IDirect3DViewport::GetBackgroundDepth
HRESULT GetBackgroundDepth(LPDIRECTDRAWSURFACE* lplpDDSurface,
LPBOOL lpValid);
Retrieves a DirectDraw surface that represents the current background-depth field associated with the viewport.
·Returns D3D_OK if successful, or an error otherwise, which may be one of the following values:
lplpDDSurface
Address that will be initialized to point to a DirectDrawSurface object representing the background depth.
lpValid
Address of a variable that is set to FALSE if no background depth is associated with the viewport.