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SCUMM: Handle note value 1 as "hold current note" in MI1 Mac
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After listening to the original music in a Mac emulator (which
unfortunately doesn't handle the music very well), I can only
conclude that note value 1 means the note should continue playing.
At first I thought maybe it was supposed to fade the current note,
or perhaps change its volume, but I can't hear any traces of
either. So I'm going to assume it just means "hold the current
note", though for the life of me I cannot think of any valid
reason for such a command. So it may be wrong, but it sounds
closer to the emulator than it did before.
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Torbjörn Andersson committed Nov 24, 2012
1 parent 076bcbc commit d3cf4d1
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Showing 4 changed files with 50 additions and 29 deletions.
47 changes: 23 additions & 24 deletions engines/scumm/player_mac.cpp
View file
Expand Up @@ -31,13 +31,14 @@

namespace Scumm {

Player_Mac::Player_Mac(ScummEngine *scumm, Audio::Mixer *mixer, int numberOfChannels, int channelMask)
Player_Mac::Player_Mac(ScummEngine *scumm, Audio::Mixer *mixer, int numberOfChannels, int channelMask, bool fadeNoteEnds)
: _vm(scumm),
_mixer(mixer),
_sampleRate(_mixer->getOutputRate()),
_soundPlaying(-1),
_numberOfChannels(numberOfChannels),
_channelMask(channelMask) {
_channelMask(channelMask),
_fadeNoteEnds(fadeNoteEnds) {
assert(scumm);
assert(mixer);
}
Expand Down Expand Up @@ -298,16 +299,7 @@ uint32 Player_Mac::durationToSamples(uint16 duration) {
}

int Player_Mac::noteToPitchModifier(byte note, Instrument *instrument) {
// TODO: Monkey Island 1 uses both note values 0 and 1 as rests.
// Perhaps 0 means an abrupt end of the current note, while 1 means it
// should drop off gradually? One of the voices in the main theme
// sounds a lot more staccato than what I hear in a Mac emulator. (But
// it's hard to tell since that emulator has problems with the music.)
// Also, some instruments (though not this particular one) have data
// after the loop end point, which could possible be used to fade out
// the instrument.

if (note > 1) {
if (note > 0) {
const int pitchIdx = note + 60 - instrument->_baseFreq;
// I don't want to use floating-point arithmetics here, but I
// ran into overflow problems with the church music in Monkey
Expand Down Expand Up @@ -356,7 +348,7 @@ int Player_Mac::readBuffer(int16 *data, const int numSamples) {
}
generated = MIN(_channel[i]._remaining, samplesLeft);
if (_channel[i]._velocity != 0) {
_channel[i]._instrument.generateSamples(ptr, _channel[i]._pitchModifier, _channel[i]._velocity, generated, _channel[i]._remaining);
_channel[i]._instrument.generateSamples(ptr, _channel[i]._pitchModifier, _channel[i]._velocity, generated, _channel[i]._remaining, _fadeNoteEnds);
}
ptr += generated;
samplesLeft -= generated;
Expand All @@ -375,7 +367,7 @@ int Player_Mac::readBuffer(int16 *data, const int numSamples) {
return numSamples;
}

void Player_Mac::Instrument::generateSamples(int16 *data, int pitchModifier, int volume, int numSamples, int remainingSamplesOnNote) {
void Player_Mac::Instrument::generateSamples(int16 *data, int pitchModifier, int volume, int numSamples, int remainingSamplesOnNote, bool fadeNoteEnds) {
int samplesLeft = numSamples;
while (samplesLeft) {
_subPos += pitchModifier;
Expand All @@ -389,16 +381,23 @@ void Player_Mac::Instrument::generateSamples(int16 *data, int pitchModifier, int

int newSample = (((int16)((_data[_pos] << 8) ^ 0x8000)) * volume) / 255;

// Fade out the last 100 samples on each note. Even at low
// output sample rates this is just a fraction of a second,
// but it gets rid of distracting "pops" at the end when the
// sample would otherwise go abruptly from something to
// nothing. This was particularly noticeable on the distaff
// notes in Loom.

remainingSamplesOnNote--;
if (remainingSamplesOnNote < 100) {
newSample = (newSample * remainingSamplesOnNote) / 100;
if (fadeNoteEnds) {
// Fade out the last 100 samples on each note. Even at
// low output sample rates this is just a fraction of a
// second, but it gets rid of distracting "pops" at the
// end when the sample would otherwise go abruptly from
// something to nothing. This was particularly
// noticeable on the distaff notes in Loom.
//
// The reason it's conditional is that Monkey Island
// appears to have a "hold current note" command, and
// if we fade out the current note in that case we
// will actually introduce new "pops".

remainingSamplesOnNote--;
if (remainingSamplesOnNote < 100) {
newSample = (newSample * remainingSamplesOnNote) / 100;
}
}

int sample = *data + newSample;
Expand Down
5 changes: 3 additions & 2 deletions engines/scumm/player_mac.h
View file
Expand Up @@ -44,7 +44,7 @@ class ScummEngine;
*/
class Player_Mac : public Audio::AudioStream, public MusicEngine {
public:
Player_Mac(ScummEngine *scumm, Audio::Mixer *mixer, int numberOfChannels, int channelMask);
Player_Mac(ScummEngine *scumm, Audio::Mixer *mixer, int numberOfChannels, int channelMask, bool fadeNoteEnds);
virtual ~Player_Mac();

void init();
Expand Down Expand Up @@ -90,12 +90,13 @@ class Player_Mac : public Audio::AudioStream, public MusicEngine {
_subPos = 0;
}

void generateSamples(int16 *data, int pitchModifier, int volume, int numSamples, int remainingSamplesOnNote);
void generateSamples(int16 *data, int pitchModifier, int volume, int numSamples, int remainingSamplesOnNote, bool fadeNoteEnds);
};

int _pitchTable[128];
int _numberOfChannels;
int _channelMask;
bool _fadeNoteEnds;

virtual bool checkMusicAvailable() { return false; }
virtual bool loadMusic(const byte *ptr) { return false; }
Expand Down
2 changes: 1 addition & 1 deletion engines/scumm/player_v3m.cpp
View file
Expand Up @@ -97,7 +97,7 @@
namespace Scumm {

Player_V3M::Player_V3M(ScummEngine *scumm, Audio::Mixer *mixer)
: Player_Mac(scumm, mixer, 5, 0x1E) {
: Player_Mac(scumm, mixer, 5, 0x1E, true) {
assert(_vm->_game.id == GID_LOOM);

// Channel 0 seems to be what was played on low-end macs, that couldn't
Expand Down
25 changes: 23 additions & 2 deletions engines/scumm/player_v5m.cpp
View file
Expand Up @@ -82,7 +82,7 @@
namespace Scumm {

Player_V5M::Player_V5M(ScummEngine *scumm, Audio::Mixer *mixer)
: Player_Mac(scumm, mixer, 3, 0x07) {
: Player_Mac(scumm, mixer, 3, 0x07, false) {
assert(_vm->_game.id == GID_MONKEY);
}

Expand Down Expand Up @@ -190,7 +190,6 @@ bool Player_V5M::loadMusic(const byte *ptr) {
}

bool Player_V5M::getNextNote(int ch, uint32 &samples, int &pitchModifier, byte &velocity) {
_channel[ch]._instrument.newNote();
if (_channel[ch]._pos >= _channel[ch]._length) {
if (!_channel[ch]._looped) {
_channel[ch]._notesLeft = false;
Expand All @@ -206,9 +205,31 @@ bool Player_V5M::getNextNote(int ch, uint32 &samples, int &pitchModifier, byte &
byte note = _channel[ch]._data[_channel[ch]._pos + 2];
samples = durationToSamples(duration);

if (note != 1) {
_channel[ch]._instrument.newNote();
}

if (note > 1) {
pitchModifier = noteToPitchModifier(note, &_channel[ch]._instrument);
velocity = _channel[ch]._data[_channel[ch]._pos + 3];
} else if (note == 1) {
// This is guesswork, but Monkey Island uses two different
// "special" note values: 0, which is clearly a rest, and 1
// which is... I thought at first it was a "soft" key off, to
// fade out the note, but listening to the music in a Mac
// emulator (which unfortunately doesn't work all that well),
// I hear no trace of fading out.
//
// It could mean "change the volume on the current note", but
// I can't hear that either, and it always seems to use the
// exact same velocity on this note.
//
// So it appears it really just is a "hold the current note",
// but why? Couldn't they just have made the original note
// longer?

pitchModifier = _channel[ch]._pitchModifier;
velocity = _channel[ch]._velocity;
} else {
pitchModifier = 0;
velocity = 0;
Expand Down

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