Cocos2D-X闪亮标题实现

Cocos2D-X闪亮标题实现最终效果图：

实现方法:

主要依懒ClippingNode类

需要的素材有:

显示标题，又作为stencil（模板)

光束(beam)....就是纯白色加点透明....可能看不出来

代码实现

1.添加标题

//标题
 auto title = Sprite::create("BeamTitle/title.png");
 title->setAnchorPoint(Vec2(0.5f, 0.5f));
 title->setPosition(Vec2(visibleSize.width / 2, visibleSize.height / 6 * 5));
 this->addChild(title);

2,加ClippingNode

ClippingNode需要设置三个内容

模板(Node *类型)，这里是标题，第一张图，不会被显示

显示目标(ClippingNode 的子节点)，这里是光束，第二张图

设置AlphaThresHold的值，简单点的说就是透明度，只有当模板透明度大于这个值时，显示目标才会绘制

//clippingNode
 auto titleStencil = Sprite::create("BeamTitle/title.png");
 auto clipTitle = ClippingNode::create(titleStencil);
 clipTitle->setAnchorPoint(Vec2(0.5f, 0.5f));
 clipTitle->setPosition(Vec2(visibleSize.width / 2, visibleSize.height / 6 * 5));
 clipTitle->setAlphaThreshold(0.0f);
 this->addChild(clipTitle);
 //Beam 光束
 auto beam = Sprite::create("BeamTitle/beam.png");
 beam->setAnchorPoint(Vec2(0.5f, 0.5f));
 auto toRight = MoveTo::create(0.5f, Vec2(200, 50));
 auto toLeft = MoveTo::create(0.5f, Vec2(-200, 50));
 auto seq = Sequence::create(toRight, toLeft, nullptr);
 auto move = RepeatForever::create(seq);
 beam->runAction(move);
 clipTitle->addChild(beam);

代码中,ClippingNode的AlphaThresHold值被设置为0.0f,标题的完全透明部分的透明度也为0.0f.所以beam在透明部分不会被显示。

额外例子

最下面的滚动条是用来设置AlphaThresHold

中间使用的模板是

增加AlphaThresHold的值，图片显示的内容越来越少。

完整代码

BeamTitle.h

#ifndef __BEAM__TITLE__CPP__
#define  __BEAM__TITLE__CPP__
#include "cocos2d.h"
#include "ui/UISlider.h"
class BeamTitle :public cocos2d::Layer{
public:
 /*
  *三个构造相关函数
  */
 static cocos2d::Scene* createScene();
 CREATE_FUNC(BeamTitle);
 bool init();
private:
 /*
  *滑动条函数
  */
 void sliderEvent(cocos2d::Ref *pSender, cocos2d::ui::Slider::EventType type);
private:
 cocos2d::ClippingNode *clip;
 cocos2d::Label *label;
};
#endif

BeamTitle.cpp

#include "BeamTitle.h"
#include "BackLayer.h"
#include "ui/UISlider.h"
USING_NS_CC;
using namespace ui;
Scene *BeamTitle::createScene(){
 auto *back = BackLayer::create();
 Layer *layer = BeamTitle::create();
 Scene*scene = Scene::create();
 scene->addChild(back);
 scene->addChild(layer);
 return scene;
}
bool BeamTitle::init(){
 if (!Layer::init())
  return false;
 auto visibleSize = Director::getInstance()->getVisibleSize();
 //标题
 auto title = Sprite::create("BeamTitle/title.png");
 title->setAnchorPoint(Vec2(0.5f, 0.5f));
 title->setPosition(Vec2(visibleSize.width / 2, visibleSize.height / 6 * 5));
 this->addChild(title);
 //clippingNode
 auto titleStencil = Sprite::create("BeamTitle/title.png");
 auto clipTitle = ClippingNode::create(titleStencil);
 clipTitle->setAnchorPoint(Vec2(0.5f, 0.5f));
 clipTitle->setPosition(Vec2(visibleSize.width / 2, visibleSize.height / 6 * 5));
 clipTitle->setAlphaThreshold(0.0f);
 this->addChild(clipTitle);
 //Beam 光束
 auto beam = Sprite::create("BeamTitle/beam.png");
 beam->setAnchorPoint(Vec2(0.5f, 0.5f));
 auto toRight = MoveTo::create(0.5f, Vec2(200, 50));
 auto toLeft = MoveTo::create(0.5f, Vec2(-200, 50));
 auto seq = Sequence::create(toRight, toLeft, nullptr);
 auto move = RepeatForever::create(seq);
 beam->runAction(move);
 clipTitle->addChild(beam);
 //滑动条
 auto slider = Slider::create();
 slider->loadBarTexture("BeamTitle/sliderTrack.png");
 slider->loadProgressBarTexture("BeamTitle/sliderProgress.png");
 slider->loadSlidBallTextures("BeamTitle/sliderThumb.png", "BeamTitle/sliderThumb.png","");
 slider->setPosition(Vec2(visibleSize.width / 2, visibleSize.height / 8));
 slider->addEventListener(CC_CALLBACK_2(BeamTitle::sliderEvent, this));
 this->addChild(slider);
 /*
  *ClippingNode
  */
 //模板
 auto stencil = Sprite::create("BeamTitle/stencil.png");
 //显示对象 猫
 auto cat = Sprite::create("BeamTitle/cat.png");
 clip = ClippingNode::create(stencil);
 clip->setAlphaThreshold(1.0f);
 clip->addChild(cat);
 clip->setPosition(visibleSize / 2);
 this->addChild(clip);
 //label 显示透明度 即 AlphaThreshold
 label = Label::createWithBMFont("BeamTitle/bitmapFontTest2.fnt", "1.0f");
 label->setScale(0.5f);
 label->setPosition(Vec2(visibleSize.width / 2, visibleSize.height / 5));
 this->addChild(label);
 return true;
}
void BeamTitle::sliderEvent(Ref *pSender, Slider::EventType type){
 if (type == Slider::EventType::ON_PERCENTAGE_CHANGED)
 {
  Slider* slider = dynamic_cast<Slider*>(pSender);
  int percent = slider->getPercent(); 
  clip->setAlphaThreshold(1.0f*percent / 100);
  char str[30];
  sprintf(str, "AlphaThresHold=%f", 1.0f*percent / 100);
  label->setString(str);
  printf("AlphaThresHold=%f", clip->getAlphaThreshold());
 }
}

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