func NewPlayer(sampleRate, channelNum, bytesPerSample int) (*Player, error) {
p := &Player{
sampleRate: sampleRate,
channelNum: channelNum,
bytesPerSample: bytesPerSample,
buffer: []byte{},
chErr: make(chan error),
chBuffer: make(chan []byte, 8),
}
if err := jni.RunOnJVM(func(vm, env, ctx uintptr) error {
audioTrack := C.jobject(nil)
bufferSize := C.int(0)
if msg := C.initAudioTrack(C.uintptr_t(vm), C.uintptr_t(env),
C.int(sampleRate), C.int(channelNum), C.int(bytesPerSample),
&audioTrack, &bufferSize); msg != nil {
return errors.New("driver: " + C.GoString(msg))
}
p.audioTrack = audioTrack
p.bufferSize = int(bufferSize)
return nil
}); err != nil {
return nil, err
}
go p.loop()
return p, nil
}
func (p *Player) loop() {
for bufInBytes := range p.chBuffer {
var bufInShorts []int16
if p.bytesPerSample == 2 {
bufInShorts = make([]int16, len(bufInBytes)/2)
for i := 0; i < len(bufInShorts); i++ {
bufInShorts[i] = int16(bufInBytes[2*i]) | (int16(bufInBytes[2*i+1]) << 8)
}
}
if err := jni.RunOnJVM(func(vm, env, ctx uintptr) error {
msg := (*C.char)(nil)
switch p.bytesPerSample {
case 1:
msg = C.writeToAudioTrack(C.uintptr_t(vm), C.uintptr_t(env),
p.audioTrack, C.int(p.bytesPerSample),
unsafe.Pointer(&bufInBytes[0]), C.int(len(bufInBytes)))
case 2:
msg = C.writeToAudioTrack(C.uintptr_t(vm), C.uintptr_t(env),
p.audioTrack, C.int(p.bytesPerSample),
unsafe.Pointer(&bufInShorts[0]), C.int(len(bufInShorts)))
}
if msg != nil {
return errors.New(C.GoString(msg))
}
return nil
}); err != nil {
p.chErr <- err
return
}
}
}
func deviceScale() float64 {
if 0 < androidDeviceScale {
return androidDeviceScale
}
if err := jni.RunOnJVM(func(vm, env, ctx uintptr) error {
androidDeviceScale = float64(C.deviceScale(C.uintptr_t(vm), C.uintptr_t(env), C.uintptr_t(ctx)))
return nil
}); err != nil {
panic(fmt.Sprintf("ui: error %v", err))
}
return androidDeviceScale
}