DDOVERLAYFX

The DDOVERLAYFX structure passes override information to the IDirectDrawSurface3::UpdateOverlay method.

typedef struct _DDOVERLAYFX{­

DWORD dwSize;

DWORD dwAlphaEdgeBlendBitDepth;

DWORD dwAlphaEdgeBlend;

DWORD dwReserved;

DWORD dwAlphaDestConstBitDepth;

union

{­

DWORD dwAlphaDestConst;

LPDIRECTDRAWSURFACE lpDDSAlphaDest;

};

DWORD dwAlphaSrcConstBitDepth;

union

{­

DWORD dwAlphaSrcConst;

LPDIRECTDRAWSURFACE lpDDSAlphaSrc;

};

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.