code: function LLink(id, type, origin_id, origin_slot, target_id, target_slot) {
          this.id = id;
          this.type = type;
          this.origin_id = origin_id;
          this.origin_slot = origin_slot;
          this.target_id = target_id;
          this.target_slot = target_slot;
  
          this._data = null;
          this._pos = new Float32Array(2); //center
      }
docs: this is the class in charge of storing link information