写的精灵灰化处理，在htc g18上显示为黑色

Cocos2d-x
#1 
CCSprite* getGraySprite(CCSprite* normalsprite) {
    if ( !normalsprite) {
        return CreateDefaultSprite();
    }
    //CCSprite转成CCimage
    CCPoint p = normalsprite->getAnchorPoint();
    normalsprite->setAnchorPoint(ccp(0, 0));
    CCRenderTexture *outTexture = CCRenderTexture::create((int)normalsprite->getContentSize().width, (int)normalsprite->getContentSize().height);
    outTexture->begin();
    normalsprite->visit();
    outTexture->end();
    normalsprite->setAnchorPoint(p);
    
    CCImage* finalImage = outTexture->newCCImage();
    unsigned char *pData = finalImage->getData();
    int iIndex = 0;
    
    for (int i = 0; i < finalImage->getHeight(); i ++){
        for (int j = 0; j < finalImage->getWidth(); j ++){
            // gray
            int iBPos = iIndex;
            unsigned int iB = pData;
            iIndex ++;
            unsigned int iG = pData;
            iIndex ++;
            unsigned int iR = pData;
            iIndex ++;
            iIndex ++;
            unsigned int iGray = 0.3 * iR + 0.4 * iG + 0.2 * iB;
            pData = pData = pData = (unsigned char)iGray;
        }
    }
    
    CCTexture2D *texture = new CCTexture2D;
    texture->initWithImage(finalImage);
    CCSprite* newSprite = CCSprite::createWithTexture(texture);
    delete finalImage;
    texture->release();
    
    //setRealContentSize(newSprite, _scaleMode);
    return newSprite;
}

在很多Android手机上可以实现正常灰化，但是在HTC G18手机上直接显示为黑色，请问这是什么问题