DDSURFACEDESC

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This structure contains a description of a surface.

This structure is used to pass surface parameters to the IDirectDraw::CreateSurface method.

It is also used to retrieve information about a surface in calls to IDirectDrawSurface::Lock and IDirectDrawSurface::GetSurfaceDesc.

The relevant members differ for each potential type of surface.

Syntax

typedef struct _DDSURFACEDESC {
  DWORD dwSize;
  DWORD dwFlags;
  DWORD dwHeight;
  DWORD dwWidth;
  LONG lPitch;
  LONG lXPitch;
  DWORD dwBackBufferCount;
  DWORD dwRefreshRate;
  LPVOID lpSurface;
  DDCOLORKEY ddckCKDestOverlay;
  DDCOLORKEY ddckCKDestBlt;
  DDCOLORKEY ddckCKSrcOverlay;
  DDCOLORKEY ddckCKSrcBlt;
  DDPIXELFORMAT ddpfPixelFormat;
  DDSCAPS ddsCaps;
  DWORD dwSurfaceSize;
} DDSURFACEDESC, FAR* LPDDSURFACEDESC; 

Members

• dwSize
  Size of the structure in bytes.

  This member must be initialized before the structure is used.

• dwFlags
  Optional control flags.

  The following table shows the possible flags.

  Flag	Description
  DDSD_BACKBUFFERCOUNT	Indicates that the dwBackBufferCount member is valid.
  DDSD_CAPS	Indicates that the ddsCaps member is valid.
  DDSD_CKDESTBLT	Indicates that the ddckCKDestBlt member is valid.
  DDSD_CKDESTOVERLAY	Indicates that the ddckCKDestOverlay member is valid.
  DDSD_CKSRCBLT	Indicates that the ddckCKSrcBlt member is valid.
  DDSD_CKSRCOVERLAY	Indicates that the ddckCKSrcOverlay member is valid.
  DDSD_HEIGHT	Indicates that the dwHeight member is valid.
  DDSD_LPSURFACE	Indicates that the lpSurface member is valid.
  DDSD_PITCH	Indicates that the lPitch member is valid.
  DDSD_PIXELFORMAT	Indicates that the ddpfPixelFormat member is valid.
  DDSD_REFRESHRATE	Indicates that the dwRefreshRate member is valid.
  DDSD_SURFACESIZE	Indicates that the dwSurfaceSize member is valid.
  DDSD_WIDTH	Indicates that the dwWidth member is valid.
  DDSD_XPITCH	Indicates that the lXpitch member is valid.

• dwHeightand dwWidth
  Dimensions, in pixels, of the surface to be created.

• lPitch
  Distance, in bytes, to the start of next line.

  When used with the IDirectDrawSurface::GetSurfaceDesc method, this is a return value.

  See remarks for more information.

• lXPitch
  Distance, in bytes, to next pixel to the right.

• dwBackBufferCount
  Number of back buffers.

• dwRefreshRate
  Refresh rate (used when the display mode is described).

  The value of zero indicates that the adapter is using its default refresh rate.

  It is not possible to change an adapter's refresh rate in Windows Embedded CE, therefore dwRefreshRate will always be 0.

• lpSurface
  Address of the associated surface memory.

  When calling IDirectDrawSurface::Lock, this member is a valid pointer to surface memory.

  See remarks for more information.

• ddckCKDestOverlay
  DDCOLORKEY structure that describes the destination color key to be used for an overlay surface.

• ddckCKDestBlt
  DDCOLORKEY structure that describes the destination color key for blit operations.

• ddckCKSrcOverlay
  DDCOLORKEY structure that describes the source color key to be used for an overlay surface.

• ddckCKSrcBlt
  DDCOLORKEY structure that describes the source color key for blit operations.

• ddpfPixelFormat
  DDPIXELFORMAT structure that describes the surface's pixel format.

• ddsCaps
  DDSCAPS structure containing the surface's capabilities.

• dwSurfaceSize
  Surface size, in bytes.

Remarks

The lPitch and lXPitch members are used to indicate the number of bytes between a pixel and the pixel directly below it onscreen and the pixel directly to the right of it onscreen. These will vary depending on the current rotation of the surface, and either value can be negative. For example:

On a 240x320 16bpp surface that is not rotated, lPitch will usually be 480 and lXPitch will be 2, and lpSurface will point to the first byte in memory of the surface.

Rotated to 90 degrees, lPitch becomes 2 and lXPitch becomes -480.

Rotated to 180 degrees, lPitch becomes -480 and lXPitch becomes -2.

Rotated to 270 degrees, lPitch becomes -2 and lXPitch becomes 480.

lpSurface always points to the memory for the pixel at (0,0), which when rotated is not going to be the first byte in memory of the surface.

The lPitch and lpSurface members are output values when calling the IDirectDrawSurface::GetSurfaceDesc method.

When creating surfaces from existing memory, or updating surface characteristics, these members are input values that describe the pitch and location of memory allocated by the calling application for use by DirectDraw.

DirectDraw does not attempt to manage or free memory allocated by the application.

Requirements