three.js/examples/jsm/loaders/obj2/worker/parallel/OBJLoader2Parser.js

/**
 * @author Kai Salmen / https://kaisalmen.de
 * Development repository: https://github.com/kaisalmen/WWOBJLoader
 */

/**
 * Parse OBJ data either from ArrayBuffer or string
 */
const OBJLoader2Parser = function () {

	let scope = this;
	this.callbacks = {
		onProgress: function ( text ) {
			scope._onProgress( text )
		},
		onAssetAvailable: function ( payload ) {
			scope._onAssetAvailable( payload )
		},
		onError: function ( errorMessage ) {
			scope._onError( errorMessage )
		}
	};
	this.contentRef = null;
	this.legacyMode = false;

	this.materials = {};
	this.materialPerSmoothingGroup = false;
	this.useOAsMesh = false;
	this.useIndices = false;
	this.disregardNormals = false;

	this.vertices = [];
	this.colors = [];
	this.normals = [];
	this.uvs = [];

	this.rawMesh = {
		objectName: '',
		groupName: '',
		activeMtlName: '',
		mtllibName: '',

		// reset with new mesh
		faceType: - 1,
		subGroups: [],
		subGroupInUse: null,
		smoothingGroup: {
			splitMaterials: false,
			normalized: - 1,
			real: - 1
		},
		counts: {
			doubleIndicesCount: 0,
			faceCount: 0,
			mtlCount: 0,
			smoothingGroupCount: 0
		}
	};

	this.inputObjectCount = 1;
	this.outputObjectCount = 1;
	this.globalCounts = {
		vertices: 0,
		faces: 0,
		doubleIndicesCount: 0,
		lineByte: 0,
		currentByte: 0,
		totalBytes: 0
	};

	this.logging = {
		enabled: true,
		debug: false
	};

};

OBJLoader2Parser.prototype = {

	constructor: OBJLoader2Parser,

	_resetRawMesh: function () {

		// faces are stored according combined index of group, material and smoothingGroup (0 or not)
		this.rawMesh.subGroups = [];
		this.rawMesh.subGroupInUse = null;
		this.rawMesh.smoothingGroup.normalized = - 1;
		this.rawMesh.smoothingGroup.real = - 1;

		// this default index is required as it is possible to define faces without 'g' or 'usemtl'
		this._pushSmoothingGroup( 1 );

		this.rawMesh.counts.doubleIndicesCount = 0;
		this.rawMesh.counts.faceCount = 0;
		this.rawMesh.counts.mtlCount = 0;
		this.rawMesh.counts.smoothingGroupCount = 0;

	},

	/**
	 * Tells whether a material shall be created per smoothing group.
	 *
	 * @param {boolean} materialPerSmoothingGroup=false
	 * @return {OBJLoader2Parser}
	 */
	setMaterialPerSmoothingGroup: function ( materialPerSmoothingGroup ) {

		this.materialPerSmoothingGroup = materialPerSmoothingGroup === true;
		return this;

	},

	/**
	 * Usually 'o' is meta-information and does not result in creation of new meshes, but mesh creation on occurrence of "o" can be enforced.
	 *
	 * @param {boolean} useOAsMesh=false
	 * @return {OBJLoader2Parser}
	 */
	setUseOAsMesh: function ( useOAsMesh ) {

		this.useOAsMesh = useOAsMesh === true;
		return this;

	},

	/**
	 * Instructs loaders to create indexed {@link BufferGeometry}.
	 *
	 * @param {boolean} useIndices=false
	 * @return {OBJLoader2Parser}
	 */
	setUseIndices: function ( useIndices ) {

		this.useIndices = useIndices === true;
		return this;

	},

	/**
	 * Tells whether normals should be completely disregarded and regenerated.
	 *
	 * @param {boolean} disregardNormals=false
	 * @return {OBJLoader2Parser}
	 */
	setDisregardNormals: function ( disregardNormals ) {

		this.disregardNormals = disregardNormals === true;
		return this;

	},

	_setMaterials: function ( materials ) {

		if ( materials === undefined || materials === null ) return;

		for ( let materialName in materials ) {

			if ( materials.hasOwnProperty( materialName ) ) {

				this.materials[ materialName ] = materials[ materialName ];

			}

		}

	},

	/**
	 * Register a function that is called once an asset (mesh/material) becomes available.
	 *
	 * @param onAssetAvailable
	 * @return {OBJLoader2Parser}
	 */
	setCallbackOnAssetAvailable: function ( onAssetAvailable ) {

		if ( onAssetAvailable !== null && onAssetAvailable !== undefined && onAssetAvailable instanceof Function ) {

			this.callbacks.onAssetAvailable = onAssetAvailable;

		}
		return this;

	},

	/**
	 * Register a function that is used to report overall processing progress.
	 *
	 * @param {Function} onProgress
	 * @return {OBJLoader2Parser}
	 */
	setCallbackOnProgress: function ( onProgress ) {

		if ( onProgress !== null && onProgress !== undefined && onProgress instanceof Function ) {

			this.callbacks.onProgress = onProgress;

		}
		return this;

	},

	/**
	 * Register an error handler function that is called if errors occur. It can decide to just log or to throw an exception.
	 *
	 * @param {Function} onError
	 * @return {OBJLoader2Parser}
	 */
	setCallbackOnError: function ( onError ) {

		if ( onError !== null && onError !== undefined && onError instanceof Function ) {

			this.callbacks.onError = onError;

		}
		return this;

	},

	/**
	 * Announce parse progress feedback which is logged to the console.
	 * @private
	 *
	 * @param {string} text Textual description of the event
	 */
	_onProgress: function ( text ) {

		let message = text ? text : '';
		if ( this.logging.enabled && this.logging.debug ) {

			console.log( message );

		}

	},

	/**
	 * Announce error feedback which is logged as error message.
	 * @private
	 *
	 * @param {String} errorMessage The event containing the error
	 */
	_onError: function ( errorMessage ) {

		if ( this.logging.enabled && this.logging.debug ) {

			console.error( errorMessage );

		}

	},

	_onAssetAvailable: function ( payload ) {

		let errorMessage = 'OBJLoader2Parser does not provide implementation for onAssetAvailable. Aborting...';
		this.callbacks.onError( errorMessage );
		throw errorMessage;

	},

	/**
	 * Enable or disable logging in general (except warn and error), plus enable or disable debug logging.
	 *
	 * @param {boolean} enabled True or false.
	 * @param {boolean} debug True or false.
	 *
	 * @return {OBJLoader2Parser}
	 */
	setLogging: function ( enabled, debug ) {

		this.logging.enabled = enabled === true;
		this.logging.debug = debug === true;
		return this;

	},

	_configure: function () {

		this._pushSmoothingGroup( 1 );
		if ( this.logging.enabled ) {

			let matKeys = Object.keys( this.materials );
			let matNames = ( matKeys.length > 0 ) ? '\n\tmaterialNames:\n\t\t- ' + matKeys.join( '\n\t\t- ' ) : '\n\tmaterialNames: None';
			let printedConfig = 'OBJLoader.Parser configuration:'
				+ matNames
				+ '\n\tmaterialPerSmoothingGroup: ' + this.materialPerSmoothingGroup
				+ '\n\tuseOAsMesh: ' + this.useOAsMesh
				+ '\n\tuseIndices: ' + this.useIndices
				+ '\n\tdisregardNormals: ' + this.disregardNormals;
			printedConfig += '\n\tcallbacks.onProgress: ' + this.callbacks.onProgress.name;
			printedConfig += '\n\tcallbacks.onAssetAvailable: ' + this.callbacks.onAssetAvailable.name;
			printedConfig += '\n\tcallbacks.onError: ' + this.callbacks.onError.name;
			console.info( printedConfig );

		}

	},

	/**
	 * Parse the provided arraybuffer
	 *
	 * @param {Uint8Array} arrayBuffer OBJ data as Uint8Array
	 */
	execute: function ( arrayBuffer ) {

		if ( this.logging.enabled ) console.time( 'OBJLoader2Parser.execute' );
		this._configure();

		let arrayBufferView = new Uint8Array( arrayBuffer );
		this.contentRef = arrayBufferView;
		let length = arrayBufferView.byteLength;
		this.globalCounts.totalBytes = length;
		let buffer = new Array( 128 );

		for ( let code, word = '', bufferPointer = 0, slashesCount = 0, i = 0; i < length; i ++ ) {

			code = arrayBufferView[ i ];
			switch ( code ) {

				// space
				case 32:
					if ( word.length > 0 ) buffer[ bufferPointer ++ ] = word;
					word = '';
					break;
				// slash
				case 47:
					if ( word.length > 0 ) buffer[ bufferPointer ++ ] = word;
					slashesCount ++;
					word = '';
					break;

				// LF
				case 10:
					if ( word.length > 0 ) buffer[ bufferPointer ++ ] = word;
					word = '';
					this.globalCounts.lineByte = this.globalCounts.currentByte;
					this.globalCounts.currentByte = i;
					this._processLine( buffer, bufferPointer, slashesCount );
					bufferPointer = 0;
					slashesCount = 0;
					break;

				// CR
				case 13:
					break;

				default:
					word += String.fromCharCode( code );
					break;

			}

		}
		this._finalizeParsing();
		if ( this.logging.enabled ) console.timeEnd( 'OBJLoader2Parser.execute' );

	},

	/**
	 * Parse the provided text
	 *
	 * @param {string} text OBJ data as string
	 */
	executeLegacy: function ( text ) {

		if ( this.logging.enabled ) console.time( 'OBJLoader2Parser.executeLegacy' );
		this._configure();
		this.legacyMode = true;
		this.contentRef = text;
		let length = text.length;
		this.globalCounts.totalBytes = length;
		let buffer = new Array( 128 );

		for ( let char, word = '', bufferPointer = 0, slashesCount = 0, i = 0; i < length; i ++ ) {

			char = text[ i ];
			switch ( char ) {

				case ' ':
					if ( word.length > 0 ) buffer[ bufferPointer ++ ] = word;
					word = '';
					break;

				case '/':
					if ( word.length > 0 ) buffer[ bufferPointer ++ ] = word;
					slashesCount ++;
					word = '';
					break;

				case '\n':
					if ( word.length > 0 ) buffer[ bufferPointer ++ ] = word;
					word = '';
					this.globalCounts.lineByte = this.globalCounts.currentByte;
					this.globalCounts.currentByte = i;
					this._processLine( buffer, bufferPointer, slashesCount );
					bufferPointer = 0;
					slashesCount = 0;
					break;

				case '\r':
					break;

				default:
					word += char;

			}

		}
		this._finalizeParsing();
		if ( this.logging.enabled ) console.timeEnd( 'OBJLoader2Parser.executeLegacy' );

	},

	_processLine: function ( buffer, bufferPointer, slashesCount ) {

		if ( bufferPointer < 1 ) return;

		let reconstructString = function ( content, legacyMode, start, stop ) {

			let line = '';
			if ( stop > start ) {

				let i;
				if ( legacyMode ) {

					for ( i = start; i < stop; i ++ ) line += content[ i ];

				} else {


					for ( i = start; i < stop; i ++ ) line += String.fromCharCode( content[ i ] );

				}
				line = line.trim();

			}
			return line;

		};

		let bufferLength, length, i, lineDesignation;
		lineDesignation = buffer[ 0 ];
		switch ( lineDesignation ) {

			case 'v':
				this.vertices.push( parseFloat( buffer[ 1 ] ) );
				this.vertices.push( parseFloat( buffer[ 2 ] ) );
				this.vertices.push( parseFloat( buffer[ 3 ] ) );
				if ( bufferPointer > 4 ) {

					this.colors.push( parseFloat( buffer[ 4 ] ) );
					this.colors.push( parseFloat( buffer[ 5 ] ) );
					this.colors.push( parseFloat( buffer[ 6 ] ) );

				}
				break;

			case 'vt':
				this.uvs.push( parseFloat( buffer[ 1 ] ) );
				this.uvs.push( parseFloat( buffer[ 2 ] ) );
				break;

			case 'vn':
				this.normals.push( parseFloat( buffer[ 1 ] ) );
				this.normals.push( parseFloat( buffer[ 2 ] ) );
				this.normals.push( parseFloat( buffer[ 3 ] ) );
				break;

			case 'f':
				bufferLength = bufferPointer - 1;

				// "f vertex ..."
				if ( slashesCount === 0 ) {

					this._checkFaceType( 0 );
					for ( i = 2, length = bufferLength; i < length; i ++ ) {

						this._buildFace( buffer[ 1 ] );
						this._buildFace( buffer[ i ] );
						this._buildFace( buffer[ i + 1 ] );

					}

					// "f vertex/uv ..."

				} else if ( bufferLength === slashesCount * 2 ) {

					this._checkFaceType( 1 );
					for ( i = 3, length = bufferLength - 2; i < length; i += 2 ) {

						this._buildFace( buffer[ 1 ], buffer[ 2 ] );
						this._buildFace( buffer[ i ], buffer[ i + 1 ] );
						this._buildFace( buffer[ i + 2 ], buffer[ i + 3 ] );

					}

					// "f vertex/uv/normal ..."

				} else if ( bufferLength * 2 === slashesCount * 3 ) {

					this._checkFaceType( 2 );
					for ( i = 4, length = bufferLength - 3; i < length; i += 3 ) {

						this._buildFace( buffer[ 1 ], buffer[ 2 ], buffer[ 3 ] );
						this._buildFace( buffer[ i ], buffer[ i + 1 ], buffer[ i + 2 ] );
						this._buildFace( buffer[ i + 3 ], buffer[ i + 4 ], buffer[ i + 5 ] );

					}

					// "f vertex//normal ..."

				} else {

					this._checkFaceType( 3 );
					for ( i = 3, length = bufferLength - 2; i < length; i += 2 ) {

						this._buildFace( buffer[ 1 ], undefined, buffer[ 2 ] );
						this._buildFace( buffer[ i ], undefined, buffer[ i + 1 ] );
						this._buildFace( buffer[ i + 2 ], undefined, buffer[ i + 3 ] );

					}

				}
				break;

			case 'l':
			case 'p':
				bufferLength = bufferPointer - 1;
				if ( bufferLength === slashesCount * 2 ) {

					this._checkFaceType( 4 );
					for ( i = 1, length = bufferLength + 1; i < length; i += 2 ) this._buildFace( buffer[ i ], buffer[ i + 1 ] );

				} else {

					this._checkFaceType( ( lineDesignation === 'l' ) ? 5 : 6 );
					for ( i = 1, length = bufferLength + 1; i < length; i ++ ) this._buildFace( buffer[ i ] );

				}
				break;

			case 's':
				this._pushSmoothingGroup( buffer[ 1 ] );
				break;

			case 'g':
				// 'g' leads to creation of mesh if valid data (faces declaration was done before), otherwise only groupName gets set
				this._processCompletedMesh();
				this.rawMesh.groupName = reconstructString( this.contentRef, this.legacyMode, this.globalCounts.lineByte + 2, this.globalCounts.currentByte );
				break;

			case 'o':
				// 'o' is meta-information and usually does not result in creation of new meshes, but can be enforced with "useOAsMesh"
				if ( this.useOAsMesh ) this._processCompletedMesh();
				this.rawMesh.objectName = reconstructString( this.contentRef, this.legacyMode, this.globalCounts.lineByte + 2, this.globalCounts.currentByte );
				break;

			case 'mtllib':
				this.rawMesh.mtllibName = reconstructString( this.contentRef, this.legacyMode, this.globalCounts.lineByte + 7, this.globalCounts.currentByte );
				break;

			case 'usemtl':
				let mtlName = reconstructString( this.contentRef, this.legacyMode, this.globalCounts.lineByte + 7, this.globalCounts.currentByte );
				if ( mtlName !== '' && this.rawMesh.activeMtlName !== mtlName ) {

					this.rawMesh.activeMtlName = mtlName;
					this.rawMesh.counts.mtlCount ++;
					this._checkSubGroup();

				}
				break;

			default:
				break;

		}

	},

	_pushSmoothingGroup: function ( smoothingGroup ) {

		let smoothingGroupInt = parseInt( smoothingGroup );
		if ( isNaN( smoothingGroupInt ) ) {

			smoothingGroupInt = smoothingGroup === "off" ? 0 : 1;

		}

		let smoothCheck = this.rawMesh.smoothingGroup.normalized;
		this.rawMesh.smoothingGroup.normalized = this.rawMesh.smoothingGroup.splitMaterials ? smoothingGroupInt : ( smoothingGroupInt === 0 ) ? 0 : 1;
		this.rawMesh.smoothingGroup.real = smoothingGroupInt;

		if ( smoothCheck !== smoothingGroupInt ) {

			this.rawMesh.counts.smoothingGroupCount ++;
			this._checkSubGroup();

		}

	},

	/**
	 * Expanded faceTypes include all four face types, both line types and the point type
	 * faceType = 0: "f vertex ..."
	 * faceType = 1: "f vertex/uv ..."
	 * faceType = 2: "f vertex/uv/normal ..."
	 * faceType = 3: "f vertex//normal ..."
	 * faceType = 4: "l vertex/uv ..." or "l vertex ..."
	 * faceType = 5: "l vertex ..."
	 * faceType = 6: "p vertex ..."
	 */
	_checkFaceType: function ( faceType ) {

		if ( this.rawMesh.faceType !== faceType ) {

			this._processCompletedMesh();
			this.rawMesh.faceType = faceType;
			this._checkSubGroup();

		}

	},

	_checkSubGroup: function () {

		let index = this.rawMesh.activeMtlName + '|' + this.rawMesh.smoothingGroup.normalized;
		this.rawMesh.subGroupInUse = this.rawMesh.subGroups[ index ];

		if ( this.rawMesh.subGroupInUse === undefined || this.rawMesh.subGroupInUse === null ) {

			this.rawMesh.subGroupInUse = {
				index: index,
				objectName: this.rawMesh.objectName,
				groupName: this.rawMesh.groupName,
				materialName: this.rawMesh.activeMtlName,
				smoothingGroup: this.rawMesh.smoothingGroup.normalized,
				vertices: [],
				indexMappingsCount: 0,
				indexMappings: [],
				indices: [],
				colors: [],
				uvs: [],
				normals: []
			};
			this.rawMesh.subGroups[ index ] = this.rawMesh.subGroupInUse;

		}

	},

	_buildFace: function ( faceIndexV, faceIndexU, faceIndexN ) {

		let subGroupInUse = this.rawMesh.subGroupInUse;
		let scope = this;
		let updateSubGroupInUse = function () {

			let faceIndexVi = parseInt( faceIndexV );
			let indexPointerV = 3 * ( faceIndexVi > 0 ? faceIndexVi - 1 : faceIndexVi + scope.vertices.length / 3 );
			let indexPointerC = scope.colors.length > 0 ? indexPointerV : null;

			let vertices = subGroupInUse.vertices;
			vertices.push( scope.vertices[ indexPointerV ++ ] );
			vertices.push( scope.vertices[ indexPointerV ++ ] );
			vertices.push( scope.vertices[ indexPointerV ] );

			if ( indexPointerC !== null ) {

				let colors = subGroupInUse.colors;
				colors.push( scope.colors[ indexPointerC ++ ] );
				colors.push( scope.colors[ indexPointerC ++ ] );
				colors.push( scope.colors[ indexPointerC ] );

			}
			if ( faceIndexU ) {

				let faceIndexUi = parseInt( faceIndexU );
				let indexPointerU = 2 * ( faceIndexUi > 0 ? faceIndexUi - 1 : faceIndexUi + scope.uvs.length / 2 );
				let uvs = subGroupInUse.uvs;
				uvs.push( scope.uvs[ indexPointerU ++ ] );
				uvs.push( scope.uvs[ indexPointerU ] );

			}
			if ( faceIndexN && ! scope.disregardNormals ) {

				let faceIndexNi = parseInt( faceIndexN );
				let indexPointerN = 3 * ( faceIndexNi > 0 ? faceIndexNi - 1 : faceIndexNi + scope.normals.length / 3 );
				let normals = subGroupInUse.normals;
				normals.push( scope.normals[ indexPointerN ++ ] );
				normals.push( scope.normals[ indexPointerN ++ ] );
				normals.push( scope.normals[ indexPointerN ] );

			}

		};

		if ( this.useIndices ) {

			if ( this.disregardNormals ) faceIndexN = undefined;
			let mappingName = faceIndexV + ( faceIndexU ? '_' + faceIndexU : '_n' ) + ( faceIndexN ? '_' + faceIndexN : '_n' );
			let indicesPointer = subGroupInUse.indexMappings[ mappingName ];
			if ( indicesPointer === undefined || indicesPointer === null ) {

				indicesPointer = this.rawMesh.subGroupInUse.vertices.length / 3;
				updateSubGroupInUse();
				subGroupInUse.indexMappings[ mappingName ] = indicesPointer;
				subGroupInUse.indexMappingsCount ++;

			} else {

				this.rawMesh.counts.doubleIndicesCount ++;

			}
			subGroupInUse.indices.push( indicesPointer );

		} else {

			updateSubGroupInUse();

		}
		this.rawMesh.counts.faceCount ++;

	},

	_createRawMeshReport: function ( inputObjectCount ) {

		return 'Input Object number: ' + inputObjectCount +
			'\n\tObject name: ' + this.rawMesh.objectName +
			'\n\tGroup name: ' + this.rawMesh.groupName +
			'\n\tMtllib name: ' + this.rawMesh.mtllibName +
			'\n\tVertex count: ' + this.vertices.length / 3 +
			'\n\tNormal count: ' + this.normals.length / 3 +
			'\n\tUV count: ' + this.uvs.length / 2 +
			'\n\tSmoothingGroup count: ' + this.rawMesh.counts.smoothingGroupCount +
			'\n\tMaterial count: ' + this.rawMesh.counts.mtlCount +
			'\n\tReal MeshOutputGroup count: ' + this.rawMesh.subGroups.length;

	},

	/**
	 * Clear any empty subGroup and calculate absolute vertex, normal and uv counts
	 */
	_finalizeRawMesh: function () {

		let meshOutputGroupTemp = [];
		let meshOutputGroup;
		let absoluteVertexCount = 0;
		let absoluteIndexMappingsCount = 0;
		let absoluteIndexCount = 0;
		let absoluteColorCount = 0;
		let absoluteNormalCount = 0;
		let absoluteUvCount = 0;
		let indices;
		for ( let name in this.rawMesh.subGroups ) {

			meshOutputGroup = this.rawMesh.subGroups[ name ];
			if ( meshOutputGroup.vertices.length > 0 ) {

				indices = meshOutputGroup.indices;
				if ( indices.length > 0 && absoluteIndexMappingsCount > 0 ) {

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

						indices[ i ] = indices[ i ] + absoluteIndexMappingsCount;

					}

				}
				meshOutputGroupTemp.push( meshOutputGroup );
				absoluteVertexCount += meshOutputGroup.vertices.length;
				absoluteIndexMappingsCount += meshOutputGroup.indexMappingsCount;
				absoluteIndexCount += meshOutputGroup.indices.length;
				absoluteColorCount += meshOutputGroup.colors.length;
				absoluteUvCount += meshOutputGroup.uvs.length;
				absoluteNormalCount += meshOutputGroup.normals.length;

			}

		}

		// do not continue if no result
		let result = null;
		if ( meshOutputGroupTemp.length > 0 ) {

			result = {
				name: this.rawMesh.groupName !== '' ? this.rawMesh.groupName : this.rawMesh.objectName,
				subGroups: meshOutputGroupTemp,
				absoluteVertexCount: absoluteVertexCount,
				absoluteIndexCount: absoluteIndexCount,
				absoluteColorCount: absoluteColorCount,
				absoluteNormalCount: absoluteNormalCount,
				absoluteUvCount: absoluteUvCount,
				faceCount: this.rawMesh.counts.faceCount,
				doubleIndicesCount: this.rawMesh.counts.doubleIndicesCount
			};

		}
		return result;

	},

	_processCompletedMesh: function () {

		let result = this._finalizeRawMesh();
		let haveMesh = result !== null;
		if ( haveMesh ) {

			if ( this.colors.length > 0 && this.colors.length !== this.vertices.length ) {

				this.callbacks.onError( 'Vertex Colors were detected, but vertex count and color count do not match!' );

			}
			if ( this.logging.enabled && this.logging.debug ) console.debug( this._createRawMeshReport( this.inputObjectCount ) );
			this.inputObjectCount ++;

			this._buildMesh( result );
			let progressBytesPercent = this.globalCounts.currentByte / this.globalCounts.totalBytes;
			this._onProgress( 'Completed [o: ' + this.rawMesh.objectName + ' g:' + this.rawMesh.groupName + '' +
				'] Total progress: ' + ( progressBytesPercent * 100 ).toFixed( 2 ) + '%' );
			this._resetRawMesh();

		}
		return haveMesh;

	},

	/**
	 * SubGroups are transformed to too intermediate format that is forwarded to the MeshReceiver.
	 * It is ensured that SubGroups only contain objects with vertices (no need to check).
	 *
	 * @param result
	 */
	_buildMesh: function ( result ) {

		let meshOutputGroups = result.subGroups;

		let vertexFA = new Float32Array( result.absoluteVertexCount );
		this.globalCounts.vertices += result.absoluteVertexCount / 3;
		this.globalCounts.faces += result.faceCount;
		this.globalCounts.doubleIndicesCount += result.doubleIndicesCount;
		let indexUA = ( result.absoluteIndexCount > 0 ) ? new Uint32Array( result.absoluteIndexCount ) : null;
		let colorFA = ( result.absoluteColorCount > 0 ) ? new Float32Array( result.absoluteColorCount ) : null;
		let normalFA = ( result.absoluteNormalCount > 0 ) ? new Float32Array( result.absoluteNormalCount ) : null;
		let uvFA = ( result.absoluteUvCount > 0 ) ? new Float32Array( result.absoluteUvCount ) : null;
		let haveVertexColors = colorFA !== null;

		let meshOutputGroup;
		let materialNames = [];

		let createMultiMaterial = ( meshOutputGroups.length > 1 );
		let materialIndex = 0;
		let materialIndexMapping = [];
		let selectedMaterialIndex;
		let materialGroup;
		let materialGroups = [];

		let vertexFAOffset = 0;
		let indexUAOffset = 0;
		let colorFAOffset = 0;
		let normalFAOffset = 0;
		let uvFAOffset = 0;
		let materialGroupOffset = 0;
		let materialGroupLength = 0;

		let materialOrg, material, materialName, materialNameOrg;
		// only one specific face type
		for ( let oodIndex in meshOutputGroups ) {

			if ( ! meshOutputGroups.hasOwnProperty( oodIndex ) ) continue;
			meshOutputGroup = meshOutputGroups[ oodIndex ];

			materialNameOrg = meshOutputGroup.materialName;
			if ( this.rawMesh.faceType < 4 ) {

				materialName = materialNameOrg + ( haveVertexColors ? '_vertexColor' : '' ) + ( meshOutputGroup.smoothingGroup === 0 ? '_flat' : '' );


			} else {

				materialName = this.rawMesh.faceType === 6 ? 'defaultPointMaterial' : 'defaultLineMaterial';

			}
			materialOrg = this.materials[ materialNameOrg ];
			material = this.materials[ materialName ];

			// both original and derived names do not lead to an existing material => need to use a default material
			if ( ( materialOrg === undefined || materialOrg === null ) && ( material === undefined || material === null ) ) {

				materialName = haveVertexColors ? 'defaultVertexColorMaterial' : 'defaultMaterial';
				material = this.materials[ materialName ];
				if ( this.logging.enabled ) {

					console.info( 'object_group "' + meshOutputGroup.objectName + '_' +
						meshOutputGroup.groupName + '" was defined with unresolvable material "' +
						materialNameOrg + '"! Assigning "' + materialName + '".' );

				}

			}
			if ( material === undefined || material === null ) {

				let materialCloneInstructions = {
					materialNameOrg: materialNameOrg,
					materialName: materialName,
					materialProperties: {
						vertexColors: haveVertexColors ? 2 : 0,
						flatShading: meshOutputGroup.smoothingGroup === 0
					}
				};
				let payload = {
					cmd: 'assetAvailable',
					type: 'material',
					materials: {
						materialCloneInstructions: materialCloneInstructions
					}
				};
				this.callbacks.onAssetAvailable( payload );

				// only set materials if they don't exist, yet
				let matCheck = this.materials[ materialName ];
				if ( matCheck === undefined || matCheck === null ) {

					this.materials[ materialName ] = materialCloneInstructions;

				}

			}

			if ( createMultiMaterial ) {

				// re-use material if already used before. Reduces materials array size and eliminates duplicates
				selectedMaterialIndex = materialIndexMapping[ materialName ];
				if ( ! selectedMaterialIndex ) {

					selectedMaterialIndex = materialIndex;
					materialIndexMapping[ materialName ] = materialIndex;
					materialNames.push( materialName );
					materialIndex ++;

				}
				materialGroupLength = this.useIndices ? meshOutputGroup.indices.length : meshOutputGroup.vertices.length / 3;
				materialGroup = {
					start: materialGroupOffset,
					count: materialGroupLength,
					index: selectedMaterialIndex
				};
				materialGroups.push( materialGroup );
				materialGroupOffset += materialGroupLength;

			} else {

				materialNames.push( materialName );

			}

			vertexFA.set( meshOutputGroup.vertices, vertexFAOffset );
			vertexFAOffset += meshOutputGroup.vertices.length;

			if ( indexUA ) {

				indexUA.set( meshOutputGroup.indices, indexUAOffset );
				indexUAOffset += meshOutputGroup.indices.length;

			}

			if ( colorFA ) {

				colorFA.set( meshOutputGroup.colors, colorFAOffset );
				colorFAOffset += meshOutputGroup.colors.length;

			}

			if ( normalFA ) {

				normalFA.set( meshOutputGroup.normals, normalFAOffset );
				normalFAOffset += meshOutputGroup.normals.length;

			}
			if ( uvFA ) {

				uvFA.set( meshOutputGroup.uvs, uvFAOffset );
				uvFAOffset += meshOutputGroup.uvs.length;

			}

			if ( this.logging.enabled && this.logging.debug ) {

				let materialIndexLine = ( selectedMaterialIndex === undefined || selectedMaterialIndex === null ) ? '' : '\n\t\tmaterialIndex: ' + selectedMaterialIndex;
				let createdReport = '\tOutput Object no.: ' + this.outputObjectCount +
					'\n\t\tgroupName: ' + meshOutputGroup.groupName +
					'\n\t\tIndex: ' + meshOutputGroup.index +
					'\n\t\tfaceType: ' + this.rawMesh.faceType +
					'\n\t\tmaterialName: ' + meshOutputGroup.materialName +
					'\n\t\tsmoothingGroup: ' + meshOutputGroup.smoothingGroup +
					materialIndexLine +
					'\n\t\tobjectName: ' + meshOutputGroup.objectName +
					'\n\t\t#vertices: ' + meshOutputGroup.vertices.length / 3 +
					'\n\t\t#indices: ' + meshOutputGroup.indices.length +
					'\n\t\t#colors: ' + meshOutputGroup.colors.length / 3 +
					'\n\t\t#uvs: ' + meshOutputGroup.uvs.length / 2 +
					'\n\t\t#normals: ' + meshOutputGroup.normals.length / 3;
				console.debug( createdReport );

			}

		}
		this.outputObjectCount ++;
		this.callbacks.onAssetAvailable(
			{
				cmd: 'assetAvailable',
				type: 'mesh',
				progress: {
					numericalValue: this.globalCounts.currentByte / this.globalCounts.totalBytes
				},
				params: {
					meshName: result.name
				},
				materials: {
					multiMaterial: createMultiMaterial,
					materialNames: materialNames,
					materialGroups: materialGroups
				},
				buffers: {
					vertices: vertexFA,
					indices: indexUA,
					colors: colorFA,
					normals: normalFA,
					uvs: uvFA
				},
				// 0: mesh, 1: line, 2: point
				geometryType: this.rawMesh.faceType < 4 ? 0 : ( this.rawMesh.faceType === 6 ) ? 2 : 1
			},
			[ vertexFA.buffer ],
			indexUA !== null ? [ indexUA.buffer ] : null,
			colorFA !== null ? [ colorFA.buffer ] : null,
			normalFA !== null ? [ normalFA.buffer ] : null,
			uvFA !== null ? [ uvFA.buffer ] : null
		);

	},

	_finalizeParsing: function () {

		if ( this.logging.enabled ) console.info( 'Global output object count: ' + this.outputObjectCount );
		if ( this._processCompletedMesh() && this.logging.enabled ) {

			let parserFinalReport = 'Overall counts: ' +
				'\n\tVertices: ' + this.globalCounts.vertices +
				'\n\tFaces: ' + this.globalCounts.faces +
				'\n\tMultiple definitions: ' + this.globalCounts.doubleIndicesCount;
			console.info( parserFinalReport );

		}

	}
};

export { OBJLoader2Parser };