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GB Audio: More sampling cleanup (fixes #1142)

This commit is contained in:
Vicki Pfau 2018-07-28 00:02:33 -07:00
parent d25d4d30ff
commit 162fd0b353
1 changed files with 28 additions and 25 deletions
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53
src/gb/audio.c
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@ -562,7 +562,7 @@ void GBAudioUpdateFrame(struct GBAudio* audio, struct mTiming* timing) {
if (audio->playingCh4 && !audio->ch4.envelope.dead) {
--audio->ch4.envelope.nextStep;
if (audio->ch4.envelope.nextStep == 0) {
int8_t sample = (audio->ch4.sample > 0) * 0x8;
int8_t sample = audio->ch4.sample > 0;
_updateEnvelope(&audio->ch4.envelope);
if (audio->ch4.envelope.dead == 2) {
mTimingDeschedule(timing, &audio->ch4Event);
@ -575,52 +575,55 @@ void GBAudioUpdateFrame(struct GBAudio* audio, struct mTiming* timing) {
}
void GBAudioSamplePSG(struct GBAudio* audio, int16_t* left, int16_t* right) {
int sampleLeft = 0;
int sampleRight = 0;
int dcOffset = audio->style == GB_AUDIO_GBA ? 0 : 0x8;
int sampleLeft = dcOffset;
int sampleRight = dcOffset;
if (audio->playingCh1 && !audio->forceDisableCh[0]) {
if (audio->ch1Left) {
sampleLeft += audio->ch1.sample;
sampleLeft -= audio->ch1.sample;
}
if (audio->ch1Right) {
sampleRight += audio->ch1.sample;
sampleRight -= audio->ch1.sample;
}
}
if (audio->playingCh2 && !audio->forceDisableCh[1]) {
if (audio->ch2Left) {
sampleLeft += audio->ch2.sample;
sampleLeft -= audio->ch2.sample;
}
if (audio->ch2Right) {
sampleRight += audio->ch2.sample;
sampleRight -= audio->ch2.sample;
}
}
if (audio->playingCh3 && !audio->forceDisableCh[2]) {
if (audio->ch3Left) {
sampleLeft += audio->ch3.sample;
sampleLeft -= audio->ch3.sample;
}
if (audio->ch3Right) {
sampleRight += audio->ch3.sample;
sampleRight -= audio->ch3.sample;
}
}
if (audio->playingCh4 && !audio->forceDisableCh[3]) {
if (audio->ch4Left) {
sampleLeft += audio->ch4.sample;
sampleLeft -= audio->ch4.sample;
}
if (audio->ch4Right) {
sampleRight += audio->ch4.sample;
sampleRight -= audio->ch4.sample;
}
}
int dcOffset = audio->style == GB_AUDIO_GBA ? 0 : 0x20A;
*left = (sampleLeft - dcOffset) * (1 + audio->volumeLeft);
*right = (sampleRight - dcOffset) * (1 + audio->volumeRight);
sampleLeft <<= 3;
sampleRight <<= 3;
*left = sampleLeft * (1 + audio->volumeLeft);
*right = sampleRight * (1 + audio->volumeRight);
}
static void _sample(struct mTiming* timing, void* user, uint32_t cyclesLate) {
@ -719,7 +722,7 @@ bool _writeEnvelope(struct GBAudioEnvelope* envelope, uint8_t value, enum GBAudi
}
static void _updateSquareSample(struct GBAudioSquareChannel* ch) {
ch->sample = ch->control.hi * ch->envelope.currentVolume * 0x8;
ch->sample = ch->control.hi * ch->envelope.currentVolume;
}
static int32_t _updateSquareChannel(struct GBAudioSquareChannel* ch) {
@ -820,19 +823,17 @@ static void _updateChannel3(struct mTiming* timing, void* user, uint32_t cyclesL
int volume;
switch (ch->volume) {
case 0:
volume = 0;
break;
case 1:
volume = 4;
break;
case 2:
volume = 2;
case 1:
volume = 0;
break;
case 3:
case 2:
volume = 1;
break;
default:
volume = 3;
case 3:
volume = 2;
break;
}
int start;
@ -870,7 +871,10 @@ static void _updateChannel3(struct mTiming* timing, void* user, uint32_t cyclesL
ch->sample = bitsCarry >> 4;
break;
}
ch->sample *= volume * 2;
if (ch->volume > 3) {
ch->sample += ch->sample << 1;
}
ch->sample >>= volume;
audio->ch3.readable = true;
if (audio->style == GB_AUDIO_DMG) {
mTimingDeschedule(audio->timing, &audio->ch3Fade);
@ -897,8 +901,7 @@ static void _updateChannel4(struct mTiming* timing, void* user, uint32_t cyclesL
do {
int lsb = ch->lfsr & 1;
ch->sample = lsb * 0x8;
ch->sample *= ch->envelope.currentVolume;
ch->sample = lsb * ch->envelope.currentVolume;
ch->lfsr >>= 1;
ch->lfsr ^= (lsb * 0x60) << (ch->power ? 0 : 8);
cycles += baseCycles;