ebiten/audio/internal/go2cpp/player_js.go

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// Copyright 2021 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package go2cpp
import (
"io"
"runtime"
"sync"
"syscall/js"
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"github.com/hajimehoshi/oto/v2"
)
type Context struct {
v js.Value
sampleRate int
channelNum int
bitDepthInBytes int
}
func NewContext(sampleRate int, channelNum, bitDepthInBytes int) *Context {
v := js.Global().Get("go2cpp").Call("createAudio", sampleRate, channelNum, bitDepthInBytes)
return &Context{
v: v,
sampleRate: sampleRate,
channelNum: channelNum,
bitDepthInBytes: bitDepthInBytes,
}
}
func (c *Context) NewPlayer(r io.Reader) oto.Player {
cond := sync.NewCond(&sync.Mutex{})
onwritten := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
cond.Signal()
return nil
})
p := &Player{
context: c,
src: r,
volume: 1,
cond: cond,
onWritten: onwritten,
}
runtime.SetFinalizer(p, (*Player).Close)
return p
}
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func (c *Context) Suspend() error {
// Do nothing so far.
return nil
}
func (c *Context) Resume() error {
// Do nothing so far.
return nil
}
func (c *Context) oneBufferSize() int {
// TODO: This must be audio.oneBufferSize(p.context.sampleRate). Avoid the duplication.
return c.sampleRate * c.channelNum * c.bitDepthInBytes / 4
}
func (c *Context) MaxBufferSize() int {
// TODO: This must be audio.maxBufferSize(p.context.sampleRate). Avoid the duplication.
return c.oneBufferSize() * 2
}
type playerState int
const (
playerStatePaused playerState = iota
playerStatePlaying
playerStateClosed
)
type Player struct {
context *Context
src io.Reader
v js.Value
state playerState
volume float64
cond *sync.Cond
err error
buf []byte
onWritten js.Func
}
func (p *Player) Pause() {
p.cond.L.Lock()
defer p.cond.L.Unlock()
if p.state == playerStateClosed {
return
}
if !p.v.Truthy() {
return
}
p.v.Call("pause")
p.state = playerStatePaused
p.cond.Signal()
}
func (p *Player) Play() {
p.cond.L.Lock()
defer p.cond.L.Unlock()
if p.state == playerStateClosed {
return
}
var runloop bool
if !p.v.Truthy() {
p.v = p.context.v.Call("createPlayer", p.onWritten)
runloop = true
}
p.v.Set("volume", p.volume)
p.v.Call("play")
// Prepare the first data as soon as possible, or the audio can get stuck.
// TODO: Get the appropriate buffer size from the C++ side.
if p.buf == nil {
n := p.context.oneBufferSize()
if max := p.context.MaxBufferSize() - p.UnplayedBufferSize(); n > max {
n = max
}
p.buf = make([]byte, n)
}
n, err := p.src.Read(p.buf)
if err != nil && err != io.EOF {
p.setErrorImpl(err)
return
}
if n > 0 {
dst := js.Global().Get("Uint8Array").New(n)
p.writeImpl(dst, p.buf[:n])
}
if runloop {
go p.loop()
}
p.state = playerStatePlaying
p.cond.Signal()
}
func (p *Player) IsPlaying() bool {
p.cond.L.Lock()
defer p.cond.L.Unlock()
return p.state == playerStatePlaying
}
func (p *Player) Reset() {
p.cond.L.Lock()
defer p.cond.L.Unlock()
if p.state == playerStateClosed {
return
}
p.state = playerStatePaused
if !p.v.Truthy() {
return
}
p.v.Call("close", true)
p.v = js.Undefined()
p.cond.Signal()
}
func (p *Player) Volume() float64 {
p.cond.L.Lock()
defer p.cond.L.Unlock()
if !p.v.Truthy() {
return p.volume
}
return p.v.Get("volume").Float()
}
func (p *Player) SetVolume(volume float64) {
p.cond.L.Lock()
defer p.cond.L.Unlock()
p.volume = volume
if !p.v.Truthy() {
return
}
p.v.Set("volume", volume)
}
func (p *Player) UnplayedBufferSize() int {
if !p.v.Truthy() {
return 0
}
return p.v.Get("unplayedBufferSize").Int()
}
func (p *Player) Err() error {
p.cond.L.Lock()
defer p.cond.L.Unlock()
return p.err
}
func (p *Player) Close() error {
runtime.SetFinalizer(p, nil)
return p.close(true)
}
func (p *Player) close(remove bool) error {
p.cond.L.Lock()
defer p.cond.L.Unlock()
return p.closeImpl(remove)
}
func (p *Player) closeImpl(remove bool) error {
if p.state == playerStateClosed {
return p.err
}
if p.v.Truthy() {
p.v.Call("close", false)
p.v = js.Undefined()
}
if remove {
p.state = playerStateClosed
p.onWritten.Release()
} else {
p.state = playerStatePaused
}
p.cond.Signal()
return p.err
}
func (p *Player) setError(err error) {
p.cond.L.Lock()
defer p.cond.L.Unlock()
p.setErrorImpl(err)
}
func (p *Player) setErrorImpl(err error) {
if p.state != playerStateClosed && p.v.Truthy() {
p.v.Call("close", true)
p.v = js.Undefined()
}
p.err = err
p.state = playerStateClosed
p.cond.Signal()
}
func (p *Player) shouldWait() bool {
if !p.v.Truthy() {
return false
}
switch p.state {
case playerStatePaused:
return true
case playerStatePlaying:
return p.v.Get("unplayedBufferSize").Int() >= p.context.MaxBufferSize()
}
return false
}
func (p *Player) waitUntilUnpaused() bool {
p.cond.L.Lock()
defer p.cond.L.Unlock()
for p.shouldWait() {
p.cond.Wait()
}
return p.v.Truthy() && p.state == playerStatePlaying
}
func (p *Player) writeImpl(dst js.Value, src []byte) {
if p.state == playerStateClosed {
return
}
if !p.v.Truthy() {
return
}
js.CopyBytesToJS(dst, src)
p.v.Call("write", dst, len(src))
}
func (p *Player) loop() {
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const readChunkSize = 4096
buf := make([]byte, readChunkSize)
dst := js.Global().Get("Uint8Array").New(readChunkSize)
for {
if !p.waitUntilUnpaused() {
return
}
p.cond.L.Lock()
n, err := p.src.Read(buf)
if err != nil && err != io.EOF {
p.setErrorImpl(err)
p.cond.L.Unlock()
return
}
if n > 0 {
p.writeImpl(dst, buf[:n])
}
if err == io.EOF {
p.closeImpl(false)
p.cond.L.Unlock()
return
}
p.cond.L.Unlock()
}
}