package
{
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.text.TextField;
 
    /**
     * 二次贝兹曲线，生成飞机路线图
     * @author jimmy.yang （yjmyzz@126.com 菩提树下的杨过 http://yjmyzz.cnblogs.com/）
     */
    //[Frame(factoryClass="Preloader")]
    public class Main extends Sprite
    {      
         
        public function Main():void
        {
            if (stage) init();
            else addEventListener(Event.ADDED_TO_STAGE, init);
        }
 
        private function init(e:Event = null):void
        {
            removeEventListener(Event.ADDED_TO_STAGE, init);       
            testBzCurve();
        }
         
        private function testBzCurve():void {
             
            var txtP0:TextField = new TextField();
            var txtP1:TextField = new TextField();
            var txtP3:TextField = new TextField();
            addChild(txtP0);
            addChild(txtP1);
            addChild(txtP3);
         
            var p0X:int = 100;
            var p0Y:int = 300;
             
            txtP0.x = p0X-10;
            txtP0.y = p0Y+10;
            txtP0.text = "浦东(PVG)";
             
            var p1X:int = 300;
            var p1Y:int = 250;
            txtP1.x = p1X;
            txtP1.y = p1Y+20;
            txtP1.text = "西安(XIY)";
             
            var p2X:int = 500;
            var p2Y:int = 50;
            txtP3.x = p2X+5;
            txtP3.y = p2Y;
            txtP3.text = "北京(PEK)";
             
             
            //人为抬高控制点，以便让曲线经过控制点
            p1X = p1X * 2 - (p0X + p2X) / 2;
            p1Y = p1Y * 2 - (p1Y + p2Y) / 2;
                 
            //生成10个示例点
            for (var t:Number = 0; t <=1; t+=0.1)
            {      
                //二次Bz曲线的公式
                var x:Number = (1 - t) * (1 - t) * p0X + 2 * t * (1 - t) * p1X + t * t * p2X;
                var y:Number = (1 - t) * (1 - t) * p0Y + 2 * t * (1 - t) * p1Y + t * t * p2Y;              
                 
                 
                 
                //Bz曲线在t点时的导数坐标
                var Fx:Number = 2 * (t - 1) * p0X + 2 * (1 - 2 * t) * p1X + 2 * t * p2X;
                var Fy:Number = 2 * (t - 1) * p0Y + 2 * (1 - 2 * t) * p1Y + 2 * t * t * p2Y;
                 
                 
                //放入小飞机
                var p:Plane = new Plane();
                addChild(p);
                p.x = x;
                p.y = y;
                p.scaleX = 0.2;
                p.scaleY = 0.2;
                p.setAngle(Fy, Fx);//导数的几何意义
                 
                 
                 
            }
             
            //画出Bz曲线（当背景用）
            graphics.lineStyle(1, 0x000000, 0.5);
            graphics.moveTo(p0X, p0Y);
            graphics.curveTo(p1X, p1Y, p2X, p2Y);
             
             
        }
         
         
 
    }
 
}