melrōse musical expression player

package core import ( "bytes" "fmt" "strings" "time" ) type Euclidean struct { Steps HasValue Beats HasValue Rotation HasValue Playback HasValue } // Play is part of Playable func (e *Euclidean) Play(ctx Context, at time.Time) error { steps := getInt(e.Steps, false) beats := getInt(e.Beats, false) rotation := getInt(e.Rotation, false) playback, ok := e.Playback.Value().(Sequenceable) if !ok { return fmt.Errorf("playback is not a sequenceable") } toggles := euclideanRhythm(steps, beats, rotation) bpm := ctx.Control().BPM() moment := at dt := WholeNoteDuration(bpm) / time.Duration(steps) for _, each := range toggles { if each { ctx.Device().Play(NoCondition, playback, bpm, moment) } moment = moment.Add(dt) } return nil } // Handle is part of TimelineEvent func (e *Euclidean) Handle(tim *Timeline, when time.Time) {} func (e *Euclidean) Storex() string { var b bytes.Buffer fmt.Fprintf(&b, "euclidean(%s,%s,%s,%s)", Storex(e.Steps), Storex(e.Beats), Storex(e.Rotation), Storex(e.Playback)) return b.String() } func (e *Euclidean) Evaluate(ctx Context) error { // copied from Loop e.Play(ctx, time.Now()) return nil } // Inspect is part of Inspectable func (e *Euclidean) Inspect(i Inspection) { steps := getInt(e.Steps, false) beats := getInt(e.Beats, false) rotation := getInt(e.Rotation, false) toggles := euclideanRhythm(steps, beats, rotation) b := new(strings.Builder) for _, each := range toggles { if each { b.WriteString("!") } else { b.WriteString(".") } } i.Properties["pattern"] = b.String() i.Properties["steps"] = e.Steps i.Properties["beats"] = e.Beats i.Properties["rotation"] = e.Rotation i.Properties["playback"] = e.Playback } // https://github.com/computermusicdesign/euclidean-rhythm/blob/master/max-example/euclidSimple.js func euclideanRhythm(steps, pulses, rotation int) []bool { rhythm := make([]bool, 0, steps) bucket := 0 for i := 0; i < steps; i++ { bucket += pulses if bucket >= steps { bucket -= steps rhythm = append(rhythm, true) } else { rhythm = append(rhythm, false) } } return rotatedRhythm(rhythm, rotation+1) } func rotatedRhythm(input []bool, rotate int) []bool { output := make([]bool, len(input)) val := len(input) - rotate for i := 0; i < len(input); i++ { j := (i + val) % len(input) if j < 0 { j *= -1 } output[i] = input[j] } return output }