ebiten/audio/otodriver.go
2021-01-07 02:14:42 +09:00

93 lines
2.1 KiB
Go

// Copyright 2020 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 audio
import (
"io"
"sync"
"github.com/hajimehoshi/oto"
)
func newOtoDriver(sampleRate int, initCh chan struct{}) *otoDriver {
return &otoDriver{
sampleRate: sampleRate,
initCh: initCh,
}
}
type otoDriver struct {
sampleRate int
initCh <-chan struct{}
c *oto.Context
once sync.Once
}
func (c *otoDriver) NewPlayer() io.WriteCloser {
return &otoPlayer{c: c}
}
func (c *otoDriver) Close() error {
if c.c == nil {
return nil
}
return c.c.Close()
}
func (c *otoDriver) ensureContext() error {
var err error
c.once.Do(func() {
<-c.initCh
c.c, err = oto.NewContext(c.sampleRate, channelNum, bytesPerSample/channelNum, bufferSize())
})
return err
}
type otoPlayer struct {
c *otoDriver
p *oto.Player
once sync.Once
}
func (p *otoPlayer) Write(buf []byte) (int, error) {
// Initialize oto.Player lazily to enable calling NewContext in an 'init' function.
// Accessing oto.Player functions requires the environment to be already initialized,
// but if Ebiten is used for a shared library, the timing when init functions are called
// is unexpectable.
// e.g. a variable for JVM on Android might not be set.
if err := p.ensurePlayer(); err != nil {
return 0, err
}
return p.p.Write(buf)
}
func (p *otoPlayer) Close() error {
if p.p == nil {
return nil
}
return p.p.Close()
}
func (p *otoPlayer) ensurePlayer() error {
if err := p.c.ensureContext(); err != nil {
return err
}
p.once.Do(func() {
p.p = p.c.c.NewPlayer()
})
return nil
}