滚动地图层的方法

玩rpg游戏的时候，会看到角色始终在屏幕中间移动，感觉是地图在动，人物位置不动，这是如何来实现的呢？

看了下面这个例子你便知道其中的道理，原理是利用DisplayObject的ScrollRect：

package

{

import flash.display.Loader;

import flash.display.Sprite;

import flash.events.Event;

import flash.events.MouseEvent;

import flash.geom.Rectangle;

import flash.net.URLRequest;

 

/**

* 滚动地图的例子：

* 将window.x和window.y放在EnterFrame中，实时修改为角色走动的坐标即可实现地图平滑滚动

* 这里简单用鼠标点击坐标作为角色的位置

* jianzi 2010.7.8

*/

public class Main extends Sprite

{

       //地图尺寸

private static const mapWidth:int = 2762;  

private static const mapHeight:int = 1558;

//地图入口坐标

private static const enterX:int = 1000;

private static const enterY:int = 1200;

 

//滚动区域

private var window:Rectangle;

//地图层

private var scene:Sprite

 

public function Main()

{

 

//地图层

scene = new Sprite();

scene.graphics.beginFill(Math.random() * 0xffffff);

scene.graphics.drawRect(0,0,mapWidth,mapHeight);

scene.graphics.endFill();

 

//加载地图

var loader:Loader = new Loader();

loader.contentLoaderInfo.addEventListener(Event.COMPLETE,onComplete);

loader.load(new URLRequest("map.jpg"));

scene.addChild(loader);

addChild(scene);

//滚动区域，设置为stage大小，定位地图在入口点(enterX,enterY)

window = new Rectangle();

window.x = enterX - stage.stageWidth/2;

window.y = enterY - stage.stageHeight/2;

window.width = stage.stageWidth;

window.height = stage.stageHeight;

this.scrollRect = window;

this.addEventListener(MouseEvent.CLICK,onClick);

}

 

private function onComplete(e:Event):void {

//......................

}

 

 

 

private function onClick(e:MouseEvent):void {

var posX:Number = int(mouseX) - stage.stageWidth/2;

var posY:Number = int(mouseY) - stage.stageWidth/2;

 

if (posX < 0) posX = 0;

else if ((posX+stage.stageWidth) > mapWidth) posX = mapWidth - stage.stageWidth;

 

if (posY < 0) posY = 0;

else if ((posY+stage.stageHeight) > mapHeight) posY = mapHeight - stage.stageHeight;

 

window.x = posX;

window.y = posY;

 

trace(window.x,window.y);

 

this.scrollRect = window;

}

 

 

}

}

转载http://jianzi0307.blog.163.com/blog/static/20812002010682374279/