/render/nodes/gltf2.js';
      import {SkyboxNode} from './js/render/nodes/skybox.js';
      import {QueryArgs} from './js/util/query-args.js';

      import WebXRPolyfill from './js/third-party/webxr-polyfill/build/webxr-polyfill.module.js';
      if (QueryArgs.getBool('usePolyfill', true)) {
        let polyfill = new WebXRPolyfill();
      }

      // XR globals.
      let xrButton = null;
      let xrRefSpace = null;

      // WebGL scene globals.
      let gl = null;
      let renderer = null;
      le