SimpleAudioEngine类中加入一函数

如下

bool isEffectPlaying(unsigned int nSoundId);

bool SimpleAudioEngine::isEffectPlaying(unsigned int nSoundId)
{
	EffectList::iterator p = sharedList().find(nSoundId);
	bool bRet = false;
	if (p != sharedList().end())
	{
		bRet = p->second->IsPlaying();
	}

	return bRet;
}