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GB Audio: Make audio unsigned with bias (fixes #749)

This commit is contained in:
Vicki Pfau 2017-07-08 21:32:51 -07:00
parent 15d66422a9
commit 539e63d49b
2 changed files with 7 additions and 6 deletions
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1
CHANGES
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@ -1,6 +1,7 @@
0.7.0: (Future) 0.7.0: (Future)
Bugfixes: Bugfixes:
- GB Audio: Fix zombie mode bit masking - GB Audio: Fix zombie mode bit masking
- GB Audio: Make audio unsigned with bias (fixes mgba.io/i/749)
Misc: Misc:
- GBA Timer: Use global cycles for timers - GBA Timer: Use global cycles for timers

12
src/gb/audio.c
View File

@ -620,8 +620,9 @@ void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
} }
} }
*left = sampleLeft * (1 + audio->volumeLeft); int dcOffset = audio->style == GB_AUDIO_GBA ? 0 : 0x1FC;
*right = sampleRight * (1 + audio->volumeRight); *left = (sampleLeft - dcOffset) * (1 + audio->volumeLeft);
*right = (sampleRight - dcOffset) * (1 + audio->volumeRight);
} }
static void _sample(struct mTiming* timing, void* user, uint32_t cyclesLate) { static void _sample(struct mTiming* timing, void* user, uint32_t cyclesLate) {
@ -710,7 +711,7 @@ bool _writeEnvelope(struct GBAudioEnvelope* envelope, uint8_t value) {
} }
static void _updateSquareSample(struct GBAudioSquareChannel* ch) { static void _updateSquareSample(struct GBAudioSquareChannel* ch) {
ch->sample = (ch->control.hi * 2 - 1) * ch->envelope.currentVolume * 0x8; ch->sample = ch->control.hi * ch->envelope.currentVolume * 0x8;
} }
static int32_t _updateSquareChannel(struct GBAudioSquareChannel* ch) { static int32_t _updateSquareChannel(struct GBAudioSquareChannel* ch) {
@ -861,8 +862,7 @@ static void _updateChannel3(struct mTiming* timing, void* user, uint32_t cyclesL
ch->sample = bitsCarry >> 4; ch->sample = bitsCarry >> 4;
break; break;
} }
ch->sample -= 8; ch->sample *= volume * 2;
ch->sample *= volume * 4;
audio->ch3.readable = true; audio->ch3.readable = true;
if (audio->style == GB_AUDIO_DMG) { if (audio->style == GB_AUDIO_DMG) {
mTimingDeschedule(audio->timing, &audio->ch3Fade); mTimingDeschedule(audio->timing, &audio->ch3Fade);
@ -889,7 +889,7 @@ static void _updateChannel4(struct mTiming* timing, void* user, uint32_t cyclesL
do { do {
int lsb = ch->lfsr & 1; int lsb = ch->lfsr & 1;
ch->sample = lsb * 0x10 - 0x8; ch->sample = lsb * 0x8;
ch->sample *= ch->envelope.currentVolume; ch->sample *= ch->envelope.currentVolume;
ch->lfsr >>= 1; ch->lfsr >>= 1;
ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8); ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8);