forked from: flash on 2010-3-16

/**
 * Copyright wwbeyondww1 ( http://wonderfl.net/user/wwbeyondww1 )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/3Fym
 */

// forked from summerTree's flash on 2010-3-16
package 
{
    //绘制一棵树
    //夏天的树人
    import flash.display.Sprite;
    import flash.display.Graphics;
    import flash.events.*;
   [SWF(backgroundColor="0xffffff", frameRate="30")];
    public class Main extends Sprite
    {
        private var shape:Sprite=new Sprite();

        public function Main()
        {
            addChild(shape);
            CreatTree(shape.graphics,300, 460, 90, 180,6);
            //CreatTree(shape.graphics,300, 400, 45, 130,2);
            //CreatTree(shape.graphics,300, 400, 135, 130,2);
        }
        //绘图对象，基本坐标px,py,角度，偏移长度，数量
        private function CreatTree(g:Graphics,px:Number,py:Number,angle:Number,len:Number,n:int):void
        {
            if (n>0)
            {
                var x1:Number=px+0.1*len*Math.cos(angle*Math.PI/180);
                var y1:Number=py-0.1*len*Math.sin(angle*Math.PI/180);

                var x2:Number=px+len*Math.cos(angle*Math.PI/180);
                var y2:Number=py-len*Math.sin(angle*Math.PI/180);

                drawLine(g,n-1,px,py,x2,y2);

                var a_l:Number = angle+30;

                var a_r:Number = angle-30;

                len = len*2/3;
                CreatTree(g,x2, y2, angle-Math.random()*10,len,  n-1);
                CreatTree(g,x1, y1, a_l,len*2/3, n-1);
                CreatTree(g,x1, y1, a_r, len*2/3,n-1);

                CreatTree(g,x2, y2, a_l,len*2/3,  n-1);
                CreatTree(g,x2, y2, a_r,len*2/3,  n-1);

            }
        }
        //绘制线
        private function drawLine(g:Graphics,n:int,x1:Number,y1:Number,x2:Number,y2:Number):void
        {
            g.lineStyle(n,0x000000);
            g.moveTo(x1,y1);
            g.lineTo(x2,y2);
        }
    }
}