1.HelloWorldScene.h

cocos2d::DrawNode* _eraser;cocos2d::RenderTexture*_renderTexture;

2.HelloWorldScene.cpp 的init方法中

Size visibleSize = Director::getInstance()->getVisibleSize();Vec2 center=Vec2(visibleSize.width*0.5f+origin.x,visibleSize.height*0.5f+origin.y);_eraser=DrawNode::create();_eraser->drawDot(Vec2::ZERO,10,Color4F(0,0,0,0));_eraser->retain();_renderTexture=RenderTexture::create((int)visibleSize.width,(int)visibleSize.height);_renderTexture->setPosition(center);addChild(_renderTexture);Sprite*spirte=Sprite::create("title_bg.jpg");spirte->setAnchorPoint(Vec2(0.5f,0.5f));spirte->setPosition(center);spirte->retain();    _renderTexture->begin();spirte->visit();_renderTexture->end();

3.触摸移动回调函数

Vec2 pos=touch->getLocation();//鼠标位置_eraser->setPosition(pos);BlendFunc blendFunc={GL_ONE,GL_ZERO};_eraser->setBlendFunc(blendFunc);_renderTexture->begin();_eraser->visit();_renderTexture->end();