ts for interactions with the DOM overlay
    document.querySelector('header').addEventListener('beforexrselect', (ev) => {
      console.log(ev.type);
      ev.preventDefault();
    });

    let xrButton = null;
    let controller1, controller2;
    let controllerGrip1, controllerGrip2;

    let container;
    let camera, scene, renderer, font;
    const tempMatrix = new THREE.Matrix4();

    let reticle;
    // hitResult will be set when reticle is visible:
    let hitResult;

    const meshMaterials = [];