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#include <dsound.h>
struct AudioDirectSound : Audio {
AudioDirectSound() { initialize(); }
~AudioDirectSound() { terminate(); }
auto availableDevices() -> string_vector {
return {"Default"};
}
auto availableFrequencies() -> vector<double> {
return {44100.0, 48000.0, 96000.0};
}
auto availableLatencies() -> vector<uint> {
return {40, 60, 80, 100};
}
auto availableChannels() -> vector<uint> {
return {2};
}
auto ready() -> bool { return _ready; }
auto blocking() -> bool { return _blocking; }
auto channels() -> uint { return _channels; }
auto frequency() -> double { return _frequency; }
auto latency() -> uint { return _latency; }
auto setBlocking(bool blocking) -> bool {
if(_blocking == blocking) return true;
_blocking = blocking;
return true;
}
auto setFrequency(double frequency) -> bool {
if(_frequency == frequency) return true;
_frequency = frequency;
return initialize();
}
auto setLatency(uint latency) -> bool {
if(_latency == latency) return true;
_latency = latency;
return initialize();
}
auto clear() -> void {
if(!ready()) return;
_ringRead = 0;
_ringWrite = _rings - 1;
_ringDistance = _rings - 1;
if(_buffer) memory::fill(_buffer, _period * _rings * 4);
_offset = 0;
if(!_secondary) return;
_secondary->Stop();
_secondary->SetCurrentPosition(0);
void* output;
DWORD size;
_secondary->Lock(0, _period * _rings * 4, &output, &size, 0, 0, 0);
memory::fill(output, size);
_secondary->Unlock(output, size, 0, 0);
_secondary->Play(0, 0, DSBPLAY_LOOPING);
}
auto output(const double samples[]) -> void {
if(!ready()) return;
_buffer[_offset] = (uint16_t)sclamp<16>(samples[0] * 32767.0) << 0;
_buffer[_offset] |= (uint16_t)sclamp<16>(samples[1] * 32767.0) << 16;
if(++_offset < _period) return;
_offset = 0;
if(_blocking) {
//wait until playback buffer has an empty ring to write new audio data to
while(_ringDistance >= _rings - 1) {
DWORD position;
_secondary->GetCurrentPosition(&position, 0);
uint ringActive = position / (_period * 4);
if(ringActive == _ringRead) continue;
//subtract number of played rings from ring distance counter
_ringDistance -= (_rings + ringActive - _ringRead) % _rings;
_ringRead = ringActive;
if(_ringDistance < 2) {
//buffer underflow; set max distance to recover quickly
_ringDistance = _rings - 1;
_ringWrite = (_rings + _ringRead - 1) % _rings;
break;
}
}
}
_ringWrite = (_ringWrite + 1) % _rings;
_ringDistance = (_ringDistance + 1) % _rings;
void* output;
DWORD size;
if(_secondary->Lock(_ringWrite * _period * 4, _period * 4, &output, &size, 0, 0, 0) == DS_OK) {
memory::copy(output, _buffer, _period * 4);
_secondary->Unlock(output, size, 0, 0);
}
}
private:
auto initialize() -> bool {
terminate();
_rings = 8;
_period = _frequency * _latency / _rings / 1000.0 + 0.5;
_buffer = new uint32_t[_period * _rings];
_offset = 0;
if(DirectSoundCreate(0, &_interface, 0) != DS_OK) return terminate(), false;
_interface->SetCooperativeLevel(GetDesktopWindow(), DSSCL_PRIORITY);
DSBUFFERDESC primaryDescription = {};
primaryDescription.dwSize = sizeof(DSBUFFERDESC);
primaryDescription.dwFlags = DSBCAPS_PRIMARYBUFFER;
primaryDescription.dwBufferBytes = 0;
primaryDescription.lpwfxFormat = 0;
_interface->CreateSoundBuffer(&primaryDescription, &_primary, 0);
WAVEFORMATEX waveFormat = {};
waveFormat.wFormatTag = WAVE_FORMAT_PCM;
waveFormat.nChannels = _channels;
waveFormat.nSamplesPerSec = (uint)_frequency;
waveFormat.wBitsPerSample = 16;
waveFormat.nBlockAlign = waveFormat.nChannels * waveFormat.wBitsPerSample / 8;
waveFormat.nAvgBytesPerSec = waveFormat.nSamplesPerSec * waveFormat.nBlockAlign;
_primary->SetFormat(&waveFormat);
DSBUFFERDESC secondaryDescription = {};
secondaryDescription.dwSize = sizeof(DSBUFFERDESC);
secondaryDescription.dwFlags = DSBCAPS_GETCURRENTPOSITION2 | DSBCAPS_CTRLFREQUENCY | DSBCAPS_GLOBALFOCUS | DSBCAPS_LOCSOFTWARE;
secondaryDescription.dwBufferBytes = _period * _rings * 4;
secondaryDescription.guid3DAlgorithm = GUID_NULL;
secondaryDescription.lpwfxFormat = &waveFormat;
_interface->CreateSoundBuffer(&secondaryDescription, &_secondary, 0);
_secondary->SetFrequency((uint)_frequency);
_secondary->SetCurrentPosition(0);
_ready = true;
clear();
return true;
}
auto terminate() -> void {
_ready = false;
if(_buffer) { delete[] _buffer; _buffer = nullptr; }
if(_secondary) { _secondary->Stop(); _secondary->Release(); _secondary = nullptr; }
if(_primary) { _primary->Stop(); _primary->Release(); _primary = nullptr; }
if(_interface) { _interface->Release(); _interface = nullptr; }
}
bool _ready = false;
bool _blocking = true;
uint _channels = 2;
double _frequency = 48000.0;
uint _latency = 40;
LPDIRECTSOUND _interface = nullptr;
LPDIRECTSOUNDBUFFER _primary = nullptr;
LPDIRECTSOUNDBUFFER _secondary = nullptr;
uint32_t* _buffer = nullptr;
uint _offset = 0;
uint _period = 0;
uint _rings = 0;
uint _ringRead = 0;
uint _ringWrite = 0;
int _ringDistance = 0;
};
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