cocos2d-x 遮罩效果实现

   

遮罩图片：白色

static   CCSprite*   createMaskedSprite(CCSprite* src, const char* maskFile, CCSize maskSize);

CCSprite*  StartupGuideLayer::createMaskedSprite(CCSprite* src, const char* maskFile, CCSize maskSize)

{

    CCSprite * mask = CCSprite::create(maskFile);

    assert(src);

    assert(mask);

    CCSize srcContent = src->getContentSize();

    CCSize maskContent = mask->getContentSize();

    CCRenderTexture * rt = CCRenderTexture::create(srcContent.width, srcContent.height, kTexture2DPixelFormat_RGBA8888);

    float ratiow = maskSize.width / maskContent.width;

    float ratioh = maskSize.height / maskContent.height;

    mask->setScaleX(ratiow);

    mask->setScaleY(ratioh);

    mask->setPosition(ccp(srcContent.width / 2, srcContent.height / 2));

    src->setPosition(ccp(srcContent.width / 2, srcContent.height / 2));

    ccBlendFunc blendFunc2 = { GL_ONE, GL_ZERO };

    mask->setBlendFunc(blendFunc2);

 

    ccBlendFunc blendFunc3 = { GL_DST_ALPHA, GL_ZERO };

    src->setBlendFunc(blendFunc3);

    rt->begin();

    mask->visit();

    src->visit();

    rt->end();

    CCSprite * retval = CCSprite::createWithTexture(rt->getSprite()->getTexture());

    retval->setFlipY(true);

    

    return retval;

}

调用例子：

        CCSprite  *  spriteGuide =  CCSprite::create(tempBuffer);

        spriteGuide =  StartupGuideLayer::createMaskedSprite(spriteGuide, "ui_mask_bai.png", m_size);