Performance Parameters

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

• IDirectMusicPerformance8::SetParam sets data on a specific track within the current control segment of the 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 Control Segments.
• IDirectMusicSegment8::SetParam sets data on a specific track within the segment.
• IDirectMusicTrack8::SetParam and IDirectMusicTrack8::SetParamEx set data on the track represented by the interface. Applications do not normally have interfaces to individual tracks.

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.

More information about parameters is contained in the following topics:

• Setting and Retrieving Track Parameters
• Disabling and Enabling Track Parameters
• Setting and Retrieving Global Parameters