func New(val, offset int) Interval {
octaves := int((val - 1) / 7.0)
diatonic := int(mt_math.Mod(float64(val-1), 7))
chromatic := DiatonicToChromatic(diatonic) + offset
return Interval{octaves, diatonic, chromatic}
}
func qualityInterval(quality Quality) func(int) Interval {
return func(val int) Interval {
diatonic := int(mt_math.Mod(float64(val-1), 7))
diff := qualityDiff(perfect(diatonic), quality)
return New(val, diff)
}
}
func (i Interval) AddInterval(o Interval) Interval {
diatonics := i.Diatonic() + o.Diatonic()
diatonicOctaves := diatonics / 7.0
diatonicRemainder := int(mt_math.Mod(float64(diatonics), 7.0))
octaves := i.Octaves() + o.Octaves() + diatonicOctaves
chromatic := i.Chromatic() + o.Chromatic()
if diatonicOctaves > 0 {
chromatic = int(mt_math.Mod(float64(chromatic), 12.0))
}
return Interval{
octaves: octaves,
diatonic: diatonicRemainder,
chromatic: chromatic,
}
}
func (p Pitch) Name(s NameStrategy) string {
semitones := int(mt_math.Mod(float64(p.interval.Semitones()), 12.0))
nameIndex := s.GetMappedIndex(semitones)
delta := semitones - interval.DiatonicToChromatic(nameIndex)
if delta == 0 {
return PitchNames[nameIndex]
}
return fmt.Sprintf("%s%s", PitchNames[nameIndex], accidentalName(delta+2))
}
func accidentalName(i int) string {
return AccidentalNames[int(mt_math.Mod(float64(i), float64(len(AccidentalNames))))]
}
C int = iota
D
E
F
G
A
B
)
var (
AccidentalNames = [5]string{"bb", "b", "", "#", "x"}
PitchNames = [7]string{"C", "D", "E", "F", "G", "A", "B"}
namesForFlats = [12]int{0, 1, 1, 2, 2, 3, 4, 4, 5, 5, 6, 6}
namesForSharps = [12]int{0, 0, 1, 1, 2, 3, 3, 4, 4, 5, 5, 6}
FlatNames = NameStrategyFunc(func(i int) int { return namesForFlats[int(mt_math.Mod(float64(i), 12))] })
SharpNames = NameStrategyFunc(func(i int) int { return namesForSharps[int(mt_math.Mod(float64(i), 12))] })
)
type NameStrategy interface {
GetMappedIndex(int) int
}
type NameStrategyFunc func(int) int
func (f NameStrategyFunc) GetMappedIndex(i int) int {
return f(i)
}
func New(semitone int, accidental int) Pitch {
return Pitch{interval.New(semitone+1, accidental)}