keyboard-presentation

import * as three from 'three'

export default function STLLoader ( manager ) {

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

}

STLLoader.prototype = {

  constructor: STLLoader,

  load: function ( url, onLoad, onProgress, onError ) {
    return new Promise((resolve, reject) => {
      var scope = this;

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

        try {

          const parsed = scope.parse(text)

          if (onLoad) {
            onLoad(parsed);
          }

          resolve(parsed)

        } catch ( exception ) {

          if ( onError ) {

            onError( exception );

          }

          reject(exception)

        }

      }, onProgress, reject );
    })
  },

  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( '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( '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' ) {

        return three.LoaderUtils.decodeText( new Uint8Array( buffer ) );

      }

      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 ) );

  }

};