DirectX SDK

IDirectDrawSurface7::Blt

The IDirectDrawSurface7::Blt method performs a bit block transfer (blit). This method does not support z-buffering or alpha blending (see alpha channel) during blit operations.

HRESULT Blt(
  LPRECT lpDestRect,                    
  LPDIRECTDRAWSURFACE7 lpDDSrcSurface,  
  LPRECT lpSrcRect,                     
  DWORD dwFlags,                        
  LPDDBLTFX lpDDBltFx                   
);

Parameters

lpDestRect

Address of a RECT structure that defines the upper-left and lower-right points of the rectangle to blit to on the destination surface. If this parameter is NULL, the entire destination surface is used.

lpDDSrcSurface

Address of an IDirectDrawSurface7 interface for the DirectDrawSurface object that is the source of the blit.

lpSrcRect

Address of a RECT structure that defines the upper-left and lower-right points of the rectangle to blit from on the source surface. If this parameter is NULL, the entire source surface is used.

dwFlags

A combination of flags that determine the valid members of the associated DDBLTFX structure, specify color-key information, or request special behavior from the method. The following flags are defined:

Validation flags
DDBLT_COLORFILL: Uses the dwFillColor member of the DDBLTFX structure as the RGB color that fills the destination rectangle on the destination surface.
DDBLT_DDFX: Uses the dwDDFX member of the DDBLTFX structure to specify the effects to use for this blit.
DDBLT_DDROPS: Uses the dwDDROP member of the DDBLTFX structure to specify the raster operations (ROPS) that are not part of the Microsoft® Win32® API.
DDBLT_DEPTHFILL: Uses the dwFillDepth member of the DDBLTFX structure as the depth value with which to fill the destination rectangle on the destination z-buffer surface.
DDBLT_KEYDESTOVERRIDE: Uses the ddckDestColorkey member of the DDBLTFX structure as the color key for the destination surface.
DDBLT_KEYSRCOVERRIDE: Uses the ddckSrcColorkey member of the DDBLTFX structure as the color key for the source surface.
DDBLT_ROP: Uses the dwROP member of the DDBLTFX structure for the ROP for this blit. These ROPs are the same as those defined in the Win32 API.
DDBLT_ROTATIONANGLE: Uses the dwRotationAngle member of the DDBLTFX structure as the rotation angle (specified in 1/100s of a degree) for the surface.
Color key flags
DDBLT_KEYDEST: Uses the color key associated with the destination surface.
DDBLT_KEYSRC: Uses the color key associated with the source surface.
Behavior flags
DDBLT_ASYNC: Performs this blit asynchronously through the first in, first out (FIFO) hardware in the order received. If no room is available in the FIFO hardware, the call fails.
DDBLT_DONOTWAIT: New for DirectX 7.0. Returns without blitting and also returns DDERR_WASSTILLDRAWING if the blitter is busy.
DDBLT_WAIT: Postpones the DDERR_WASSTILLDRAWING return value if the blitter is busy, and returns as soon as the blit can be set up or another error occurs.
Obsolete and unsupported flags
All DDBLT_ALPHA flag values.: Not currently implemented.
All DDBLT_ZBUFFER flag values: This method does not currently support z-aware blit operations. None of the flags beginning with "DDBLT_ZBUFFER" are supported in this release of DirectX.

lpDDBltFx

Address of the DDBLTFX structure.

Return Values

If the method succeeds, the return value is DD_OK.

If it fails, the method can return one of the following error values:

DDERR_GENERIC

DDERR_INVALIDCLIPLIST

DDERR_WASSTILLDRAWING

Remarks

This method is capable of synchronous or asynchronous blits (the latter is the default behavior), either display memory to display memory, display memory to system memory, system memory to display memory, or system memory to system memory. The blits can be performed by using source color keys and destination color keys. Arbitrary stretching or shrinking is performed if the source and destination rectangles are not the same size.

Typically, IDirectDrawSurface7::Blt returns immediately with an error if the blitter is busy and the blit could not be set up. Specify the DDBLT_WAIT flag to request a synchronous blit. When you include the DDBLT_WAIT flag, the method waits until the blit can be set up or another error occurs before it returns.

RECT structures are defined so that the right and bottom members are exclusive—therefore, right minus left equals the width of the rectangle, not 1 less than the width.

Requirements

  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 98.
  Header: Declared in ddraw.h.