Smarter division handling

This commit is contained in:
Matthias Neeracher 2009-03-14 23:02:20 +00:00
parent a116648d23
commit 1eb64d2e55

View File

@ -215,9 +215,23 @@ void VLPlistVisitor::VisitChord(VLChord & c)
}
}
//
// We try to keep the number of divisions as small as possible, so we keep track
// of all note onsets per quarter note. In addition, we keep track of potential
// swing 8ths [0, 1/8]->[0,1/6] and
// swing 16ths [0,1/16]->[0,1/12] [1/8,3/16]->[1/8,1/6]
// so we can recognize swing songs containing triplets and note them with 3 (6)
// divisions instead of 6 (12)
//
enum {
kPotentialSwing8th = 12,
kPotentialSwing16th
};
- (void)readMelody:(NSArray *)melody inMeasure:(size_t)measNo onsets:(int *)onsets
{
VLFraction at(0);
int lastOnset = 0;
VLFraction tiedStart(0);
VLLyricsNote tiedNote;
uint8_t prevKind[20];
@ -284,8 +298,23 @@ void VLPlistVisitor::VisitChord(VLChord & c)
song->AddNote(note, measNo, at);
if (!(note.fTied & VLNote::kTiedWithPrev)) {
VLFraction inQuarter = at % VLFraction(1,4);
++onsets[inQuarter.fNum * 48 / inQuarter.fDenom];
VLFraction inQuarter = at % VLFraction(1,4);
int onset = inQuarter.fNum * 48 / inQuarter.fDenom;
++onsets[onset];
switch (onset) {
case 3:
if (lastOnset == 0)
++onsets[kPotentialSwing16th];
break;
case 6:
if (lastOnset == 0)
++onsets[kPotentialSwing8th];
break;
case 9:
if (lastOnset == 6 || lastOnset == 3 || lastOnset == 0)
++onsets[kPotentialSwing16th];
break;
}
}
advanceAt:
at += note.fDuration;
@ -319,7 +348,7 @@ advanceAt:
std::vector<size_t> repeatStack;
size_t measNo = 0;
int onsets[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int onsets[14] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
for (NSEnumerator * me = [measures objectEnumerator];
NSDictionary * mdict = [me nextObject];
++measNo
@ -389,13 +418,23 @@ advanceAt:
song->fMeasures.pop_back();
if (!song->fProperties.back().fDivisions) {
if (!(onsets[1]+onsets[5]+onsets[7]+onsets[11]))
if (!(onsets[3]+onsets[9]))
if (!(onsets[2]+onsets[4]+onsets[8]+onsets[10]))
if (!(onsets[3]+onsets[9]-onsets[kPotentialSwing16th]))
if (onsets[kPotentialSwing16th]) {
song->fProperties.back().fDivisions = 12;
song->ChangeDivisions(song->fProperties.size()-1, 6);
} else if (!(onsets[2]+onsets[4]+onsets[8]+onsets[10])) {
song->fProperties.back().fDivisions = 2;
else if (!(onsets[2]+onsets[6]+onsets[10]))
song->fProperties.back().fDivisions = 3;
else
} else if (!(onsets[2]+onsets[10]
+ onsets[6]-onsets[kPotentialSwing8th])) {
if (onsets[kPotentialSwing8th]) {
song->fProperties.back().fDivisions = 6;
song->ChangeDivisions(song->fProperties.size()-1, 3);
} else {
song->fProperties.back().fDivisions = 3;
}
} else {
song->fProperties.back().fDivisions = 6;
}
else if (!(onsets[2]+onsets[4]+onsets[8]+onsets[10]))
song->fProperties.back().fDivisions = 4;
else