function Vec2() {
      var x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
      var y = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : x;

      _classCallCheck(this, Vec2);

      this.type = "Vec2";
      this._x = x;
      this._y = y;
    }
Here we create a Vec2 class object
   This is a really basic Vector2 class used for vector calculations
   Highly based on https://github.com/mrdoob/three.js/blob/dev/src/math/Vector2.js and http://glmatrix.net/docs/vec2.js.html
     params :
   @x (float): X component of our vector
   @y (float): Y component of our vector
     returns :
   @this: our Vec2 class object
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