otomatalabs/furnace
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potentially breaking change: better freq formula

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now using a 4096-entry-long table for calculating final period/frequency
see issue #303
This commit is contained in:
tildearrow 2022-03-25 02:52:41 -05:00
parent 03da02711a
commit ed857b20c4
3 changed files with 22 additions and 5 deletions
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12
src/engine/engine.cpp
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@ -832,9 +832,17 @@ double DivEngine::calcBaseFreq(double clock, double divider, int note, bool peri
int DivEngine::calcFreq(int base, int pitch, bool period, int octave) {
if (song.linearPitch) {
pitch+=2048;
if (pitch<0) pitch=0;
if (pitch>4095) pitch=4095;
return period?
(base*reversePitchTable[pitch])>>10:
(base*pitchTable[pitch])>>10;
/*
return period?
base*pow(2,-(double)pitch/(12.0*128.0))/(98.0+globalPitch*6.0)*98.0:
(base*pow(2,(double)pitch/(12.0*128.0))*(98+globalPitch*6))/98;
*/
}
return period?
base-pitch:
@ -2850,6 +2858,10 @@ bool DivEngine::init() {
for (int i=0; i<64; i++) {
vibTable[i]=127*sin(((double)i/64.0)*(2*M_PI));
}
for (int i=0; i<4096; i++) {
reversePitchTable[i]=round(1024.0*pow(2.0,(2048.0-(double)i)/(12.0*128.0)));
pitchTable[i]=round(1024.0*pow(2.0,((double)i-2048.0)/(12.0*128.0)));
}
for (int i=0; i<DIV_MAX_CHANS; i++) {
isMuted[i]=0;