Send MIDI Program Change over USB MIDI

[Ekolide]

Hiya.

The Haxophone has a Control Mode where you can change the Program on the Soundfont that FluidSynth has loaded. Currently, it does not send MIDI Program Change messages over USB MIDI at the same time. So changing the instrument +1 on the FluidSynth side does not change the instrument on the USB MIDI side.

I don't know how it's currently implemented in code, but libfluidsynth documentation states it uses MIDI Program Change. My suggestion is that this gets passed along to the USB MIDI service.

Let me know if there's any questions or anything that needs to be clarified.

[jcard0na]

It make sense to send the program change to the MIDI host, yes. If anyone wants to work on this, the required changes are small:

1. Add a midi_out reference to

   haxo-rs/src/commands.rs

   Lines 30 to 34 in 5b79df0

   	pub(crate) struct Command<'a> {
   	synth: &'a Synth,
   	prog_number: i32,
   	last_cmd_key: CommandKeys,
   	}

2. Add program_change() here:

   haxo-rs/src/midi.rs

   Lines 49 to 52 in 5b79df0

   	pub fn noteoff(&mut self, note: i32) {
   	const NOTE_OFF_MSG: u8 = 0x80;
   	let _ = self.conn_out.send(&[NOTE_OFF_MSG, note as u8, 0u8]);
   	}

   
   That is...

        let _ = self.conn_out.send(&[NOTE_OFF_MSG, note as u8, 0u8]); 
     } 
+    pub fn prog_chng(&mut self, prog: i32) {
+       const PROG_CHNG_MSG: u8 = 0xC0;
+        let _ = self.conn_out.send(&[PROG_CHNG_MSG, prog as u8]);
+    }
  }

3. Send the midi command from the function that implements the instrument change:

   haxo-rs/src/commands.rs

   Line 62 in 5b79df0

   self.synth.program_change(0, self.prog_number);

  self.synth.program_change(0, self.prog_number);
+ #[cfg(feature = "midi")]
+ self.midi_out.prog_chng(self.prog_number);
  info!("New MIDI program number {}", self.prog_number);