人参を育てようとしているところ

http://en.wikipedia.org/wiki/L-system#Example_8:_Fractal_plant

by ahchang 29 May 2009

• Forked from Nek's LSystem Plant
• Diff: 19
• Related works: 3
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/**
 * Copyright ahchang ( http://wonderfl.net/user/ahchang )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/39en
 */

// forked from Nek's LSystem Plant
// forked from Nek's flash on 2009-5-24
// http://en.wikipedia.org/wiki/L-system#Example_8:_Fractal_plant
package {
    import flash.display.Sprite;
    import flash.display.MovieClip;
    import flash.events.*;
    public class LSystem extends Sprite {
        private const VARIABLES:String = "XF";
        private const CONSTANTS:String = "+-";
        private var start:String = "X";
        private var rules:Array = [];
        private var iterations:int = 6;
        private const STEP_LENGTH:Number = 1.2;
        private const ANGLE:Number = 25*Math.PI/180;
        
        private var penX:Number = 0;
        private var penY:Number = 0;
        private var penA:Number = 65*Math.PI/180;
        
        private var _penX:Number;
        private var _penY:Number;
        private var _penA:Number;
        
        private var canvas:MovieClip;
        
        private var storage:Array = [];
        
        public function LSystem () {
            canvas = new MovieClip();
            addChild(canvas);
            canvas.x = stage.stageWidth / 2;
            canvas.y = 450;
            canvas.rotation = 180+45;
            rules["X"] = "F-[[X]+X]+F[+FX]-X";
            rules["F"] = "FF";
            canvas.graphics.lineStyle(0,0x82D50F);
            addEventListener(Event.ENTER_FRAME, loop);
        }
        public function loop(e:Event = null):void {
            start = start.split("X").join(rules["X"]);
            start = start.split("F").join(rules["F"]);
           
            --iterations;
            if (iterations == 0) {removeEventListener(Event.ENTER_FRAME, loop);draw();};
        }
        public function draw():void {
            //carrot
            var carrot:Sprite = new Sprite();
            carrot.graphics.beginFill(0xffa500);
            carrot.graphics.drawCircle(0, 0, 40);
            carrot.x = stage.stageWidth / 2;
            carrot.y = stage.stageHeight + 10;
            
            addChild(carrot);
            canvas.graphics.moveTo(penX,penY);
            var step:String;
            while (start.length >0) 
            {    
                step = start.substr(0,1);
                start = start.substr(1);
                drawStep(step);
            }
        }
        public function drawStep(s:String):void {
            switch (s) {
                case "F": stepF(); break;
                case "+": turnL(); break;
                case "-": turnR(); break;
                case "[": store(); break;
                case "]": restore(); break;
                case "X": break;
                default: return;
                }
        }
        public function stepF():void {
            penX = penX+STEP_LENGTH*Math.cos(penA);
            penY = penY+STEP_LENGTH*Math.sin(penA);
            canvas.graphics.lineTo(penX , penY);
            }
         
         public function store():void {
             storage.push({x:penX,y:penY,a:penA});

            }   
         public function restore():void {
             var c:Object = storage.pop();
             penX = c.x;
             penY = c.y;
             penA = c.a;
             canvas.graphics.moveTo(penX,penY);
             }
         
         public function turnL():void {
             penA += ANGLE;
            }
         public function turnR():void {
             penA -= ANGLE;
            }
    }
}