Practice05 - Elliptic Motion

reference from
http://gihyo.jp/dev/serial/01/as3/0022

by tspringk 13 Apr 2012

Embed

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

package {
    import flash.display.Graphics;
    import flash.display.Shape;
    import flash.events.Event;
    import flash.filters.BlurFilter;
    
    import flash.display.Sprite;
    import flash.display.MovieClip;

    public class Practice05 extends MovieClip {
        
        private var initX:int = 0;
        private var initY:int = 0;
        private var initSize:int = 50;
        
        private var nDegree:Number = 0;
        private var nRadian:Number = 0;
        private var nSpeed:Number = 5;
        private var nDegreeToRadian:Number = Math.PI / 180;
        private var nCenterX:Number = stage.stageWidth / 2;
        private var nCenterY:Number = stage.stageHeight / 2;
        private var nRadiusX:Number = 100;
        private var nRadiusY:Number = 50;
        private var nCos:Number = Math.cos(nRadian);
        private var nSin:Number = Math.sin(nRadian);
            
        public function Practice05() {
            var ball:Shape = new Shape();
            var ballG:Graphics = ball.graphics;
            ballG.beginFill(0xffcc00, 1.0);
            ballG.drawCircle  ( initX, initY , initSize);
            this.addChild(ball);
            
            addEventListener(Event.ENTER_FRAME, xMoveX);
            addEventListener(Event.ENTER_FRAME, xMoveY);
            addEventListener(Event.ENTER_FRAME, xScale);
            addEventListener(Event.ENTER_FRAME, xBlur);
            addEventListener(Event.ENTER_FRAME, xUpdate);
        }
        private function xMoveX(eventObject:Event):void {
          x = nCenterX + nCos * nRadiusX;
        }
        private function xMoveY(eventObject:Event):void {
          y = nCenterY + nSin * nRadiusY;
        }
        private function xScale(eventObject:Event):void {
          scaleX = scaleY = xGetIndexZ(0.8,1);
          scaleX *= xGetIndexZ();
        }
        private function xBlur(eventObject:Event):void {
          var nBlur:Number=xGetIndexZ(10,0);
          var myBlur:BlurFilter=new BlurFilter(nBlur,nBlur/2);
          filters=[myBlur];
        }
        private function xUpdate(eventObject:Event):void {
          nDegree+=nSpeed;
          nDegree = (nDegree%360+360)%360;
          nRadian=nDegree*nDegreeToRadian;
          nCos=Math.cos(nRadian);
          nSin=Math.sin(nRadian);
        }
        private function xGetIndexZ(nMin:Number=-1, nMax:Number=1):Number {
          var nIndexZ:Number = (nMax-nMin)*(nSin+1)/2+nMin;
          return nIndexZ;
        }
    }
}