在cocos2d-x中,常通过Sprite的boundingBox()方法来获取该Sprite的边框,这个边框最常用的用途就是做为碰撞框了。但是如果你在一个Sprite(比如A)中通过addChild加入一个子Sprite(比如B),则B通过boundingBox()获取到的边框,比如boundingBox_B相对于父Layer来说,位置是不准的,这会导致明明按中了B,却得不到该有的响应。
一个校正的代码如下,首先是加入子Sprite的方法:
StartPanel::StartPanel() { initWithFile("startpage.png"); CCDirector *pDirector = CCDirector::sharedDirector(); CCSize winSize = pDirector->getWinSize(); float screenWidth = winSize.width; float screenHeight = winSize.height; CCSize backgroundSize = this->getContentSize(); backgroundWidth = backgroundSize.width; backgroundHeight = backgroundSize.height; scaleX = screenWidth / backgroundWidth; scaleY = screenHeight / backgroundHeight; this->setScaleX(scaleX); this->setScaleY(scaleY); this->setPosition(ccp(screenWidth * 0.5f, screenHeight * 0.5f)); play = CCSprite::spriteWithFile("play.png"); float scaleDuration = 1.0f; CCScaleBy* bigScale = CCScaleBy::actionWithDuration(scaleDuration, 2.0f); CCScaleBy* smallScale = CCScaleBy::actionWithDuration(scaleDuration, 0.5f); CCSequence* scaleSequence = CCSequence::actionOneTwo(bigScale, smallScale); CCRepeatForever* scaleForever = CCRepeatForever::actionWithAction(scaleSequence); play->runAction(scaleForever); play->setPosition(ccp(backgroundWidth * 0.5f, backgroundHeight * 0.3f)); this->addChild(play); }
其中StartPanel本身是一个Sprite,然后加入了Play这个子Sprite,同时StartPanel和Play都进行了自身的缩放(Play是一个实时的缩放动画)。则Play的boundingBox()的校正代码如下:
CCRect StartPanel::getPlayBoundingBox() { if(play != NULL) { CCRect oldBoundingBox = play->boundingBox(); float offsetX = this->getPosition().x - backgroundWidth * 0.5f * scaleX; float offsetY = this->getPosition().y - backgroundHeight * 0.5f * scaleY; CCRect newBoundingBox = CCRectMake(oldBoundingBox.origin.x * scaleX + offsetX, oldBoundingBox.origin.y * scaleY + offsetY, oldBoundingBox.size.width * scaleX, oldBoundingBox.size.height * scaleY); return newBoundingBox; } else { return CCRectZero; } }
效果图如下:
完毕,特此记录。