ffrgb / meshviewer

define(function () {

  var self = this;

  self.distance = function distance(a, b) {

    return Math.pow(a.x - b.x, 2) + Math.pow(a.y - b.y, 2);

  };

  self.distancePoint = function distancePoint(a, b) {

    return Math.sqrt(distance(a, b));

  };

  self.distanceLink = function distanceLink(p, a, b) {

    /* http://stackoverflow.com/questions/849211 */

    var l2 = distance(a, b);

    if (l2 === 0) {

      return distance(p, a);

    }

    var t = ((p.x - a.x) * (b.x - a.x) + (p.y - a.y) * (b.y - a.y)) / l2;

    if (t < 0) {

      return distance(p, a);

    }

    if (t > 1) {

      return distance(p, b);

    }

    return distancePoint(p, {

      x: a.x + t * (b.x - a.x),

      y: a.y + t * (b.y - a.y)

    });

  };

  return self;

});