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This method performs a bit block transfer. This method does not support Z-buffering or alpha blending (see alpha channel) during blit operations.
Syntax
HRESULT Blt( LPRECT lpDestRect, LPDIRECTDRAWSURFACE lpDDSrcSurface, LPRECT lpSrcRect, DWORD dwFlags, LPDDBLTFX lpDDBltFx ); |
Parameters
- lpDestRect
-
Address of a RECTstructure 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 will be used.
- lpDDSrcSurface
-
Address of an IDirectDrawSurfaceinterface for the DirectDrawSurfaceobject that is the source of the blit.
- lpSrcRect
-
Address of a RECTstructure 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 will be used.
- dwFlags
-
A combination of flags that determine the valid members of the associated DDBLTFXstructure, specify color key information, or that request special behavior from the method.
The following table shows the possible validation flags.
Flag Description DDBLT_COLORFILL
Uses the dwFillColormember of the DDBLTFXstructure as the RGB color that fills the destination rectangle on the destination surface.
DDBLT_KEYDESTOVERRIDE
Uses the ddckDestColorkeymember of the DDBLTFXstructure as the color key for the destination surface.
DDBLT_KEYSRCOVERRIDE
Uses the ddckSrcColorkeymember of the DDBLTFXstructure as the color key for the source surface.
DDBLT_ROP
Uses the dwROPmember of the DDBLTFXstructure for the ROP for this blit. These ROPs are the same as those defined in the Win32 API.
The following table shows the possible color key flags.
Flag Description DDBLT_KEYDEST
Uses the color key associated with the destination surface.
DDBLT_KEYSRC
Uses the color key associated with the source surface.
The following table shows the possible behavior flags.
Flag Description DDBLT_WAITNOTBUSY
Waits for a previously initiated drawing operation to complete instead of returning immediately with the DDERR_WASSTILLDRAWINGreturn value.
If a previous drawing operation is in progress at the time of the call, this flag defers returning from the call until the new blit operation begins or an error occurs.
DDBLT_WAITVSYNC
Waits for a V-Sync before performing the blit operation.
- lpDDBltFx
-
Address of the DDBLTFXstructure.
Return Value
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 |
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DDERR_NOALPHAHW |
|
DDERR_NOBLTHW |
|
DDERR_NOCLIPLIST |
|
DDERR_NORASTEROPHW |
|
DDERR_NOSTRETCHHW |
|
DDERR_SURFACEBUSY |
|
DDERR_SURFACELOST |
|
DDERR_UNSUPPORTED |
|
DDERR_WASSTILLDRAWING |
For more information on these error codes see DirectDraw Return Values.
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, IDirectDrawSurface::Bltreturns immediately with an error if the blitter is busy and the blit could not be set up. Specify the DDBLT_WAITNOTBUSY flag to request a synchronous blit. When you include the DDBLT_WAITNOTBUSY flag, the method waits until the blit can be set up or another error occurs before it returns.
The RECTstructures are defined so that the rightand bottommembers are exclusive: rightminus leftequals the width of the rectangle, not one less than the width.
Requirements
| Header | ddraw.h |
| Library | ddraw.lib |
| Windows Embedded CE | Windows Embedded CE 6.0 and later |
| Windows Mobile | Pocket PC for Windows Mobile Version 5.0 and later, Smartphone for Windows Mobile Version 5.0 and later |