func NewAudio() *Audio {
as = sdl_audio.AudioSpec{
Freq: 44100,
Format: sdl_audio.AUDIO_S16SYS,
Channels: 1,
Out_Silence: 0,
Samples: uint16(SampleSize),
Out_Size: 0,
}
if sdl_audio.OpenAudio(&as, nil) < 0 {
log.Fatal(sdl.GetError())
}
sdl_audio.PauseAudio(false)
return &Audio{
samples: make([]int16, SampleSize),
}
}
// Opens SDL audio.
// If 'playbackFrequency' is 0, the frequency will be equivalent to PLAYBACK_FREQUENCY.
func NewSDLAudio(app *spectrum.Application, playbackFrequency uint, hqAudio bool) (*SDLAudio, error) {
if playbackFrequency == 0 {
playbackFrequency = PLAYBACK_FREQUENCY
}
if playbackFrequency < MIN_PLAYBACK_FREQUENCY {
return nil, errors.New(fmt.Sprintf("playback frequency of %d Hz is too low", playbackFrequency))
}
// Open SDL audio
var spec sdl_audio.AudioSpec
{
spec.Freq = int(playbackFrequency)
spec.Format = sdl_audio.AUDIO_S16SYS
spec.Channels = 1
spec.Samples = uint16(2048 * float32(playbackFrequency) / PLAYBACK_FREQUENCY)
if sdl_audio.OpenAudio(&spec, &spec) != 0 {
return nil, errors.New(sdl.GetError())
}
if app.Verbose {
app.PrintfMsg("%#v", spec)
}
}
audio := &SDLAudio{
data: make(chan *spectrum.AudioData),
playback: make(chan *spectrum.AudioData, 2*BUFSIZE_IDEAL), // Use a buffered Go channel
playbackLoopFinished: make(chan byte),
forwarderLoopFinished: nil,
sdlAudioUnpaused: false,
bufSize: 0,
freq: uint(spec.Freq),
virtualFreq: uint(spec.Freq),
hqAudio: hqAudio,
}
go forwarderLoop(app.NewEventLoop(), audio)
go playbackLoop(app, audio)
return audio, nil
}
func (a *Audio) Run() {
as := sdl_audio.AudioSpec{
Freq: 44100,
Format: sdl_audio.AUDIO_S16SYS,
Channels: 1,
Out_Silence: 0,
Samples: uint16(SampleSize),
Out_Size: 0,
}
if sdl_audio.OpenAudio(&as, nil) < 0 {
log.Fatal(sdl.GetError())
}
sdl_audio.PauseAudio(false)
for {
select {
case s := <-a.sample:
a.AppendSample(s)
}
}
}
func NewAudio(frequency int, sampleSize int) (audio *SDLAudio, err error) {
spec := sdl_audio.AudioSpec{
Freq: frequency,
Format: sdl_audio.AUDIO_S16SYS,
Channels: 1,
Out_Silence: 0,
Samples: uint16(sampleSize),
Out_Size: 0,
}
if sdl_audio.OpenAudio(&spec, nil) < 0 {
err = errors.New(sdl.GetError())
return
}
sdl_audio.PauseAudio(false)
audio = &SDLAudio{
samples: make([]int16, sampleSize),
input: make(chan int16),
}
return
}