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Improved DirectSound volume ramping algorithm.

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This commit is contained in:
casey langen 2017-03-08 22:04:29 -08:00
parent 126a9c2958
commit 493da2a7bd
1 changed files with 10 additions and 3 deletions
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13
src/contrib/directsoundout/DirectSoundOut.cpp
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@ -158,14 +158,21 @@ void DirectSoundOut::SetVolume(double volume) {
if (this->state != StateStopped) { if (this->state != StateStopped) {
if (this->secondaryBuffer) { if (this->secondaryBuffer) {
double db = (volume < 0.0001f) /* normalize between 1 and 10000 (DSBVOLUME_MIN) */
? DSBVOLUME_MIN double scaled = fabs(volume * 10000);
: log10(this->volume) * 6000.f; scaled = scaled < 0 ? 1 : scaled;
/* found on experts-exchange (20181717) */
double db = ((log10(scaled) / 4) * 10000) - 10000;
if (db > DSBVOLUME_MAX) { if (db > DSBVOLUME_MAX) {
db = DSBVOLUME_MAX; db = DSBVOLUME_MAX;
} }
if (db < DSBVOLUME_MIN) {
db = DSBVOLUME_MIN;
}
this->secondaryBuffer->SetVolume((LONG) db); this->secondaryBuffer->SetVolume((LONG) db);
} }
} }