examples/vr_crop/quickhull.js
function VertexNode(point) {
    this.point = point;
    this.prev = null;
    this.next = null;
    this.face = null; // the face that is able to see this vertex
  }
function VertexNode(point) {
    this.point = point;
    this.prev = null;
    this.next = null;
    this.face = null; // the face that is able to see this vertex
  }
A vertex as a double linked list node.