DDOVERLAYFX

The DDOVERLAYFX structure passes override information to the IDirectDrawSurface4::UpdateOverlay method.

typedef struct _DDOVERLAYFX{ 
    DWORD dwSize; 
    DWORD dwAlphaEdgeBlendBitDepth; 
    DWORD dwAlphaEdgeBlend; 
    DWORD dwReserved; 
    DWORD dwAlphaDestConstBitDepth; 
    union 
    { 
        DWORD               dwAlphaDestConst; 
        LPDIRECTDRAWSURFACE lpDDSAlphaDest; 
    } DUMMYUNIONNAMEN(1);
    DWORD dwAlphaSrcConstBitDepth; 
    union 
    { 
        DWORD               dwAlphaSrcConst; 
        LPDIRECTDRAWSURFACE lpDDSAlphaSrc; 
    } DUMMYUNIONNAMEN(2);
    DDCOLORKEY dckDestColorkey; 
    DDCOLORKEY dckSrcColorkey; 
 
    DWORD dwDDFX; 
    DWORD dwFlags; 
} DDOVERLAYFX,FAR *LPDDOVERLAYFX; 
 

Members

dwSize

Size of the structure, in bytes. This members must be initialized before the structure is used.

dwAlphaEdgeBlendBitDepth

Bit depth used to specify the constant for an alpha edge blend.

dwAlphaEdgeBlend

Constant to use as the alpha for an edge blend.

dwReserved

Reserved for future use.

dwAlphaDestConstBitDepth

Bit depth used to specify the alpha constant for a destination.

dwAlphaDestConst

Constant to use as the alpha channel for a destination.

lpDDSAlphaDest

Address of a surface to use as the alpha channel for a destination.

dwAlphaSrcConstBitDepth

Bit depth used to specify the alpha constant for a source.

dwAlphaSrcConst

Constant to use as the alpha channel for a source.

lpDDSAlphaSrc

Address of a surface to use as the alpha channel for a source.

dckDestColorkey

Destination color key override.

dckSrcColorkey

Source color key override.

dwDDFX

Overlay FX flags.

DDOVERFX_ARITHSTRETCHY

If stretching, use arithmetic stretching along the y-axis for this overlay.

DDOVERFX_MIRRORLEFTRIGHT

Mirror the overlay around the vertical axis.

DDOVERFX_MIRRORUPDOWN

Mirror the overlay around the horizontal axis.

dwFlags

This member is currently not used and must be set to 0.

Remarks

The unions in this structure have been updated to work with compilers that don't support nameless unions. If your compiler doesn't support nameless unions, define the NONAMELESSUNION token before including the Ddraw.h header file.

QuickInfo

  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 ddraw.h.