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AGOS: Fix some Elvira 1 tracks not looping

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Some Elvira 1 music tracks would not loop properly. These tracks make use of
the loop event, which stores the position in the MIDI stream where the parser
will later loop to. An event is optionally preceded by a delta, as indicated by
the _noDelta property of the parser. However, when looping, this flag was not
set to the state matching the event after the loop point. This would sometimes
cause the parser to interpret a MIDI event as a delta, which would break the
parsing.
This is fixed by storing the _noDelta flag with the loop data and setting it
to the stored value when looping.
This commit is contained in:
Coen Rampen 2022-05-15 22:12:23 +02:00
parent 07a6b54f54
commit 287490fe0b
1 changed files with 6 additions and 2 deletions
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8
engines/agos/midiparser_s1d.cpp
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@ -39,6 +39,7 @@ private:
struct Loop {
uint16 timer;
byte *start, *end;
bool noDelta;
} _loops[16];
// Data for monophonic chords mode.
@ -65,7 +66,7 @@ protected:
public:
MidiParser_S1D(uint8 source = 0, bool monophonicChords = false) : MidiParser(source),
_monophonicChords(monophonicChords), _data(nullptr), _noDelta(false) {
Common::fill(_loops, _loops + ARRAYSIZE(_loops), Loop { 0, 0, 0 });
Common::fill(_loops, _loops + ARRAYSIZE(_loops), Loop { 0, 0, 0, false });
Common::fill(_highestNote, _highestNote + ARRAYSIZE(_highestNote), 0);
Common::fill(_lastPlayedNoteTime, _lastPlayedNoteTime + ARRAYSIZE(_lastPlayedNoteTime), 0);
}
@ -133,6 +134,7 @@ void MidiParser_S1D::parseNextEvent(EventInfo &info) {
const int16 loopIterations = int8(*_position._playPos++);
if (!loopIterations) {
_loops[info.channel()].start = _position._playPos;
_loops[info.channel()].noDelta = _noDelta;
} else {
if (!_loops[info.channel()].timer) {
if (_loops[info.channel()].start) {
@ -141,11 +143,13 @@ void MidiParser_S1D::parseNextEvent(EventInfo &info) {
// Go to the start of the loop
_position._playPos = _loops[info.channel()].start;
_noDelta = _loops[info.channel()].noDelta;
info.loop = true;
}
} else {
if (_loops[info.channel()].timer) {
_position._playPos = _loops[info.channel()].start;
_noDelta = _loops[info.channel()].noDelta;
info.loop = true;
}
--_loops[info.channel()].timer;
@ -277,7 +281,7 @@ void MidiParser_S1D::resetTracking() {
MidiParser::resetTracking();
// The first event never contains any delta.
_noDelta = true;
memset(_loops, 0, sizeof(_loops));
Common::fill(_loops, _loops + ARRAYSIZE(_loops), Loop { 0, 0, 0, false });
}
MidiParser *MidiParser_createS1D(uint8 source, bool monophonicChords) { return new MidiParser_S1D(source, monophonicChords); }