feat(tracker): add menu item to export .wav

Also refactor the common functions for .wav export into base package so that both sointu-play and tracker can use same functions.

audioexport.go

@@ -0,0 +1,101 @@
+package sointu
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"math"
+)
+
+func Wav(buffer []float32, pcm16 bool) ([]byte, error) {
+	buf := new(bytes.Buffer)
+	wavHeader(len(buffer), pcm16, buf)
+	err := rawToBuffer(buffer, pcm16, buf)
+	if err != nil {
+		return nil, fmt.Errorf("Wav failed: %v", err)
+	}
+	return buf.Bytes(), nil
+}
+
+func Raw(buffer []float32, pcm16 bool) ([]byte, error) {
+	buf := new(bytes.Buffer)
+	err := rawToBuffer(buffer, pcm16, buf)
+	if err != nil {
+		return nil, fmt.Errorf("Raw failed: %v", err)
+	}
+	return buf.Bytes(), nil
+}
+
+func rawToBuffer(data []float32, pcm16 bool, buf *bytes.Buffer) error {
+	var err error
+	if pcm16 {
+		int16data := make([]int16, len(data))
+		for i, v := range data {
+			int16data[i] = int16(clamp(int(v*math.MaxInt16), math.MinInt16, math.MaxInt16))
+		}
+		err = binary.Write(buf, binary.LittleEndian, int16data)
+	} else {
+		err = binary.Write(buf, binary.LittleEndian, data)
+	}
+	if err != nil {
+		return fmt.Errorf("could not binary write data to binary buffer: %v", err)
+	}
+	return nil
+}
+
+// wavHeader writes a wave header for either float32 or int16 .wav file into the
+// bytes.buffer. It needs to know the length of the buffer and assumes stereo
+// sound, so the length in stereo samples (L + R) is bufferlength / 2. If pcm16
+// = true, then the header is for int16 audio; pcm16 = false means the header is
+// for float32 audio. Assumes 44100 Hz sample rate.
+func wavHeader(bufferLength int, pcm16 bool, buf *bytes.Buffer) {
+	// Refer to: http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
+	numChannels := 2
+	sampleRate := 44100
+	var bytesPerSample, chunkSize, fmtChunkSize, waveFormat int
+	var factChunk bool
+	if pcm16 {
+		bytesPerSample = 2
+		chunkSize = 36 + bytesPerSample*bufferLength
+		fmtChunkSize = 16
+		waveFormat = 1 // PCM
+		factChunk = false
+	} else {
+		bytesPerSample = 4
+		chunkSize = 50 + bytesPerSample*bufferLength
+		fmtChunkSize = 18
+		waveFormat = 3 // IEEE float
+		factChunk = true
+	}
+	buf.Write([]byte("RIFF"))
+	binary.Write(buf, binary.LittleEndian, uint32(chunkSize))
+	buf.Write([]byte("WAVE"))
+	buf.Write([]byte("fmt "))
+	binary.Write(buf, binary.LittleEndian, uint32(fmtChunkSize))
+	binary.Write(buf, binary.LittleEndian, uint16(waveFormat))
+	binary.Write(buf, binary.LittleEndian, uint16(numChannels))
+	binary.Write(buf, binary.LittleEndian, uint32(sampleRate))
+	binary.Write(buf, binary.LittleEndian, uint32(sampleRate*numChannels*bytesPerSample)) // avgBytesPerSec
+	binary.Write(buf, binary.LittleEndian, uint16(numChannels*bytesPerSample))            // blockAlign
+	binary.Write(buf, binary.LittleEndian, uint16(8*bytesPerSample))                      // bits per sample
+	if fmtChunkSize > 16 {
+		binary.Write(buf, binary.LittleEndian, uint16(0)) // size of extension
+	}
+	if factChunk {
+		buf.Write([]byte("fact"))
+		binary.Write(buf, binary.LittleEndian, uint32(4))            // fact chunk size
+		binary.Write(buf, binary.LittleEndian, uint32(bufferLength)) // sample length
+	}
+	buf.Write([]byte("data"))
+	binary.Write(buf, binary.LittleEndian, uint32(bytesPerSample*bufferLength))
+}
+
+func clamp(value, min, max int) int {
+	if value < min {
+		return min
+	}
+	if value > max {
+		return max
+	}
+	return value
+}

cmd/sointu-play/main.go

@@ -1,13 +1,10 @@
 package main
 
 import (
-	"bytes"
-	"encoding/binary"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"io/ioutil"
-	"math"
 	"os"
 	"path/filepath"
 	"strings"
@@ -111,38 +108,22 @@ func main() {
 				return fmt.Errorf("error playing: %v", err)
 			}
 		}
-		var data interface{}
-		data = buffer
-		if *pcm {
-			int16buffer := make([]int16, len(buffer))
-			for i, v := range buffer {
-				int16buffer[i] = int16(clamp(int(v*math.MaxInt16), math.MinInt16, math.MaxInt16))
-			}
-			data = int16buffer
-		}
 		if *rawOut {
-			buf := new(bytes.Buffer)
-			err := binary.Write(buf, binary.LittleEndian, data)
+			raw, err := sointu.Raw(buffer, *pcm)
 			if err != nil {
-				return fmt.Errorf("could not binary write data to binary buffer: %v", err)
+				return fmt.Errorf("could not generate .raw file: %v", err)
 			}
-			if err := output(".raw", buf.Bytes()); err != nil {
-				return fmt.Errorf("error outputting raw audio file: %v", err)
+			if err := output(".raw", raw); err != nil {
+				return fmt.Errorf("error outputting .raw file: %v", err)
 			}
 		}
 		if *wavOut {
-			buf := new(bytes.Buffer)
-			header := createWavHeader(len(buffer), *pcm)
-			err := binary.Write(buf, binary.LittleEndian, header)
+			wav, err := sointu.Wav(buffer, *pcm)
 			if err != nil {
-				return fmt.Errorf("could not binary write header to binary buffer: %v", err)
+				return fmt.Errorf("could not generate .wav file: %v", err)
 			}
-			err = binary.Write(buf, binary.LittleEndian, data)
-			if err != nil {
-				return fmt.Errorf("could not binary write data to binary buffer: %v", err)
-			}
-			if err := output(".wav", buf.Bytes()); err != nil {
-				return fmt.Errorf("error outputting wav audio file: %v", err)
+			if err := output(".wav", wav); err != nil {
+				return fmt.Errorf("error outputting .wav file: %v", err)
 			}
 		}
 		return nil
@@ -185,57 +166,3 @@ func printUsage() {
 	fmt.Fprintf(os.Stderr, "Sointu command line utility for playing .asm/.json song files.\nUsage: %s [flags] [path ...]\n", os.Args[0])
 	flag.PrintDefaults()
 }
-
-func createWavHeader(bufferLength int, pcm bool) []byte {
-	// Refer to: http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
-	numChannels := 2
-	sampleRate := 44100
-	var bytesPerSample, chunkSize, fmtChunkSize, waveFormat int
-	var factChunk bool
-	if pcm {
-		bytesPerSample = 2
-		chunkSize = 36 + bytesPerSample*bufferLength
-		fmtChunkSize = 16
-		waveFormat = 1 // PCM
-		factChunk = false
-	} else {
-		bytesPerSample = 4
-		chunkSize = 50 + bytesPerSample*bufferLength
-		fmtChunkSize = 18
-		waveFormat = 3 // IEEE float
-		factChunk = true
-	}
-	buf := new(bytes.Buffer)
-	buf.Write([]byte("RIFF"))
-	binary.Write(buf, binary.LittleEndian, uint32(chunkSize))
-	buf.Write([]byte("WAVE"))
-	buf.Write([]byte("fmt "))
-	binary.Write(buf, binary.LittleEndian, uint32(fmtChunkSize))
-	binary.Write(buf, binary.LittleEndian, uint16(waveFormat))
-	binary.Write(buf, binary.LittleEndian, uint16(numChannels))
-	binary.Write(buf, binary.LittleEndian, uint32(sampleRate))
-	binary.Write(buf, binary.LittleEndian, uint32(sampleRate*numChannels*bytesPerSample)) // avgBytesPerSec
-	binary.Write(buf, binary.LittleEndian, uint16(numChannels*bytesPerSample))            // blockAlign
-	binary.Write(buf, binary.LittleEndian, uint16(8*bytesPerSample))                      // bits per sample
-	if fmtChunkSize > 16 {
-		binary.Write(buf, binary.LittleEndian, uint16(0)) // size of extension
-	}
-	if factChunk {
-		buf.Write([]byte("fact"))
-		binary.Write(buf, binary.LittleEndian, uint32(4))            // fact chunk size
-		binary.Write(buf, binary.LittleEndian, uint32(bufferLength)) // sample length
-	}
-	buf.Write([]byte("data"))
-	binary.Write(buf, binary.LittleEndian, uint32(bytesPerSample*bufferLength))
-	return buf.Bytes()
-}
-
-func clamp(value, min, max int) int {
-	if value < min {
-		return min
-	}
-	if value > max {
-		return max
-	}
-	return value
-}

tracker/gioui/files.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"path/filepath"
+	"time"
 
 	"gioui.org/app"
 	"gopkg.in/yaml.v3"
@@ -82,3 +83,33 @@ func (t *Tracker) saveSong(filename string) bool {
 	t.SetChangedSinceSave(false)
 	return true
 }
+
+func (t *Tracker) exportWav(pcm16 bool) {
+	filename, err := dialog.File().Filter(".wav file", "wav").Title("Export .wav").Save()
+	if err != nil {
+		return
+	}
+	var extension = filepath.Ext(filename)
+	if extension == "" {
+		filename = filename + ".wav"
+	}
+	synth, err := t.synthService.Compile(t.Song().Patch)
+	if err != nil {
+		t.Alert.Update(fmt.Sprintf("Error compiling the patch during export: %v", err), Error, time.Second*3)
+		return
+	}
+	for i := 0; i < 32; i++ {
+		synth.Release(i)
+	}
+	data, _, err := sointu.Play(synth, t.Song()) // render the song to calculate its length
+	if err != nil {
+		t.Alert.Update(fmt.Sprintf("Error rendering the song during export: %v", err), Error, time.Second*3)
+		return
+	}
+	buffer, err := sointu.Wav(data, pcm16)
+	if err != nil {
+		t.Alert.Update(fmt.Sprintf("Error converting to .wav: %v", err), Error, time.Second*3)
+		return
+	}
+	ioutil.WriteFile(filename, buffer, 0644)
+}

tracker/gioui/layout.go

@@ -39,6 +39,22 @@ func (t *Tracker) Layout(gtx layout.Context) {
 	for t.ConfirmSongDialog.BtnCancel.Clicked() {
 		t.ConfirmSongDialog.Visible = false
 	}
+	dstyle = ConfirmDialog(t.Theme, t.WaveTypeDialog, "Export .wav in int16 or float32 sample format?")
+	dstyle.ShowAlt = true
+	dstyle.OkStyle.Text = "Int16"
+	dstyle.AltStyle.Text = "Float32"
+	dstyle.Layout(gtx)
+	for t.WaveTypeDialog.BtnOk.Clicked() {
+		t.exportWav(true)
+		t.WaveTypeDialog.Visible = false
+	}
+	for t.WaveTypeDialog.BtnAlt.Clicked() {
+		t.exportWav(false)
+		t.WaveTypeDialog.Visible = false
+	}
+	for t.WaveTypeDialog.BtnCancel.Clicked() {
+		t.WaveTypeDialog.Visible = false
+	}
 }
 
 func (t *Tracker) confirmedSongAction() {

tracker/gioui/songpanel.go

@@ -61,6 +61,8 @@ func (t *Tracker) layoutMenuBar(gtx C) D {
 		case 3:
 			t.SaveSongAsFile()
 		case 4:
+			t.WaveTypeDialog.Visible = true
+		case 5:
 			t.TryQuit()
 		}
 		clickedItem, hasClicked = t.Menus[0].Clicked()
@@ -93,6 +95,7 @@ func (t *Tracker) layoutMenuBar(gtx C) D {
 			MenuItem{IconBytes: icons.FileFolder, Text: "Open Song", ShortcutText: shortcutKey + "O"},
 			MenuItem{IconBytes: icons.ContentSave, Text: "Save Song", ShortcutText: shortcutKey + "S"},
 			MenuItem{IconBytes: icons.ContentSave, Text: "Save Song As..."},
+			MenuItem{IconBytes: icons.ImageAudiotrack, Text: "Export Wav..."},
 			MenuItem{IconBytes: icons.ActionExitToApp, Text: "Quit"},
 		)),
 		layout.Rigid(t.layoutMenu("Edit", &t.MenuBar[1], &t.Menus[1], unit.Dp(160),

tracker/gioui/tracker.go

@@ -70,6 +70,7 @@ type Tracker struct {
 	PatternOrderScrollBar *ScrollBar
 	ConfirmInstrDelete    *Dialog
 	ConfirmSongDialog     *Dialog
+	WaveTypeDialog        *Dialog
 	ConfirmSongActionType int
 	window                *app.Window
 
@@ -82,6 +83,7 @@ type Tracker struct {
 	errorChannel chan error
 	quitted      bool
 	audioContext sointu.AudioContext
+	synthService sointu.SynthService
 
 	*tracker.Model
 }
@@ -165,8 +167,10 @@ func New(audioContext sointu.AudioContext, synthService sointu.SynthService, syn
 		PatternOrderScrollBar: &ScrollBar{Axis: layout.Vertical},
 		ConfirmInstrDelete:    new(Dialog),
 		ConfirmSongDialog:     new(Dialog),
+		WaveTypeDialog:        new(Dialog),
 		errorChannel:          make(chan error, 32),
 		window:                window,
+		synthService:          synthService,
 	}
 	t.Model = tracker.NewModel()
 	vuBufferObserver := make(chan []float32)