本文介绍游戏中常见的滚动播放的公告栏实现
要点
- 文字内容横向或者纵向滚动
- 文字只在区域内显示，超出区域部分不显示
相关头文件
** "2d/CCClippingNode.h" **
注意：在cocos2dx 3.x版本中，方法名中的CC命名方式已经弃用，但是文件名中的CC依然有，所以此处的头文件名中的CC打头无法去除
实现
头文件
#pragma once
#include "cocos2d.h"
#include "2d/CCClippingNode.h"
USING_NS_CC;
class PannelNews :public Node
{
protected:
Node* _holder;
Sprite* _newsBg;
Label* _news;
DrawNode* _shap;
ClippingNode* _cliper;
public:
PannelNews();
~PannelNews();
virtual bool init() override;
void layout();
void scrollText(float);
CREATE_FUNC(PannelNews);
};
源文件
#include "PannelNews.h"
PannelNews::PannelNews()
{
_holder = NULL;
_newsBg = NULL;
_news = NULL;
_shap = NULL;
_cliper = NULL;
}
PannelNews::~PannelNews() {}
bool PannelNews::init()
{
if (!Node::init())
return false;
setPosition(Point(640.f, 585.f));
_holder = Node::create();
addChild(_holder);
_newsBg = Sprite::create("newsBg.png");
_holder->addChild(_newsBg);
_shap = DrawNode::create();
Point point[4] = { Point(60.f,0.f), Point(710.f,0.f), Point(710.f,35.f), Point(60.f,35.f)};
//标记显示的矩形区域
_shap->drawPolygon(point, 4, Color4F(355, 255, 255, 255), 2, Color4F(255, 255, 255, 255));
//剪切用于显示的矩形区域，参数对应：用于标识区域的Point(Vec2)数组指针，数组长度，填充颜色，边框宽度，边框颜色
_cliper = ClippingNode::create();
_cliper->setStencil(_shap);
_cliper->setAnchorPoint(Point(0.5, 0.5));
_newsBg->addChild(_cliper);
_news = Label::createWithSystemFont(UserDefault::getInstance()->getStringForKey(KEY_LOCAL_NEWS, "公告内容"), "Microsoft Yahei", 24);
_news->setColor(Color3B(214, 213, 213));
_cliper->addChild(_news);
layout();
return true;
}
void PannelNews::layout()
{
_news->setAnchorPoint(Point::ZERO);
_news->setPosition(Point(720, 10));//设置公告文字内容的初始位置
schedule(schedule_selector(PannelNews::scrollText));//实现公告文字滚动
}
void PannelNews::scrollText(float)
{
_news->getPosition().x < (-1 * _news->getContentSize().width) ? _news->setPositionX(720) : _news->setPositionX(_news->getPositionX() - 2);
}
- ClippingNode可以用于设定一个区域作为其显示区域，其子节点只可在该区域内才可显示，超出区域部分则无法显示，可用于公告、通知、聊天框、区域弹幕、弹幕游戏的保护罩等
