Cocos2d-x 抖动效果实现

发表于2018-08-01
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抖动效果一般是出现在战争类游戏炸弹爆炸或者渲染游戏画面效果上。这样抖动效果想要实现也不难,只需要了解抖动的原理即可,所谓抖动,那么就是不停地在一个范围内变换位置,最后还原到原来的位置。


下面贴出抖动效果CCShake这个动作的源码(代码中已经注释的很清楚了):
Cocos2dx全屏抖动,个别对象抖动  
/** 
 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__  

CPP  
#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)));  
}  

用法:
pSprite->runAction(CCShake::create(0.1f,10));  
pSprite:想抖动的物体  
第一个参数是:抖动的时间  
第一个参数是:抖动的幅度  

注意
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();

原文链接

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