code: function parallax(progress) {
    var range = this.options.range || 0;
    var offset = progress * range;        // TODO add provision for speed as well
  
    this.transforms.position[1] = offset;   // just vertical for now
  }
docs: Parallax an element.
  @param {Float} progress  Current progress data of the scene, between 0 and 1.
  @this {Object}
  @return {void}