Babylon.js/Viewer/src/loader/plugins/msftLodLoaderPlugin.ts

import { ISceneLoaderPlugin, ISceneLoaderPluginAsync } from 'babylonjs';
import { IGLTFLoaderExtension, GLTF2 } from 'babylonjs-loaders';

import { ViewerModel } from '../../model/viewerModel';
import { ILoaderPlugin } from './loaderPlugin';

/**
 * A loder plugin to use MSFT_lod extension correctly (glTF)
 */
export class MSFTLodLoaderPlugin implements ILoaderPlugin {

    private _model: ViewerModel;

    public onInit(loader: ISceneLoaderPlugin | ISceneLoaderPluginAsync, model: ViewerModel) {
        this._model = model;
    }

    public onExtensionLoaded(extension: IGLTFLoaderExtension) {
        if (extension.name === "MSFT_lod" && this._model.configuration.loaderConfiguration) {
            const MSFT_lod = extension as GLTF2.Loader.Extensions.MSFT_lod;
            MSFT_lod.enabled = !!this._model.configuration.loaderConfiguration.progressiveLoading;
            MSFT_lod.maxLODsToLoad = this._model.configuration.loaderConfiguration.maxLODsToLoad || Number.MAX_VALUE;
        }
    }
}