ffrgb / meshviewer

define(function () {

  return {

    distance: function distance(a, b) {

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

    },

    distancePoint: function distancePoint(a, b) {

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

    },

    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);

      } else 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)

      });

    }

  };

});