cocos2dx学习笔记：自定义动作实现圆周运动

cocos2dx学习笔记：自定义动作实现圆周运动发布时间：2020-12-14 19:42:41  所属栏目：百科  来源：网络整理 
导读：From: http://cstriker1407.info/blog/cocos2dx-study-notes-custom-actions-realization-of-circular-motion/ 最近在翻帖子的时候发现很多大牛都自己实现自定义动作，而不是通过各种动作进行组合，正好最近需要一个圆周运动的效果，就自己写了一个自定义的

                    From:  http://cstriker1407.info/blog/cocos2dx-study-notes-custom-actions-realization-of-circular-motion/
 
最近在翻帖子的时候发现很多大牛都自己实现自定义动作，而不是通过各种动作进行组合，正好最近需要一个圆周运动的效果，就自己写了一个自定义的动作，这里备注下大致的实现思路。
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1备注：
2数学复习：
3实现方式：
备注：
 该动作并未实际应用在游戏中，可能有bug。
数学复习：
 截图来自【http://202.113.29.3/nankaisource/mathhands/Elementary%20mathematics/0103/010301/01030101.htm】
实现方式：
 可参考这篇文章来实现：【http://www.52php.cn/article/p-fdrufoeg-bcr.html】
作者自己也写了一个功能增强版的圆周运动，可以实现螺旋线式的圆周运动。代码比较简单，就不在细说了。
自己的实现：
CircleMoveAct.h：
 
       #ifndef __CIRCLE_MOVE_ACT_H__ 
     
#define __CIRCLE_MOVE_ACT_H__
 
#include "cocos2d.h" 
      
 //http://202.113.29.3/nankaisource/mathhands/Elementary%20mathematics/0103/010301/01030101.htm 
      
 classCircleMoveAct :publiccocos2d::CCActionInterval 
      
 { 
      
public: 
      
 boolinitWithDuration(floatduration,constcocos2d::CCPoint& center,scaleDiff,255)!important; border:0px!important; white-space:normal; margin:0px!important; outline:0px!important; text-align:left!important; float:none!important; vertical-align:baseline!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-weight:normal!important; font-style:normal!important; min-height:inherit!important">angle); 
      
virtualcocos2d::CCObject* copyWithZone(cocos2d::CCZone* pZone); 
      
virtualvoidstartWithTarget(cocos2d::CCNode *pTarget); 
      
update(floattime); 
      
staticCircleMoveAct* create(scale,61)!important; border:0px!important; white-space:normal; margin:0px!important; outline:0px!important; text-align:left!important; float:none!important; vertical-align:baseline!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-weight:bold!important; font-style:normal!important; min-height:inherit!important">protected: 
      
m_duration; 
      
cocos2d::CCPoint m_center; 
      
m_scaleDiff; 
      
m_currScale; 
      
m_angle; 
      
m_anglePreFrame; 
      
intm_frameCnts; 
      
cocos2d::CCPoint m_initPos; 
      
}; 
      
#endif // __CIRCLE_MOVE_ACT_H__

CircleMoveAct.cpp：

#include "CircleMoveAct.h" 
      
USING_NS_CC; 
      
CircleMoveAct* CircleMoveAct::create(CCPoint& center,255)!important; border:0px!important; white-space:normal; margin:0px!important; outline:0px!important; text-align:left!important; float:none!important; vertical-align:baseline!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; font-weight:normal!important; font-style:normal!important; min-height:inherit!important">angle) 
      
CircleMoveAct *pRet =newCircleMoveAct(); 
      
pRet->initWithDuration(duration,center,scale,angle); 
      
pRet->autorelease(); 
      
returnpRet; 
      
} 
      
 CircleMoveAct::initWithDuration(angle) 
      
{ 
      
if(CCActionInterval::initWithDuration(duration)) 
      
this->m_duration = duration; 
      
->m_center = center; 
      
->m_scaleDiff = scaleDiff; 
      
->m_currScale = 1.0f; 
      
->m_angle = angle; 
      
/************************************************************************/ 
      
/* 计算每次update调用时需要转动的弧度 */ 
      
->m_anglePreFrame = angle / duration * CCDirector::sharedDirector()->getAnimationInterval() / (180 / M_PI); 
      
->m_frameCnts = 0; 
      
returntrue; 
      
falseCCObject* CircleMoveAct::copyWithZone(CCZone *pZone) 
      
CCZone* pNewZone = NULL; 
      
CircleMoveAct* pCopy = NULL; 
      
if(pZone && pZone->m_pCopyObject) 
      
pCopy = (CircleMoveAct*)(pZone->m_pCopyObject); 
      
} 
      
else 
      
pCopy =CircleMoveAct(); 
      
pZone = pNewZone =CCZone(pCopy); 
      
CCActionInterval::copyWithZone(pZone); 
      
pCopy->initWithDuration(m_duration,m_center,m_scaleDiff,m_angle); 
      
CC_SAFE_DELETE(pNewZone); 
      
pCopy; 
      
CircleMoveAct::startWithTarget(CCNode *pTarget) 
      
CCActionInterval::startWithTarget(pTarget); 
      
m_initPos = pTarget->getPosition(); 
      
CircleMoveAct::update() 
      
m_frameCnts++; 
      
m_currScale += m_scaleDiff; 
      
CCPoint newPos = ccpRotateByAngle(m_initPos,m_frameCnts * m_anglePreFrame); 
      
CCPoint diff = ccpSub(newPos,m_center); 
      
newPos = diff * m_currScale + m_center; 
      
m_pTarget->setPosition(newPos); 
      
//debug 
      
#if 0 
      
CCDrawNode *node = CCDrawNode::create(); 
      
node->drawDot(newPos,3,ccc4f(128,128,128)); 
      
m_pTarget->getParent()->addChild(node); 
      
#endif 
      
}

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