void PUParticleSystem3D::stopParticleSystem()
{
    if (_state != State::STOP)
    {
        _state = State::STOP;
    }

    for (auto iter : _children)
    {
        PUParticleSystem3D *system = dynamic_cast<PUParticleSystem3D *>(iter);
        if (system)
            system->stopParticleSystem();
    }
}