PDD_VPORTCB_UPDATE callback function (ddrawint.h)
The DdVideoPortUpdate callback function starts and stops the VPE object, and modifies the VPE object data stream.
Syntax
PDD_VPORTCB_UPDATE PddVportcbUpdate;
DWORD PddVportcbUpdate(
PDD_UPDATEVPORTDATA unnamedParam1
)
{...}
Parameters
unnamedParam1
Points to a DD_UPDATEVPORTDATA structure that contains the information required for the driver to update the VPE object.
Return value
DdVideoPortUpdate returns one of the following callback codes:
Remarks
DirectDraw drivers that support VPE must implement DdVideoPortUpdate.
When the dwFlags member of the DD_UPDATEVPORTDATA structure at lpUpdate is DDRAWI_VPORTSTART or DDRAWI_VPORTUPDATE, the driver should do the following:
- Check all flags in the dwVPFlags member of the DDVIDEOPORTINFO structure to which the lpVideoInfo member of DD_UPDATEVPORTDATA points. These flags describe how the driver should transfer video data to a surface (or surfaces); for example, they indicate whether the driver should perform autoflipping, crop the video or VBI data, etc.
- Set up loops in the hardware to write video and/or VBI data to the surfaces in the order in which the surfaces are stored in the array(s). The driver should return as quickly as possible after setting up these loops.
- If autoflipping has been requested, store the frame buffer offset for each surface in the driver's internal data structure. The surface offsets should be stored in the order in which the surfaces occur in the DD_SURFACE_INT arrays at the lplpDDSurface and lplpDDVBISurface members of DD_UPDATEVPORTDATA. In this way, when DdUpdateOverlay is called, the driver has a record of the flipping order of the surface chain.
If the driver's hardware cannot support the number of surfaces specified when autoflipping is requested, DdVideoPortUpdate should fail the call by setting DDERR_UNSUPPORTED in the ddRVal member of DD_UPDATEVPORTDATA.
The number of surfaces in the video and VBI surface chains can be different; that is, the dwNumAutoflip and dwNumVBIAutoflip members of DD_UPDATEVPORTDATA can be different values.
When dwFlags is DDRAWI_VPORTSTOP, the driver should return immediately. The driver should not poll until the data stream stops.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Desktop |
| Header | ddrawint.h (include Winddi.h) |