@openhps/core/dist/esm/three/loaders/Loader.js

Open Hybrid Positioning System - Core component

import { DefaultLoadingManager } from './LoadingManager.js';

/**
 * Abstract base class for loaders.
 *
 * @abstract
 */
class Loader {
  /**
   * Constructs a new loader.
   *
   * @param {LoadingManager} [manager] - The loading manager.
   */
  constructor(manager) {
    /**
     * The loading manager.
     *
     * @type {LoadingManager}
     * @default DefaultLoadingManager
     */
    this.manager = manager !== undefined ? manager : DefaultLoadingManager;

    /**
     * The crossOrigin string to implement CORS for loading the url from a
     * different domain that allows CORS.
     *
     * @type {string}
     * @default 'anonymous'
     */
    this.crossOrigin = 'anonymous';

    /**
     * Whether the XMLHttpRequest uses credentials.
     *
     * @type {boolean}
     * @default false
     */
    this.withCredentials = false;

    /**
     * The base path from which the asset will be loaded.
     *
     * @type {string}
     */
    this.path = '';

    /**
     * The base path from which additional resources like textures will be loaded.
     *
     * @type {string}
     */
    this.resourcePath = '';

    /**
     * The [request header]{@link https://developer.mozilla.org/en-US/docs/Glossary/Request_header}
     * used in HTTP request.
     *
     * @type {Object<string, any>}
     */
    this.requestHeader = {};
  }

  /**
   * This method needs to be implemented by all concrete loaders. It holds the
   * logic for loading assets from the backend.
   *
   * @param {string} url - The path/URL of the file to be loaded.
   * @param {Function} onLoad - Executed when the loading process has been finished.
   * @param {onProgressCallback} [onProgress] - Executed while the loading is in progress.
   * @param {onErrorCallback} [onError] - Executed when errors occur.
   */
  load( /* url, onLoad, onProgress, onError */) {}

  /**
   * A async version of {@link Loader#load}.
   *
   * @param {string} url - The path/URL of the file to be loaded.
   * @param {onProgressCallback} [onProgress] - Executed while the loading is in progress.
   * @return {Promise} A Promise that resolves when the asset has been loaded.
   */
  loadAsync(url, onProgress) {
    const scope = this;
    return new Promise(function (resolve, reject) {
      scope.load(url, resolve, onProgress, reject);
    });
  }

  /**
   * This method needs to be implemented by all concrete loaders. It holds the
   * logic for parsing the asset into three.js entities.
   *
   * @param {any} data - The data to parse.
   */
  parse( /* data */) {}

  /**
   * Sets the `crossOrigin` String to implement CORS for loading the URL
   * from a different domain that allows CORS.
   *
   * @param {string} crossOrigin - The `crossOrigin` value.
   * @return {Loader} A reference to this instance.
   */
  setCrossOrigin(crossOrigin) {
    this.crossOrigin = crossOrigin;
    return this;
  }

  /**
   * Whether the XMLHttpRequest uses credentials such as cookies, authorization
   * headers or TLS client certificates, see [XMLHttpRequest.withCredentials]{@link https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/withCredentials}.
   *
   * Note: This setting has no effect if you are loading files locally or from the same domain.
   *
   * @param {boolean} value - The `withCredentials` value.
   * @return {Loader} A reference to this instance.
   */
  setWithCredentials(value) {
    this.withCredentials = value;
    return this;
  }

  /**
   * Sets the base path for the asset.
   *
   * @param {string} path - The base path.
   * @return {Loader} A reference to this instance.
   */
  setPath(path) {
    this.path = path;
    return this;
  }

  /**
   * Sets the base path for dependent resources like textures.
   *
   * @param {string} resourcePath - The resource path.
   * @return {Loader} A reference to this instance.
   */
  setResourcePath(resourcePath) {
    this.resourcePath = resourcePath;
    return this;
  }

  /**
   * Sets the given request header.
   *
   * @param {Object} requestHeader - A [request header]{@link https://developer.mozilla.org/en-US/docs/Glossary/Request_header}
   * for configuring the HTTP request.
   * @return {Loader} A reference to this instance.
   */
  setRequestHeader(requestHeader) {
    this.requestHeader = requestHeader;
    return this;
  }
}

/**
 * Callback for onProgress in loaders.
 *
 * @callback onProgressCallback
 * @param {ProgressEvent} event - An instance of `ProgressEvent` that represents the current loading status.
 */

/**
 * Callback for onError in loaders.
 *
 * @callback onErrorCallback
 * @param {Error} error - The error which occurred during the loading process.
 */

/**
 * The default material name that is used by loaders
 * when creating materials for loaded 3D objects.
 *
 * Note: Not all loaders might honor this setting.
 *
 * @static
 * @type {string}
 * @default '__DEFAULT'
 */
Loader.DEFAULT_MATERIAL_NAME = '__DEFAULT';
export { Loader };