The IDirect3DViewport3::NextLight method enumerates the Direct3DLight objects associated with the viewport.
HRESULT NextLight(
  LPDIRECT3DLIGHT lpDirect3DLight,  
  LPDIRECT3DLIGHT* lplpDirect3DLight,  
  DWORD dwFlags                     
);
 If the method succeeds, the return value is D3D_OK.
If the method fails, the return value may be one of the following values:
| DDERR_INVALIDOBJECT | 
| DDERR_INVALIDPARAMS | 
This method is unchanged from its implementation in the IDirect3DViewport2 interface.
  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in d3d.h.
  Import Library: Use ddraw.lib.