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#include <dsound.h>
struct AudioDS : Audio {
~AudioDS() { term(); }
LPDIRECTSOUND ds = nullptr;
LPDIRECTSOUNDBUFFER dsb_p = nullptr;
LPDIRECTSOUNDBUFFER dsb_b = nullptr;
DSBUFFERDESC dsbd;
WAVEFORMATEX wfx;
struct {
uint rings = 0;
uint latency = 0;
uint32_t* buffer = nullptr;
uint bufferoffset = 0;
uint readring = 0;
uint writering = 0;
int distance = 0;
} device;
struct {
HWND handle = nullptr;
bool synchronize = false;
uint frequency = 22050;
uint latency = 120;
} settings;
auto cap(const string& name) -> bool {
if(name == Audio::Handle) return true;
if(name == Audio::Synchronize) return true;
if(name == Audio::Frequency) return true;
if(name == Audio::Latency) return true;
return false;
}
auto get(const string& name) -> any {
if(name == Audio::Handle) return (uintptr_t)settings.handle;
if(name == Audio::Synchronize) return settings.synchronize;
if(name == Audio::Frequency) return settings.frequency;
if(name == Audio::Latency) return settings.latency;
return {};
}
auto set(const string& name, const any& value) -> bool {
if(name == Audio::Handle && value.is<uintptr_t>()) {
settings.handle = (HWND)value.get<uintptr_t>();
return true;
}
if(name == Audio::Synchronize && value.is<bool>()) {
settings.synchronize = value.get<bool>();
if(ds) clear();
return true;
}
if(name == Audio::Frequency && value.is<uint>()) {
settings.frequency = value.get<uint>();
if(ds) init();
return true;
}
if(name == Audio::Latency && value.is<uint>()) {
//latency settings below 40ms causes DirectSound to hang
settings.latency = max(40u, value.get<uint>());
if(ds) init();
return true;
}
return false;
}
auto sample(uint16_t left, uint16_t right) -> void {
device.buffer[device.bufferoffset++] = left + (right << 16);
if(device.bufferoffset < device.latency) return;
device.bufferoffset = 0;
DWORD pos, size;
void* output;
if(settings.synchronize) {
//wait until playback buffer has an empty ring to write new audio data to
while(device.distance >= device.rings - 1) {
dsb_b->GetCurrentPosition(&pos, 0);
uint activering = pos / (device.latency * 4);
if(activering == device.readring) continue;
//subtract number of played rings from ring distance counter
device.distance -= (device.rings + activering - device.readring) % device.rings;
device.readring = activering;
if(device.distance < 2) {
//buffer underflow; set max distance to recover quickly
device.distance = device.rings - 1;
device.writering = (device.rings + device.readring - 1) % device.rings;
break;
}
}
}
device.writering = (device.writering + 1) % device.rings;
device.distance = (device.distance + 1) % device.rings;
if(dsb_b->Lock(device.writering * device.latency * 4, device.latency * 4, &output, &size, 0, 0, 0) == DS_OK) {
memcpy(output, device.buffer, device.latency * 4);
dsb_b->Unlock(output, size, 0, 0);
}
}
auto clear() -> void {
device.readring = 0;
device.writering = device.rings - 1;
device.distance = device.rings - 1;
device.bufferoffset = 0;
if(device.buffer) memset(device.buffer, 0, device.latency * device.rings * 4);
if(!dsb_b) return;
dsb_b->Stop();
dsb_b->SetCurrentPosition(0);
DWORD size;
void* output;
dsb_b->Lock(0, device.latency * device.rings * 4, &output, &size, 0, 0, 0);
memset(output, 0, size);
dsb_b->Unlock(output, size, 0, 0);
dsb_b->Play(0, 0, DSBPLAY_LOOPING);
}
auto init() -> bool {
settings.handle = GetDesktopWindow();
device.rings = 8;
device.latency = settings.frequency * settings.latency / device.rings / 1000.0 + 0.5;
device.buffer = new uint32_t[device.latency * device.rings];
device.bufferoffset = 0;
if(DirectSoundCreate(0, &ds, 0) != DS_OK) return term(), false;
ds->SetCooperativeLevel((HWND)settings.handle, DSSCL_PRIORITY);
memory::fill(&dsbd, sizeof(dsbd));
dsbd.dwSize = sizeof(dsbd);
dsbd.dwFlags = DSBCAPS_PRIMARYBUFFER;
dsbd.dwBufferBytes = 0;
dsbd.lpwfxFormat = 0;
ds->CreateSoundBuffer(&dsbd, &dsb_p, 0);
memory::fill(&wfx, sizeof(wfx));
wfx.wFormatTag = WAVE_FORMAT_PCM;
wfx.nChannels = 2;
wfx.nSamplesPerSec = settings.frequency;
wfx.wBitsPerSample = 16;
wfx.nBlockAlign = wfx.wBitsPerSample / 8 * wfx.nChannels;
wfx.nAvgBytesPerSec = wfx.nSamplesPerSec * wfx.nBlockAlign;
dsb_p->SetFormat(&wfx);
memory::fill(&dsbd, sizeof(dsbd));
dsbd.dwSize = sizeof(dsbd);
dsbd.dwFlags = DSBCAPS_GETCURRENTPOSITION2 | DSBCAPS_CTRLFREQUENCY | DSBCAPS_GLOBALFOCUS | DSBCAPS_LOCSOFTWARE;
dsbd.dwBufferBytes = device.latency * device.rings * sizeof(uint32_t);
dsbd.guid3DAlgorithm = GUID_NULL;
dsbd.lpwfxFormat = &wfx;
ds->CreateSoundBuffer(&dsbd, &dsb_b, 0);
dsb_b->SetFrequency(settings.frequency);
dsb_b->SetCurrentPosition(0);
clear();
return true;
}
auto term() -> void {
if(device.buffer) {
delete[] device.buffer;
device.buffer = nullptr;
}
if(dsb_b) { dsb_b->Stop(); dsb_b->Release(); dsb_b = nullptr; }
if(dsb_p) { dsb_p->Stop(); dsb_p->Release(); dsb_p = nullptr; }
if(ds) { ds->Release(); ds = nullptr; }
}
};
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