ce = null;
    let xrGLFactory = null;
    let xrFramebuffer = null;
    let stereoUtil = null;

    // WebGL scene globals.
    let gl = null;
    let renderer = null;
    let scene = new Scene();

    // Layer globals
    let projLayer = null;
    let quadLayer1 = null;
    let quadTexture1 = null;
    let quadTexture1Width = 0;
    let quadTexture1Height = 0;
    let quad1Collider = null;
    let quadLayer2 = null;
    let quadTexture2 = null;
    let quadTexture2Width = 0;
    let quadTexture2Height = 0