package {
        import flash.display.DisplayObject;
        import flash.display.Sprite;
        import flash.display.StageScaleMode;
        import flash.display.StageAlign;
        import flash.events.Event;
        import flash.geom.Point;

        [SWF(backgroundColor=0x000000)]
        public class @ax-lib-flex-animation-code-01-NodeGarden-NodeGardenGrid extends Sprite
        {
                private var particles:Vector.<DisplayObject>;
                private var numParticles:uint = 500;
                private var minDist:Number = 50;
                private var springAmount:Number = .001;
                private var grid:CollisionGrid;
                
                public function @ax-lib-flex-animation-code-01-NodeGarden-NodeGardenGrid()
                {
                        init();
                }
                
                private function init():void
                {
                        stage.scaleMode = StageScaleMode.NO_SCALE;
                        stage.align = StageAlign.TOP_LEFT;
                        
                        grid = new CollisionGrid(stage.stageWidth, stage.stageHeight, 50);
                        particles = new Vector.<DisplayObject>();
                        for(var i:uint = 0; i < numParticles; i++)
                        {
                                var particle:Ball = new Ball(3, 0xffffff);
                                particle.x = Math.random() * stage.stageWidth;
                                particle.y = Math.random() * stage.stageHeight;
                                particle.vx = Math.random() * 6 - 3;
                                particle.vy = Math.random() * 6 - 3;
                                addChild(particle);
                                particles.push(particle);
                        }
                        
                        addEventListener(Event.ENTER_FRAME, onEnterFrame);
                }

                private function onEnterFrame(event:Event):void
                {
                        graphics.clear();
                        for(var i:uint = 0; i < numParticles; i++)
                        {
                                var particle:Ball = particles[i] as Ball;
                                particle.x += particle.vx;
                                particle.y += particle.vy;
                                if(particle.x > stage.stageWidth)
                                {
                                        particle.x = 0;
                                }
                                else if(particle.x < 0)
                                {
                                        particle.x = stage.stageWidth;
                                }
                                if(particle.y > stage.stageHeight)
                                {
                                        particle.y = 0;
                                }
                                else if(particle.y < 0)
                                {
                                        particle.y = stage.stageHeight;
                                }
                        }
                        grid.check(particles);
                        var checks:Vector.<DisplayObject> = grid.checks;
                        trace(checks.length);
                        var numChecks:int = checks.length;
                        for(i=0; i < numChecks; i += 2)
                        {
                                var partA:Ball = checks[i] as Ball;
                                var partB:Ball = checks[i + 1] as Ball;
                                spring(partA, partB);
                        }
                }
                
                private function spring(partA:Ball, partB:Ball):void
                {
                        var dx:Number = partB.x - partA.x;
                        var dy:Number = partB.y - partA.y;
                        var dist:Number = Math.sqrt(dx * dx + dy * dy);
                        if(dist < minDist)
                        {
                                graphics.lineStyle(1, 0xffffff, 1 - dist / minDist);
                                graphics.moveTo(partA.x, partA.y);
                                graphics.lineTo(partB.x, partB.y);
                                var ax:Number = dx * springAmount;
                                var ay:Number = dy * springAmount;
                                partA.vx += ax;
                                partA.vy += ay;
                                partB.vx -= ax;
                                partB.vy -= ay;
                        }
                }
        }
}