forked from: GREEN粒子

by nabe 15 Jan 2009

Embed

// forked from nabe's GREEN粒子
package {
    import flash.display.*;
    import flash.events.*;

    [SWF(width="465", height="465", backgroundColor="0", frameRate="24")]
    public class Program_ extends Sprite {

        private const W_:uint = stage.stageWidth;
        private const H_:uint = stage.stageHeight;

        public function Program_ () {
            addEventListener(Event.ADDED_TO_STAGE, init_);
        }

        private function init_ (evnet_:Event):void {
            removeEventListener(Event.ADDED_TO_STAGE, init_);

            x = W_>>1;
            y = H_>>1;

            for (var i:int = 0; i < 20; i++) {
                addChild(new GN_);
            }
        }
    }
}

    import flash.display.*;
    import flash.events.*;
    import flash.geom.*;

    class GN_ extends Sprite {

        private var vx_:Number;
        private var vy_:Number;
        private var k_:Number;

        public function GN_ () {
            draw_();
            reset_();
            addEventListener(Event.ENTER_FRAME, update_);
        }

        private function update_ (evnet_:Event):void {
            x += vx_;
            y += vy_;
            if (Math.random() < 0.75) {
                vx_ += 0.5 * (Math.random() - 0.5);
                vy_ += 0.5 * (Math.random() - 0.5);
            }
            alpha *= k_;
            if (alpha < 0.001) reset_();
        }

        private function reset_ ():void {
            x = 100 * (Math.random() - 0.5);
            y = 100 * (Math.random() - 0.5);
            alpha = (Math.random() + 3) * 0.25;
            vx_ = 3 * (Math.random() - 0.5);
            vy_ = 3 * (Math.random() - 0.5);
            k_ = (Math.random() + 19) * 0.05;
        }

        private function draw_ ():void {
            var rect_:Rectangle = new Rectangle(-100, -100, 200, 200);
            var matrix_:Matrix = new Matrix();
            matrix_.createGradientBox(200, 200, 0, -100, -100);
            var g_:Graphics = graphics;
            g_.beginGradientFill(
                GradientType.RADIAL,
                [0xAAFFEE, 0x33CC99, 0x00CC99],
                [0.75, 0.25, 0],
                [0, 0xF, 0xCF],
                matrix_, SpreadMethod.PAD, InterpolationMethod.RGB, 0
            );
            g_.drawEllipse(rect_.x, rect_.y, rect_.width, rect_.height);
            g_.endFill();
        }
    }