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#include <dsound.h>
struct AudioDirectSound : AudioDriver {
AudioDirectSound& self = *this;
AudioDirectSound(Audio& super) : AudioDriver(super) {}
~AudioDirectSound() { terminate(); }
auto create() -> bool override {
super.setChannels(2);
super.setFrequency(48000);
super.setLatency(40);
return initialize();
}
auto driver() -> string override { return "DirectSound 7.0"; }
auto ready() -> bool override { return _ready; }
auto hasBlocking() -> bool override { return true; }
auto hasFrequencies() -> vector<u32> override {
return {44100, 48000, 96000};
}
auto hasLatencies() -> vector<u32> override {
return {40, 60, 80, 100};
}
auto setBlocking(bool blocking) -> bool override { return true; }
auto setFrequency(u32 frequency) -> bool override { return initialize(); }
auto setLatency(u32 latency) -> bool override { return initialize(); }
auto clear() -> void override {
if(!ready()) return;
_ringRead = 0;
_ringWrite = _rings - 1;
_ringDistance = _rings - 1;
if(_buffer) memory::fill<u32>(_buffer, _period * _rings);
_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<u8>(output, size);
_secondary->Unlock(output, size, 0, 0);
_secondary->Play(0, 0, DSBPLAY_LOOPING);
}
auto output(const f64 samples[]) -> void override {
if(!ready()) return;
_buffer[_offset] = (u16)sclamp<16>(samples[0] * 32767.0) << 0;
_buffer[_offset] |= (u16)sclamp<16>(samples[1] * 32767.0) << 16;
if(++_offset < _period) return;
_offset = 0;
if(self.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);
u32 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<u32>(output, _buffer, _period);
_secondary->Unlock(output, size, 0, 0);
}
}
private:
auto initialize() -> bool {
terminate();
_rings = 8;
_period = self.frequency * self.latency / _rings / 1000.0 + 0.5;
_buffer = new u32[_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 = self.channels;
waveFormat.nSamplesPerSec = self.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(self.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;
LPDIRECTSOUND _interface = nullptr;
LPDIRECTSOUNDBUFFER _primary = nullptr;
LPDIRECTSOUNDBUFFER _secondary = nullptr;
u32* _buffer = nullptr;
u32 _offset = 0;
u32 _period = 0;
u32 _rings = 0;
u32 _ringRead = 0;
u32 _ringWrite = 0;
s32 _ringDistance = 0;
};
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