Cocos2d-x 抖动效果实现

/** 
 desc:让指定控件抖动 
 一个CCNode同时执行多个CCShake动作,或者一个CCShake没有完又执行一个CCShake的话就会出现问题,会出现偏移的现象! 
 解决方案: 
 1).不要同时执行多个CCShake动作. 
 2.自己外部记录这个CCNode的位置,执行完成后手动setPosition(); 
 */  
#ifndef __SHAKE_H__  
#define __SHAKE_H__  
#include "actions/CCActionInterval.h"  
/** 
 * 按指定频度范围内抖动[-strength_x,strength_x][-strength_y, strength_y] 
 */  
class CCShake : public cocos2d::CCActionInterval  
｛  
public:  
    CCShake();  
    // Create the action with a time and a strength (same in x and y)  
    static CCShake* create(float d, float strength );  
    // Create the action with a time and strengths (different in x and y)  
    static CCShake* createWithStrength(float d, float strength_x, float strength_y );  
    bool initWithDuration(float d, float strength_x, float strength_y );  
protected:  
    virtual void startWithTarget(cocos2d::CCNode *pTarget);  
    virtual void update(float time);  
    virtual void stop(void);  
    // Initial position of the shaked node  
    float m_initial_x, m_initial_y;  
    // Strength of the action  
    float m_strength_x, m_strength_y;  
｝;  
/** 
 * 线性抖动(剩余时间越短，抖动范围越小) 
 */  
class CCFallOffShake : public CCShake  
｛  
public:  
    CCFallOffShake();  
    // Create the action with a time and a strength (same in x and y)  
    static CCFallOffShake* create(float d, float strength );  
    // Create the action with a time and strengths (different in x and y)  
    static CCFallOffShake* createWithStrength(float d, float strength_x, float strength_y );  
protected:  
    virtual void update(float time);  
｝;  
#endif //__SHAKE_H__  

#include "ShakeAction.h"  
#include "cocos2d.h"  
USING_NS_CC;  
// not really useful, but I like clean default constructors  
CCShake::CCShake() : m_strength_x(0), m_strength_y(0), m_initial_x(0), m_initial_y(0)  
｛  
｝  
CCShake* CCShake::create( float d, float strength )  
｛  
    // call other construction method with twice the same strength  
    return createWithStrength( d, strength, strength );  
｝  
CCShake* CCShake::createWithStrength(float duration, float strength_x, float strength_y)  
｛  
    CCShake *pRet = new CCShake();  
    if (pRet && pRet->initWithDuration(duration, strength_x, strength_y))  
    ｛  
        pRet->autorelease();  
    ｝  
    else  
    ｛  
        CC_SAFE_DELETE(pRet);  
    ｝  
    return pRet;  
｝  
bool CCShake::initWithDuration(float duration, float strength_x, float strength_y)  
｛  
    if (CCActionInterval::initWithDuration(duration))  
    ｛  
        m_strength_x = strength_x;  
        m_strength_y = strength_y;  
        return true;  
    ｝  
    return false;  
｝  
// Helper function. I included it here so that you can compile the whole file  
// it returns a random value between min and max included  
static float fgRangeRand( float min, float max )  
｛  
    float rnd = CCRANDOM_0_1();  
    return rnd*(max-min)+min;  
｝  
void CCShake::update(float dt)  
｛  
    float randx = fgRangeRand( -m_strength_x, m_strength_x )*dt;  
    float randy = fgRangeRand( -m_strength_y, m_strength_y )*dt;  
    // move the target to a shaked position  
    m_pTarget->setPosition( ccpAdd(ccp(m_initial_x, m_initial_y),ccp( randx, randy)));  
｝  
void CCShake::startWithTarget(CCNode *pTarget)  
｛  
    CCActionInterval::startWithTarget( pTarget );  
    // save the initial position  
    m_initial_x = pTarget->getPosition().x;  
    m_initial_y = pTarget->getPosition().y;  
｝  
void CCShake::stop(void)  
｛  
    // Action is done, reset clip position  
    this->getTarget()->setPosition( ccp( m_initial_x, m_initial_y ) );  
    CCActionInterval::stop();  
｝  
///////////////////////////////////////////////////////////////////////////////  
CCFallOffShake::CCFallOffShake()  
｛  
｝  
// Create the action with a time and a strength (same in x and y)  
CCFallOffShake* CCFallOffShake::create(float d, float strength )  
｛  
    return createWithStrength( d, strength, strength );  
｝  
// Create the action with a time and strengths (different in x and y)  
CCFallOffShake* CCFallOffShake::createWithStrength(float duration, float strength_x, float strength_y)  
｛  
    CCFallOffShake *pRet = new CCFallOffShake();  
    if (pRet && pRet->initWithDuration(duration, strength_x, strength_y))  
    ｛  
        pRet->autorelease();  
    ｝  
    else  
    ｛  
        CC_SAFE_DELETE(pRet);  
    ｝  
    return pRet;  
｝  
void CCFallOffShake::update(float dt)  
｛  
    float rate = (getDuration() - getElapsed())/getDuration();  
    if (rate < 0.f) ｛  
        rate = 0.f;  
    ｝  
    float randx = fgRangeRand( -m_strength_x, m_strength_x )*rate;  
    float randy = fgRangeRand( -m_strength_y, m_strength_y )*rate;  
    // move the target to a shaked position  
    m_pTarget->setPosition( ccpAdd(ccp(m_initial_x, m_initial_y),ccp( randx, randy)));  
｝