diff options
| -rw-r--r-- | backends/midi/ym2612.cpp | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/backends/midi/ym2612.cpp b/backends/midi/ym2612.cpp index 6e4b6b077b..804be02a8f 100644 --- a/backends/midi/ym2612.cpp +++ b/backends/midi/ym2612.cpp @@ -315,16 +315,17 @@ void Operator2612::frequency(int freq) { void Operator2612::nextTick(uint16 rate, const int *phasebuf, int *outbuf, int buflen) { if (_state == _s_ready) return; - if (_state == _s_attacking && _attackTime <= 0) + if (_state == _s_attacking && _attackTime <= 0) { + _currentLevel = 0; _state = _s_decaying; + } - int32 increment; + int32 levelIncrement; int32 target; State next_state; - bool switching; + const int32 zero_level = ((int32)0x7f << 15); while (buflen) { - switching = false; switch (_state) { case _s_ready: return; @@ -333,23 +334,24 @@ void Operator2612::nextTick(uint16 rate, const int *phasebuf, int *outbuf, int b next_state = _s_attacking; break; case _s_decaying: - increment = _decayRate; + levelIncrement = _decayRate; target = _sustainLevel; next_state = _s_sustaining; break; case _s_sustaining: - increment = _sustainRate; - target = ((int32)0x7f << 15); + levelIncrement = _sustainRate; + target = zero_level; next_state = _s_ready; break; case _s_releasing: - increment = _releaseRate; - target = ((int32)0x7f << 15); + levelIncrement = _releaseRate; + target = zero_level; next_state = _s_ready; break; } - for (; buflen && !switching; --buflen, ++phasebuf, ++outbuf) { + bool switching = false; + do { if (next_state == _s_attacking) { // Attack phase ++_tickCount; @@ -369,7 +371,7 @@ void Operator2612::nextTick(uint16 rate, const int *phasebuf, int *outbuf, int b } } else { // Decay, Sustain and Release phases - _currentLevel += increment; + _currentLevel += levelIncrement; if (_currentLevel >= target) { _currentLevel = target; _state = next_state; @@ -379,7 +381,7 @@ void Operator2612::nextTick(uint16 rate, const int *phasebuf, int *outbuf, int b int32 level = _currentLevel + _totalLevel; int32 output = 0; - if (level < ((int32)0x7f << 15)) { + if (level < zero_level) { _phase &= 0x3ffff; int phaseShift = *phasebuf >> 2; // 正しい変調量は? 3 じゃ小さすぎで 2 じゃ大きいような。 if (_feedbackLevel) @@ -410,7 +412,10 @@ void Operator2612::nextTick(uint16 rate, const int *phasebuf, int *outbuf, int b _lastOutput = output; *outbuf += output; - } + --buflen; + ++phasebuf; + ++outbuf; + } while (buflen && !switching); } } |