flash小球沿不规则的路径移动

  用了BitmapData.getPixel();来做的.原理:路径为一像素的纯色的不规则的曲线(如红色),用getPixel();记录曲线上的所有坐标.

import flash.display.BitmapData;  
import flash.geom.Point;  
var pointArr:Array = [];  
var ypos:Number = 200;  
var curve:MovieClip = this.createEmptyMovieClip("curve", 10);  
with (curve) {  
lineStyle(1, 0xFF0000);  
moveTo(0, ypos);  
for (var i:Number = 0; i<550; i += 6) {  
   lineTo(i, ypos+i/10*Math.sin(i/20));  
}  
}  
var X:Number = curve._width;  
var Y:Number = ypos+curve._height;  
var copyBitmap:BitmapData = new BitmapData(X, Y, true, 0);  
copyBitmap.draw(curve);  
var color:Number = Number(0xFF0000);  
for (var i:Number = 0; i<X; i += 10) {  
for (var j:Number = 0; j<Y; j++) {  
   if (copyBitmap.getPixel(i, j) == color) {  
    pointArr.push(new Point(i, j));  
    break;  
   }  
}  
}  
copyBitmap.dispose();  
var ball:MovieClip = this.createEmptyMovieClip("ball", 20);  
with(ball){  
lineStyle(20);  
moveTo(0, 0);  
lineTo(.2, 0);  
}  
this.onEnterFrame = function() {  
ball._x = pointArr[0].x;  
ball._y = pointArr[0].y-10;  
pointArr.shift();  
if (pointArr.length == 0) {  
   delete this.onEnterFrame;  
   trace("over");  
}  
};