.author;
				group.userData.type = info.type;
				group.userData.fileName = info.fileName;
				info.group = group;
				const subobjectInfos = await Promise.all( promises );
				for ( let i = 0, l = subobjectInfos.length; i < l; i ++ ) {

					const subobject = info.subobjects[ i ];
					const subobjectInfo = subobjectInfos[ i ];
					if ( subobjectInfo === null ) {

						// the subobject failed to load
						continue;

					}

					// if the subobject was loaded as a separate group then apply the parent scopes materials
					if ( subobjectInfo.isGroup ) {

						const subobjectGroup = subobjectInfo;
						subobject.matrix.decompose( subobjectGroup.position, subobjectGroup.quaternion, subobjectGroup.scale );
						subobjectGroup.userData.startingConstructionStep = subobject.startingConstructionStep;
						subobjectGroup.name = subobject.fileName;
						loader.applyMaterialsToMesh( subobjectGroup, subobject.colorCode, info.materials );
						subobjectGroup.userData.colorCode = subobject.colorCode;
						group.add( subobjectGroup );
						continue;

					}

					// add the subobject group if it has children in case it has both children and primitives
					if ( subobjectInfo.group.children.length ) {

						group.add( subobjectInfo.group );

					}

					// transform the primitives into the local space of the parent piece and append them to
					// to the parent primitives list.
					const parentLineSegments = info.lineSegments;
					const parentConditionalSegments = info.conditionalSegments;
					const parentFaces = info.faces;
					const lineSegments = subobjectInfo.lineSegments;
					const conditionalSegments = subobjectInfo.conditionalSegments;
					const faces = subobjectInfo.faces;
					const matrix = subobject.matrix;
					const inverted = subobject.inverted;
					const matrixScaleInverted = matrix.determinant() < 0;
					const colorCode = subobject.colorCode;
					const lineColorCode = colorCode === MAIN_COLOUR_CODE ? MAIN_EDGE_COLOUR_CODE : colorCode;
					for ( let i = 0, l = lineSegments.length; i < l; i ++ ) {

						const ls = lineSegments[ i ];
						const vertices = ls.vertices;
						vertices[ 0 ].applyMatrix4( matrix );
						vertices[ 1 ].applyMatrix4( matrix );
						ls.colorCode = ls.colorCode === MAIN_EDGE_COLOUR_CODE ? lineColorCode : ls.colorCode;
						ls.material = ls.material || getMaterialFromCode( ls.colorCode, ls.colorCode, info.materials, true );
						parentLineSegments.push( ls );

					}

					for ( let i = 0, l = conditionalSegments.length; i < l; i ++ ) {

						const os = conditionalSegments[ i ];
						const vertices = os.vertices;
						const controlPoints = os.controlPoints;
						vertices[ 0 ].applyMatrix4( matrix );
						vertices[ 1 ].applyMatrix4( matrix );
						controlPoints[ 0 ].applyMatrix4( matrix );
						controlPoints[ 1 ].applyMatrix4( matrix );
						os.colorCode = os.colorCode === MAIN_EDGE_COLOUR_CODE ? lineColorCode : os.colorCode;
						os.material = os.material || getMaterialFromCode( os.colorCode, os.colorCode, info.materials, true );
						parentConditionalSegments.push( os );

					}

					for ( let i = 0, l = faces.length; i < l; i ++ ) {

						const tri = faces[ i ];
						const vertices = tri.vertices;
						for ( let i = 0, l = vertices.length; i < l; i ++ ) {

							vertices[ i ].applyMatrix4( matrix );

						}

						tri.colorCode = tri.colorCode === MAIN_COLOUR_CODE ? colorCode : tri.colorCode;
						tri.material = tri.material || getMaterialFromCode( tri.colorCode, colorCode, info.materials, false );
						faceMaterials.add( tri.colorCode );

						// If the scale of the object is negated then the triangle winding order
						// needs to be flipped.
						if ( matrixScaleInverted !== inverted ) {

							vertices.reverse();

						}

						parentFaces.push( tri );

					}

					info.totalFaces += subobjectInfo.totalFaces;

				}

				// Apply the parent subobjects pass through material code to this object. This is done several times due
				// to material scoping.
				if ( subobject ) {

					loader.applyMaterialsToMesh( group, subobject.colorCode, info.materials );
					group.userData.colorCode = subobject.colorCode;

				}

				return info;

			};

			// Track material use to see if we need to use the normal smooth slow path for hard edges.
			for ( let i = 0, l = info.faces; i < l; i ++ ) {

				faceMaterials.add( info.faces[ i ].colorCode );

			}

			await processInfoSubobjects( info );
			if ( loader.smoothNormals ) {

				const checkSubSegments = faceMaterials.size > 1;
				generateFaceNormals( info.faces );
				smoothNormals( info.faces, info.lineSegments, checkSubSegments );

			}

			// Add the primitive objects and metadata.
			const group = info.group;
			if ( info.faces.length > 0 ) {

				group.add( createObject( info.faces, 3, false, info.totalFaces ) );

			}

			if ( info.lineSegments.length > 0 ) {

				group.add( createObject( info.lineSegments, 2 ) );

			}

			if ( info.conditionalSegments.length > 0 ) {

				group.add( createObject( info.conditionalSegments, 2, true ) );

			}

			return group;

		}
		hasCachedModel( fileName ) {

			return fileName !== null && fileName.toLowerCase() in this._cache;

		}
		async getCachedModel( fileName ) {

			if ( fileName !== null && this.hasCachedModel( fileName ) ) {

				const key = fileName.toLowerCase();
				const group = await this._cache[ key ];
				return group.clone();

			} else {

				return null;

			}

		}

		// Loads and parses the model with the given file name. Returns a cached copy if available.
		async loadModel( fileName ) {

			const parseCache = this.parseCache;
			const key = fileName.toLowerCase();
			if ( this.hasCachedModel( fileName ) ) {

				// Return cached model if available.
				return this.getCachedModel( fileName );

			} else {

				// Otherwise parse a new model.
				// Ensure the file data is loaded and pre parsed.
				await parseCache.ensureDataLoaded( fileName );
				const info = parseCache.getData( fileName );
				const promise = this.processIntoMesh( info );

				// Now that the file has loaded it's possible that another part parse has been waiting in parallel
				// so check the cache again to see if it's been added since the last async operation so we don't
				// do unnecessary work.
				if ( this.hasCachedModel( fileName ) ) {

					return this.getCachedModel( fileName );

				}

				// Cache object if it's a part so it can be reused later.
				if ( isPartType( info.type ) ) {

					this._cache[ key ] = promise;

				}

				// return a copy
				const group = await promise;
				return group.clone();

			}

		}

		// parses the given model text into a renderable object. Returns cached copy if available.
		async parseModel( text ) {

			const parseCache = this.parseCache;
			const info = parseCache.parse( text );
			if ( isPartType( info.type ) && this.hasCachedModel( info.fileName ) ) {

				return this.getCachedModel( info.fileName );

			}

			return this.processIntoMesh( info );

		}

	}
	function sortByMaterial( a, b ) {

		if ( a.colorCode === b.colorCode ) {

			return 0;

		}

		if ( a.colorCode < b.colorCode ) {

			return - 1;

		}

		return 1;

	}

	function createObject( elements, elementSize, isConditionalSegments = false, totalElements = null ) {

		// Creates a THREE.LineSegments (elementSize = 2) or a THREE.Mesh (elementSize = 3 )
		// With per face / segment material, implemented with mesh groups and materials array

		// Sort the faces or line segments by color code to make later the mesh groups
		elements.sort( sortByMaterial );
		if ( totalElements === null ) {

			totalElements = elements.length;

		}

		const positions = new Float32Array( elementSize * totalElements * 3 );
		const normals = elementSize === 3 ? new Float32Array( elementSize * totalElements * 3 ) : null;
		const materials = [];
		const quadArray = new Array( 6 );
		const bufferGeometry = new THREE.BufferGeometry();
		let prevMaterial = null;
		let index0 = 0;
		let numGroupVerts = 0;
		let offset = 0;
		for ( let iElem = 0, nElem = elements.length; iElem < nElem; iElem ++ ) {

			const elem = elements[ iElem ];
			let vertices = elem.vertices;
			if ( vertices.length === 4 ) {

				quadArray[ 0 ] = vertices[ 0 ];
				quadArray[ 1 ] = vertices[ 1 ];
				quadArray[ 2 ] = vertices[ 2 ];
				quadArray[ 3 ] = vertices[ 0 ];
				quadArray[ 4 ] = vertices[ 2 ];
				quadArray[ 5 ] = vertices[ 3 ];
				vertices = quadArray;

			}

			for ( let j = 0, l = vertices.length; j < l; j ++ ) {

				const v = vertices[ j ];
				const index = offset + j * 3;
				positions[ index + 0 ] = v.x;
				positions[ index + 1 ] = v.y;
				positions[ index + 2 ] = v.z;

			}

			// create the normals array if this is a set of faces
			if ( elementSize === 3 ) {

				if ( ! elem.faceNormal ) {

					const v0 = vertices[ 0 ];
					const v1 = vertices[ 1 ];
					const v2 = vertices[ 2 ];
					_tempVec0.subVectors( v1, v0 );
					_tempVec1.subVectors( v2, v1 );
					elem.faceNormal = new THREE.Vector3().crossVectors( _tempVec0, _tempVec1 ).normalize();

				}

				let elemNormals = elem.normals;
				if ( elemNormals.length === 4 ) {

					quadArray[ 0 ] = elemNormals[ 0 ];
					quadArray[ 1 ] = elemNormals[ 1 ];
					quadArray[ 2 ] = elemNormals[ 2 ];
					quadArray[ 3 ] = elemNormals[ 0 ];
					quadArray[ 4 ] = elemNormals[ 2 ];
					quadArray[ 5 ] = elemNormals[ 3 ];
					elemNormals = quadArray;

				}

				for ( let j = 0, l = elemNormals.length; j < l; j ++ ) {

					// use face normal if a vertex normal is not provided
					let n = elem.faceNormal;
					if ( elemNormals[ j ] ) {

						n = elemNormals[ j ].norm;

					}

					const index = offset + j * 3;
					normals[ index + 0 ] = n.x;
					normals[ index + 1 ] = n.y;
					normals[ index + 2 ] = n.z;

				}

			}

			if ( prevMaterial !== elem.colorCode ) {

				if ( prevMaterial !== null ) {

					bufferGeometry.addGroup( index0, numGroupVerts, materials.length - 1 );

				}

				const material = elem.material;
				if ( material !== null ) {

					if ( elementSize === 3 ) {

						materials.push( material );

					} else if ( elementSize === 2 ) {

						if ( isConditionalSegments ) {

							materials.push( material.userData.edgeMaterial.userData.conditionalEdgeMaterial );

						} else {

							materials.push( material.userData.edgeMaterial );

						}

					}

				} else {

					// If a material has not been made available yet then keep the color code string in the material array
					// to save the spot for the material once a parent scopes materials are being applied to the object.
					materials.push( elem.colorCode );

				}

				prevMaterial = elem.colorCode;
				index0 = offset / 3;
				numGroupVerts = vertices.length;

			} else {

				numGroupVerts += vertices.length;

			}

			offset += 3 * vertices.length;

		}

		if ( numGroupVerts > 0 ) {

			bufferGeometry.addGroup( index0, Infinity, materials.length - 1 );

		}

		bufferGeometry.setAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );
		if ( normals !== null ) {

			bufferGeometry.setAttribute( 'normal', new THREE.BufferAttribute( normals, 3 ) );

		}

		let object3d = null;
		if ( elementSize === 2 ) {

			if ( isConditionalSegments ) {

				object3d = new ConditionalLineSegments( bufferGeometry, materials.length === 1 ? materials[ 0 ] : materials );

			} else {

				object3d = new THREE.LineSegments( bufferGeometry, materials.length === 1 ? materials[ 0 ] : materials );

			}

		} else if ( elementSize === 3 ) {

			object3d = new THREE.Mesh( bufferGeometry, materials.length === 1 ? materials[ 0 ] : materials );

		}

		if ( isConditionalSegments ) {

			object3d.isConditionalLine = true;
			const controlArray0 = new Float32Array( elements.length * 3 * 2 );
			const controlArray1 = new Float32Array( elements.length * 3 * 2 );
			const directionArray = new Float32Array( elements.length * 3 * 2 );
			for ( let i = 0, l = elements.length; i < l; i ++ ) {

				const os = elements[ i ];
				const vertices = os.vertices;
				const controlPoints = os.controlPoints;
				const c0 = controlPoints[ 0 ];
				const c1 = controlPoints[ 1 ];
				const v0 = vertices[ 0 ];
				const v1 = vertices[ 1 ];
				const index = i * 3 * 2;
				controlArray0[ index + 0 ] = c0.x;
				controlArray0[ index + 1 ] = c0.y;
				controlArray0[ index + 2 ] = c0.z;
				controlArray0[ index + 3 ] = c0.x;
				controlArray0[ index + 4 ] = c0.y;
				controlArray0[ index + 5 ] = c0.z;
				controlArray1[ index + 0 ] = c1.x;
				controlArray1[ index + 1 ] = c1.y;
				controlArray1[ index + 2 ] = c1.z;
				controlArray1[ index + 3 ] = c1.x;
				controlArray1[ index + 4 ] = c1.y;
				controlArray1[ index + 5 ] = c1.z;
				directionArray[ index + 0 ] = v1.x - v0.x;
				directionArray[ index + 1 ] = v1.y - v0.y;
				directionArray[ index + 2 ] = v1.z - v0.z;
				directionArray[ index + 3 ] = v1.x - v0.x;
				directionArray[ index + 4 ] = v1.y - v0.y;
				directionArray[ index + 5 ] = v1.z - v0.z;

			}

			bufferGeometry.setAttribute( 'control0', new THREE.BufferAttribute( controlArray0, 3, false ) );
			bufferGeometry.setAttribute( 'control1', new THREE.BufferAttribute( controlArray1, 3, false ) );
			bufferGeometry.setAttribute( 'direction', new THREE.BufferAttribute( directionArray, 3, false ) );

		}

		return object3d;

	}

	//

	class LDrawLoader extends THREE.Loader {

		constructor( manager ) {

			super( manager );

			// Array of THREE.Material
			this.materials = [];
			this.materialLibrary = {};

			// This also allows to handle the embedded text files ("0 FILE" lines)
			this.partsCache = new LDrawPartsGeometryCache( this );

			// This object is a map from file names to paths. It agilizes the paths search. If it is not set then files will be searched by trial and error.
			this.fileMap = {};

			// Initializes the materials library with default materials
			this.setMaterials( [] );

			// If this flag is set to true the vertex normals will be smoothed.
			this.smoothNormals = true;

			// The path to load parts from the LDraw parts library from.
			this.partsLibraryPath = '';

			// Material assigned to not available colors for meshes and edges
			this.missingColorMaterial = new THREE.MeshStandardMaterial( {
				color: 0xFF00FF,
				roughness: 0.3,
				metalness: 0
			} );
			this.missingColorMaterial.name = 'Missing material';
			this.missingEdgeColorMaterial = new THREE.LineBasicMaterial( {
				color: 0xFF00FF
			} );
			this.missingEdgeColorMaterial.name = 'Missing material - Edge';
			this.missingConditionalEdgeColorMaterial = new LDrawConditionalLineMaterial( {
				fog: true,
				color: 0xFF00FF
			} );
			this.missingConditionalEdgeColorMaterial.name = 'Missing material - Conditional Edge';
			this.missingColorMaterial.userData.edgeMaterial = this.missingEdgeColorMaterial;
			this.missingEdgeColorMaterial.userData.conditionalEdgeMaterial = this.missingConditionalEdgeColorMaterial;

		}
		setPartsLibraryPath( path ) {

			this.partsLibraryPath = path;
			return this;

		}
		async preloadMaterials( url ) {

			const fileLoader = new THREE.FileLoader( this.manager );
			fileLoader.setPath( this.path );
			fileLoader.setRequestHeader( this.requestHeader );
			fileLoader.setWithCredentials( this.withCredentials );
			const text = await fileLoader.loadAsync( url );
			const colorLineRegex = /^0 !COLOUR/;
			const lines = text.split( /[\n\r]/g );
			const materials = [];
			for ( let i = 0, l = lines.length; i < l; i ++ ) {

				const line = lines[ i ];
				if ( colorLineRegex.test( line ) ) {

					const directive = line.replace( colorLineRegex, '' );
					const material = this.parseColorMetaDirective( new LineParser( directive ) );
					materials.push( material );

				}

			}

			this.setMaterials( materials );

		}
		load( url, onLoad, onProgress, onError ) {

			const fileLoader = new THREE.FileLoader( this.manager );
			fileLoader.setPath( this.path );
			fileLoader.setRequestHeader( this.requestHeader );
			fileLoader.setWithCredentials( this.withCredentials );
			fileLoader.load( url, text => {

				this.partsCache.parseModel( text, this.materialLibrary ).then( group => {

					this.applyMaterialsToMesh( group, MAIN_COLOUR_CODE, this.materialLibrary, true );
					this.computeConstructionSteps( group );
					group.userData.fileName = url;
					onLoad( group );

				} ).catch( onError );

			}, onProgress, onError );

		}
		parse( text, onLoad ) {

			this.partsCache.parseModel( text, this.materialLibrary ).then( group => {

				this.applyMaterialsToMesh( group, MAIN_COLOUR_CODE, this.materialLibrary, true );
				this.computeConstructionSteps( group );
				group.userData.fileName = '';
				onLoad( group );

			} );

		}
		setMaterials( materials ) {

			this.materialLibrary = {};
			this.materials = [];
			for ( let i = 0, l = materials.length; i < l; i ++ ) {

				this.addMaterial( materials[ i ] );

			}

			// Add default main triangle and line edge materials (used in pieces that can be colored with a main color)
			this.addMaterial( this.parseColorMetaDirective( new LineParser( 'Main_Colour CODE 16 VALUE #FF8080 EDGE #333333' ) ) );
			this.addMaterial( this.parseColorMetaDirective( new LineParser( 'Edge_Colour CODE 24 VALUE #A0A0A0 EDGE #333333' ) ) );
			return this;

		}
		setFileMap( fileMap ) {

			this.fileMap = fileMap;
			return this;

		}
		addMaterial( material ) {

			// Adds a material to the material library which is on top of the parse scopes stack. And also to the materials array

			const matLib = this.materialLibrary;
			if ( ! matLib[ material.userData.code ] ) {

				this.materials.push( material );
				matLib[ material.userData.code ] = material;

			}

			return this;

		}
		getMaterial( colorCode ) {

			if ( colorCode.startsWith( '0x2' ) ) {

				// Special 'direct' material value (RGB color)
				const color = colorCode.substring( 3 );
				return this.parseColorMetaDirective( new LineParser( 'Direct_Color_' + color + ' CODE -1 VALUE #' + color + ' EDGE #' + color + '' ) );

			}

			return this.materialLibrary[ colorCode ] || null;

		}

		// Applies the appropriate materials to a prebuilt hierarchy of geometry. Assumes that color codes are present
		// in the material array if they need to be filled in.
		applyMaterialsToMesh( group, parentColorCode, materialHierarchy, finalMaterialPass = false ) {

			// find any missing materials as indicated by a color code string and replace it with a material from the current material lib
			const loader = this;
			const parentIsPassthrough = parentColorCode === MAIN_COLOUR_CODE;
			group.traverse( c => {

				if ( c.isMesh || c.isLineSegments ) {

					if ( Array.isArray( c.material ) ) {

						for ( let i = 0, l = c.material.length; i < l; i ++ ) {

							if ( ! c.material[ i ].isMaterial ) {

								c.material[ i ] = getMaterial( c, c.material[ i ] );

							}

						}

					} else if ( ! c.material.isMaterial ) {

						c.material = getMaterial( c, c.material );

					}

				}

			} );

			// Returns the appropriate material for the object (line or face) given color code. If the code is "pass through"
			// (24 for lines, 16 for edges) then the pass through color code is used. If that is also pass through then it's
			// simply returned for the subsequent material application.
			function getMaterial( c, colorCode ) {

				// if our parent is a passthrough color code and we don't have the current material color available then
				// return early.
				if ( parentIsPassthrough && ! ( colorCode in materialHierarchy ) && ! finalMaterialPass ) {

					return colorCode;

				}

				const forEdge = c.isLineSegments || c.isConditionalLine;
				const isPassthrough = ! forEdge && colorCode === MAIN_COLOUR_CODE || forEdge && colorCode === MAIN_EDGE_COLOUR_CODE;
				if ( isPassthrough ) {

					colorCode = parentColorCode;

				}

				let material = null;
				if ( colorCode in materialHierarchy ) {

					material = materialHierarchy[ colorCode ];

				} else if ( finalMaterialPass ) {

					// see if we can get the final material from from the "getMaterial" function which will attempt to
					// parse the "direct" colors
					material = loader.getMaterial( colorCode );
					if ( material === null ) {

						// otherwise throw a warning if this is final opportunity to set the material
						console.warn( `LDrawLoader: Material properties for code ${colorCode} not available.` );

						// And return the 'missing color' material
						material = loader.missingColorMaterial;

					}

				} else {

					return colorCode;

				}

				if ( c.isLineSegments ) {

					material = material.userData.edgeMaterial;
					if ( c.isConditionalLine ) {

						material = material.userData.conditionalEdgeMaterial;

					}

				}

				return material;

			}

		}
		getMainMaterial() {

			return this.getMaterial( MAIN_COLOUR_CODE );

		}
		getMainEdgeMaterial() {

			const mat = this.getMaterial( MAIN_EDGE_COLOUR_CODE );
			return mat ? mat.userData.edgeMaterial : null;

		}
		parseColorMetaDirective( lineParser ) {

			// Parses a color definition and returns a THREE.Material

			let code = null;

			// Triangle and line colors
			let color = 0xFF00FF;
			let edgeColor = 0xFF00FF;

			// Transparency
			let alpha = 1;
			let isTransparent = false;
			// Self-illumination:
			let luminance = 0;
			let finishType = FINISH_TYPE_DEFAULT;
			let edgeMaterial = null;
			const name = lineParser.getToken();
			if ( ! name ) {

				throw new Error( 'LDrawLoader: Material name was expected after "!COLOUR tag' + lineParser.getLineNumberString() + '.' );

			}

			// Parse tag tokens and their parameters
			let token = null;
			while ( true ) {

				token = lineParser.getToken();
				if ( ! token ) {

					break;

				}

				if ( ! parseLuminance( token ) ) {

					switch ( token.toUpperCase() ) {

						case 'CODE':
							code = lineParser.getToken();
							break;
						case 'VALUE':
							color = lineParser.getToken();
							if ( color.startsWith( '0x' ) ) {

								color = '#' + color.substring( 2 );

							} else if ( ! color.startsWith( '#' ) ) {

								throw new Error( 'LDrawLoader: Invalid color while parsing material' + lineParser.getLineNumberString() + '.' );

							}

							break;
						case 'EDGE':
							edgeColor = lineParser.getToken();
							if ( edgeColor.startsWith( '0x' ) ) {

								edgeColor = '#' + edgeColor.substring( 2 );

							} else if ( ! edgeColor.startsWith( '#' ) ) {

								// Try to see if edge color is a color code
								edgeMaterial = this.getMaterial( edgeColor );
								if ( ! edgeMaterial ) {

									throw new Error( 'LDrawLoader: Invalid edge color while parsing material' + lineParser.getLineNumberString() + '.' );

								}

								// Get the edge material for this triangle material
								edgeMaterial = edgeMaterial.userData.edgeMaterial;

							}

							break;
						case 'ALPHA':
							alpha = parseInt( lineParser.getToken() );
							if ( isNaN( alpha ) ) {

								throw new Error( 'LDrawLoader: Invalid alpha value in material definition' + lineParser.getLineNumberString() + '.' );

							}

							alpha = Math.max( 0, Math.min( 1, alpha / 255 ) );
							if ( alpha < 1 ) {

								isTransparent = true;

							}

							break;
						case 'LUMINANCE':
							if ( ! parseLuminance( lineParser.getToken() ) ) {

								throw new Error( 'LDrawLoader: Invalid luminance value in material definition' + LineParser.getLineNumberString() + '.' );

							}

							break;
						case 'CHROME':
							finishType = FINISH_TYPE_CHROME;
							break;
						case 'PEARLESCENT':
							finishType = FINISH_TYPE_PEARLESCENT;
							break;
						case 'RUBBER':
							finishType = FINISH_TYPE_RUBBER;
							break;
						case 'MATTE_METALLIC':
							finishType = FINISH_TYPE_MATTE_METALLIC;
							break;
						case 'METAL':
							finishType = FINISH_TYPE_METAL;
							break;
						case 'MATERIAL':
							// Not implemented
							lineParser.setToEnd();
							break;
						default:
							throw new Error( 'LDrawLoader: Unknown token "' + token + '" while parsing material' + lineParser.getLineNumberString() + '.' );

					}

				}

			}

			let material = null;
			switch ( finishType ) {

				case FINISH_TYPE_DEFAULT:
					material = new THREE.MeshStandardMaterial( {
						color: color,
						roughness: 0.3,
						metalness: 0
					} );
					break;
				case FINISH_TYPE_PEARLESCENT:
					// Try to imitate pearlescency by making the surface glossy
					material = new THREE.MeshStandardMaterial( {
						color: color,
						roughness: 0.3,
						metalness: 0.25
					} );
					break;
				case FINISH_TYPE_CHROME:
					// Mirror finish surface
					material = new THREE.MeshStandardMaterial( {
						color: color,
						roughness: 0,
						metalness: 1
					} );
					break;
				case FINISH_TYPE_RUBBER:
					// Rubber finish
					material = new THREE.MeshStandardMaterial( {
						color: color,
						roughness: 0.9,
						metalness: 0
					} );
					break;
				case FINISH_TYPE_MATTE_METALLIC:
					// Brushed metal finish
					material = new THREE.MeshStandardMaterial( {
						color: color,
						roughness: 0.8,
						metalness: 0.4
					} );
					break;
				case FINISH_TYPE_METAL:
					// Average metal finish
					material = new THREE.MeshStandardMaterial( {
						color: color,
						roughness: 0.2,
						metalness: 0.85
					} );
					break;
				default:
					// Should not happen
					break;

			}

			material.transparent = isTransparent;
			material.premultipliedAlpha = true;
			material.opacity = alpha;
			material.depthWrite = ! isTransparent;
			material.color.convertSRGBToLinear();
			material.polygonOffset = true;
			material.polygonOffsetFactor = 1;
			if ( luminance !== 0 ) {

				material.emissive.set( material.color ).multiplyScalar( luminance );

			}

			if ( ! edgeMaterial ) {

				// This is the material used for edges
				edgeMaterial = new THREE.LineBasicMaterial( {
					color: edgeColor,
					transparent: isTransparent,
					opacity: alpha,
					depthWrite: ! isTransparent
				} );
				edgeMaterial.userData.code = code;
				edgeMaterial.name = name + ' - Edge';
				edgeMaterial.color.convertSRGBToLinear();

				// This is the material used for conditional edges
				edgeMaterial.userData.conditionalEdgeMaterial = new LDrawConditionalLineMaterial( {
					fog: true,
					transparent: isTransparent,
					depthWrite: ! isTransparent,
					color: edgeColor,
					opacity: alpha
				} );
				edgeMaterial.userData.conditionalEdgeMaterial.color.convertSRGBToLinear();
				edgeMaterial.userData.conditionalEdgeMaterial.userData.code = code;
				edgeMaterial.userData.conditionalEdgeMaterial.name = name + ' - Conditional Edge';

			}

			material.userData.code = code;
			material.name = name;
			material.userData.edgeMaterial = edgeMaterial;
			this.addMaterial( material );
			return material;
			function parseLuminance( token ) {

				// Returns success

				let lum;
				if ( token.startsWith( 'LUMINANCE' ) ) {

					lum = parseInt( token.substring( 9 ) );

				} else {

					lum = parseInt( token );

				}

				if ( isNaN( lum ) ) {

					return false;

				}

				luminance = Math.max( 0, Math.min( 1, lum / 255 ) );
				return true;

			}

		}
		computeConstructionSteps( model ) {

			// Sets userdata.constructionStep number in THREE.Group objects and userData.numConstructionSteps number in the root THREE.Group object.

			let stepNumber = 0;
			model.traverse( c => {

				if ( c.isGroup ) {

					if ( c.userData.startingConstructionStep ) {

						stepNumber ++;

					}

					c.userData.constructionStep = stepNumber;

				}

			} );
			model.userData.numConstructionSteps = stepNumber + 1;

		}

	}

	THREE.LDrawLoader = LDrawLoader;

} )();