paths-js/beachline.js

Paths.js ========

'use strict';

Object.defineProperty(exports, '__esModule', {
  value: true
});

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

var _binarytree = require('./binarytree');

var _binarytree2 = _interopRequireDefault(_binarytree);

var _segment = require('./segment');

var _segment2 = _interopRequireDefault(_segment);

var _geom = require('./geom');

var _geom2 = _interopRequireDefault(_geom);

function Beachline(item, parent, l, r, cEvent) {
  _binarytree2['default'].call(this, item, parent, l, r);
  this.cEvent = cEvent;
}

Beachline.prototype = Object.create(_binarytree2['default'].prototype);

Beachline.prototype.isLeaf = function () {
  return this.l === undefined;
};

Beachline.prototype.getArcNodeOnSite = function (site) {
  var curNode = this;
  var solN = undefined;

  while (!curNode.isLeaf()) {
    curNode.item.pl[1] < curNode.item.pr[1] ? solN = 0 : solN = 1;
    curNode = site[0] < _geom2['default'].parabolsCrossX(curNode.item.pl, curNode.item.pr, site[1])[solN] ? curNode.l : curNode.r;
  }
  return curNode;
};

Beachline.prototype.addArc = function (newArcSite, arcsNodes) {
  var lArcNode = arcsNodes[0];
  var crossedArcNode = arcsNodes[1];
  var rArcNode = arcsNodes[2];
  var crossedArcSite = crossedArcNode.item;
  var crossPoint = [newArcSite[0], newArcSite[1] - _geom2['default'].distPointToParabol(newArcSite, crossedArcSite)];
  var newLHalfedge = new _segment2['default'](crossedArcSite, newArcSite, crossPoint);
  var newRHalfedge = new _segment2['default'](newArcSite, crossedArcSite, crossPoint);

  crossedArcNode.item = newLHalfedge;
  crossedArcNode.addLChild(new Beachline(crossedArcSite));
  crossedArcNode.addRChild(new Beachline(newRHalfedge));
  crossedArcNode.r.addLChild(new Beachline(newArcSite));
  crossedArcNode.r.addRChild(new Beachline(crossedArcSite));

  if (lArcNode != undefined && lArcNode.cEvent != undefined) {
    lArcNode.cEvent.arcsNodes[2] = crossedArcNode.l;
  }
  if (rArcNode != undefined && rArcNode.cEvent != undefined) {
    rArcNode.cEvent.arcsNodes[0] = crossedArcNode.r.r;
  }
};

Beachline.prototype.rmArc = function (newEdgeStart, arcsNodes, edgesNodes) {
  var liveLArcNode = arcsNodes[0];
  var deadArcNode = arcsNodes[1];
  var liveRArcNode = arcsNodes[2];

  if (deadArcNode.isRChild()) {
    var liveCutBranch = edgesNodes[0].l;
    var midEdgeNode = edgesNodes[0];
    var topEdgeNode = edgesNodes[1];
  } else {
    var liveCutBranch = edgesNodes[1].r;
    var midEdgeNode = edgesNodes[1];
    var topEdgeNode = edgesNodes[0];
  }

  topEdgeNode.item = new _segment2['default'](liveLArcNode.item, liveRArcNode.item, newEdgeStart);

  if (midEdgeNode.isRChild()) {
    midEdgeNode.parent.r = liveCutBranch;
  } else {
    midEdgeNode.parent.l = liveCutBranch;
  }
  liveCutBranch.parent = midEdgeNode.parent;
};

exports['default'] = Beachline;
module.exports = exports['default'];