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4/8/2010

The following code example shows how to set the DirectDraw capability bits for RGB overlays that cannot be flipped.

Note:
To make the following code example easier to read, security checking and error handling are not included. This code example should not be used in a release configuration unless it has been modified to include them.
Copy Code 
#include "precomp.h"

// callbacks from the DIRECTDRAW object

DDHAL_DDCALLBACKS cbDDCallbacks =
{
	sizeof( DDHAL_DDCALLBACKS ),
		DDHAL_CB32_CREATESURFACE		|
		DDHAL_CB32_WAITFORVERTICALBLANK |
		DDHAL_CB32_CANCREATESURFACE	 |
//	DDHAL_CB32_CREATEPALETTE		|
//	DDHAL_CB32_GETSCANLINE		|
		0,
	DDGPECreateSurface,
	DDGPEWaitForVerticalBlank,
	DDGPECanCreateSurface,
	NULL,
	NULL
};

// callbacks from the DIRECTDRAWSURFACE object

DDHAL_DDSURFACECALLBACKS cbDDSurfaceCallbacks =
{
	sizeof( DDHAL_DDSURFACECALLBACKS ),
		DDHAL_SURFCB32_DESTROYSURFACE	 |
		DDHAL_SURFCB32_LOCK			 |
		DDHAL_SURFCB32_UNLOCK			 |
		DDHAL_SURFCB32_SETCOLORKEY		|
		DDHAL_SURFCB32_GETBLTSTATUS	 |
		DDHAL_SURFCB32_UPDATEOVERLAY	|
		DDHAL_SURFCB32_SETOVERLAYPOSITION |
//	DDHAL_SURFCB32_SETPALETTE		 |
		0,
	DDGPEDestroySurface,
	NULL,
	DDGPELock,
	DDGPEUnlock,
	DDGPESetColorKey,
	HalGetBltStatus,
	NULL,
	HalUpdateOverlay,
	HalSetOverlayPosition,
	NULL
};

// InitDDHALInfo must set up this information
unsigned long	g_nVideoMemorySize  = 0L;
unsigned char *  g_pVideoMemory	= NULL; // virtual address of
video
											 // memory from
client's side
DWORD			g_nTransparentColor = 0L;

EXTERN_C void 
buildDDHALInfo(
	LPDDHALINFO lpddhi,
	DWORD modeidx 
	)
{
	GPEFlat * pGPEFlat = static_cast<GPEFlat *>(GetDDGPE());

	if( !g_pVideoMemory )   // in case this is called more than
once...
	{
		unsigned long VideoMemoryStart;

		pGPEFlat->GetVirtualVideoMemory( &VideoMemoryStart,
										 &g_nVideoMemorySize );
		DEBUGMSG( GPE_ZONE_INIT,
		(TEXT("GetVirtualVideoMemory returned addr=0x%08x
size=%d\r\n"),
		 VideoMemoryStart, g_nVideoMemorySize));

		g_pVideoMemory = (BYTE*)VideoMemoryStart;
		DEBUGMSG( GPE_ZONE_INIT,
				 (TEXT("gpVidMem=%08x\r\n"), g_pVideoMemory ));
}

	memset( lpddhi, 0, sizeof(DDHALINFO) );  // Clear the DDHALINFO
											 // structure
	lpddhi->dwSize = sizeof(DDHALINFO);

	lpddhi->lpDDCallbacks = &cbDDCallbacks;
	lpddhi->lpDDSurfaceCallbacks = &cbDDSurfaceCallbacks;

	lpddhi->GetDriverInfo = HalGetDriverInfo;

	// Capability bits.
	lpddhi->ddCaps.dwSize = sizeof(DDCAPS);

	lpddhi->ddCaps.dwVidMemTotal  = g_nVideoMemorySize;
	lpddhi->ddCaps.dwVidMemFree   = g_nVideoMemorySize;
	lpddhi->ddCaps.dwVidMemStride = 0;

	lpddhi->ddCaps.ddsCaps.dwCaps =
		DDSCAPS_FRONTBUFFER		 |
		DDSCAPS_OVERLAY			 |
		DDSCAPS_PRIMARYSURFACE	|
		DDSCAPS_SYSTEMMEMORY		|
		DDSCAPS_VIDEOMEMORY		 |
		0;

	lpddhi->ddCaps.dwNumFourCCCodes = 0;
	lpddhi->ddCaps.dwPalCaps = 0;
	lpddhi->ddCaps.dwMiscCaps = 0;

	// DirectDraw Blttting caps refer to hardware blitting support
only.
	lpddhi->ddCaps.dwBltCaps = 0;
	lpddhi->ddCaps.dwCKeyCaps = 0;
	lpddhi->ddCaps.dwAlphaCaps = 0;

	// Overlay caps.
	lpddhi->ddCaps.dwOverlayCaps = DDOVERLAYCAPS_FOURCC;

	lpddhi->ddCaps.dwMaxVisibleOverlays = 1;
	lpddhi->ddCaps.dwCurrVisibleOverlays = 0;

	lpddhi->ddCaps.dwAlignBoundarySrc = 0;
	lpddhi->ddCaps.dwAlignSizeSrc = 0;
	lpddhi->ddCaps.dwAlignBoundaryDest = 0;
	lpddhi->ddCaps.dwAlignSizeDest = 0;

	lpddhi->ddCaps.dwMinOverlayStretch = 1000;
	lpddhi->ddCaps.dwMaxOverlayStretch = 1000;
}

See Also

Concepts

Overlay Surfaces