Reference Source

src/plugins/XKTLoaderPlugin/XKTLoaderPlugin.js

import {utils} from "../../viewer/scene/utils.js"
import {PerformanceModel} from "../../viewer/scene/PerformanceModel/PerformanceModel.js";
import {Plugin} from "../../viewer/Plugin.js";
import {XKTDefaultDataSource} from "./XKTDefaultDataSource.js";
import {IFCObjectDefaults} from "../../viewer/metadata/IFCObjectDefaults.js";

import {ParserV1} from "./parsers/ParserV1.js";
import {ParserV2} from "./parsers/ParserV2.js";
import {ParserV3} from "./parsers/ParserV3.js";
import {ParserV4} from "./parsers/ParserV4.js";
import {ParserV5} from "./parsers/ParserV5.js";
import {ParserV6} from "./parsers/ParserV6.js";
import {ParserV7} from "./parsers/ParserV7.js";
import {ParserV8} from "./parsers/ParserV8.js";
import {ParserV9} from "./parsers/ParserV9.js";

const parsers = {};

parsers[ParserV1.version] = ParserV1;
parsers[ParserV2.version] = ParserV2;
parsers[ParserV3.version] = ParserV3;
parsers[ParserV4.version] = ParserV4;
parsers[ParserV5.version] = ParserV5;
parsers[ParserV6.version] = ParserV6;
parsers[ParserV7.version] = ParserV7;
parsers[ParserV8.version] = ParserV8;
parsers[ParserV9.version] = ParserV9;

/**
 * {@link Viewer} plugin that loads models from xeokit's optimized *````.XKT````* format.
 *
 * <a href="https://xeokit.github.io/xeokit-sdk/examples/#loading_XKT_OTCConferenceCenter"><img src="http://xeokit.io/img/docs/XKTLoaderPlugin/XKTLoaderPlugin.png"></a>
 *
 * [[Run this example](https://xeokit.github.io/xeokit-sdk/examples/#loading_XKT_OTCConferenceCenter)]
 *
 * ## Overview
 *
 * * XKTLoaderPlugin is the most efficient way to load high-detail models into xeokit.
 * * An *````.XKT````* file is a single BLOB containing a model, compressed using geometry quantization
 * and [pako](https://nodeca.github.io/pako/).
 * * Supports double-precision coordinates.
 * * Set the position, scale and rotation of each model as you load it.
 * * Filter which IFC types get loaded.
 * * Configure initial default appearances for IFC types.
 * * Set a custom data source for *````.XKT````* and IFC metadata files.
 * * Option to load multiple copies of the same model, without object ID clashes.
 *
 * ## Creating *````.XKT````* Files and Metadata
 *
 * We have several sways to convert your files into XKT. See these tutorials for more info:
 *
 * * [Converting Models to XKT with convert2xkt](https://www.notion.so/xeokit/Converting-Models-to-XKT-with-convert2xkt-fa567843313f4db8a7d6535e76da9380) - how to convert various file formats (glTF, IFC, CityJSON, LAS/LAZ...) to XKT using our nodejs-based converter.
 * * [Converting IFC Models to XKT using 3rd-Party Open Source Tools](https://www.notion.so/xeokit/Converting-IFC-Models-to-XKT-using-3rd-Party-Open-Source-Tools-c373e48bc4094ff5b6e5c5700ff580ee) - how to convert IFC files to XKT using 3rd-party open source CLI tools.
 *
 * ## Scene representation
 *
 * When loading a model, XKTLoaderPlugin creates an {@link Entity} that represents the model, which
 * will have {@link Entity#isModel} set ````true```` and will be registered by {@link Entity#id}
 * in {@link Scene#models}. The XKTLoaderPlugin also creates an {@link Entity} for each object within the
 * model. Those Entities will have {@link Entity#isObject} set ````true```` and will be registered
 * by {@link Entity#id} in {@link Scene#objects}.
 *
 * ## Metadata
 *
 * Since XKT V8, model metadata is included in the XKT file. If the XKT file has metadata, then loading it creates
 * model metadata components within the Viewer, namely a {@link MetaModel} corresponding to the model {@link Entity},
 * and a {@link MetaObject} for each object {@link Entity}.
 *
 * Each {@link MetaObject} has a {@link MetaObject#type}, which indicates the classification of its corresponding
 * {@link Entity}. When loading metadata, we can also configure XKTLoaderPlugin with a custom lookup table of initial
 * values to set on the properties of each type of {@link Entity}. By default, XKTLoaderPlugin uses its own map of
 * default colors and visibilities for IFC element types.
 *
 * For XKT versions prior to V8, we provided the metadata to XKTLoaderPlugin as an accompanying JSON file to load. We can
 * still do that for all XKT versions, and for XKT V8+ it will override any metadata provided within the XKT file.
 *
 * ## Usage
 *
 * In the example below we'll load the Schependomlaan model from a [.XKT file](https://github.com/xeokit/xeokit-sdk/tree/master/examples/models/xkt/schependomlaan).
 *
 * This will create a bunch of {@link Entity}s that represents the model and its objects, along with a {@link MetaModel} and {@link MetaObject}s
 * that hold their metadata.
 *
 * Since this model contains IFC types, the XKTLoaderPlugin will set the initial appearance of each object
 * {@link Entity} according to its IFC type in {@link XKTLoaderPlugin#objectDefaults}.
 *
 * Read more about this example in the user guide on [Viewing BIM Models Offline](https://www.notion.so/xeokit/Viewing-an-IFC-Model-with-xeokit-c373e48bc4094ff5b6e5c5700ff580ee).
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#BIMOffline_XKT_metadata_Schependomlaan)]
 *
 * ````javascript
 * import {Viewer, XKTLoaderPlugin} from "xeokit-sdk.es.js";
 *
 * //------------------------------------------------------------------------------------------------------------------
 * // 1. Create a Viewer,
 * // 2. Arrange the camera
 * //------------------------------------------------------------------------------------------------------------------
 *
 * // 1
 * const viewer = new Viewer({
 *      canvasId: "myCanvas",
 *      transparent: true
 * });
 *
 * // 2
 * viewer.camera.eye = [-2.56, 8.38, 8.27];
 * viewer.camera.look = [13.44, 3.31, -14.83];
 * viewer.camera.up = [0.10, 0.98, -0.14];
 *
 * //------------------------------------------------------------------------------------------------------------------
 * // 1. Create a XKTLoaderPlugin,
 * // 2. Load a building model and JSON IFC metadata
 * //------------------------------------------------------------------------------------------------------------------
 *
 * // 1
 * const xktLoader = new XKTLoaderPlugin(viewer);
 *
 * // 2
 * const model = xktLoader.load({          // Returns an Entity that represents the model
 *     id: "myModel",
 *     src: "./models/xkt/Schependomlaan.xkt",
 *     edges: true
 * });
 *
 * model.on("loaded", () => {
 *
 *     //--------------------------------------------------------------------------------------------------------------
 *     // 1. Find metadata on the third storey
 *     // 2. Select all the objects in the building's third storey
 *     // 3. Fit the camera to all the objects on the third storey
 *     //--------------------------------------------------------------------------------------------------------------
 *
 *     // 1
 *     const metaModel = viewer.metaScene.metaModels["myModel"];       // MetaModel with ID "myModel"
 *     const metaObject
 *          = viewer.metaScene.metaObjects["0u4wgLe6n0ABVaiXyikbkA"];  // MetaObject with ID "0u4wgLe6n0ABVaiXyikbkA"
 *
 *     const name = metaObject.name;                                   // "01 eerste verdieping"
 *     const type = metaObject.type;                                   // "IfcBuildingStorey"
 *     const parent = metaObject.parent;                               // MetaObject with type "IfcBuilding"
 *     const children = metaObject.children;                           // Array of child MetaObjects
 *     const objectId = metaObject.id;                                 // "0u4wgLe6n0ABVaiXyikbkA"
 *     const objectIds = viewer.metaScene.getObjectIDsInSubtree(objectId);   // IDs of leaf sub-objects
 *     const aabb = viewer.scene.getAABB(objectIds);                   // Axis-aligned boundary of the leaf sub-objects
 *
 *     // 2
 *     viewer.scene.setObjectsSelected(objectIds, true);
 *
 *     // 3
 *     viewer.cameraFlight.flyTo(aabb);
 * });
 *
 * // Find the model Entity by ID
 * model = viewer.scene.models["myModel"];
 *
 * // Destroy the model
 * model.destroy();
 * ````
 *
 * ## Transforming
 *
 * We have the option to rotate, scale and translate each  *````.XKT````* model as we load it.
 *
 * This lets us load multiple models, or even multiple copies of the same model, and position them apart from each other.
 *
 * In the example below, we'll scale our model to half its size, rotate it 90 degrees about its local X-axis, then
 * translate it 100 units along its X axis.
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#loading_XKT_Duplex_transform)]
 *
 * ````javascript
 * xktLoader.load({
 *      src: "./models/xkt/Duplex.ifc.xkt",
 *      rotation: [90,0,0],
 *      scale: [0.5, 0.5, 0.5],
 *      position: [100, 0, 0]
 * });
 * ````
 *
 * ## Including and excluding IFC types
 *
 * We can also load only those objects that have the specified IFC types.
 *
 * In the example below, we'll load only the objects that represent walls.
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#BIMOffline_XKT_includeTypes)]
 *
 * ````javascript
 * const model2 = xktLoader.load({
 *     id: "myModel2",
 *     src: "./models/xkt/OTCConferenceCenter.xkt",
 *     includeTypes: ["IfcWallStandardCase"]
 * });
 * ````
 *
 * We can also load only those objects that **don't** have the specified IFC types.
 *
 * In the example below, we'll load only the objects that do not represent empty space.
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#BIMOffline_XKT_excludeTypes)]
 *
 * ````javascript
 * const model3 = xktLoader.load({
 *     id: "myModel3",
 *     src: "./models/xkt/OTCConferenceCenter.xkt",
 *     excludeTypes: ["IfcSpace"]
 * });
 * ````
 *
 * ## Configuring initial IFC object appearances
 *
 * We can specify the custom initial appearance of loaded objects according to their IFC types.
 *
 * This is useful for things like:
 *
 * * setting the colors to our objects according to their IFC types,
 * * automatically hiding ````IfcSpace```` objects, and
 * * ensuring that ````IfcWindow```` objects are always transparent.
 * <br>
 * In the example below, we'll load a model, while configuring ````IfcSpace```` elements to be always initially invisible,
 * and ````IfcWindow```` types to be always translucent blue.
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#BIMOffline_XKT_objectDefaults)]
 *
 * ````javascript
 * const myObjectDefaults = {
 *
 *      IfcSpace: {
 *          visible: false
 *      },
 *      IfcWindow: {
 *          colorize: [0.337255, 0.303922, 0.870588], // Blue
 *          opacity: 0.3
 *      },
 *
 *      //...
 *
 *      DEFAULT: {
 *          colorize: [0.5, 0.5, 0.5]
 *      }
 * };
 *
 * const model4 = xktLoader.load({
 *      id: "myModel4",
 *      src: "./models/xkt/Duplex.ifc.xkt",
 *      objectDefaults: myObjectDefaults // Use our custom initial default states for object Entities
 * });
 * ````
 *
 * When we don't customize the appearance of IFC types, as just above, then IfcSpace elements tend to obscure other
 * elements, which can be confusing.
 *
 * It's often helpful to make IfcSpaces transparent and unpickable, like this:
 *
 * ````javascript
 * const xktLoader = new XKTLoaderPlugin(viewer, {
 *    objectDefaults: {
 *        IfcSpace: {
 *            pickable: false,
 *            opacity: 0.2
 *        }
 *    }
 * });
 * ````
 *
 * Alternatively, we could just make IfcSpaces invisible, which also makes them unpickable:
 *
 * ````javascript
 * const xktLoader = new XKTLoaderPlugin(viewer, {
 *    objectDefaults: {
 *        IfcSpace: {
 *            visible: false
 *        }
 *    }
 * });
 * ````
 *
 * ## Configuring a custom data source
 *
 * By default, XKTLoaderPlugin will load *````.XKT````* files and metadata JSON over HTTP.
 *
 * In the example below, we'll customize the way XKTLoaderPlugin loads the files by configuring it with our own data source
 * object. For simplicity, our custom data source example also uses HTTP, using a couple of xeokit utility functions.
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#loading_XKT_dataSource)]
 *
 * ````javascript
 * import {utils} from "xeokit-sdk.es.js";
 *
 * class MyDataSource {
 *
 *      constructor() {
 *      }
 *
 *      // Gets metamodel JSON
 *      getMetaModel(metaModelSrc, ok, error) {
 *          console.log("MyDataSource#getMetaModel(" + metaModelSrc + ", ... )");
 *          utils.loadJSON(metaModelSrc,
 *              (json) => {
 *                  ok(json);
 *              },
 *              function (errMsg) {
 *                  error(errMsg);
 *              });
 *      }
 *
 *      // Gets the contents of the given .XKT file in an arraybuffer
 *      getXKT(src, ok, error) {
 *          console.log("MyDataSource#getXKT(" + xKTSrc + ", ... )");
 *          utils.loadArraybuffer(src,
 *              (arraybuffer) => {
 *                  ok(arraybuffer);
 *              },
 *              function (errMsg) {
 *                  error(errMsg);
 *              });
 *      }
 * }
 *
 * const xktLoader2 = new XKTLoaderPlugin(viewer, {
 *       dataSource: new MyDataSource()
 * });
 *
 * const model5 = xktLoader2.load({
 *      id: "myModel5",
 *      src: "./models/xkt/Duplex.ifc.xkt"
 * });
 * ````
 *
 * ## Loading multiple copies of a model, without object ID clashes
 *
 * Sometimes we need to load two or more instances of the same model, without having clashes
 * between the IDs of the equivalent objects in the model instances.
 *
 * As shown in the example below, we do this by setting {@link XKTLoaderPlugin#globalizeObjectIds} ````true```` before we load our models.
 *
 * * [[Run example](https://xeokit.github.io/xeokit-sdk/examples/#TreeViewPlugin_Containment_MultipleModels)]
 *
 * ````javascript
 * xktLoader.globalizeObjectIds = true;
 *
 * const model = xktLoader.load({
 *      id: "model1",
 *      src: "./models/xkt/Schependomlaan.xkt"
 * });
 *
 * const model2 = xktLoader.load({
 *    id: "model2",
 *    src: "./models/xkt/Schependomlaan.xkt"
 * });
 * ````
 *
 * For each {@link Entity} loaded by these two calls, {@link Entity#id} and {@link MetaObject#id} will get prefixed by
 * the ID of their model, in order to avoid ID clashes between the two models.
 *
 * An Entity belonging to the first model will get an ID like this:
 *
 * ````
 * myModel1#0BTBFw6f90Nfh9rP1dlXrb
 * ````
 *
 * The equivalent Entity in the second model will get an ID like this:
 *
 * ````
 * myModel2#0BTBFw6f90Nfh9rP1dlXrb
 * ````
 *
 * Now, to update the visibility of both of those Entities collectively, using {@link Scene#setObjectsVisible}, we can
 * supply just the IFC product ID part to that method:
 *
 * ````javascript
 * myViewer.scene.setObjectVisibilities("0BTBFw6f90Nfh9rP1dlXrb", true);
 * ````
 *
 * The method, along with {@link Scene#setObjectsXRayed}, {@link Scene#setObjectsHighlighted} etc, will internally expand
 * the given ID to refer to the instances of that Entity in both models.
 *
 * We can also, of course, reference each Entity directly, using its globalized ID:
 *
 * ````javascript
 * myViewer.scene.setObjectVisibilities("myModel1#0BTBFw6f90Nfh9rP1dlXrb", true);
 *````
 *
 * @class XKTLoaderPlugin
 */
class XKTLoaderPlugin extends Plugin {

    /**
     * @constructor
     *
     * @param {Viewer} viewer The Viewer.
     * @param {Object} cfg  Plugin configuration.
     * @param {String} [cfg.id="XKTLoader"] Optional ID for this plugin, so that we can find it within {@link Viewer#plugins}.
     * @param {Object} [cfg.objectDefaults] Map of initial default states for each loaded {@link Entity} that represents an object.  Default value is {@link IFCObjectDefaults}.
     * @param {Object} [cfg.dataSource] A custom data source through which the XKTLoaderPlugin can load model and metadata files. Defaults to an instance of {@link XKTDefaultDataSource}, which loads uover HTTP.
     * @param {String[]} [cfg.includeTypes] When loading metadata, only loads objects that have {@link MetaObject}s with {@link MetaObject#type} values in this list.
     * @param {String[]} [cfg.excludeTypes] When loading metadata, never loads objects that have {@link MetaObject}s with {@link MetaObject#type} values in this list.
     * @param {Boolean} [cfg.excludeUnclassifiedObjects=false] When loading metadata and this is ````true````, will only load {@link Entity}s that have {@link MetaObject}s (that are not excluded). This is useful when we don't want Entitys in the Scene that are not represented within IFC navigation components, such as {@link TreeViewPlugin}.
     * @param {Boolean} [cfg.reuseGeometries=true] Indicates whether to enable geometry reuse (````true```` by default) or whether to internally expand
     * all geometry instances into batches (````false````), and not use instancing to render them. Setting this ````false```` can significantly
     * improve Viewer performance for models that have a lot of geometry reuse, but may also increase the amount of
     * browser and GPU memory they require. See [#769](https://github.com/xeokit/xeokit-sdk/issues/769) for more info.
     * @param {Number} [cfg.maxGeometryBatchSize=50000000] Maximum geometry batch size, as number of vertices. This is optionally supplied
     * to limit the size of the batched geometry arrays that {@link PerformanceModel} internally creates for batched geometries.
     * A low value means less heap allocation/de-allocation while loading batched geometries, but more draw calls and
     * slower rendering speed. A high value means larger heap allocation/de-allocation while loading, but less draw calls
     * and faster rendering speed. It's recommended to keep this somewhere roughly between ````50000```` and ````50000000```.
     */
    constructor(viewer, cfg = {}) {

        super("XKTLoader", viewer, cfg);

        this._maxGeometryBatchSize = cfg.maxGeometryBatchSize;

        this.dataSource = cfg.dataSource;
        this.objectDefaults = cfg.objectDefaults;
        this.includeTypes = cfg.includeTypes;
        this.excludeTypes = cfg.excludeTypes;
        this.excludeUnclassifiedObjects = cfg.excludeUnclassifiedObjects;
        this.reuseGeometries = cfg.reuseGeometries;
    }

    /**
     * Gets the ````.xkt```` format versions supported by this XKTLoaderPlugin/
     * @returns {string[]}
     */
    get supportedVersions() {
        return Object.keys(parsers);
    }

    /**
     * Gets the custom data source through which the XKTLoaderPlugin can load models and metadata.
     *
     * Default value is {@link XKTDefaultDataSource}, which loads via HTTP.
     *
     * @type {Object}
     */
    get dataSource() {
        return this._dataSource;
    }

    /**
     * Sets a custom data source through which the XKTLoaderPlugin can load models and metadata.
     *
     * Default value is {@link XKTDefaultDataSource}, which loads via HTTP.
     *
     * @type {Object}
     */
    set dataSource(value) {
        this._dataSource = value || new XKTDefaultDataSource();
    }

    /**
     * Gets map of initial default states for each loaded {@link Entity} that represents an object.
     *
     * Default value is {@link IFCObjectDefaults}.
     *
     * @type {{String: Object}}
     */
    get objectDefaults() {
        return this._objectDefaults;
    }

    /**
     * Sets map of initial default states for each loaded {@link Entity} that represents an object.
     *
     * Default value is {@link IFCObjectDefaults}.
     *
     * @type {{String: Object}}
     */
    set objectDefaults(value) {
        this._objectDefaults = value || IFCObjectDefaults;
    }

    /**
     * Gets the whitelist of the IFC types loaded by this XKTLoaderPlugin.
     *
     * When loading models with metadata, causes this XKTLoaderPlugin to only load objects whose types are in this
     * list. An object's type is indicated by its {@link MetaObject}'s {@link MetaObject#type}.
     *
     * Default value is ````undefined````.
     *
     * @type {String[]}
     */
    get includeTypes() {
        return this._includeTypes;
    }

    /**
     * Sets the whitelist of the IFC types loaded by this XKTLoaderPlugin.
     *
     * When loading models with metadata, causes this XKTLoaderPlugin to only load objects whose types are in this
     * list. An object's type is indicated by its {@link MetaObject}'s {@link MetaObject#type}.
     *
     * Default value is ````undefined````.
     *
     * @type {String[]}
     */
    set includeTypes(value) {
        this._includeTypes = value;
    }

    /**
     * Gets the blacklist of IFC types that are never loaded by this XKTLoaderPlugin.
     *
     * When loading models with metadata, causes this XKTLoaderPlugin to **not** load objects whose types are in this
     * list. An object's type is indicated by its {@link MetaObject}'s {@link MetaObject#type}.
     *
     * Default value is ````undefined````.
     *
     * @type {String[]}
     */
    get excludeTypes() {
        return this._excludeTypes;
    }

    /**
     * Sets the blacklist of IFC types that are never loaded by this XKTLoaderPlugin.
     *
     * When loading models with metadata, causes this XKTLoaderPlugin to **not** load objects whose types are in this
     * list. An object's type is indicated by its {@link MetaObject}'s {@link MetaObject#type}.
     *
     * Default value is ````undefined````.
     *
     * @type {String[]}
     */
    set excludeTypes(value) {
        this._excludeTypes = value;
    }

    /**
     * Gets whether we load objects that don't have IFC types.
     *
     * When loading models with metadata and this is ````true````, XKTLoaderPlugin will not load objects
     * that don't have IFC types.
     *
     * Default value is ````false````.
     *
     * @type {Boolean}
     */
    get excludeUnclassifiedObjects() {
        return this._excludeUnclassifiedObjects;
    }

    /**
     * Sets whether we load objects that don't have IFC types.
     *
     * When loading models with metadata and this is ````true````, XKTLoaderPlugin will not load objects
     * that don't have IFC types.
     *
     * Default value is ````false````.
     *
     * @type {Boolean}
     */
    set excludeUnclassifiedObjects(value) {
        this._excludeUnclassifiedObjects = !!value;
    }

    /**
     * Gets whether XKTLoaderPlugin globalizes each {@link Entity#id} and {@link MetaObject#id} as it loads a model.
     *
     * Default value is ````false````.
     *
     * @type {Boolean}
     */
    get globalizeObjectIds() {
        return this._globalizeObjectIds;
    }

    /**
     * Sets whether XKTLoaderPlugin globalizes each {@link Entity#id} and {@link MetaObject#id} as it loads a model.
     *
     * Set  this ````true```` when you need to load multiple instances of the same model, to avoid ID clashes
     * between the objects in the different instances.
     *
     * When we load a model with this set ````true````, then each {@link Entity#id} and {@link MetaObject#id} will be
     * prefixed by the ID of the model, ie. ````<modelId>#<objectId>````.
     *
     * {@link Entity#originalSystemId} and {@link MetaObject#originalSystemId} will always hold the original, un-prefixed, ID values.
     *
     * Default value is ````false````.
     *
     * See the main {@link XKTLoaderPlugin} class documentation for usage info.
     *
     * @type {Boolean}
     */
    set globalizeObjectIds(value) {
        this._globalizeObjectIds = !!value;
    }

    /**
     * Gets whether XKTLoaderPlugin enables geometry reuse when loading models.
     *
     * Default value is ````true````.
     *
     * @type {Boolean}
     */
    get reuseGeometries() {
        return this._reuseGeometries;
    }

    /**
     * Sets whether XKTLoaderPlugin enables geometry reuse when loading models.
     *
     * Default value is ````true````.
     *
     * Geometry reuse saves memory, but can impact Viewer performance when there are many reused geometries. For
     * this reason, we can set this ````false```` to disable geometry reuse for models loaded by this XKTLoaderPlugin
     * (which will then "expand" the geometry instances into batches instead).
     *
     * The result will be be less WebGL draw calls (which are expensive), at the cost of increased memory footprint.
     *
     * See [#769](https://github.com/xeokit/xeokit-sdk/issues/769) for more info.
     *
     * @type {Boolean}
     */
    set reuseGeometries(value) {
        this._reuseGeometries = value !== false;
    }

    /**
     * Loads an ````.xkt```` model into this XKTLoaderPlugin's {@link Viewer}.
     *
     * Since xeokit/xeokit-sdk 1.9.0, XKTLoaderPlugin has supported XKT 8, which bundles the metamodel
     * data (eg. an IFC element hierarchy) in the XKT file itself. For XKT 8, we therefore no longer need to
     * load the metamodel data from a separate accompanying JSON file, as we did with previous XKT versions.
     * However, if we do choose to specify a separate metamodel JSON file to load (eg. for backward compatibility
     * in data pipelines), then that metamodel will be loaded and the metamodel in the XKT 8 file will be ignored.
     *
     * @param {*} params Loading parameters.
     * @param {String} [params.id] ID to assign to the root {@link Entity#id}, unique among all components in the Viewer's {@link Scene}, generated automatically by default.
     * @param {String} [params.src] Path to a *````.xkt````* file, as an alternative to the ````xkt```` parameter.
     * @param {ArrayBuffer} [params.xkt] The *````.xkt````* file data, as an alternative to the ````src```` parameter.
     * @param {String} [params.metaModelSrc] Path to an optional metadata file, as an alternative to the ````metaModelData```` parameter.
     * @param {*} [params.metaModelData] JSON model metadata, as an alternative to the ````metaModelSrc```` parameter.
     * @param {{String:Object}} [params.objectDefaults] Map of initial default states for each loaded {@link Entity} that represents an object. Default value is {@link IFCObjectDefaults}.
     * @param {String[]} [params.includeTypes] When loading metadata, only loads objects that have {@link MetaObject}s with {@link MetaObject#type} values in this list.
     * @param {String[]} [params.excludeTypes] When loading metadata, never loads objects that have {@link MetaObject}s with {@link MetaObject#type} values in this list.
     * @param {Boolean} [params.edges=false] Whether or not xeokit renders the model with edges emphasized.
     * @param {Number[]} [params.origin=[0,0,0]] The model's World-space double-precision 3D origin. Use this to position the model within xeokit's World coordinate system, using double-precision coordinates.
     * @param {Number[]} [params.position=[0,0,0]] The model single-precision 3D position, relative to the ````origin```` parameter.
     * @param {Number[]} [params.scale=[1,1,1]] The model's scale.
     * @param {Number[]} [params.rotation=[0,0,0]] The model's orientation, given as Euler angles in degrees, for each of the X, Y and Z axis.
     * @param {Number[]} [params.matrix=[1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1]] The model's world transform matrix. Overrides the position, scale and rotation parameters. Relative to ````origin````.
     * @param {Boolean} [params.edges=false] Indicates if the model's edges are initially emphasized.
     * @param {Boolean} [params.saoEnabled=true] Indicates if Scalable Ambient Obscurance (SAO) will apply to the model. SAO is configured by the Scene's {@link SAO} component. Only works when {@link SAO#enabled} is also ````true````
     * @param {Boolean} [params.pbrEnabled=false] Indicates if physically-based rendering (PBR) will apply to the model. Only works when {@link Scene#pbrEnabled} is also ````true````.
     * @param {Number} [params.backfaces=false] When we set this ````true````, then we force rendering of backfaces for the model. When
     * we leave this ````false````, then we allow the Viewer to decide when to render backfaces. In that case, the
     * Viewer will hide backfaces on watertight meshes, show backfaces on open meshes, and always show backfaces on meshes when we slice them open with {@link SectionPlane}s.
     * @param {Boolean} [params.excludeUnclassifiedObjects=false] When loading metadata and this is ````true````, will only load {@link Entity}s that have {@link MetaObject}s (that are not excluded). This is useful when we don't want Entitys in the Scene that are not represented within IFC navigation components, such as {@link TreeViewPlugin}.
     * @param {Boolean} [params.globalizeObjectIds=false] Indicates whether to globalize each {@link Entity#id} and {@link MetaObject#id}, in case you need to prevent ID clashes with other models. See {@link XKTLoaderPlugin#globalizeObjectIds} for more info.
     * @param {Boolean} [params.reuseGeometries=true] Indicates whether to enable geometry reuse (````true```` by default) or whether to expand
     * all geometry instances into batches (````false````), and not use instancing to render them. Setting this ````false```` can significantly
     * improve Viewer performance for models that have excessive geometry reuse, but may also increases the amount of
     * browser and GPU memory used by the model. See [#769](https://github.com/xeokit/xeokit-sdk/issues/769) for more info.
     * @returns {Entity} Entity representing the model, which will have {@link Entity#isModel} set ````true```` and will be registered by {@link Entity#id} in {@link Scene#models}.
     */
    load(params = {}) {

        if (params.id && this.viewer.scene.components[params.id]) {
            this.error("Component with this ID already exists in viewer: " + params.id + " - will autogenerate this ID");
            delete params.id;
        }

        const performanceModel = new PerformanceModel(this.viewer.scene, utils.apply(params, {
            isModel: true,
            maxGeometryBatchSize: this._maxGeometryBatchSize,
            origin: params.origin
        }));

        const modelId = performanceModel.id;  // In case ID was auto-generated

        if (!params.src && !params.xkt) {
            this.error("load() param expected: src or xkt");
            return performanceModel; // Return new empty model
        }

        const options = {};
        const includeTypes = params.includeTypes || this._includeTypes;
        const excludeTypes = params.excludeTypes || this._excludeTypes;
        const objectDefaults = params.objectDefaults || this._objectDefaults;

        options.reuseGeometries = (params.reuseGeometries !== null && params.reuseGeometries !== undefined ) ? params.reuseGeometries : (this._reuseGeometries !== false);

        if (includeTypes) {
            options.includeTypesMap = {};
            for (let i = 0, len = includeTypes.length; i < len; i++) {
                options.includeTypesMap[includeTypes[i]] = true;
            }
        }

        if (excludeTypes) {
            options.excludeTypesMap = {};
            for (let i = 0, len = excludeTypes.length; i < len; i++) {
                options.excludeTypesMap[excludeTypes[i]] = true;
            }
        }

        if (objectDefaults) {
            options.objectDefaults = objectDefaults;
        }

        options.excludeUnclassifiedObjects = (params.excludeUnclassifiedObjects !== undefined) ? (!!params.excludeUnclassifiedObjects) : this._excludeUnclassifiedObjects;
        options.globalizeObjectIds = (params.globalizeObjectIds !== undefined) ? (!!params.globalizeObjectIds) : this._globalizeObjectIds;

        if (params.metaModelSrc || params.metaModelData) {

            const processMetaModelData = (metaModelData) => {

                const metaModel = this.viewer.metaScene.createMetaModel(modelId, metaModelData, {
                    includeTypes: includeTypes,
                    excludeTypes: excludeTypes,
                    globalizeObjectIds: this.globalizeObjectIds
                });

                if (!metaModel) {
                    return false;
                }

                if (params.src) {
                    this._loadModel(params.src, params, options, performanceModel);
                } else {
                    this._parseModel(params.xkt, params, options, performanceModel);
                }

                performanceModel.once("destroyed", () => {
                    this.viewer.metaScene.destroyMetaModel(performanceModel.id);
                });

                return true;
            };

            if (params.metaModelSrc) {

                const metaModelSrc = params.metaModelSrc;

                this.viewer.scene.canvas.spinner.processes++;

                this._dataSource.getMetaModel(metaModelSrc, (metaModelData) => {

                    if (performanceModel.destroyed) {
                        return;
                    }

                    if (!processMetaModelData(metaModelData)) {

                        this.error(`load(): Failed to load model metadata for model '${modelId} from '${metaModelSrc}' - metadata not valid`);

                        performanceModel.fire("error", "Metadata not valid");
                    }

                    this.viewer.scene.canvas.spinner.processes--;

                }, (errMsg) => {

                    this.error(`load(): Failed to load model metadata for model '${modelId} from  '${metaModelSrc}' - ${errMsg}`);

                    performanceModel.fire("error", `Failed to load model metadata from  '${metaModelSrc}' - ${errMsg}`);

                    this.viewer.scene.canvas.spinner.processes--;
                });

            } else if (params.metaModelData) {

                if (!processMetaModelData(params.metaModelData)) {

                    this.error(`load(): Failed to load model metadata for model '${modelId} from '${params.metaModelSrc}' - metadata not valid`);

                    performanceModel.fire("error", "Metadata not valid");
                }
            }

        } else {
            if (params.src) {
                this._loadModel(params.src, params, options, performanceModel);
            } else {
                this._parseModel(params.xkt, params, options, performanceModel);
            }
        }

        return performanceModel;
    }

    _loadModel(src, params, options, performanceModel) {

        const spinner = this.viewer.scene.canvas.spinner;

        spinner.processes++;

        this._dataSource.getXKT(params.src, (arrayBuffer) => {
                this._parseModel(arrayBuffer, params, options, performanceModel);
                spinner.processes--;
            },
            (errMsg) => {
                spinner.processes--;
                this.error(errMsg);
                performanceModel.fire("error", errMsg);
            });
    }

    _parseModel(arrayBuffer, params, options, performanceModel) {

        if (performanceModel.destroyed) {
            return;
        }

        const dataView = new DataView(arrayBuffer);
        const dataArray = new Uint8Array(arrayBuffer);
        const xktVersion = dataView.getUint32(0, true);
        const parser = parsers[xktVersion];

        if (!parser) {
            this.error("Unsupported .XKT file version: " + xktVersion + " - this XKTLoaderPlugin supports versions " + Object.keys(parsers));
            return;
        }

        this.log("Loading .xkt V" + xktVersion);

        const numElements = dataView.getUint32(4, true);
        const elements = [];
        let byteOffset = (numElements + 2) * 4;
        for (let i = 0; i < numElements; i++) {
            const elementSize = dataView.getUint32((i + 2) * 4, true);
            elements.push(dataArray.subarray(byteOffset, byteOffset + elementSize));
            byteOffset += elementSize;
        }

        parser.parse(this.viewer, options, elements, performanceModel);

        performanceModel.finalize();

        this._createDefaultMetaModelIfNeeded(performanceModel, params, options);

        performanceModel.scene.once("tick", () => {
            if (performanceModel.destroyed) {
                return;
            }
            performanceModel.scene.fire("modelLoaded", performanceModel.id); // FIXME: Assumes listeners know order of these two events
            performanceModel.fire("loaded", true, false); // Don't forget the event, for late subscribers
        });
    }

    _createDefaultMetaModelIfNeeded(performanceModel, params, options) {

        const metaModelId = performanceModel.id;

        if (!this.viewer.metaScene.metaModels[metaModelId]) {

            const metaModelData = {
                metaObjects: []
            };

            metaModelData.metaObjects.push({
                id: metaModelId,
                type: "default",
                name: metaModelId,
                parent: null
            });

            const entityList = performanceModel.entityList;

            for (let i = 0, len = entityList.length; i < len; i++) {
                const entity = entityList[i];
                if (entity.isObject) {
                    metaModelData.metaObjects.push({
                        id: entity.id,
                        type: "default",
                        name: entity.id,
                        parent: metaModelId
                    });
                }
            }

            const src = params.src;

            this.viewer.metaScene.createMetaModel(metaModelId, metaModelData, {

                includeTypes: options.includeTypes,
                excludeTypes: options.excludeTypes,
                globalizeObjectIds: options.globalizeObjectIds,

                getProperties: async (propertiesId) => {
                    return await this._dataSource.getProperties(src, propertiesId);
                }
            });

            performanceModel.once("destroyed", () => {
                this.viewer.metaScene.destroyMetaModel(metaModelId);
            });
        }
    }
}

export {XKTLoaderPlugin}