Physical Relationships

/**
 * Copyright bradsedito ( http://wonderfl.net/user/bradsedito )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/eKQX
 */

    
    
    
    
package 
{
    import flash.display.Sprite;
    import flash.events.Event;
    
    
    public class PhysicalRelationships extends Sprite 
    {        
        public  var circle:Sprite = new Sprite();
        public  var number:Number = 5;        
        private var circles:Array = new Array();
        private var circleVX:Array = new Array();
        private var circleVY:Array = new Array();
        private var REAL_NUMBER_OF_CIRCLES:Number = 0;
        private var numberOfCircles:Number = 20; 


        public function PhysicalRelationships() 
        {     
            circle.graphics.beginFill(0xFFEEDD);
            circle.graphics.drawCircle(30,40,25);
            circle.graphics.endFill();
            this.addChild(circle);
            
            REAL_NUMBER_OF_CIRCLES = numberOfCircles;
            while(numberOfCircles>0)
            {
                var c:Sprite = new Sprite();
                c.graphics.beginFill(0xa4bed4);
                c.graphics.drawCircle(0,0,5);
                c.graphics.endFill();
                c.x = 30+numberOfCircles*10;
                c.y = 40+numberOfCircles*10;
                circleVX.push(0);
                circleVY.push(0);
                circles.push(c);
                this.addChild(c);
                
                numberOfCircles = numberOfCircles-1;
            }
            
            this.addEventListener(Event.ENTER_FRAME,doStuff);
        }
        
        public function doStuff( e:Event=null ):void
        {
            number = number+1;       
            circle.x = number;
            
            var i:int = REAL_NUMBER_OF_CIRCLES;
            while(i>0){
                
                //f=m1 m2 G/r2
                var c:Sprite = circles[i-1];
                var dx:Number = this.stage.mouseX-c.x;
                var dy:Number = this.stage.mouseY-c.y;
                var d:Number = Math.sqrt(dx*dx+dy*dy);
                var ndx:Number = dx/d;
                var ndy:Number = dy/d;
                var F:Number = -10/(d*d);
                circleVX[i-1] += F*ndx;
                circleVY[i-1] += F*ndy;
                c.x += circleVX[i-1];
                c.y += circleVY[i-1];
                i--;
            }  
        }

    }
}