// au demonstrates basic audio library (vu/audio/al) capabilities.
// It checks that OpenAL is installed and the bindings are working
// by loading and playing a sound.
func au() {
al.Init() // map the bindings to the OpenAL dynamic library.
// open the default device.
if dev := al.OpenDevice(""); dev != nil {
defer al.CloseDevice(dev)
// create a context on the device.
if ctx := al.CreateContext(dev, nil); ctx != nil {
defer al.MakeContextCurrent(nil)
defer al.DestroyContext(ctx)
al.MakeContextCurrent(ctx)
// create buffers and sources
var buffer, source uint32
al.GenBuffers(1, &buffer)
al.GenSources(1, &source)
// read in the audio data.
sound := &data.Sound{}
loader := data.NewLoader()
loader.Load("bloop", &sound)
if sound == nil {
log.Printf("au: error loading audio file", "bloop")
return
}
// copy the audio data into the buffer
tag := &autag{}
format := tag.audioFormat(sound)
if format < 0 {
log.Printf("au: error recognizing audio format")
return
}
al.BufferData(buffer, int32(format), al.Pointer(&(sound.AudioData[0])), int32(sound.DataSize), int32(sound.Frequency))
// attach the source to a buffer.
al.Sourcei(source, al.BUFFER, int32(buffer))
// check for any audio library errors that have happened up to this point.
if err := al.GetError(); err != 0 {
log.Printf("au: OpenAL error ", err)
return
}
// Start playback and give enough time for the playback to finish.
al.SourcePlay(source)
time.Sleep(500 * time.Millisecond)
return
}
log.Printf("au: error, failed to get a context")
}
log.Printf("au: error, failed to get a device")
}
// Shutdown closes down the openal library. This is only expected to be called
// once by the engine when it is shutting down.
func (a *openal) Shutdown() {
al.MakeContextCurrent(nil)
if a.ctx != nil {
al.DestroyContext(a.ctx)
}
if a.dev != nil {
al.CloseDevice(a.dev)
}
}
// Init runs the one time openal library initialization. It is only expected to
// be called once by the engine on startup.
func (a *openal) Init() (err error) {
al.Init()
if err = a.validate(); err != nil {
return
}
// create an openal context for all sounds.
if a.dev = al.OpenDevice(""); a.dev != nil {
if a.ctx = al.CreateContext(a.dev, nil); a.ctx != nil {
al.MakeContextCurrent(a.ctx)
return // success
}
}
return fmt.Errorf("Could not initialize openal audio")
}