Returns a specific buffer in the ISurfacePresenter interface.
HRESULT GetBuffer( UINT backBufferIndex, REFIID riid, void **ppBuffer );
- [in] The index of the desired back buffer.
- [in] The interface from which to get the back buffer.
- [out, retval] A buffer in the surface presenter.
Returns S_OK if successful, or an error value otherwise.
The interface request must match the mode that the presenter was opened with.