docs: function CardboardUI(gl) {
    this.gl = gl;
  
    this.attribs = {
      position: 0
    };
    this.program = Util.linkProgram(gl, uiVS, uiFS, this.attribs);
    this.uniforms = Util.getProgramUniforms(gl, this.program);
  
    this.vertexBuffer = gl.createBuffer();
    this.gearOffset = 0;
    this.gearVertexCount = 0;
    this.arrowOffset = 0;
    this.arrowVertexCount = 0;
  
    this.projMat = new Float32Array(16);
  
    this.listener = null;
  
    this.onResize();
  }