cocos2dx实现刮奖效果

本文实例为大家分享了cocos2dx刮奖效果实现代码，供大家参考，具体内容如下

刮奖效果其实挺简单的，需要用到RenderTexture来进行渲染，通过你所要渲染的图层，把该层的颜色进行设置混合就可以达到效果，具体看代码，我用的lua实现的。

local winsize = cc.Director:sharedDirector():getWinSize();
local dataSprite = cc.Sprite:create("Star.png")--要把这个图片刮出来
dataSprite:setAnchorPoint(cc.p(0.5, 0.5));
dataSprite:move(winsize.width / 2.0, winsize.height / 2.0);
self:addChild(dataSprite) 

pEarse = cc.DrawNode:create()
pEarse:drawDot(cc.p(0, 0), 5, cc.c4f(1, 0, 0, 1));
pEarse:retain() 

pRTex = cc.RenderTexture:create(winsize.width, winsize.height);
pRTex:setPosition(cc.p(winsize.width / 2, winsize.height / 2));
--this:addChild(pRTex);
pRTex:retain() 

local pBg = cc.Sprite:create("d1.png");--这个作为当“油漆层”
pBg:setAnchorPoint(cc.p(0.5, 0.5));
pBg:move(winsize.width / 2.0, winsize.height / 2.0); 

pRTex:begin();
dataSprite:visit();
pBg:visit();
pRTex:endToLua();
local layer=cc.Layer:create()
self:addChild(layer, 1000)
layer:addChild(pRTex);
layer:setNodeTouch(handler(self, self.onTouchStart)) 

鼠标移动代码：

function shop.erasure(event)
 -- body
 print("erasure: ", event.name)
 --todo
 print("moved")
 local touchPoint = event.pos
 pEarse:setPosition(event.pos.x, event.pos.y);
 -- 设置混合模式
 local blendFunc = { GL_ONE, GL_ZERO };
 pEarse:setBlendFunc(blendFunc);
 -- 将橡皮擦的像素渲染到画布上，与原来的像素进行混合
 pRTex:begin();
 pEarse:visit();
 pRTex:endToLua(); 

end 

C++代码：

void function()

{

  //test code
  auto aPanelSprite = Sprite::create("potentiometerTrack.png");
  aPanelSprite->setPosition(Vec2(s.width / 2, s.height / 2));
  this->addChild(aPanelSprite); 

  pEase = DrawNode::create();
  pEase->retain();
  pEase->drawDot(Point(0, 0), 4.0f, Color4F(255, 0, 0, 255)); 

  pRender = RenderTexture::create(s.width, s.height);
  pRender->retain();
  pRender->setPosition(Vec2(s.width / 2, s.height / 2));
  this->addChild(pRender); //渲染纹理层需加入该父节点层 

 auto pBg = Sprite::create("potentiometerProgress.png"); //这个作为当“油漆层”
 pBg->setAnchorPoint(Point(0.5, 0.5));
 pBg->setPosition(Vec2(s.width / 2, s.height / 2)); 

 pRender->begin();
 aPanelSprite->visit();
 pBg->visit();
 pRender->end(); 

 auto listener = EventListenerTouchOneByOne::create();
 listener->setSwallowTouches(true); 

 listener->onTouchBegan = CC_CALLBACK_2(SpriteEaseBezier::onTouchBegan, this);
 listener->onTouchMoved = CC_CALLBACK_2(SpriteEaseBezier::onTouchMoved, this); 

 auto _eventDispatcher = CCDirector::getInstance()->getEventDispatcher();
 _eventDispatcher->addEventListenerWithFixedPriority(listener, -10);
} 

bool SpriteEaseBezier::onTouchBegan(Touch *touch, Event *unused_event)
{
 CCLOG("SpriteEaseBezier::onTouchBegan");
 return true;
} 

void SpriteEaseBezier::onTouchMoved(Touch *touch, Event *unused_event)
{
 auto touchPoint = touch->getLocation();
 pEase->setPosition(touchPoint.x, touchPoint.y); 

 BlendFunc blendFunc = { GL_ONE, GL_ZERO };
 pEase->setBlendFunc(blendFunc); 

 pRender->begin();
 pEase->visit();
 pRender->end();
 CCLOG("SpriteEaseBezier::onTouchMoved");
}

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