// NewPlayer returns a new Player.
// It initializes the underlying audio devices and the related resources.
func NewPlayer(src io.ReadSeeker, format Format, sampleRate int64) (*Player, error) {
device.Lock()
defer device.Unlock()
if device.d == nil {
device.d = alc.Open("")
c := device.d.CreateContext(nil)
if !alc.MakeContextCurrent(c) {
return nil, fmt.Errorf("player: cannot initiate a new player")
}
}
s := al.GenSources(1)
if code := al.Error(); code != 0 {
return nil, fmt.Errorf("player: cannot generate an audio source [err=%x]", code)
}
bufs := al.GenBuffers(2)
if err := lastErr(); err != nil {
return nil, err
}
return &Player{
t: &track{format: format, src: src, rate: sampleRate},
source: s[0],
bufs: bufs,
}, nil
}
func (p *Player) prepare(offset int64, force bool) error {
p.muPrep.Lock()
defer p.muPrep.Unlock()
if !force && p.prep {
return nil
}
if len(p.bufs) > 0 {
p.source.UnqueueBuffers(p.bufs)
al.DeleteBuffers(p.bufs)
}
if _, err := p.t.src.Seek(offset, 0); err != nil {
return err
}
p.bufs = []al.Buffer{}
// TODO(jbd): Limit the number of buffers in use, unqueue and reuse
// the existing buffers as buffers are processed.
buf := make([]byte, 128*1024)
size := offset
for {
n, err := p.t.src.Read(buf)
if n > 0 {
size += int64(n)
b := al.GenBuffers(1)
b[0].BufferData(uint32(formatToCode[p.t.format]), buf[:n], int32(p.t.rate))
p.bufs = append(p.bufs, b[0])
}
if err == io.EOF {
break
}
if err != nil {
return err
}
}
p.size = size
if len(p.bufs) > 0 {
p.source.QueueBuffers(p.bufs)
}
p.prep = true
return nil
}