Joystick control for LimeJS

gistfile1.js

goog.provide('remote.Joystick');

goog.require('lime.Sprite');
goog.require('lime.animation.FadeTo');
goog.require('lime.Circle');
goog.require('goog.events.Event');

/**
 Usage:
 var joystick = new remote.Joystick().setSize(200, 200).setFill('#c00').setPosition(100, 100);
 layer.appendChild(joystick);
 goog.events.listen(joystick, 'impulse', function(e){
   var velocityX = e.v[0];
   var velocityY = e.v[1];
 });
*/

remote.Joystick = function(){
    lime.Sprite.call(this);
    
    this.EASING = 0.2;
    this.SPRING = 0.005;
    this.FRICTION = 0.95;
    this.LAG = 50;
    this.RADIUS = 80;
    
    this.control = new lime.Layer();
    
    this.mousePosition = this.control.getPosition().clone();
    this.realPosition = this.control.getPosition().clone();
    
    this.outer = new lime.Circle().setFill(0,0,100,.3).setSize(150,150);
    this.inner = new lime.Circle().setFill(255,215,0).setSize(60,60);
    
    this.control.appendChild(this.outer);
    this.control.appendChild(this.inner);
    
    this.appendChild(this.control);
    this.control.setOpacity(0);

    goog.events.listen(this,['mousedown','touchstart'],this.downHandler_,false,this);
    
    lime.scheduleManager.schedule(this.draw_,this);

}
goog.inherits(remote.Joystick,lime.Sprite);


remote.Joystick.prototype.downHandler_ = function(e){
    e.swallow(['mousemove','touchmove'],this.moveHandler_);
    e.swallow(['mouseup','touchend','touchcancel'],this.upHandler_);
    
    this.control.setPosition(e.position.clone());
    this.mousePosition=(e.position.clone());
    this.realPosition=(e.position.clone());
    
    this.move(e);
    
    this.control.runAction(new lime.animation.FadeTo(1).setDuration(.3));
}

remote.Joystick.prototype.moveHandler_ = function(e){
    this.move(e);
}

remote.Joystick.prototype.upHandler_ = function(e){
    this.cancel();
    this.control.runAction(new lime.animation.FadeTo(0).setDuration(.3));
}

remote.Joystick.prototype.move = function(e){
    var len1 = this.RADIUS;
    var len2 = this.RADIUS*4;
    var mp = goog.math.Vec2.difference(e.position,this.control.getPosition());
    var dt = goog.math.Vec2.dot(mp,mp);
    if(dt>len2*len2) return this.cancel();
    
    if(dt>len1*len1) mp = mp.normalize().scale(len1);
    
    this.mousePosition = goog.math.Coordinate.sum(mp,this.control.getPosition());
}

remote.Joystick.prototype.cancel = function(){
    this.mousePosition = this.control.getPosition().clone();
}

remote.Joystick.prototype.draw_ = function(){
    var delta = goog.math.Vec2.difference(this.mousePosition,this.realPosition);
    var v = new goog.math.Vec2(
            delta.x * Math.abs(delta.x) * (this.EASING / this.LAG),
            delta.y * Math.abs(delta.y) * (this.EASING / this.LAG)
        );
    this.realPosition.x+=v.x;
    this.realPosition.y+=v.y;
    var pos = goog.math.Coordinate.difference(this.realPosition,this.control.getPosition());
   
    if(Math.abs(pos.x)>5 || Math.abs(pos.y)>5){
        var ev = new goog.events.Event('impulse');
        ev.v=[pos.x/this.RADIUS,pos.y/this.RADIUS];
        this.dispatchEvent(ev);
    }
     this.inner.setPosition(pos);
}

remote.Joystick.prototype.getValue = function(){
    var val = goog.math.Vec2.fromCoordinate(this.inner.getPosition());
    val.scale(1/this.RADIUS);
    return val;
}