DXGKDDI_VIDPNTOPOLOGY_ENUMPATHTARGETSFROMSOURCE callback function (d3dkmddi.h)
The pfnEnumPathTargetsFromSource function returns the identifier of one of the video present targets associated with a specified video present source.
Syntax
DXGKDDI_VIDPNTOPOLOGY_ENUMPATHTARGETSFROMSOURCE DxgkddiVidpntopologyEnumpathtargetsfromsource;
NTSTATUS DxgkddiVidpntopologyEnumpathtargetsfromsource(
[in] IN_CONST_D3DKMDT_HVIDPNTOPOLOGY hVidPnTopology,
[in] IN_CONST_D3DDDI_VIDEO_PRESENT_SOURCE_ID VidPnSourceId,
[in] IN_CONST_D3DKMDT_VIDPN_PRESENT_PATH_INDEX VidPnPresentPathIndex,
[out] OUT_PD3DDDI_VIDEO_PRESENT_TARGET_ID pVidPnTargetId
)
{...}
Parameters
[in] hVidPnTopology
A handle to a VidPN topology object. The display miniport driver previously obtained this handle by calling the pfnGetTopology function of the DXGK_VIDPN_INTERFACE interface.
[in] VidPnSourceId
An integer that identifies a particular video present source.
[in] VidPnPresentPathIndex
A zero-based index into the set of paths that contain the source identified by VidPnSourceId.
[out] pVidPnTargetId
A pointer to a variable that receives the target identifier.
Return value
The pfnEnumPathTargetsFromSource function returns one of the following values:
| Return code | Description |
|---|---|
| STATUS_SUCCESS | The function succeeded. |
| STATUS_GRAPHICS_INVALID_VIDPN_TOPOLOGY | The handle supplied in hVidPnTopology was invalid. |
| STATUS_INVALID_PARAMETER | The pointer supplied in pVidPnTargetId was in valid. |
Remarks
VidPnPresentPathIndex is not an index into the set of all paths in the topology identified by hVidPnTopology. It is an index into a subset of all the paths in the topology: specifically, the subset of all paths that contain the source identified by VidPnSourceId.
To enumerate (in a given topology) all the targets associated with a particular source, perform the following steps.
Call pfnGetNumPathsFromSource to determine the number N of paths that contain the source of interest. Think of those paths as an indexed set with indices 0, 1, ... N - 1.
For each index 0 though N - 1, pass the source identifier and the index to pfnEnumPathTargetsFromSource.
A topology is a collection paths, each of which contains a (source, target) pair. It is possible for a particular source to appear in more than one path. For example, one source can be paired with two distinct targets in the case of a clone view.
VidPN source identifiers are assigned by the operating system. DxgkDdiStartDevice, implemented by the display miniport driver, returns the number N of video present sources supported by the display adapter. Then the operating system assigns identifiers 0, 1, 2, ... N - 1.
VidPN target identifiers are assigned by the display miniport driver. DxgkDdiQueryChildRelations, implemented by the display miniport driver, returns an array of DXGK_CHILD_DESCRIPTOR structures, each of which contains an identifier.
The D3DKMDT_HVIDPNTOPOLOGY and D3DKMDT_VIDPN_PRESENT_PATH_INDEX data types are defined in D3dkmdt.h.
The D3DDDI_VIDEO_PRESENT_SOURCE_ID and D3DDDI_VIDEO_PRESENT_TARGET_ID data types are defined in D3dukmdt.h.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista |
| Target Platform | Desktop |
| Header | d3dkmddi.h (include D3dkmddi.h) |
| IRQL | PASSIVE_LEVEL |