three.js/examples/js/loaders/OBJLoader.js

/**
 * @author mrdoob / http://mrdoob.com/
 */

THREE.OBJLoader = function ( manager ) {

	this.manager = ( manager !== undefined ) ? manager : THREE.DefaultLoadingManager;

};

THREE.OBJLoader.prototype = {

	constructor: THREE.OBJLoader,

	load: function ( url, onLoad, onProgress, onError ) {

		var scope = this;

		var loader = new THREE.XHRLoader( scope.manager );
		loader.setCrossOrigin( this.crossOrigin );
		loader.load( url, function ( text ) {

			onLoad( scope.parse( text ) );

		} );

	},

	parse: function ( text ) {

		function vector( x, y, z ) {

			return new THREE.Vector3( x, y, z );

		}

		function uv( u, v ) {

			return new THREE.Vector2( u, v );

		}

		function face3( a, b, c, normals ) {

			return new THREE.Face3( a, b, c, normals );

		}
    
		var object = new THREE.Object3D();
		var geometry, material, mesh;
    var face_offset = 0;
    
    function add_face( a, b, c, normals_inds ) {
      if ( normals_inds === undefined ) {
        geometry.faces.push( face3(
  				parseInt( a ) - (face_offset + 1),
  				parseInt( b ) - (face_offset + 1),
  				parseInt( c ) - (face_offset + 1)
  			) );
      } else {
        geometry.faces.push( face3(
  				parseInt( a ) - (face_offset + 1),
  				parseInt( b ) - (face_offset + 1),
  				parseInt( c ) - (face_offset + 1),
  				[
  					normals[ parseInt( normals_inds[ 0 ] ) - 1 ].clone(),
  					normals[ parseInt( normals_inds[ 1 ] ) - 1 ].clone(),
  					normals[ parseInt( normals_inds[ 2 ] ) - 1 ].clone()
  				]
  			) );
      }
    }
    
    function add_uvs( a, b, c ) {
			geometry.faceVertexUvs[ 0 ].push( [
				uvs[ parseInt( a ) - 1 ].clone(),
				uvs[ parseInt( b ) - 1 ].clone(),
				uvs[ parseInt( c ) - 1 ].clone()
			] );
    }
    
    function handle_face_line(faces, uvs, normals_inds) {

  		if ( faces[ 3 ] === undefined ) {
        
        add_face( faces[ 0 ], faces[ 1 ], faces[ 2 ], normals_inds );
        
        if (!(uvs === undefined) && uvs.length > 0) {
          add_uvs( uvs[ 0 ], uvs[ 1 ], uvs[ 2 ] );
        }

      } else {
        
        if (!(normals_inds === undefined) && normals_inds.length > 0) {
          add_face( faces[ 0 ], faces[ 1 ], faces[ 3 ], [ normals_inds[ 0 ], normals_inds[ 1 ], normals_inds[ 3 ] ]);
          add_face( faces[ 1 ], faces[ 2 ], faces[ 3 ], [ normals_inds[ 1 ], normals_inds[ 2 ], normals_inds[ 3 ] ]);
        } else {
          add_face( faces[ 0 ], faces[ 1 ], faces[ 3 ]);
          add_face( faces[ 1 ], faces[ 2 ], faces[ 3 ]);
        }
        
        if (!(uvs === undefined) && uvs.length > 0) {
          add_uvs( uvs[ 0 ], uvs[ 1 ], uvs[ 3 ] );
          add_uvs( uvs[ 1 ], uvs[ 2 ], uvs[ 3 ] );
        }

  		}
      
    }

		// create mesh if no objects in text

		if ( /^o /gm.test( text ) === false ) {

			geometry = new THREE.Geometry();
			material = new THREE.MeshLambertMaterial();
			mesh = new THREE.Mesh( geometry, material );
			object.add( mesh );

		}

		var vertices = [];
		var verticesCount = 0;
		var normals = [];
		var uvs = [];

		// v float float float

		var vertex_pattern = /v( +[\d|\.|\+|\-|e]+)( +[\d|\.|\+|\-|e]+)( +[\d|\.|\+|\-|e]+)/;

		// vn float float float

		var normal_pattern = /vn( +[\d|\.|\+|\-|e]+)( +[\d|\.|\+|\-|e]+)( +[\d|\.|\+|\-|e]+)/;

		// vt float float

		var uv_pattern = /vt( +[\d|\.|\+|\-|e]+)( +[\d|\.|\+|\-|e]+)/;

		// f vertex vertex vertex ...

		var face_pattern1 = /f( +\d+)( +\d+)( +\d+)( +\d+)?/;

		// f vertex/uv vertex/uv vertex/uv ...

		var face_pattern2 = /f( +(\d+)\/(\d+))( +(\d+)\/(\d+))( +(\d+)\/(\d+))( +(\d+)\/(\d+))?/;

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

		var face_pattern3 = /f( +(\d+)\/(\d+)\/(\d+))( +(\d+)\/(\d+)\/(\d+))( +(\d+)\/(\d+)\/(\d+))( +(\d+)\/(\d+)\/(\d+))?/;

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

		var face_pattern4 = /f( +(\d+)\/\/(\d+))( +(\d+)\/\/(\d+))( +(\d+)\/\/(\d+))( +(\d+)\/\/(\d+))?/

		//

		var lines = text.split( '\n' );

		for ( var i = 0; i < lines.length; i ++ ) {

			var line = lines[ i ];
			line = line.trim();

			var result;

			if ( line.length === 0 || line.charAt( 0 ) === '#' ) {

				continue;

			} else if ( ( result = vertex_pattern.exec( line ) ) !== null ) {

				// ["v 1.0 2.0 3.0", "1.0", "2.0", "3.0"]

				geometry.vertices.push( vector(
					parseFloat( result[ 1 ] ),
					parseFloat( result[ 2 ] ),
					parseFloat( result[ 3 ] )
				) );

			} else if ( ( result = normal_pattern.exec( line ) ) !== null ) {

				// ["vn 1.0 2.0 3.0", "1.0", "2.0", "3.0"]

				normals.push( vector(
					parseFloat( result[ 1 ] ),
					parseFloat( result[ 2 ] ),
					parseFloat( result[ 3 ] )
				) );

			} else if ( ( result = uv_pattern.exec( line ) ) !== null ) {

				// ["vt 0.1 0.2", "0.1", "0.2"]

				uvs.push( uv(
					parseFloat( result[ 1 ] ),
					parseFloat( result[ 2 ] )
				) );

			} else if ( ( result = face_pattern1.exec( line ) ) !== null ) {

				// ["f 1 2 3", "1", "2", "3", undefined]

        handle_face_line([ result[ 1 ], result[ 2 ], result[ 3 ], result[ 4 ] ]);

			} else if ( ( result = face_pattern2.exec( line ) ) !== null ) {

				// ["f 1/1 2/2 3/3", " 1/1", "1", "1", " 2/2", "2", "2", " 3/3", "3", "3", undefined, undefined, undefined]
        
        handle_face_line(
          [ result[ 2 ], result[ 5 ], result[ 8 ], result[ 11 ] ], //faces
          [ result[ 3 ], result[ 6 ], result[ 9 ], result[ 12 ] ] //uv
        );

			} else if ( ( result = face_pattern3.exec( line ) ) !== null ) {

				// ["f 1/1/1 2/2/2 3/3/3", " 1/1/1", "1", "1", "1", " 2/2/2", "2", "2", "2", " 3/3/3", "3", "3", "3", undefined, undefined, undefined, undefined]

        handle_face_line(
          [ result[ 2 ], result[ 6 ], result[ 10 ], result[ 14 ] ], //faces
          [ result[ 3 ], result[ 7 ], result[ 11 ], result[ 15 ] ], //uv
          [ result[ 4 ], result[ 8 ], result[ 12 ], result[ 16 ] ] //normal
        );

			} else if ( ( result = face_pattern4.exec( line ) ) !== null ) {

				// ["f 1//1 2//2 3//3", " 1//1", "1", "1", " 2//2", "2", "2", " 3//3", "3", "3", undefined, undefined, undefined]

        handle_face_line(
          [ result[ 2 ], result[ 5 ], result[ 8 ], result[ 11 ] ], //faces
          [ ], //uv
          [ result[ 3 ], result[ 6 ], result[ 9 ], result[ 12 ] ] //normal
        );

			} else if ( /^o /.test( line ) ) {

				// object

        if (!(geometry === undefined)) {
          face_offset = face_offset + geometry.vertices.length;
        }
        
				geometry = new THREE.Geometry();
				material = new THREE.MeshLambertMaterial();

				mesh = new THREE.Mesh( geometry, material );
				mesh.name = line.substring( 2 ).trim();
				object.add( mesh );

				verticesCount = 0;

			} else if ( /^g /.test( line ) ) {

				// group

			} else if ( /^usemtl /.test( line ) ) {

				// material

				material.name = line.substring( 7 ).trim();

			} else if ( /^mtllib /.test( line ) ) {

				// mtl file

			} else if ( /^s /.test( line ) ) {

				// smooth shading

			} else {

				// console.log( "THREE.OBJLoader: Unhandled line " + line );

			}

		}

		for ( var i = 0, l = object.children.length; i < l; i ++ ) {

			var geometry = object.children[ i ].geometry;

			geometry.computeCentroids();
			geometry.computeFaceNormals();
			geometry.computeBoundingSphere();

		}
    
		return object;

	}

};