feat(go/audio): implement basic audio output with oto

splitting implementation into a separate package to potentially allow for other sorts of output, too.

go4k/audio/oto/otoplayer.go

@@ -0,0 +1,54 @@
+package oto
+
+import (
+	"fmt"
+	"github.com/hajimehoshi/oto"
+	"github.com/vsariola/sointu/go4k/audio"
+)
+
+// OtoPlayer wraps github.com/hajimehoshi/oto to play sointu-style float32[] audio
+type OtoPlayer struct {
+	context *oto.Context
+	player  *oto.Player
+}
+
+// Play implements the audio.Player interface for OtoPlayer
+func (o *OtoPlayer) Play(floatBuffer []float32) (err error) {
+	if byteBuffer, err := audio.FloatBufferTo16BitLE(floatBuffer); err != nil {
+		return fmt.Errorf("error writing to player: %w", err)
+	} else if _, err := o.player.Write(byteBuffer); err != nil {
+		return fmt.Errorf("error writing to player: %w", err)
+	} else {
+		fmt.Printf("%#v\n", floatBuffer[0:100])
+		fmt.Printf("%#v\n", byteBuffer[0:200])
+	}
+
+	return nil
+}
+
+// Close disposes of resources
+func (o *OtoPlayer) Close() error {
+	if err := o.player.Close(); err != nil {
+		return fmt.Errorf("error closing player: %w", err)
+	}
+	if err := o.context.Close(); err != nil {
+		return fmt.Errorf("error closing oto context: %w", err)
+	}
+	return nil
+}
+
+const otoBufferSize = 8192
+
+// NewPlayer creates and initializes a new OtoPlayer
+func NewPlayer() (*OtoPlayer, error) {
+	context, err := oto.NewContext(44100, 2, 2, otoBufferSize)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create oto context: %w", err)
+	}
+	player := context.NewPlayer()
+
+	return &OtoPlayer{
+		context: context,
+		player:  player,
+	}, nil
+}