Cocos2d-x 水果忍者划痕效果

网上找的一个关于水果忍者划痕的，效果还算凑合。其原理就是基于OpenGL绘制直线，因为版本号过老，此处笔者改动了一些方法，粘贴后可直接使用

适用于Cocos2d-x 2.2.1

.h文件里须要添�的代码：

void draw();

void drawLine();

virtual void ccTouchesBegan(CCSet *pTouches,CCEvent *pEvent);

virtual void ccTouchesMoved(CCSet *pTouches,CCEvent *pEvent);

virtual void ccTouchesEnded(CCSet *pTouches,CCEvent *pEvent);

std::list<CCPoint> pointList;

.cpp文件里

void HelloWorld::draw()

{

drawLine();

}

void HelloWorld::drawLine()

{

int tickSubCount = 10;

int pointListKeepCount = 500;

for (int i=0; i<tickSubCount ; i++)

{

if (pointList.size() >0)

{

pointList.pop_front();

}

else

{

break;

}

}

while (pointList.size() > pointListKeepCount)

{

pointList.pop_front();

}

float max_lineWidth = 5;

float min_lineWidth = 1;

int   alpha_min = 10;

int   alpha_max =  200;

int  R = arc4random()%255;

int  G = arc4random()%255;

int  B = arc4random()%255;

int pointListCount = pointList.size();

std::list <CCPoint>::iterator it =pointList.begin();

float pointIndex = 0;

for(;it!=pointList.end();it++)

{

int distanceToMiddle = fabs(pointIndex-pointListCount/2);

float percent = 1.0-(float)distanceToMiddle/(float)(pointListCount/2.0);

float lintWidth = min_lineWidth + max_lineWidth*percent;

int alpha = alpha_min +alpha_max*percent;

ccc4(R,G,B,alpha );

ccPointSize(lintWidth);

ccDrawPoint( *it );

pointIndex++;

}

}

void HelloWorld::ccTouchesBegan(CCSet *pTouches,CCEvent *pEvent)

{

CCSetIterator it = pTouches->begin();

CCTouch* touch = (CCTouch*)*it;

CCPoint beginPoint = touch->getLocationInView();

beginPoint = CCDirector::sharedDirector()->convertToGL(beginPoint);

pointList.push_back(beginPoint);

}

void HelloWorld::ccTouchesMoved(CCSet *pTouches,CCEvent *pEvent)

{

CCSetIterator it = pTouches->begin();

CCTouch* touch = (CCTouch*)*it;

CCPoint nextPoint = touch->getLocationInView( );

nextPoint = CCDirector::sharedDirector()->convertToGL(nextPoint);

CCPoint preMovePoint = touch->getPreviousLocationInView();

preMovePoint = CCDirector::sharedDirector()->convertToGL(preMovePoint);

float distance = ccpDistance(nextPoint, preMovePoint);

if (distance > 1)

{

int d = (int)distance;

for (int i =0; i < d; i++ )

{

float distanceX = nextPoint.x - preMovePoint.x;

float distanceY = nextPoint.y - preMovePoint.y;

float percent = i / distance;

CCPoint newPoint;

newPoint.x = preMovePoint.x + (distanceX * percent);

newPoint.y = preMovePoint.y + (distanceY * percent);

pointList.push_back(newPoint);

}

}

}

void HelloWorld::ccTouchesEnded(CCSet *pTouches,CCEvent *pEvent)

{

pointList.clear();

}