坐标旋转版圆周运动(包含坐标误差版本和正确版本）

FishRoundFly.as

package demo
{
    import flash.display.Sprite;
    import flash.events.*;
    import flash.geom.Matrix;
    import flash.geom.Point;

    public class FishRoundFly extends Sprite
    {
        private var fish:Sprite = new Sprite;
//        private var centerPoint:Point = new Point;
        private var increaseDegree:Number = 1;
        
        private var cos:Number;
        private var sin:Number;
        private var radias:Number;
        private var preX:Number;
        private var preY:Number;
        private var currentX:Number;
        private var currentY:Number;
        public function FishRoundFly()
        {
            fish.graphics.beginFill(0);
            fish.graphics.drawRect(0,0,20,20);
            addChild(fish);
            
            fish.x = 50
            fish.y = 0;
            currentX = fish.x;
            currentY = fish.y
            radias = increaseDegree*Math.PI/180;
            cos = Math.cos(radias);
            sin = Math.sin(radias);

            this.addEventListener(Event.ENTER_FRAME,updateFrame);
            this.graphics.lineStyle(1);
        }
        protected function updateFrame(event:Event):void
        {
            preX = currentX;
            preY = currentY;
            currentX = preX * cos - preY * sin;
            currentY = preY * cos + preX * sin;
            fish.x = currentX;
            fish.y = currentY;
            this.graphics.lineTo(fish.x,fish.y);
            trace("preX",preX,"curX",currentX,"fishX",fish.x);
        }
    }
}

FishRoundFly_deviation.as

package demo
{
    import flash.display.Sprite;
    import flash.events.*;

    public class FishRoundFly extends Sprite
    {
        private var fish:Sprite = new Sprite;
//        private var centerPoint:Point = new Point;
        private var increaseDegree:Number = 1;
        
        private var cos:Number;
        private var sin:Number;
        private var radias:Number;
        private var preX:Number;
        private var preY:Number;
        
        public function FishRoundFly()
        {
            fish.graphics.beginFill(0);
            fish.graphics.drawRect(0,0,20,20);
            addChild(fish);
            
            fish.x = 50
            fish.y = 0;
            radias = increaseDegree*Math.PI/180;
            cos = Math.cos(radias);
            sin = Math.sin(radias);

            this.addEventListener(Event.ENTER_FRAME,updateFrame);
            this.graphics.lineStyle(1);
        }
        protected function updateFrame(event:Event):void
        {
            preX = fish.x;
            preY = fish.y;
            fish.x = preX * cos - preY * sin;
            fish.y = preY * cos + preX * sin;
            this.graphics.lineTo(fish.x,fish.y);
        }
    }
}