three-stl-loader.js

module.exports = function( THREE ) {

	/**
	 * @author aleeper / http://adamleeper.com/
	 * @author mrdoob / http://mrdoob.com/
	 * @author gero3 / https://github.com/gero3
	 * @author Mugen87 / https://github.com/Mugen87
	 *
	 * Description: A THREE loader for STL ASCII files, as created by Solidworks and other CAD programs.
	 *
	 * Supports both binary and ASCII encoded files, with automatic detection of type.
	 *
	 * The loader returns a non-indexed buffer geometry.
	 *
	 * Limitations:
	 *  Binary decoding supports "Magics" color format (http://en.wikipedia.org/wiki/STL_(file_format)#Color_in_binary_STL).
	 *  There is perhaps some question as to how valid it is to always assume little-endian-ness.
	 *  ASCII decoding assumes file is UTF-8.
	 *
	 * Usage:
	 *  var loader = new THREE.STLLoader();
	 *  loader.load( './models/stl/slotted_disk.stl', function ( geometry ) {
	 *    scene.add( new THREE.Mesh( geometry ) );
	 *  });
	 *
	 * For binary STLs geometry might contain colors for vertices. To use it:
	 *  // use the same code to load STL as above
	 *  if (geometry.hasColors) {
	 *    material = new THREE.MeshPhongMaterial({ opacity: geometry.alpha, vertexColors: THREE.VertexColors });
	 *  } else { .... }
	 *  var mesh = new THREE.Mesh( geometry, material );
	 */


	THREE.STLLoader = function ( manager ) {

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

	};

	THREE.STLLoader.prototype = {

		constructor: THREE.STLLoader,

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

			var scope = this;

			var loader = new THREE.FileLoader( scope.manager );
			loader.setResponseType( 'arraybuffer' );
			loader.load( url, function ( text ) {

				onLoad( scope.parse( text ) );

			}, onProgress, onError );

		},

		parse: function ( data ) {

			function isBinary( data ) {

				var expect, face_size, n_faces, reader;
				reader = new DataView( data );
				face_size = ( 32 / 8 * 3 ) + ( ( 32 / 8 * 3 ) * 3 ) + ( 16 / 8 );
				n_faces = reader.getUint32( 80, true );
				expect = 80 + ( 32 / 8 ) + ( n_faces * face_size );

				if ( expect === reader.byteLength ) {

					return true;

				}

				// An ASCII STL data must begin with 'solid ' as the first six bytes.
				// However, ASCII STLs lacking the SPACE after the 'd' are known to be
				// plentiful.  So, check the first 5 bytes for 'solid'.

				// US-ASCII ordinal values for 's', 'o', 'l', 'i', 'd'

				var solid = [ 115, 111, 108, 105, 100 ];

				for ( var i = 0; i < 5; i ++ ) {

					// If solid[ i ] does not match the i-th byte, then it is not an
					// ASCII STL; hence, it is binary and return true.

					if ( solid[ i ] != reader.getUint8( i, false ) ) return true;

	 			}

				// First 5 bytes read "solid"; declare it to be an ASCII STL

				return false;

			}

			function parseBinary( data ) {

				var reader = new DataView( data );
				var faces = reader.getUint32( 80, true );

				var r, g, b, hasColors = false, colors;
				var defaultR, defaultG, defaultB, alpha;

				// process STL header
				// check for default color in header ("COLOR=rgba" sequence).

				for ( var index = 0; index < 80 - 10; index ++ ) {

					if ( ( reader.getUint32( index, false ) == 0x434F4C4F /*COLO*/ ) &&
						( reader.getUint8( index + 4 ) == 0x52 /*'R'*/ ) &&
						( reader.getUint8( index + 5 ) == 0x3D /*'='*/ ) ) {

						hasColors = true;
						colors = [];

						defaultR = reader.getUint8( index + 6 ) / 255;
						defaultG = reader.getUint8( index + 7 ) / 255;
						defaultB = reader.getUint8( index + 8 ) / 255;
						alpha = reader.getUint8( index + 9 ) / 255;

					}

				}

				var dataOffset = 84;
				var faceLength = 12 * 4 + 2;

				var geometry = new THREE.BufferGeometry();

				var vertices = [];
				var normals = [];

				for ( var face = 0; face < faces; face ++ ) {

					var start = dataOffset + face * faceLength;
					var normalX = reader.getFloat32( start, true );
					var normalY = reader.getFloat32( start + 4, true );
					var normalZ = reader.getFloat32( start + 8, true );

					if ( hasColors ) {

						var packedColor = reader.getUint16( start + 48, true );

						if ( ( packedColor & 0x8000 ) === 0 ) {

							// facet has its own unique color

							r = ( packedColor & 0x1F ) / 31;
							g = ( ( packedColor >> 5 ) & 0x1F ) / 31;
							b = ( ( packedColor >> 10 ) & 0x1F ) / 31;

						} else {

							r = defaultR;
							g = defaultG;
							b = defaultB;

						}

					}

					for ( var i = 1; i <= 3; i ++ ) {

						var vertexstart = start + i * 12;

						vertices.push( reader.getFloat32( vertexstart, true ) );
						vertices.push( reader.getFloat32( vertexstart + 4, true ) );
						vertices.push( reader.getFloat32( vertexstart + 8, true ) );

						normals.push( normalX, normalY, normalZ );

						if ( hasColors ) {

							colors.push( r, g, b );

						}

					}

				}

				geometry.addAttribute( 'position', new THREE.BufferAttribute( new Float32Array( vertices ), 3 ) );
				geometry.addAttribute( 'normal', new THREE.BufferAttribute( new Float32Array( normals ), 3 ) );

				if ( hasColors ) {

					geometry.addAttribute( 'color', new THREE.BufferAttribute( new Float32Array( colors ), 3 ) );
					geometry.hasColors = true;
					geometry.alpha = alpha;

				}

				return geometry;

			}

			function parseASCII( data ) {

				var geometry = new THREE.BufferGeometry();
				var patternFace = /facet([\s\S]*?)endfacet/g;
				var faceCounter = 0;

				var patternFloat = /[\s]+([+-]?(?:\d+.\d+|\d+.|\d+|.\d+)(?:[eE][+-]?\d+)?)/.source;
				var patternVertex = new RegExp( 'vertex' + patternFloat + patternFloat + patternFloat, 'g' );
				var patternNormal = new RegExp( 'normal' + patternFloat + patternFloat + patternFloat, 'g' );

				var vertices = [];
				var normals = [];

				var normal = new THREE.Vector3();

				var result;

				while ( ( result = patternFace.exec( data ) ) !== null ) {

					var vertexCountPerFace = 0;
					var normalCountPerFace = 0;

					var text = result[ 0 ];

					while ( ( result = patternNormal.exec( text ) ) !== null ) {

						normal.x = parseFloat( result[ 1 ] );
						normal.y = parseFloat( result[ 2 ] );
						normal.z = parseFloat( result[ 3 ] );
						normalCountPerFace ++;

					}

					while ( ( result = patternVertex.exec( text ) ) !== null ) {

						vertices.push( parseFloat( result[ 1 ] ), parseFloat( result[ 2 ] ), parseFloat( result[ 3 ] ) );
						normals.push( normal.x, normal.y, normal.z );
						vertexCountPerFace ++;

					}

					// every face have to own ONE valid normal

					if ( normalCountPerFace !== 1 ) {

						console.error( 'THREE.STLLoader: Something isn\'t right with the normal of face number ' + faceCounter );

					}

					// each face have to own THREE valid vertices

					if ( vertexCountPerFace !== 3 ) {

						console.error( 'THREE.STLLoader: Something isn\'t right with the vertices of face number ' + faceCounter );

					}

					faceCounter ++;

				}

				geometry.addAttribute( 'position', new THREE.Float32BufferAttribute( vertices, 3 ) );
				geometry.addAttribute( 'normal', new THREE.Float32BufferAttribute( normals, 3 ) );

				return geometry;

			}

			function ensureString( buffer ) {

				if ( typeof buffer !== 'string' ) {

					var array_buffer = new Uint8Array( buffer );

					if ( window.TextDecoder !== undefined ) {

						return new TextDecoder().decode( array_buffer );

					}

					var str = '';

					for ( var i = 0, il = buffer.byteLength; i < il; i ++ ) {

						str += String.fromCharCode( array_buffer[ i ] ); // implicitly assumes little-endian

					}

					return str;

				} else {

					return buffer;

				}

			}

			function ensureBinary( buffer ) {

				if ( typeof buffer === 'string' ) {

					var array_buffer = new Uint8Array( buffer.length );
					for ( var i = 0; i < buffer.length; i ++ ) {

						array_buffer[ i ] = buffer.charCodeAt( i ) & 0xff; // implicitly assumes little-endian

					}
					return array_buffer.buffer || array_buffer;

				} else {

					return buffer;

				}

			}

			// start

			var binData = ensureBinary( data );

			return isBinary( binData ) ? parseBinary( binData ) : parseASCII( ensureString( data ) );

		}

	};

	return THREE.STLLoader;
};