Music Parameters

DirectMusic lets you control many aspects of track behavior by changing parameters on the fly, using one of the following SetParam methods:

• IDirectMusicPerformance::SetParam sets data on a specific track within the current control segment of this performance. The control segment is normally the primary segment, but a secondary segment can be designated as the control segment when it is played. See DMUS_SEGF_FLAGS.
• IDirectMusicSegment::SetParam sets data on a specific track within this segment.
• IDirectMusicTrack::SetParam sets data on this track.

In addition, the IDirectMusicPerformance::SetGlobalParam method lets you set values that apply across the entire performance.

The equivalent GetParam and GetGlobalParam methods retrieve current values for a track or the performance.

In order to have the music respond immediately to a changed parameter, an application can flush messages from the queue by using the IDirectMusicPerformance::Invalidate method. This method causes all tracks to resend messages from the specified point forward.

More information about parameters is contained in the following topics:

• Setting and Retrieving Track Parameters
• Setting and Retrieving Global Parameters