loaders.gl/src/laz-loader/laslaz.js

Framework-independent loaders for 3D graphics formats

/*
  Modified from Uday Verma and Howard Butler's plasio
  https://github.com/verma/plasio/
  MIT License
*/

// laslaz.js - treat as compiled code
/* eslint-disable */

(function(scope) {
  'use strict';

  var pointFormatReaders = {
    0: function(dv) {
      return {
        position: [dv.getInt32(0, true), dv.getInt32(4, true), dv.getInt32(8, true)],
        intensity: dv.getUint16(12, true),
        classification: dv.getUint8(15, true)
      };
    },
    1: function(dv) {
      return {
        position: [dv.getInt32(0, true), dv.getInt32(4, true), dv.getInt32(8, true)],
        intensity: dv.getUint16(12, true),
        classification: dv.getUint8(15, true)
      };
    },
    2: function(dv) {
      return {
        position: [dv.getInt32(0, true), dv.getInt32(4, true), dv.getInt32(8, true)],
        intensity: dv.getUint16(12, true),
        classification: dv.getUint8(15, true),
        color: [dv.getUint16(20, true), dv.getUint16(22, true), dv.getUint16(24, true)]
      };
    },
    3: function(dv) {
      return {
        position: [dv.getInt32(0, true), dv.getInt32(4, true), dv.getInt32(8, true)],
        intensity: dv.getUint16(12, true),
        classification: dv.getUint8(15, true),
        color: [dv.getUint16(28, true), dv.getUint16(30, true), dv.getUint16(32, true)]
      };
    }
  };

  function readAs(buf, Type, offset, count) {
    count = count === undefined || count === 0 ? 1 : count;
    var sub = buf.slice(offset, offset + Type.BYTES_PER_ELEMENT * count);

    var r = new Type(sub);
    if (count === 1) return r[0];

    var ret = [];
    for (var i = 0; i < count; i++) {
      ret.push(r[i]);
    }

    return ret;
  }

  function parseLASHeader(arraybuffer) {
    var o = {};

    o.pointsOffset = readAs(arraybuffer, Uint32Array, 32 * 3);
    o.pointsFormatId = readAs(arraybuffer, Uint8Array, 32 * 3 + 8);
    o.pointsStructSize = readAs(arraybuffer, Uint16Array, 32 * 3 + 8 + 1);
    o.pointsCount = readAs(arraybuffer, Uint32Array, 32 * 3 + 11);

    var start = 32 * 3 + 35;
    o.scale = readAs(arraybuffer, Float64Array, start, 3);
    start += 24; // 8*3
    o.offset = readAs(arraybuffer, Float64Array, start, 3);
    start += 24;

    var bounds = readAs(arraybuffer, Float64Array, start, 6);
    start += 48; // 8*6;
    o.maxs = [bounds[0], bounds[2], bounds[4]];
    o.mins = [bounds[1], bounds[3], bounds[5]];

    return o;
  }

  var msgIndex = 0;
  var waitHandlers = {};

  // This method is scope-wide since the nacl module uses this fuction to notify
  // us of events
  scope.handleMessage = function(message_event) {
    var msg = message_event.data;
    var resolver = waitHandlers[msg.id];
    delete waitHandlers[msg.id];

    // call the callback in a separate context, make sure we've cleaned our
    // state out before the callback is invoked since it may queue more doExchanges
    setTimeout(function() {
      if (msg.error) return resolver.reject(new Error(msg.message || 'Unknown Error'));

      if (msg.hasOwnProperty('count') && msg.hasOwnProperty('hasMoreData')) {
        return resolver.resolve({
          buffer: msg.result,
          count: msg.count,
          hasMoreData: msg.hasMoreData
        });
      }

      resolver.resolve(msg.result);
    }, 0);
  };

  var doDataExchange = function(cmd, callback) {
    cmd.id = msgIndex.toString();
    msgIndex++;

    var resolver = Promise.defer();
    waitHandlers[cmd.id] = resolver;

    nacl_module.postMessage(cmd);

    return resolver.promise.cancellable();
  };

  // LAS Loader
  // Loads uncompressed files
  //
  var LASLoader = function(arraybuffer) {
    this.arraybuffer = arraybuffer;
  };

  LASLoader.prototype.open = function() {
    // nothing needs to be done to open this file
    //
    this.readOffset = 0;
    return new Promise(function(res, rej) {
      setTimeout(res, 0);
    });
  };

  LASLoader.prototype.getHeader = function() {
    var o = this;

    return new Promise(function(res, rej) {
      setTimeout(function() {
        o.header = parseLASHeader(o.arraybuffer);
        res(o.header);
      }, 0);
    });
  };

  LASLoader.prototype.readData = function(count, offset, skip) {
    var o = this;

    return new Promise(function(res, rej) {
      setTimeout(function() {
        if (!o.header)
          return rej(new Error('Cannot start reading data till a header request is issued'));

        var start;
        if (skip <= 1) {
          count = Math.min(count, o.header.pointsCount - o.readOffset);
          start = o.header.pointsOffset + o.readOffset * o.header.pointsStructSize;
          var end = start + count * o.header.pointsStructSize;
          res({
            buffer: o.arraybuffer.slice(start, end),
            count: count,
            hasMoreData: o.readOffset + count < o.header.pointsCount
          });
          o.readOffset += count;
        } else {
          var pointsToRead = Math.min(count * skip, o.header.pointsCount - o.readOffset);
          var bufferSize = Math.ceil(pointsToRead / skip);
          var pointsRead = 0;

          var buf = new Uint8Array(bufferSize * o.header.pointsStructSize);
          for (var i = 0; i < pointsToRead; i++) {
            if (i % skip === 0) {
              start = o.header.pointsOffset + o.readOffset * o.header.pointsStructSize;
              var src = new Uint8Array(o.arraybuffer, start, o.header.pointsStructSize);

              buf.set(src, pointsRead * o.header.pointsStructSize);
              pointsRead++;
            }

            o.readOffset++;
          }

          res({
            buffer: buf.buffer,
            count: pointsRead,
            hasMoreData: o.readOffset < o.header.pointsCount
          });
        }
      }, 0);
    });
  };

  LASLoader.prototype.close = function() {
    var o = this;
    return new Promise(function(res, rej) {
      o.arraybuffer = null;
      setTimeout(res, 0);
    });
  };

  // LAZ Loader
  // Uses NaCL module to load LAZ files
  //
  var LAZLoader = function(arraybuffer) {
    this.arraybuffer = arraybuffer;
    this.ww = new Worker(`workers/laz-loader-worker.js`);

    this.nextCB = null;
    var o = this;

    this.ww.onmessage = function(e) {
      if (o.nextCB !== null) {
        o.nextCB(e.data);
        o.nextCB = null;
      }
    };

    this.dorr = function(req, cb) {
      o.nextCB = cb;
      o.ww.postMessage(req);
    };
  };

  LAZLoader.prototype.open = function() {
    // nothing needs to be done to open this file
    //
    var o = this;
    return new Promise(function(res, rej) {
      o.dorr({type: 'open', arraybuffer: o.arraybuffer}, function(r) {
        if (r.status !== 1) return rej(new Error('Failed to open file'));

        res(true);
      });
    });
  };

  LAZLoader.prototype.getHeader = function() {
    var o = this;

    return new Promise(function(res, rej) {
      o.dorr({type: 'header'}, function(r) {
        if (r.status !== 1) return rej(new Error('Failed to get header'));

        res(r.header);
      });
    });
  };

  LAZLoader.prototype.readData = function(count, offset, skip) {
    var o = this;

    return new Promise(function(res, rej) {
      o.dorr({type: 'read', count: count, offset: offset, skip: skip}, function(r) {
        if (r.status !== 1) return rej(new Error('Failed to read data'));
        res({
          buffer: r.buffer,
          count: r.count,
          hasMoreData: r.hasMoreData
        });
      });
    });
  };

  LAZLoader.prototype.close = function() {
    var o = this;

    return new Promise(function(res, rej) {
      o.dorr({type: 'close'}, function(r) {
        if (r.status !== 1) return rej(new Error('Failed to close file'));

        res(true);
      });
    });
  };

  // A single consistent interface for loading LAS/LAZ files
  var LASFile = function(arraybuffer) {
    this.arraybuffer = arraybuffer;

    this.determineVersion();
    if (this.version > 13) throw new Error('Only file versions <= 1.3 are supported at this time');

    this.determineFormat();
    if (pointFormatReaders[this.formatId] === undefined)
      throw new Error('The point format ID is not supported');

    this.loader = this.isCompressed
      ? new LAZLoader(this.arraybuffer)
      : new LASLoader(this.arraybuffer);
  };

  LASFile.prototype.determineFormat = function() {
    var formatId = readAs(this.arraybuffer, Uint8Array, 32 * 3 + 8);
    var bit_7 = (formatId & 0x80) >> 7;
    var bit_6 = (formatId & 0x40) >> 6;

    if (bit_7 === 1 && bit_6 === 1) throw new Error('Old style compression not supported');

    this.formatId = formatId & 0x3f;
    this.isCompressed = bit_7 === 1 || bit_6 === 1;
  };

  LASFile.prototype.determineVersion = function() {
    var ver = new Int8Array(this.arraybuffer, 24, 2);
    this.version = ver[0] * 10 + ver[1];
    this.versionAsString = ver[0] + '.' + ver[1];
  };

  LASFile.prototype.open = function() {
    return this.loader.open();
  };

  LASFile.prototype.getHeader = function() {
    return this.loader.getHeader();
  };

  LASFile.prototype.readData = function(count, start, skip) {
    return this.loader.readData(count, start, skip);
  };

  LASFile.prototype.close = function() {
    return this.loader.close();
  };

  // Decodes LAS records into points
  //
  var LASDecoder = function(buffer, len, header) {
    this.arrayb = buffer;
    this.decoder = pointFormatReaders[header.pointsFormatId];
    this.pointsCount = len;
    this.pointSize = header.pointsStructSize;
    this.scale = header.scale;
    this.offset = header.offset;
    this.mins = header.mins;
    this.maxs = header.maxs;
  };

  LASDecoder.prototype.getPoint = function(index) {
    if (index < 0 || index >= this.pointsCount) throw new Error('Point index out of range');

    var dv = new DataView(this.arrayb, index * this.pointSize, this.pointSize);
    return this.decoder(dv);
  };

  LASFile.prototype.getUnpacker = function() {
    return LASDecoder;
  };

  scope.LASFile = LASFile;
  scope.LASModuleWasLoaded = false;
})(module.exports);

/* eslint no-use-before-define: 2 */