bool midi_init(void)
{
OSStatus result;
result = CreateAUGraph();
if (result != 0) return false;
result = AUGraphInitialize(s_graph);
if (result != 0) return false;
result = AUGraphStart(s_graph);
if (result != 0) return false;
return true;
}
int main (int argc, const char * argv[]) {
AUGraph graph = 0;
AudioUnit synthUnit;
OSStatus result;
char* bankPath = 0;
UInt8 midiChannelInUse = 0; //we're using midi channel 1...
// this is the only option to main that we have...
// just the full path of the sample bank...
// On OS X there are known places were sample banks can be stored
// Library/Audio/Sounds/Banks - so you could scan this directory and give the user options
// about which sample bank to use...
if (argc > 1)
bankPath = const_cast<char*>(argv[1]);
require_noerr (result = CreateAUGraph (graph, synthUnit), home);
// if the user supplies a sound bank, we'll set that before we initialize and start playing
if (bankPath)
{
FSSpec soundBankSpec;
require_noerr (result = PathToFSSpec (bankPath, soundBankSpec), home);
printf ("Setting Sound Bank:%s\n", bankPath);
require_noerr (result = AudioUnitSetProperty (synthUnit,
kMusicDeviceProperty_SoundBankFSSpec,
kAudioUnitScope_Global, 0,
&soundBankSpec, sizeof(soundBankSpec)), home);
}
// ok we're set up to go - initialize and start the graph
require_noerr (result = AUGraphInitialize (graph), home);
//set our bank
require_noerr (result = MusicDeviceMIDIEvent(synthUnit,
kMidiMessage_ControlChange << 4 | midiChannelInUse,
kMidiMessage_BankMSBControl, 0,
0/*sample offset*/), home);
require_noerr (result = MusicDeviceMIDIEvent(synthUnit,
kMidiMessage_ProgramChange << 4 | midiChannelInUse,
0/*prog change num*/, 0,
0/*sample offset*/), home);
CAShow (graph); // prints out the graph so we can see what it looks like...
require_noerr (result = AUGraphStart (graph), home);
// we're going to play an octave of MIDI notes: one a second
for (int i = 0; i < 13; i++) {
UInt32 noteNum = i + 60;
UInt32 onVelocity = 127;
UInt32 noteOnCommand = kMidiMessage_NoteOn << 4 | midiChannelInUse;
printf ("Playing Note: Status: 0x%lX, Note: %ld, Vel: %ld\n", noteOnCommand, noteNum, onVelocity);
require_noerr (result = MusicDeviceMIDIEvent(synthUnit, noteOnCommand, noteNum, onVelocity, 0), home);
// sleep for a second
usleep (1 * 1000 * 1000);
require_noerr (result = MusicDeviceMIDIEvent(synthUnit, noteOnCommand, noteNum, 0, 0), home);
}
// ok we're done now
home:
if (graph) {
AUGraphStop (graph); // stop playback - AUGraphDispose will do that for us but just showing you what to do
DisposeAUGraph (graph);
}
return result;
}
