### IDirectDrawSurface3::Blt

The IDirectDrawSurface3::Blt method performs a bit block transfer. This method (as well as the IDirectDrawSurface3 version) does not currently support z-buffering or alpha blending (see alpha channel) during blit operations.

HRESULT Blt(

LPRECT lpDestRect,

LPDIRECTDRAWSURFACE3 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 on the destination surface to be blitted to. If this parameter is NULL, the entire destination surface will be used.
lpDDSrcSurface
  Address of the DirectDraw surface that is the source for the blit operation.
lpSrcRect
  Address of a RECT structure that defines the upper-left and lower-right points of the rectangle on the source surface to be blitted from. If this parameter is NULL, the entire source surface will be used.

dwFlags

DDBLT_ALPHADEST
| Uses either the alpha information in pixel format or the alpha channel surface attached to the destination surface as the alpha channel for this blit.
DDBLT_ALPHADESTCONSTOVERRIDE
| Uses the dwAlphaDestConst member of the DDBLTFX structure as the alpha channel for the destination surface for this blit.
DDBLT_ALPHADESTNEG
| Indicates that the destination surface becomes more transparent as the alpha value increases (0 is opaque).
DDBLT_ALPHADESTSURFACEOVERRIDE
| Uses the lpDDSAlphaDest member of the DDBLTFX structure as the alpha channel for the destination for this blit.
DDBLT_ALPHAEDGEBLEND
| Uses the dwAlphaEdgeBlend member of the DDBLTFX structure as the alpha channel for the edges of the image that border the color key colors.
DDBLT_ALPHASRC
| Uses either the alpha information in pixel format or the alpha channel surface attached to the source surface as the alpha channel for this blit.
DDBLT_ALPHASRCCONSTOVERRIDE
| Uses the dwAlphaSrcConst member of the DDBLTFX structure as the alpha channel for the source for this blit.
DDBLT_ALPHASRCNEG
| Indicates that the source surface becomes more transparent as the alpha value increases (0 is opaque).
DDBLT_ALPHASRCSURFACEOVERRIDE
| Uses the lpDDSAlphaSrc member of the DDBLTFX structure as the alpha channel for the source for this blit.
DDBLT_ASYNC
| Performs this blit asynchronously through the FIFO in the order received. If no room is available in the FIFO hardware, the call fails.
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 dwDDROPS member of the DDBLTFX structure to specify the raster operations (ROPS) that are not part of the 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_KEYDEST
| Uses the color key associated with the destination surface.
DDBLT_KEYDESTOVERRIDE
| Uses the dckDestColorkey member of the DDBLTFX structure as the color key for the destination surface.
DDBLT_KEYSRC
| Uses the color key associated with the source surface.
DDBLT_KEYSRCOVERRIDE
| Uses the dckSrcColorkey 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 1/100th of a degree) for the surface.
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.
DDBLT_ZBUFFER
| Performs a z-buffered blit using the z-buffers attached to the source and destination surfaces and the dwZBufferOpCode member of the DDBLTFX structure as the z-buffer opcode.
DDBLT_ZBUFFERDESTCONSTOVERRIDE
| Performs a z-buffered blit using the dwZDestConst and dwZBufferOpCode members of the DDBLTFX structure as the z-buffer and z-buffer opcode, respectively, for the destination.
DDBLT_ZBUFFERDESTOVERRIDE
| Performs a z-buffered blit using the lpDDSZBufferDest and dwZBufferOpCode members of the DDBLTFX structure as the z-buffer and z-buffer opcode, respectively, for the destination.
DDBLT_ZBUFFERSRCCONSTOVERRIDE
| Performs a z-buffered blit using the dwZSrcConst and dwZBufferOpCode members of the DDBLTFX structure as the z-buffer and z-buffer opcode, respectively, for the source.
DDBLT_ZBUFFERSRCOVERRIDE
| Performs a z-buffered blit using the lpDDSZBufferSrc and dwZBufferOpCode members of the DDBLTFX structure as the z-buffer and z-buffer opcode, respectively, for the source.

lpDDBltFx
  Address of the DDBLTFX structure.

##### Return Values

If the method succeeds, the return value is DD_OK.

If the method fails, the return value may be one of the following error values:

DDERR_GENERIC
DDERR_INVALIDCLIPLIST
DDERR_INVALIDOBJECT
DDERR_INVALIDPARAMS
DDERR_INVALIDRECT
DDERR_NOALPHAHW
DDERR_NOBLTHW
DDERR_NOCLIPLIST
DDERR_NODDROPSHW
DDERR_NOMIRRORHW
DDERR_NORASTEROPHW
DDERR_NOROTATIONHW
DDERR_NOSTRETCHHW
DDERR_NOZBUFFERHW
DDERR_SURFACEBUSY
DDERR_SURFACELOST
DDERR_UNSUPPORTED

##### Remarks

This method is capable of synchronous or asynchronous blits (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 will be performed if the source and destination rectangles are not the same size.

Typically, IDirectDrawSurface3::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.

Note that RECT structures are defined so that the right and bottom members are exclusive¾therefore, right - left equals the width of the rectangle, not one less than the width.