package main import "math" import "errors" import "github.com/faiface/beep" import "github.com/faiface/beep/speaker" import "git.tebibyte.media/sashakoshka/tomo" import "git.tebibyte.media/sashakoshka/tomo/elements/fun" import "git.tebibyte.media/sashakoshka/tomo/layouts/basic" import "git.tebibyte.media/sashakoshka/tomo/elements/basic" import "git.tebibyte.media/sashakoshka/tomo/elements/fun/music" import _ "git.tebibyte.media/sashakoshka/tomo/backends/x" const sampleRate = 44100 const bufferSize = 256 var tuning = music.EqualTemparment { A4: 440 } var waveform = 0 var playing = map[music.Note] *beep.Ctrl { } func main () { speaker.Init(sampleRate, bufferSize) tomo.Run(run) } func run () { window, _ := tomo.NewWindow(2, 2) window.SetTitle("Piano") container := basicElements.NewContainer(basicLayouts.Vertical { true, true }) window.Adopt(container) controlBar := basicElements.NewContainer(basicLayouts.Horizontal { true, false }) label := basicElements.NewLabel("Play a song!", false) controlBar.Adopt(label, true) waveformButton := basicElements.NewButton("Sine") waveformButton.OnClick (func () { waveform = (waveform + 1) % 5 switch waveform { case 0: waveformButton.SetText("Sine") case 1: waveformButton.SetText("Square") case 2: waveformButton.SetText("Saw") case 3: waveformButton.SetText("Triangle") case 4: waveformButton.SetText("Supersaw") } }) controlBar.Adopt(waveformButton, false) container.Adopt(controlBar, false) piano := fun.NewPiano(2, 5) container.Adopt(piano, true) piano.OnPress(playNote) piano.OnRelease(stopNote) window.OnClose(tomo.Stop) window.Show() } func stopNote (note music.Note) { if _, is := playing[note]; !is { return } speaker.Lock() playing[note].Streamer = nil delete(playing, note) speaker.Unlock() } func playNote (note music.Note) { streamer, _ := Tone(sampleRate, int(tuning.Tune(note)), waveform, 0.3) stopNote(note) speaker.Lock() playing[note] = &beep.Ctrl { Streamer: streamer } speaker.Unlock() speaker.Play(playing[note]) } // https://github.com/faiface/beep/blob/v1.1.0/generators/toner.go // Adapted to be a bit more versatile. type toneStreamer struct { position float64 delta float64 waveform int gain float64 } func Tone ( sr beep.SampleRate, freq int, waveform int, gain float64, ) ( beep.Streamer, error, ) { if int(sr) / freq < 2 { return nil, errors.New ( "tone generator: samplerate must be at least " + "2 times greater then frequency") } tone := new(toneStreamer) tone.position = 0.0 tone.waveform = waveform steps := float64(sr) / float64(freq) tone.delta = 1.0 / steps tone.gain = gain return tone, nil } func (tone *toneStreamer) nextSample () (sample float64) { switch tone.waveform { case 0: sample = math.Sin(tone.position * 2.0 * math.Pi) case 1: if tone.position > 0.5 { sample = 1 } else { sample = -1 } case 2: sample = (tone.position - 0.5) * 2 case 3: sample = 1 - math.Abs(tone.position - 0.5) * 4 case 4: sample = -1 + 13.7 * tone.position + 28.32 * tone.position * tone.position + 15.62 * tone.position * tone.position * tone.position } _, tone.position = math.Modf(tone.position + tone.delta) return } func (tone *toneStreamer) Stream (buf [][2]float64) (int, bool) { for i := 0; i < len(buf); i++ { sample := tone.nextSample() * tone.gain buf[i] = [2]float64{sample, sample} } return len(buf), true } func (tone *toneStreamer) Err () error { return nil }