Forked from:: ton's forked from: BrownianMotion

forked from: forked from: BrownianMotion

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license : All rights reserved
modified : 2009-01-19 20:22:28

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// forked from ton's forked from: BrownianMotion
// forked from ton's BrownianMotion
package {
    import flash.display.*;
    import flash.events.*;
    import frocessing.core.F5BitmapData2D;
    import net.hires.debug.Stats;
    
    [SWF(frameRate="60", backgroundColor="#000000")]
    public class BrownianMotion extends Sprite {

private const N:int = 500;
        private const MAX_R:int = 50;
        private const W:int = 465;
        private const H:int = 465;

private var list:Vector.<Dot>;
        private var fg:F5BitmapData2D;

function BrownianMotion()
        {
            fg = new F5BitmapData2D(W, H, false, 0xff000000);
            addChild( new Bitmap(fg.bitmapData) );
            fg.strokeAlpha = 0.1;
            list = new Vector.<Dot>(N, true);
            for (var i:int = 0; i < N; i++) {
                var d:Dot = new Dot(Math.random()*0xffffff);
                var r:Number = Math.sqrt(Math.random()) * MAX_R;
                var angle:Number = Math.random() * (2 * Math.PI);
                d.x = Math.cos(angle) * r;
                d.y = Math.sin(angle) * r;
                d.vx = 0;
                d.vy = 0;
                list[i] = d;
            }
            //addChild( new Stats() );
            addEventListener(Event.ENTER_FRAME, onEnterFrameHandler);
        }

private function onEnterFrameHandler(event:Event):void 
        {
            fg.beginDraw();
            fg.translate( W>>1, H>>1 );
            for (var i:int = 0; i < N; i++)
            {
                var d:Dot = list[i];
                d.update();
                fg.strokeColor = 0x000000;
                fg.pixel( d.x+1, d.y+1 );
                fg.strokeColor = d.color;
                fg.pixel( d.x, d.y );
            }
            fg.endDraw();
        }
    }
}

class Dot{
    public var vx:Number;
    public var vy:Number;
    public var x:Number;
    public var y:Number;
    public var color:uint;
    private const X:Number = 0.2;
    private const F:Number = 0.95;
    function Dot(color:uint) {
        this.color = color;
    }
    public function update():void {
        vx += Math.random() * X * 2 - X;
        vy += Math.random() * X * 2 - X;
        vx *= F;
        vy *= F;
        x += vx;
        y += vy;
    }
}

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