cocos2dx用裁剪区域CCClippingNode实现滚动字幕

bool TestLayer::init()

{

    CCSize size = CCDirector::sharedDirector()->getVisibleSize();

       

    //创建要显示的文字

    text = CCLabelTTF::create("text\nbaibai\n白白\nbaibai\nhaha\nhaha\nahha\n", "", 30);

    text->setPosition(ccp(100, -120));

     

    //绘制裁剪区域

    CCDrawNode* shap = CCDrawNode::create();

    CCPoint point[4] = {ccp(0,0), ccp(200, 0), ccp(200, 200), ccp(0, 200)};

    shap->drawPolygon(point, 4, ccc4f(355, 255, 255, 255), 2, ccc4f(255, 255, 255, 255));

    CCClippingNode* cliper = CCClippingNode::create();

    cliper->setStencil(shap);

    cliper->setAnchorPoint(ccp(.5, .5));

    cliper->setPosition(ccp(100, 20));

    addChild(cliper);

    //把要滚动的文字加入到裁剪区域

    cliper->addChild(text);

     

    //文字滚动，超出范围后从新开始

    schedule(schedule_selector(CTestLayer::rollText));

    return true;

}

void TestLayer::rollText(float)

{

    text->getPositionY()>300 ? text->setPositionY(-150) : text->setPositionY(text->getPositionY()+2);

}