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implement tremolo

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This commit is contained in:
tildearrow 2023-02-04 16:08:20 -05:00
parent 43ba2ff8f2
commit 31ccb58a48
3 changed files with 28 additions and 0 deletions
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23
src/engine/playback.cpp
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@ -689,6 +689,13 @@ void DivEngine::processRow(int i, bool afterDelay) {
// - then a volume slide down starts to the low boundary, and then when this is reached a volume slide up begins
// - this process repeats until 0700 or 0Axy are found
// - note that a volume value does not stop tremolo - instead it glitches this whole thing up
if (chan[i].tremoloDepth==0) {
chan[i].tremoloPos=0;
}
chan[i].tremoloDepth=effectVal&15;
chan[i].tremoloRate=effectVal>>4;
// tremolo and vol slides are incompatiblw
chan[i].volSpeed=0;
break;
case 0x0a: // volume ramp
// TODO: non-0x-or-x0 value should be treated as 00
@ -698,6 +705,9 @@ void DivEngine::processRow(int i, bool afterDelay) {
} else {
chan[i].volSpeed=(effectVal>>4)*64;
}
// tremolo and vol slides are incompatible
chan[i].tremoloDepth=0;
chan[i].tremoloRate=0;
} else {
chan[i].volSpeed=0;
}
@ -838,10 +848,16 @@ void DivEngine::processRow(int i, bool afterDelay) {
if (!song.arpNonPorta) dispatchCmd(DivCommand(DIV_CMD_PRE_PORTA,i,false,0));
break;
case 0xf3: // fine volume ramp up
// tremolo and vol slides are incompatible
chan[i].tremoloDepth=0;
chan[i].tremoloRate=0;
chan[i].volSpeed=effectVal;
dispatchCmd(DivCommand(DIV_CMD_HINT_VOL_SLIDE,i,chan[i].volSpeed));
break;
case 0xf4: // fine volume ramp down
// tremolo and vol slides are incompatible
chan[i].tremoloDepth=0;
chan[i].tremoloRate=0;
chan[i].volSpeed=-effectVal;
dispatchCmd(DivCommand(DIV_CMD_HINT_VOL_SLIDE,i,chan[i].volSpeed));
break;
@ -868,6 +884,9 @@ void DivEngine::processRow(int i, bool afterDelay) {
} else {
chan[i].volSpeed=(effectVal>>4)*256;
}
// tremolo and vol slides are incompatible
chan[i].tremoloDepth=0;
chan[i].tremoloRate=0;
} else {
chan[i].volSpeed=0;
}
@ -1239,6 +1258,10 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
} else {
dispatchCmd(DivCommand(DIV_CMD_VOLUME,i,chan[i].volume>>8));
}
} else if (chan[i].tremoloDepth>0) {
chan[i].tremoloPos+=chan[i].tremoloRate;
chan[i].tremoloPos&=127;
dispatchCmd(DivCommand(DIV_CMD_VOLUME,i,MAX(0,chan[i].volume-(tremTable[chan[i].tremoloPos]*chan[i].tremoloDepth))>>8));
}
}
if (chan[i].vibratoDepth>0) {