void SoundGen2GS::playMidiSound() {
if (_disabledMidi)
return;
const uint8 *p;
uint8 parm1, parm2;
static uint8 cmd, ch;
if (_playingSound == -1 || _vm->_game.sounds[_playingSound] == NULL) {
warning("Error playing Apple IIGS MIDI sound resource");
_playing = false;
return;
}
IIgsMidi *midiObj = (IIgsMidi *) _vm->_game.sounds[_playingSound];
_playing = true;
p = midiObj->getPtr();
midiObj->_soundBufTicks++;
while (true) {
uint8 readByte = *p;
// Check for end of MIDI sequence marker (Can also be here before delta-time)
if (readByte == MIDI_BYTE_STOP_SEQUENCE) {
debugC(3, kDebugLevelSound, "End of MIDI sequence (Before reading delta-time)");
_playing = false;
midiObj->rewind();
return;
} else if (readByte == MIDI_BYTE_TIMER_SYNC) {
debugC(3, kDebugLevelSound, "Timer sync");
p++; // Jump over the timer sync byte as it's not needed
continue;
}
uint8 deltaTime = readByte;
if (midiObj->_midiTicks + deltaTime > midiObj->_soundBufTicks) {
break;
}
midiObj->_midiTicks += deltaTime;
p++; // Jump over the delta-time byte as it was already taken care of
// Check for end of MIDI sequence marker (This time it after reading delta-time)
if (*p == MIDI_BYTE_STOP_SEQUENCE) {
debugC(3, kDebugLevelSound, "End of MIDI sequence (After reading delta-time)");
_playing = false;
midiObj->rewind();
return;
}
// Separate byte into command and channel if it's a command byte.
// Otherwise use running status (i.e. previously set command and channel).
if (*p & 0x80) {
cmd = *p++;
ch = cmd & 0x0f;
cmd >>= 4;
}
switch (cmd) {
case MIDI_CMD_NOTE_OFF:
parm1 = *p++;
parm2 = *p++;
midiNoteOff(ch, parm1, parm2);
break;
case MIDI_CMD_NOTE_ON:
parm1 = *p++;
parm2 = *p++;
midiNoteOn(ch, parm1, parm2);
break;
case MIDI_CMD_CONTROLLER:
parm1 = *p++;
parm2 = *p++;
midiController(ch, parm1, parm2);
break;
case MIDI_CMD_PROGRAM_CHANGE:
parm1 = *p++;
midiProgramChange(ch, parm1);
break;
case MIDI_CMD_PITCH_WHEEL:
parm1 = *p++;
parm2 = *p++;
uint16 wheelPos = ((parm2 & 0x7F) << 7) | (parm1 & 0x7F); // 14-bit value
midiPitchWheel(wheelPos);
break;
}
}
void SoundGen2GS::advanceMidiPlayer() {
if (_disableMidi)
return;
const uint8 *p;
uint8 parm1, parm2;
static uint8 cmd, chn;
if (_playingSound == -1 || _vm->_game.sounds[_playingSound] == NULL) {
warning("Error playing Apple IIGS MIDI sound resource");
_playing = false;
return;
}
IIgsMidi *midiObj = (IIgsMidi *) _vm->_game.sounds[_playingSound];
_ticks++;
_playing = true;
p = midiObj->getPtr();
while (true) {
// Check for end of MIDI sequence marker (Can also be here before delta-time)
if (*p == MIDI_STOP_SEQUENCE) {
debugC(3, kDebugLevelSound, "End of MIDI sequence (Before reading delta-time)");
_playing = false;
midiObj->rewind();
return;
}
if (*p == MIDI_TIMER_SYNC) {
debugC(3, kDebugLevelSound, "Timer sync");
p++; // Jump over the timer sync byte as it's not needed
continue;
}
// Check for delta time
uint8 delta = *p;
if (midiObj->_ticks + delta > _ticks)
break;
midiObj->_ticks += delta;
p++;
// Check for end of MIDI sequence marker (This time it after reading delta-time)
if (*p == MIDI_STOP_SEQUENCE) {
debugC(3, kDebugLevelSound, "End of MIDI sequence (After reading delta-time)");
_playing = false;
midiObj->rewind();
return;
}
// Separate byte into command and channel if it's a command byte.
// Otherwise use running status (i.e. previously set command and channel).
if (*p & 0x80) {
cmd = *p++;
chn = cmd & 0x0f;
cmd >>= 4;
}
switch (cmd) {
case MIDI_NOTE_OFF:
parm1 = *p++;
parm2 = *p++;
debugC(3, kDebugLevelSound, "channel %X: note off (key = %d, velocity = %d)", chn, parm1, parm2);
midiNoteOff(chn, parm1, parm2);
break;
case MIDI_NOTE_ON:
parm1 = *p++;
parm2 = *p++;
debugC(3, kDebugLevelSound, "channel %X: note on (key = %d, velocity = %d)", chn, parm1, parm2);
midiNoteOn(chn, parm1, parm2);
break;
case MIDI_CONTROLLER:
parm1 = *p++;
parm2 = *p++;
debugC(3, kDebugLevelSound, "channel %X: controller %02X = %02X", chn, parm1, parm2);
// The tested Apple IIGS AGI MIDI resources only used
// controllers 0 (Bank select?), 7 (Volume) and 64 (Sustain On/Off).
// Controller 0's parameter was in range 94-127,
// controller 7's parameter was in range 0-127 and
// controller 64's parameter was always 0 (i.e. sustain off).
switch (parm1) {
case 7:
_channels[chn].setVolume(parm2);
break;
}
break;
case MIDI_PROGRAM_CHANGE:
parm1 = *p++;
debugC(3, kDebugLevelSound, "channel %X: program change %02X", chn, parm1);
_channels[chn].setInstrument(getInstrument(parm1));
break;
case MIDI_PITCH_WHEEL:
parm1 = *p++;
parm2 = *p++;
debugC(3, kDebugLevelSound, "channel %X: pitch wheel (unimplemented)", chn);
break;
default:
debugC(3, kDebugLevelSound, "channel %X: unimplemented command %02X", chn, cmd);
break;
}
}