| Microsoft DirectX 9.0 SDK Update (October 2004) |
The IDirectMusicTrack8::InitPlay method is called when a track is ready to start playing. The method returns a pointer to state data.
Syntax
HRESULT InitPlay(
IDirectMusicSegmentState* pSegmentState,
IDirectMusicPerformance* pPerformance,
void** ppStateData,
DWORD dwVirtualTrackID,
DWORD dwFlags
);
Parameters
pSegmentState
Address of the calling IDirectMusicSegmentState or IDirectMusicSegmentState8 interface.
pPerformance
Address of the calling IDirectMusicPerformance or IDirectMusicPerformance8 interface.
ppStateData
Address of a variable that receives a pointer to state information. The format and use of the data is specific to the track. The data should be created in the InitPlay method and freed in the IDirectMusicTrack8::EndPlay method. The pointer is passed to the IDirectMusicTrack8::Play and IDirectMusicTrack8::PlayEx methods.
dwVirtualTrackID
Virtual track ID assigned to this track instance.
dwFlags
DMUS_SEGF_FLAGS that control the track's behavior. See Remarks.
Return Values
If the method succeeds, the return value is S_OK.
If it fails, the method can return one of the error values shown in the following table.
| Return code |
| DMUS_E_NOT_INIT |
| E_OUTOFMEMORY |
| E_POINTER |
Remarks
The dwFlags parameter passes the flags that were handed to the performance in the call to IDirectMusicPerformance8::PlaySegment or IDirectMusicPerformance8::PlaySegmentEx. The track determines how it should perform, based on the DMUS_SEGF_CONTROL and DMUS_SEGF_SECONDARY flags. For example, the tempo track automatically plays the tempo changes only if it is part of a primary segment or a secondary control segment (DMUS_SEGF_SECONDARY is not set, or DMUS_SEGF_CONTROL is set).
A track can return NULL in *ppStateData.
Requirements
Header: Declared in dmplugin.h.
See Also