为图层上的N多怪物创建站立时的动画

说在前面的话：

怪物在地图上的位置是不变的，但它们都有对应的原地站立时的动画。大家可能会对这些怪物分别创建动画。这样做没错，但是想想就觉得麻烦：如果有100种怪物的话，难道要定义100个动画模板吗？答案是否定的。可以参考下testcpp下的TMXReadWriteTest例子。

有DEMO下载。

看代码：

#pragma once

#include "cocos2d.h"

class Enemy : public cocos2d::CCObject
{
public:
	Enemy(void);
	~Enemy(void);

	// 怪物在TileMap上的位置
	cocos2d::CCPoint position;
	
	// 怪物初始的图块ID
	int startGid;
};

class HelloWorld : public cocos2d::CCLayer
{
private:
	cocos2d::CCTMXTiledMap* m_pTiledMap;
	cocos2d::CCArray* m_pEnemyAry;
	cocos2d::CCTMXLayer* m_pEnemyLayer;
private:
	void updateEnemyAnimation(float dt);
public:
	HelloWorld() {
		m_pTiledMap = NULL;
		m_pEnemyAry = NULL;
		m_pEnemyLayer = NULL;
	}

	~HelloWorld() {
	}

    // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
    virtual bool init();  

    // there's no 'id' in cpp, so we recommand to return the exactly class pointer
    static cocos2d::CCScene* scene();
    
    // a selector callback
    void menuCloseCallback(CCObject* pSender);

    // implement the "static node()" method manually
    CREATE_FUNC(HelloWorld);
};

#endif  // __HELLOWORLD_SCENE_H__

bool HelloWorld::init()
{
    bool bRet = false;
    do 
    {
        CC_BREAK_IF(! CCLayer::init());

		m_pTiledMap = CCTMXTiledMap::create("map_01.tmx");
		this->addChild(m_pTiledMap);

		m_pEnemyAry = CCArray::create();
		m_pEnemyAry->retain();

		m_pEnemyLayer = m_pTiledMap->layerNamed("enemy");
		CCSize s = m_pEnemyLayer->getLayerSize();
		for (int i = 0; i < s.width; i++) {
			for (int j = 0; j < s.height; j++) {
				// 位置对应的图块ID
				int gid = m_pEnemyLayer->tileGIDAt(ccp(i, j));
				if (gid != 0) {
					Enemy* enemy = new Enemy();
					if (enemy)
						enemy->autorelease();
					else {
						CC_SAFE_DELETE(enemy);
						continue;
					}
					enemy->position = ccp(i, j);
					enemy->startGid = gid;
					m_pEnemyAry->addObject(enemy);
				}
			}
		}

		this->schedule(schedule_selector(HelloWorld::updateEnemyAnimation), 0.2F);

        bRet = true;
    } while (0);

    return bRet;
}

// 更新图块位置的动画
void HelloWorld::updateEnemyAnimation(float dt) {
	CCObject* obj = NULL;
	Enemy* enemy = NULL;
	CCARRAY_FOREACH(m_pEnemyAry, obj) {
		enemy = (Enemy*) obj;
		if (enemy != NULL) {
			// 获取指定位置的图块ID
			int gid = m_pEnemyLayer->tileGIDAt(enemy->position);
			// 如果指定位置没有图块则执行下一次循环
			if (gid == 0)continue;
			gid++;
			if ((gid - enemy->startGid) > 3)
				gid = enemy->startGid;
			// 在指定位置上设置新的图块ID
			m_pEnemyLayer->setTileGID(gid, enemy->position);
		}
	}
}