AUDIO: Make MT-32 emulator play MIDI events immediately.

This fixes the Indiana Jones and the Fate of Atlantis specific issue reported
in bug #6242 "AUDIO: Built-In MT-32 MUNT Produces Wrong Sounds".

Delaying MIDI events has been introduced with Munt 1.3.0.

Regression from 00992c1e68444a8123ffc89a971751cecf7287ed.

1 files changed, 7 insertions, 0 deletions

diff --git a/audio/softsynth/mt32.cpp b/audio/softsynth/mt32.cpp
index 4420657854..67f2df1f6d 100644
--- a/audio/softsynth/mt32.cpp
+++ b/audio/softsynth/mt32.cpp
@@ -212,6 +212,13 @@ int MidiDriver_MT32::open() {
 	double gain = (double)ConfMan.getInt("midi_gain") / 100.0;
 	_synth->setOutputGain(1.0f * gain);
 	_synth->setReverbOutputGain(0.68f * gain);
+	// We let the synthesizer play MIDI messages immediately. Our MIDI
+	// handling is synchronous to sample generation. This makes delaying MIDI
+	// events result in odd sound output in some cases. For example, the
+	// shattering window in the Indiana Jones and the Fate of Atlantis intro
+	// will sound like a bell if we use any delay here.
+	// Bug #6242 "AUDIO: Built-In MT-32 MUNT Produces Wrong Sounds".
+	_synth->setMIDIDelayMode(MT32Emu::MIDIDelayMode_IMMEDIATE);
 
 	_initializing = false;