Ebiten example - audio
// +build example
// This is an example to implement an audio player.
// See examples/wav for a simpler example to play a sound file.
package main
import (
"fmt"
"image/color"
"io/ioutil"
"log"
"time"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/audio"
"github.com/hajimehoshi/ebiten/audio/mp3"
"github.com/hajimehoshi/ebiten/audio/wav"
"github.com/hajimehoshi/ebiten/ebitenutil"
)
const (
screenWidth = 320
screenHeight = 240
// This sample rate doesn't match with wav/mp3's sample rate,
// but decoders adjust them.
sampleRate = 48000
)
var (
playerBarImage *ebiten.Image
playerCurrentImage *ebiten.Image
)
func init() {
playerBarImage, _ = ebiten.NewImage(300, 4, ebiten.FilterNearest)
playerBarImage.Fill(&color.RGBA{0x80, 0x80, 0x80, 0xff})
playerCurrentImage, _ = ebiten.NewImage(4, 10, ebiten.FilterNearest)
playerCurrentImage.Fill(&color.RGBA{0xff, 0xff, 0xff, 0xff})
}
type Input struct {
mouseButtonStates map[ebiten.MouseButton]int
keyStates map[ebiten.Key]int
}
func (i *Input) update() {
for _, key := range []ebiten.Key{ebiten.KeyP, ebiten.KeyS, ebiten.KeyX, ebiten.KeyZ, ebiten.KeyB} {
if !ebiten.IsKeyPressed(key) {
i.keyStates[key] = 0
} else {
i.keyStates[key]++
}
}
if !ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
i.mouseButtonStates[ebiten.MouseButtonLeft] = 0
} else {
i.mouseButtonStates[ebiten.MouseButtonLeft]++
}
}
func (i *Input) isKeyTriggered(key ebiten.Key) bool {
return i.keyStates[key] == 1
}
func (i *Input) isKeyPressed(key ebiten.Key) bool {
return i.keyStates[key] > 0
}
func (i *Input) isMouseButtonTriggered(mouseButton ebiten.MouseButton) bool {
return i.mouseButtonStates[mouseButton] == 1
}
type Player struct {
input *Input
audioContext *audio.Context
audioPlayer *audio.Player
current time.Duration
total time.Duration
seBytes []uint8
seCh chan []uint8
volume128 int
}
var (
musicPlayer *Player
)
func playerBarRect() (x, y, w, h int) {
w, h = playerBarImage.Size()
x = (screenWidth - w) / 2
y = screenHeight - h - 16
return
}
func NewPlayer(audioContext *audio.Context) (*Player, error) {
const bytesPerSample = 4 // TODO: This should be defined in audio package
wavF, err := ebitenutil.OpenFile("_resources/audio/jab.wav")
if err != nil {
return nil, err
}
mp3F, err := ebitenutil.OpenFile("_resources/audio/classic.mp3")
if err != nil {
return nil, err
}
s, err := mp3.Decode(audioContext, mp3F)
if err != nil {
return nil, err
}
p, err := audio.NewPlayer(audioContext, s)
if err != nil {
return nil, err
}
player := &Player{
input: &Input{
mouseButtonStates: map[ebiten.MouseButton]int{},
keyStates: map[ebiten.Key]int{},
},
audioContext: audioContext,
audioPlayer: p,
total: time.Second * time.Duration(s.Size()) / bytesPerSample / sampleRate,
volume128: 128,
seCh: make(chan []uint8),
}
if player.total == 0 {
player.total = 1
}
player.audioPlayer.Play()
go func() {
s, err := wav.Decode(audioContext, wavF)
if err != nil {
log.Fatal(err)
return
}
b, err := ioutil.ReadAll(s)
if err != nil {
log.Fatal(err)
return
}
player.seCh <- b
}()
return player, nil
}
func (p *Player) update() error {
p.input.update()
select {
case p.seBytes = <-p.seCh:
close(p.seCh)
p.seCh = nil
default:
}
if p.audioPlayer.IsPlaying() {
p.current = p.audioPlayer.Current()
}
p.updateBar()
p.updatePlayPause()
p.updateSE()
p.updateVolume()
if p.input.isKeyTriggered(ebiten.KeyB) {
b := ebiten.IsRunnableInBackground()
ebiten.SetRunnableInBackground(!b)
}
if err := p.audioContext.Update(); err != nil {
return err
}
return nil
}
func (p *Player) updateSE() {
if p.seBytes == nil {
return
}
if !p.input.isKeyTriggered(ebiten.KeyP) {
return
}
sePlayer, _ := audio.NewPlayerFromBytes(p.audioContext, p.seBytes)
sePlayer.Play()
}
func (p *Player) updateVolume() {
if p.input.isKeyPressed(ebiten.KeyZ) {
p.volume128--
}
if p.input.isKeyPressed(ebiten.KeyX) {
p.volume128++
}
if p.volume128 < 0 {
p.volume128 = 0
}
if 128 < p.volume128 {
p.volume128 = 128
}
p.audioPlayer.SetVolume(float64(p.volume128) / 128)
}
func (p *Player) updatePlayPause() {
if !p.input.isKeyTriggered(ebiten.KeyS) {
return
}
if p.audioPlayer.IsPlaying() {
p.audioPlayer.Pause()
return
}
p.audioPlayer.Play()
}
func (p *Player) updateBar() {
if !p.input.isMouseButtonTriggered(ebiten.MouseButtonLeft) {
return
}
// Start seeking.
x, y := ebiten.CursorPosition()
bx, by, bw, bh := playerBarRect()
const padding = 4
if y < by-padding || by+bh+padding <= y {
return
}
if x < bx || bx+bw <= x {
return
}
pos := time.Duration(x-bx) * p.total / time.Duration(bw)
p.current = pos
p.audioPlayer.Seek(pos)
}
func (p *Player) close() error {
return p.audioPlayer.Close()
}
func (p *Player) draw(screen *ebiten.Image) {
op := &ebiten.DrawImageOptions{}
x, y, w, h := playerBarRect()
op.GeoM.Translate(float64(x), float64(y))
screen.DrawImage(playerBarImage, op)
currentTimeStr := "00:00"
// Current Time
c := p.current
m := (c / time.Minute) % 100
s := (c / time.Second) % 60
currentTimeStr = fmt.Sprintf("%02d:%02d", m, s)
// Bar
cw, ch := playerCurrentImage.Size()
cx := int(time.Duration(w)*c/p.total) + x - cw/2
cy := y - (ch-h)/2
op = &ebiten.DrawImageOptions{}
op.GeoM.Translate(float64(cx), float64(cy))
screen.DrawImage(playerCurrentImage, op)
msg := fmt.Sprintf(`FPS: %0.2f
Press S to toggle Play/Pause
Press P to play SE
Press Z or X to change volume of the music
Press B to switch the run-in-background state
%s`, ebiten.CurrentFPS(), currentTimeStr)
ebitenutil.DebugPrint(screen, msg)
}
func update(screen *ebiten.Image) error {
if err := musicPlayer.update(); err != nil {
return err
}
if ebiten.IsRunningSlowly() {
return nil
}
musicPlayer.draw(screen)
return nil
}
func main() {
audioContext, err := audio.NewContext(sampleRate)
if err != nil {
log.Fatal(err)
}
musicPlayer, err = NewPlayer(audioContext)
if err != nil {
log.Fatal(err)
}
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Audio (Ebiten Demo)"); err != nil {
log.Fatal(err)
}
if musicPlayer != nil {
if err := musicPlayer.close(); err != nil {
log.Fatal(err)
}
}
}