COCOS2D-X 实现图片区域内滚动

制作游戏过程中也许会碰到这样的需求，写出来给大家分享。 转载请注明，谢谢。

先show一下效果：

实现思路：

通过CCSprite::setTextureRect修改图像显示区间，通过注册定时器任务实时刷新并显示。

废话不多说，上代码。

参考代码如下：

头文件：

class ScollDisplay : public CCNode{public:    CREATE_FUNC(ScollDisplay);            // 设置显示对象    void setDisPlayObj(CCSprite *pObj, CCSize dispSize, float speed, EDirection direction = ktLeft, bool bForever = true);    // 开始交替显示    void startShow();    private:    ScollDisplay();    ~ScollDisplay();        virtual bool init();        // 接受定时更新    virtual void display(float dt);        protected:    bool       m_bIsStarted;    CCRect     m_curRect;       // 当前的显示区域 通过调整这个来达到滚轴效果    CCSprite  *m_pScollObj;    float      m_fSpeed;        // 每帧滚动速度    EDirection m_direction;     // 滚动方向    bool       m_bScollEnd;     // 滚动结束    bool       m_bScollForever; // 不断滚动还是滚动一次};

代码实现：

////  ScollDisplay.cpp//  Island of Jiang////  Created by apple on 13-6-21.////#include "ScollDisplay.h"ScollDisplay::ScollDisplay():m_bIsStarted(false), m_pScollObj(NULL), m_fSpeed(0), m_direction(ktLeft), m_bScollEnd(false), m_bScollForever(true){}ScollDisplay::~ScollDisplay(){}// 初始化bool ScollDisplay::init(){    return true;}// 设置显示对象void ScollDisplay::setDisPlayObj(CCSprite *pObj, CCSize dispSize, float speed, EDirection direction, bool bForever){    CC_RETURN_NONE_IF(!pObj);            m_bIsStarted = false;    m_pScollObj = pObj;    m_curRect   = CCRectMake(0, 0, dispSize.width, dispSize.height); // 初始显示区域    m_fSpeed    = speed;    m_direction = direction;    m_bScollForever = bForever;    m_bScollEnd = false;}// 开始交替显示void ScollDisplay::startShow(){    // 防止重复    if (m_bIsStarted) {        return;    }        schedule(schedule_selector(ScollDisplay::display));    display(0); // display first}// 接受定时更新void ScollDisplay::display(float dt){    // 处理滚动逻辑    if (!m_pScollObj) {        return;    }        // 滚动到位了    if (m_bScollEnd) {        return;    }        CCSize textureSize = m_pScollObj->getTexture()->getContentSizeInPixels();    CCSize winSize = m_curRect.size;        // x最大坐标 ＝ 窗口宽度 － 素材宽度 * 缩放比    float min_X = 0;    float max_X = (textureSize.width * m_pScollObj->getScaleX()) - winSize.width;        // y最大坐标 ＝ 窗口高度 - 素材高度 * 缩放比    float min_Y = 0;    float max_Y = (textureSize.height * m_pScollObj->getScaleY()) - winSize.height;        // 计算偏差 并判断是否需要复位    float fxOffset = 0;    float fyOffset = 0;    switch (m_direction) {        case ktDown:            // first time init            if (!m_bIsStarted) {                m_curRect.origin.y = min_Y;                m_bIsStarted = true;            }                        fyOffset += m_fSpeed;            m_curRect.origin.y += fyOffset;            if (m_curRect.origin.y > max_Y) {                if (m_bScollForever) {                    m_curRect.origin.y = min_Y;  // 复位                }                else                {                    m_bScollEnd = true;                }                return;            }            break;        case ktLeft:            // first time init            if (!m_bIsStarted) {                m_curRect.origin.x = min_X;                m_bIsStarted = true;            }                        fxOffset += m_fSpeed;            m_curRect.origin.x += fxOffset;            if (m_curRect.origin.x  > max_X) {                if (m_bScollForever) {                    m_curRect.origin.x = min_X; // 复位                }                else                {                    m_bScollEnd = true;                }                return;            }            break;        case ktRight:            // first time init            if (!m_bIsStarted) {                m_curRect.origin.x = max_X;                m_bIsStarted = true;            }                        fxOffset -= m_fSpeed;            m_curRect.origin.x += fxOffset;            if (m_curRect.origin.x  < min_X) {                if (m_bScollForever) {                    m_curRect.origin.x = max_X; // 复位                }                else                {                    m_bScollEnd = true;                }                return;            }            break;        case ktUp:            // first time init            if (!m_bIsStarted) {                m_curRect.origin.y = max_Y;                m_bIsStarted = true;            }                        fyOffset -= m_fSpeed;            m_curRect.origin.y += fyOffset;            if (m_curRect.origin.y < min_Y) {                if (m_bScollForever) {                    m_curRect.origin.y = max_Y;  // 复位                }                else                {                    m_bScollEnd = true;                }                return;            }            break;                    default:            CCLog("direction [%d] is invalid.", m_direction);            return;    }        // 通过设置特定区域来实现滚动    m_pScollObj->setTextureRect(m_curRect);}

代码调用：

void GameMenuLayer::onNodeLoaded(cocos2d::CCNode * pNode,  cocos2d::extension::CCNodeLoader * pNodeLoader) {        // scoll upgrade pic    ScollDisplay *scollObj = ScollDisplay::create();    scollObj->setDisPlayObj(m_pUpgrade, CCSizeMake(115, 76), 1.0f);    scollObj->startShow();    this->addChild(scollObj);    }