Cocos2dx实现场景无限滚动

在游戏中，人物行走，其实是背景向相反方向移动，给玩家形成了一个人物向前移动的错觉。

详细步骤如下，懒得码字了，代码中注释得很清楚：

1 做一个人物无限原地踏步的动画，代码如下所示：

        //创建人物精灵
        CCSprite *mainsprite = CCSprite::create("s_1.png");
        
        //动画部分，创建动画动作
        CCAnimation * animation = CCAnimation::create();

        //给动画动作添加帧
        animation->addSpriteFrameWithFileName("s_1.png");
        animation->addSpriteFrameWithFileName("s_2.png");
        animation->addSpriteFrameWithFileName("s_3.png");
        animation->addSpriteFrameWithFileName("s_4.png");
        animation->addSpriteFrameWithFileName("s_5.png");
        animation->addSpriteFrameWithFileName("s_6.png");
        
        animation->setDelayPerUnit(0.05f);    //设置动画帧时间
        animation->setRestoreOriginalFrame(true);    //动画执行后还原初始状态
        //运行奔跑动画
        
        //将主角精灵放在屏幕放下角
        mainsprite->setPosition(ccp(mainsprite->getContentSize().width/2 , mainsprite->getContentSize().height));
        
        //CCActionInterval *run = CCMoveBy::create(10, ccp((size.width - mainsprite->getContentSize().width/2), (size.height - mainsprite->getContentSize().height/2)));
        mainsprite->runAction(CCRepeatForever::create(CCAnimate::create(animation)));

        this->addChild(mainsprite, 4);

2. 添加背景图片到场景中，背景图片精灵为awakenjoys的保护数据成员，代码如下：

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"

class Awakenjoys : public cocos2d::CCLayer
{
public:
    // 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(Awakenjoys);
    void update(float dt);
protected:
    cocos2d::CCSprite *bgSprite;
    cocos2d::CCSprite *bgSprite1;
};

#endif  // __HELLOWORLD_SCENE_H__

3. 调用scheduleUpdate定时器（每帧都会执行一次）进行滚动背景处理：

        //创建背景图1精灵
        bgSprite = CCSprite::create("bgroup.jpg");
        bgSprite->setPosition(ccp(0, 0));    //屏幕左下角
        this->addChild(bgSprite, -1);        //添加到场景中

        //创建背景图2精灵
        bgSprite1 = CCSprite::create("bgroup1.jpg");
        bgSprite1->setPosition(ccp(0, 0));    //屏幕左下角
        this->addChild(bgSprite1, -2);        //添加到场景中

        bgSprite->setAnchorPoint(ccp(0, 0));    //设置锚点位置为屏幕左下角
        bgSprite1->setAnchorPoint(ccp(1, 0));    //设置锚点位置为屏幕右下角

        //调用scheduleUpdate进行滚动地图处理
        scheduleUpdate();

4. scheduleUpdate()定时器内容：

void Awakenjoys::update(float dt)
{
    CCPoint bgSprite_p = bgSprite->getPosition();  
    CCPoint bgSprite1_p = bgSprite->getPosition(); 

    bgSprite->setPosition(ccp(bgSprite_p.x -4, bgSprite_p.y));
    bgSprite1->setPosition(ccp(bgSprite1_p.x -4, bgSprite1_p.y));

    if (bgSprite_p.x < 0)
    {
        float temp = bgSprite_p.x + CCDirector::sharedDirector()->getWinSize().height;
        bgSprite->setPosition(ccp(temp, bgSprite_p.y)); 

    }

    if (bgSprite1_p.x < 0)
    {
        float temp = bgSprite1_p.x + CCDirector::sharedDirector()->getWinSize().height;
        bgSprite1->setPosition(ccp(temp, bgSprite1_p.y)); 

    }