iTowns / itowns / 19039246919

import { CRS } from '@itowns/geographic';

import LASParser from 'Parser/LASParser';

import Fetcher from 'Provider/Fetcher';

import Source from 'Source/Source';

import { CopcSource, EntwinePointTileSource } from 'Main';

import { LRUCache } from 'lru-cache';

const cachedSources = new LRUCache({ max: 500 });

/**

 * An object defining the source of Entwine Point Tile data. It fetches and

 * parses the main configuration file of Entwine Point Tile format,

 * [`ept.json`](https://entwine.io/entwine-point-tile.html#ept-json).

 *

 * @extends Source

 *

 * @property {boolean} isEntwinePointTileSource - Used to checkout whether this

 * source is a EntwinePointTileSource. Default is true. You should not change

 * this, as it is used internally for optimisation.

 * @property {string} url - The URL of the directory containing the whole

 * Entwine Point Tile structure.

 * @property {Object[]|PointCloudSource[]} sources - Array of all the source described in the VPC.

 * initialized with mockSource that will be replace by COPC or EPT Source as soon as any data need

 * to be loaded.

 */

class VpcSource extends Source {

    /**

     * @param {Object} config - The configuration, see {@link Source} for

     * available values.

     * @param {number} [config.colorDepth] - Color depth (in bits).

     * Either 8 or 16 bits. By defaults it will be set to 8 bits for LAS 1.2 and

     * 16 bits for later versions (as mandatory by the specification).

     */

    constructor(config) {

        super(config);

        this.isVpcSource = true;

        this.sources = [];

        this.parser = LASParser.parseChunk;

        this.fetcher = Fetcher.arrayBuffer;

        this.colorDepth = config.colorDepth;

        this.spacing = Infinity;

        this.whenReady = Fetcher.json(this.url, this.networkOptions)

            .then((metadata) => {

                this.metadata = metadata;

                // Set boundsConformings (the bbox) of the VPC Layer

                const boundsConformings = metadata.features.map(f => f.properties['proj:bbox']);

                this.boundsConforming = [

                    Math.min(...boundsConformings.map(b => b[0])),

                    Math.min(...boundsConformings.map(b => b[1])),

                    Math.min(...boundsConformings.map(b => b[2])),

                    Math.max(...boundsConformings.map(b => b[3])),

                    Math.max(...boundsConformings.map(b => b[4])),

                    Math.max(...boundsConformings.map(b => b[5])),

                ];

                // Set the zmin and zmax from the source

                this.minElevation = this.boundsConforming[2];

                this.maxElevation = this.boundsConforming[5];

                // Set the Crs of the VPC Layer (currently we only use the first)

                const projsWkt2 = [...new Set(metadata.features.map(f => f.properties['proj:wkt2']))];

                this.crs = CRS.defsFromWkt(projsWkt2[0]);

                /* Set  several object (MockSource) to mock the source that will need to be instantiated.

                 We don't want all child source to be instantiated at once as it will send the fetch request

                 (current architectural choice) thus we want to delay the instanciation of the child source

                 when the data need to be load on a particular node.

                 Creation of 1 mockSource for each item in the stack (that will be replace by a real source

                 when needed, when we will call the load on a node depending of that source).

                */

                this._promises = [];

                this.urls = metadata.features.map(f => f.assets.data.href);

                this.urls.forEach((url, i) => {

                    const whenReady = new Promise((re, rj) => {

                        // waiting for this.instantiate(source);

                        this._promises.push({ resolve: re, reject: rj });

                    }).then((res) => {

                        // replace the mock source by the real source (instantiated)

                        this.sources[i] = res;

                        return res;

                    }).catch((err) => {

                    });

                    const mockSource = {

                        url,

                        boundsConforming: boundsConformings[i],

                        whenReady,

                        sId: i,

                    };

                    this.sources.push(mockSource);

                });

                return this.sources;

            });

    }

    /**

     * We created several objects mocking a source at the intantiation of the vpc layer.

     * The following method will be called when we need to instantiate the real source (COPC or EPT).

     * The mock source contain the url to instantiate the source as well as a promise that

     * will be resolve when the source.whenReady promise will resolve.

     * To avoid instanciating several time the same source, we use a cache to store the

     * whenReady promise of the source (cachedSources).

     *

     * @param {object} source - The mock source used to instantiate the real source.

     * @param {object} source.url - The url of the source to instanciate.

     */

    instantiate(source) {

        let newSource;

        const url = source.url;

        let cachedSrc = cachedSources.get(url);

        if (!cachedSrc) {

            if (url.includes('.copc')) {

                newSource = new CopcSource({ url });

            } else if (url.includes('.json')) {

                newSource = new EntwinePointTileSource({ url });

            cachedSrc = newSource;

            cachedSources.set(url, cachedSrc);

        }

        this._promises[source.sId].resolve(cachedSrc.whenReady);

    }

}

export default VpcSource;