/*****
 *
 *   Point2D.js
 *
 *   copyright 2001-2002, Kevin Lindsey
 *
 *****/

/*****
 *
 *   Point2D
 *
 *****/

/*****
 *
 *   constructor
 *
 *****/
function Point2D(x, y) {
  if ( arguments.length > 0 ) {
    this.init(x, y);
  }
}


/*****
 *
 *   init
 *
 *****/
Point2D.prototype.init = function(x, y) {
  this.x = x;
  this.y = y;
};


/*****
 *
 *   add
 *
 *****/
Point2D.prototype.add = function(that) {
  return new Point2D(this.x+that.x, this.y+that.y);
};


/*****
 *
 *   addEquals
 *
 *****/
Point2D.prototype.addEquals = function(that) {
  this.x += that.x;
  this.y += that.y;
  
  return this;
};


/*****
 *
 *   scalarAdd
 *
 *****/
Point2D.prototype.scalarAdd = function(scalar) {
  return new Point2D(this.x+scalar, this.y+scalar);
};


/*****
 *
 *   scalarAddEquals
 *
 *****/
Point2D.prototype.scalarAddEquals = function(scalar) {
  this.x += scalar;
  this.y += scalar;
  
  return this;
};


/*****
 *
 *   subtract
 *
 *****/
Point2D.prototype.subtract = function(that) {
  return new Point2D(this.x-that.x, this.y-that.y);
};


/*****
 *
 *   subtractEquals
 *
 *****/
Point2D.prototype.subtractEquals = function(that) {
  this.x -= that.x;
  this.y -= that.y;
  
  return this;
};


/*****
 *
 *   scalarSubtract
 *
 *****/
Point2D.prototype.scalarSubtract = function(scalar) {
  return new Point2D(this.x-scalar, this.y-scalar);
};
/*****
 *
 *   scalarSubtractEquals
 *
 *****/
Point2D.prototype.scalarSubtractEquals = function(scalar) {
  this.x -= scalar;
  this.y -= scalar;
  
  return this;
};


/*****
 *
 *   multiply
 *
 *****/
Point2D.prototype.multiply = function(scalar) {
  return new Point2D(this.x*scalar, this.y*scalar);
};

/*****
 *
 *   multiplyxy
 *  Added by Hawkeye King hawkeye@aruke.com
 *   
 *****/
Point2D.prototype.multiplyxy = function(scalarx, scalary) {
  return new Point2D(this.x*scalarx, this.y*scalary);
};


/*****
 *
 *   multiplyEquals
 *
 *****/
Point2D.prototype.multiplyEquals = function(scalar) {
  this.x *= scalar;
  this.y *= scalar;
  
  return this;
};


/*****
 *
 *   divide
 *
 *****/
Point2D.prototype.divide = function(scalar) {
  return new Point2D(this.x/scalar, this.y/scalar);
};


/*****
 *
 *   divideEquals
 *
 *****/
Point2D.prototype.divideEquals = function(scalar) {
  this.x /= scalar;
  this.y /= scalar;

  return this;
};


/*****
 *
 *   comparison methods
 *
 *****/

/*****
 *
 *   eq - equal
 *
 *****/
Point2D.prototype.eq = function(that) {
  return ( this.x == that.x && this.y == that.y );
};


/*****
 *
 *   lt - less than
 *
 *****/
Point2D.prototype.lt = function(that) {
  return ( this.x < that.x && this.y < that.y );
};


/*****
 *
 *   lte - less than or equal
 *
 *****/
Point2D.prototype.lte = function(that) {
  return ( this.x <= that.x && this.y <= that.y );
};


/*****
 *
 *   gt - greater than
 *
 *****/
Point2D.prototype.gt = function(that) {
  return ( this.x > that.x && this.y > that.y );
};


/*****
 *
 *   gte - greater than or equal
 *
 *****/
Point2D.prototype.gte = function(that) {
  return ( this.x >= that.x && this.y >= that.y );
};


/*****
 *
 *   utility methods
 *
 *****/

/*****
 *
 *   lerp
 *
 *****/
Point2D.prototype.lerp = function(that, t) {
  return new Point2D(
		     this.x + (that.x - this.x) * t,
		     this.y + (that.y - this.y) * t
		     );
};


/*****
 *
 *   distanceFrom
 *
 *****/
Point2D.prototype.distanceFrom = function(that) {
  var dx = this.x - that.x;
  var dy = this.y - that.y;
  
  return Math.sqrt(dx*dx + dy*dy);
};


/*****
 *
 *   min
 *
 *****/
Point2D.prototype.min = function(that) {
  return new Point2D(
		     Math.min( this.x, that.x ),
		     Math.min( this.y, that.y )
		     );
};


/*****
 *
 *   max
 *
 *****/
Point2D.prototype.max = function(that) {
  return new Point2D(
		     Math.max( this.x, that.x ),
		     Math.max( this.y, that.y )
		     );
};


/*****
 *
 *   toString
 *
 *****/
Point2D.prototype.toString = function() {
  return this.x + "," + this.y;
};


/*****
 *
 *   get/set methods
 *
 *****/

/*****
 *
 *   setXY
 *
 *****/
Point2D.prototype.setXY = function(x, y) {
  this.x = x;
  this.y = y;
};


/*****
 *
 *   setFromPoint
 *
 *****/
Point2D.prototype.setFromPoint = function(that) {
  this.x = that.x;
  this.y = that.y;
};


/*****
 *
 *   swap
 *
 *****/
Point2D.prototype.swap = function(that) {
  var x = this.x;
  var y = this.y;
  
  this.x = that.x;
  this.y = that.y;

  that.x = x;
  that.y = y;
};