|Microsoft DirectX 9.0|
DirectMusic lets you control many aspects of track behavior by changing parameters during playback, using one of the following SetParam methods:
The IDirectMusicPerformance8::SetGlobalParam method enables you to set values that apply across the entire performance.
The equivalent GetParam and GetGlobalParam methods retrieve current values for a track or the performance.
To have the music respond immediately to a changed parameter, an application can flush messages from the queue by using the IDirectMusicPerformance8::Invalidate method. This method causes all tracks to resend messages from the specified point forward.