forked from: forked from: Group Velocity

/**
 * Copyright alexnotkin ( http://wonderfl.net/user/alexnotkin )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/2mcL
 */

// forked from taka_milk's forked from: Group Velocity
// forked from k_tsushima's Group Velocity
package 
{
    import flash.display.*;
    import flash.events.*;
    /**
     * ...
     * @author k_tsushima
     *Imitation of http://homepage3.nifty.com/iromono/kougi/qm/vpvg3.html
     */
    [SWF(backgroundColor="0x000000")]
    public class sin_curve extends Sprite
    {
        public function sin_curve():void {
            if (stage) init();
            else addEventListener(Event.ADDED_TO_STAGE, init);
        }
        
        private var s1:Sprite = new Sprite();
        private var s2:Sprite = new Sprite();
        private var s12:Sprite = new Sprite();
        private var s12b:Sprite = new Sprite();
        private var t:uint = 0;
        
        private function init(e:Event = null):void {
            stage.quality = "high";
            stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.align = StageAlign.TOP_LEFT;
            stage.addChild(s1);
            stage.addChild(s2);
            stage.addChild(s12);
            stage.addChild(s12b);
            stage.addEventListener(Event.ENTER_FRAME, drawSin);
            
        }
        
        private function drawSin(e:Event = null):void {
            if (t > 0) {
                s1.graphics.clear();
                s2.graphics.clear();
                s12.graphics.clear();
                s12b.graphics.clear();
            }
            var w:Number = stage.stageWidth;
            var h:Number = stage.stageHeight;
            var rad:Number = 2 * Math.PI / 280;
            var k1:Number = 4 * rad; 
            var k2:Number = 4.4 * rad;
            var omega1:Number = 2 * t * rad; 
            var omega2:Number = 2 * t * rad* 2;
            s1.graphics.lineStyle(4, 0x000000);
            s1.graphics.moveTo(0, h / 2-h/8*Math.sin(-omega1));
            s2.graphics.lineStyle(3, 0x000000);
            s2.graphics.moveTo(0, h / 2-h/8*Math.sin(-omega2));
            s12.graphics.lineStyle(2, 0x000000);
            s12.graphics.moveTo(0, h / 2-h/8*Math.sin(-omega1)-h/8*Math.sin(-omega2));
            s12b.graphics.lineStyle(1, 0x000000);
            s12b.graphics.moveTo(0, h / 2-h/4*Math.cos(-(omega1-omega2)/2));
            for (var i:uint = 1; i < w; i++) { 
                var y1:Number = h / 8 * Math.sin(k1 * i - omega1);
                var y2:Number = h / 8 * Math.sin(k2 * i - omega2);
                s1.graphics.lineTo(i, h/2-y1);
                s2.graphics.lineTo(i, h/2-y2);
                s12.graphics.lineTo(i,h/2-(y1+y2));
                s12b.graphics.lineTo(i,h/2-h/4*Math.cos(((k1-k2)*i-(omega1-omega2))/2));
            }
            t++;
        }
    }
    
}