HRESULT CreateViewport(LPDIRECT3DVIEWPORT* lplpD3DViewport,
IUnknown* pUnkOuter);
Creates a Direct3DViewport object. The viewport is associated with a Direct3DDevice object by using the IDirect3DDevice::AddViewport method.
·Returns D3D_OK if successful, or an error otherwise, which may be one of the following values:
lplpD3DViewport
Address that will be filled with a pointer to an IDirect3DViewport interface if the call succeeds.
pUnkOuter
This parameter is provided for future compatibility with COM aggregation features. Currently, however, the IDirect3D::CreateViewport method returns an error if this parameter is anything but NULL.