The D3DLIGHTDATA structure describes the points to be lit and resulting colors in calls to the IDirect3DViewport3::LightElements method.
typedef struct _D3DLIGHTDATA { 
    DWORD                dwSize; 
    LPD3DLIGHTINGELEMENT lpIn; 
    DWORD                dwInSize; 
    LPD3DTLVERTEX        lpOut; 
    DWORD                dwOutSize; 
} D3DLIGHTDATA, *LPD3DLIGHTDATA; 
   Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in d3dtypes.h.