Capability Bits for Non-flippable YV12 Overlays (Windows Embedded CE 6.0)

1/6/2010

The following code example shows how to set the DirectDraw capability bits for YV12 overlays that cannot be flipped.

#include "precomp.h"

DWORD g_FourCC[] = {
    FOURCC_YV12,
};

#define MAX_FOURCC ( sizeof ( g_FourCC ) / sizeof ( g_FourCC[0] ) )

// 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;

    lpddhi->lpdwFourCC = g_FourCC;

    // 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 = MAX_FOURCC;
    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