@giro3d/giro3d/formats/BilFormat.js

A JS/WebGL framework for 3D geospatial data visualization

import { DataTexture, FloatType, LinearFilter, RGFormat } from 'three';
import WorkerPool from '../utils/WorkerPool';
import ImageFormat from './ImageFormat';
import { decodeRaster } from './bilWorker';
let workerPool = null;
function createWorker() {
  return new Worker(URL.createObjectURL(new Blob([atob('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')], {type: "text/javascript"})), {
    type: 'module',
    name: 'bil'
  });
}

/**
 * Decoder for [BIL](https://desktop.arcgis.com/en/arcmap/10.3/manage-data/raster-and-images/bil-bip-and-bsq-raster-files.htm) images.
 *
 * At the moment, only single band BIL files are supported and it is tested only on IGN elevation
 * WMS and WMTS layers.
 *
 * ```js
 *  // Create an elevation source
 * const source = new WmsSource({
 *     url: 'https://data.geopf.fr/wms-r',
 *     projection: 'EPSG:2154',
 *     layer: 'ELEVATION.ELEVATIONGRIDCOVERAGE.HIGHRES',
 *     imageFormat: 'image/x-bil;bits=32',
 *     format: new BilFormat(),
 * });
 *
 * const elevationLayer = new ElevationLayer({ source });
 *
 * map.addLayer(elevationLayer);
 *
 * ```
 * [See it in action](/examples/ign_ortho_elevation.html).
 *
 */
class BilFormat extends ImageFormat {
  isBilFormat = true;
  type = 'BilFormat';
  _enableWorkers = true;

  /**
   * @param options - Decoder options.
   */
  constructor(options) {
    super(true, FloatType);
    this._enableWorkers = options?.enableWorkers ?? true;
  }

  /**
   * Decode a Bil blob into a
   * [DataTexture](https://threejs.org/docs/?q=texture#api/en/textures/DataTexture) containing
   * the elevation data. At the moment only one band BIL is supported.
   *
   * @param blob - the data to decode
   * @param options - the decoding options
   */

  async decode(blob, options) {
    const buffer = await blob.arrayBuffer();
    const floatArray = new Float32Array(buffer);
    const noData = options?.noDataValue;
    let result;
    if (this._enableWorkers) {
      if (workerPool == null) {
        workerPool = new WorkerPool({
          createWorker
        });
      }
      result = await workerPool.queue('DecodeBilTerrainMessage', {
        buffer,
        noData
      });
    } else {
      result = decodeRaster(floatArray, noData);
    }
    const texture = new DataTexture(new Float32Array(result.data), options.width, options.height, RGFormat, FloatType);
    texture.needsUpdate = true;
    texture.generateMipmaps = false;
    texture.magFilter = LinearFilter;
    texture.minFilter = LinearFilter;
    return {
      texture,
      min: result.min,
      max: result.max
    };
  }
}
export default BilFormat;