DepthStencilbuffer *Framebuffer::getStencilbuffer()
{
    Renderbuffer *rb = mStencilbufferPointer.get();

    if (rb != NULL && rb->isStencilbuffer())
    {
        return static_cast<DepthStencilbuffer*>(rb->getStorage());
    }
    else
    {
        return NULL;
    }
}
Colorbuffer *Framebuffer::getColorbuffer()
{
    Renderbuffer *rb = mColorbufferPointer.get();

    if (rb != NULL && rb->isColorbuffer())
    {
        return static_cast<Colorbuffer*>(rb->getStorage());
    }
    else
    {
        return NULL;
    }
}