// forked from cellfusion's Particle Sample
// write as3 code here..
// 大量のパーティクルを発生させてみた
// マウスを押してる間でてくるよ
package
{
    import flash.display.Sprite;
    import flash.display.StageQuality;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import net.hires.debug.Stats;

[SWF(width="465", height="465", backgroundColor="0x000000", frameRate="30")]  
	
    public class ParticleSample extends Sprite
    {
        private var _particles:Array = [];
        private var _emitter:Emitter;
        private var _emitter2:Emitter;
        // 1フレーム間に発生させる Particle 数
        private const PARTICLE_NUM:uint = 4;

public function ParticleSample()
        {
            stage.quality = StageQuality.BEST;
            setup();
            addChild(new Stats());
        }
        
        private function setup():void
        {
            _emitter = new Emitter();
            _emitter2 = new Emitter();
            addChild(_emitter);
            addChild(_emitter2);

for (var i:uint = 0; i < 10000; i++) {
                _particles.push(new Particle());
            }

addEventListener(Event.ENTER_FRAME, draw);
            
            stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseDown);
        }
        
        private function draw(event:Event):void
        {
            _emitter.update();
            _emitter2.update(_emitter);

for each (var p:Particle in _particles) {
                if (!p.destroy) {
                    //p.vx += 0.64;
                    //p.vy -= .24;
                    p.update();
                }
            }
        }
        
        private function mouseDown(event:MouseEvent):void
        {
            addEventListener(Event.ENTER_FRAME, createParticle);
            stage.addEventListener(MouseEvent.MOUSE_UP, mouseUp);
        }

private function mouseUp(event:MouseEvent):void
        {
            stage.removeEventListener(MouseEvent.MOUSE_UP, mouseUp);
            removeEventListener(Event.ENTER_FRAME, createParticle);
        }
        
        private function createParticle(event:Event):void
        {
            var count:uint = 0;
            for each (var p:Particle in _particles) {
                // 停止している Particle を探す
                if (p.destroy) {
                    if((Math.random() * 2) >> 0)
                    {
                        p.x = _emitter.x;
                        p.y = _emitter.y;
                        p.init();
                    }
                    else
                    {
                        p.x = _emitter2.x;
                        p.y = _emitter2.y;
                        p.init(.4);
                    }
                    addChild(p);
                    count++;
                }
                if (count > PARTICLE_NUM) break;
            }
        }
    }
}

import flash.display.Sprite;

class Emitter extends Sprite
{
    public var vx:Number = 0;
    public var vy:Number = 0;
    public var ax:Number = 0;
    public var ay:Number = 0;
    private const DT:Number = .04;
    private const DT2:Number = DT * DT;

public function Emitter()
    {       
        //graphics.beginFill(0x808080);
        //graphics.drawCircle(0, 0, 10);
        //graphics.endFill();
    }

public function update($emitter:Emitter = null):void
    {
        var ax:Number;
        var ay:Number;
        if($emitter == null)
        {
            ax = (root.mouseX - x) * 120;
            ay = (root.mouseY - y) * 120;
        }
        else
        {
            ax = ($emitter.x - x) * 64;
            ay = ($emitter.y - y) * 64;
        }

vx += ax * DT;
        vy += ay * DT;
        vx *= 0.9;
        vy *= 0.9;

x += vx * DT + .5 * ax * DT2;
        y += vy * DT + .5 * ay * DT2;
        
        ax = ay = 0;
    }
}

import flash.filters.BlurFilter;

class Particle extends Sprite
{
    public var vx:Number;
    public var vy:Number;
    public var life:Number;
    public var defSize:Number;
    public var size:Number;
    public var color:Number;
    public var inc:int;

private var _count:uint;
    private var _destroy:Boolean;

public function Particle()
    {
        size = Math.random() * 9 + 9;
        defSize = size;
        
        changeColor(Math.random() * 80, Math.random() * 155, Math.random() * 155 + 100);
        drawGraphics();
        
        //filters = [new BlurFilter(4,4,1)];
        
        // 大量のオブジェクトを重ねるとおかしくなる
        blendMode = "add";

_destroy = true;
    }
    
    private function drawGraphics():void
    {
        graphics.clear();
        graphics.beginFill(color);
        graphics.drawCircle(0, 0, size);
        graphics.endFill();
    }
    
    private function changeColor($r:uint, $g:uint, $b:uint):void
    {
        var red:uint = Math.floor($r);
        var green:uint = Math.floor($g);
        var blue:uint = Math.floor($b);
        color = (red << 16) | (green << 8) | (blue);      
    }

public function init($k:Number=1):void
    {
        vx = Math.random() * 30 - 15;
        vy = Math.random() * 2 - 1;
        life = Math.random() * 60 + 20;
        _count = 0;
        alpha = 1 * $k;
        size = defSize;
        changeColor(Math.random() * 80 / $k, Math.random() * 155, Math.random() * 155 + 100);
        drawGraphics();
        inc = ((Math.random() * 2) >> 0);
        _destroy = false;
    }

public function update():void
    {
        x += vx;
        y += vy;
        alpha -= .024 / Math.abs(inc);

_count++;
        size += inc
        drawGraphics();
        
        // 死亡フラグ
        if (life < _count) {
            _destroy = true;
            parent.removeChild(this);
        }
    }

public function get destroy():Boolean
    {
        return _destroy;
    }
}

forked from: Particle Sample