19 unsigned wantedFreq,
unsigned wantedSamples)
22 SDL_AudioSpec desired;
23 desired.freq = narrow<int>(wantedFreq);
24 desired.samples = narrow<Uint16>(std::bit_ceil(wantedSamples));
26 desired.format = AUDIO_F32SYS;
27 desired.callback = audioCallbackHelper;
28 desired.userdata =
this;
30 SDL_AudioSpec obtained;
31 deviceID = SDL_OpenAudioDevice(
nullptr, SDL_FALSE, &desired, &obtained,
32 SDL_AUDIO_ALLOW_FREQUENCY_CHANGE);
34 throw MSXException(
"Unable to open SDL audio: ", SDL_GetError());
37 frequency = obtained.freq;
38 fragmentSize = obtained.samples;
40 mixBufferSize = narrow<unsigned>(3 * (obtained.size /
sizeof(
StereoFloat)) + 1);
41 mixBuffer.resize(mixBufferSize);
47 SDL_CloseAudioDevice(deviceID);
50void SDLSoundDriver::reInit()
52 SDL_LockAudioDevice(deviceID);
55 SDL_UnlockAudioDevice(deviceID);
62 SDL_PauseAudioDevice(deviceID, 1);
71 SDL_PauseAudioDevice(deviceID, 0);
85void SDLSoundDriver::audioCallbackHelper(
void* userdata, uint8_t* strm,
int len)
87 assert((len & 7) == 0);
89 audioCallback(std::span{
reinterpret_cast<StereoFloat*
>(strm),
90 len / (2 *
sizeof(
float))});
93unsigned SDLSoundDriver::getBufferFilled()
const
95 int result = narrow_cast<int>(writeIdx - readIdx);
96 if (result < 0) result += narrow<int>(mixBufferSize);
97 assert((0 <= result) && (narrow<unsigned>(result) < mixBufferSize));
101unsigned SDLSoundDriver::getBufferFree()
const
106 unsigned result = mixBufferSize - 1 - getBufferFilled();
107 assert(narrow_cast<int>(result) >= 0);
108 assert(result < mixBufferSize);
112void SDLSoundDriver::audioCallback(std::span<StereoFloat> stream)
114 auto len = stream.size();
116 size_t available = getBufferFilled();
117 auto num = narrow<unsigned>(
std::min(len, available));
118 if ((readIdx + num) < mixBufferSize) {
119 ranges::copy(std::span{&mixBuffer[readIdx], num}, stream);
122 unsigned len1 = mixBufferSize - readIdx;
123 ranges::copy(std::span{&mixBuffer[readIdx], len1}, stream);
124 unsigned len2 = num - len1;
125 ranges::copy(std::span{&mixBuffer[0], len2}, stream.subspan(len1));
128 auto missing = narrow_cast<ptrdiff_t>(len - available);
137 SDL_LockAudioDevice(deviceID);
138 unsigned free = getBufferFree();
139 if (buffer.size() > free) {
141 if (board && !board->getMSXMixer().isSynchronousMode() &&
144 SDL_UnlockAudioDevice(deviceID);
146 SDL_LockAudioDevice(deviceID);
147 board->getRealTime().resync();
148 free = getBufferFree();
149 }
while (buffer.size() > free);
152 buffer = buffer.subspan(0, free);
155 assert(buffer.size() <= free);
156 if ((writeIdx + buffer.size()) < mixBufferSize) {
158 writeIdx += narrow<unsigned>(buffer.size());
160 unsigned len1 = mixBufferSize - writeIdx;
161 ranges::copy(buffer.subspan(0, len1), &mixBuffer[writeIdx]);
162 unsigned len2 = narrow<unsigned>(buffer.size()) - len1;
163 ranges::copy(buffer.subspan(len1, len2), &mixBuffer[0]);
167 SDL_UnlockAudioDevice(deviceID);
ThrottleManager & getThrottleManager()
Contains the main loop of openMSX.
GlobalSettings & getGlobalSettings()
MSXMotherBoard * getMotherBoard() const
void uploadBuffer(std::span< const StereoFloat > buffer) override
void unmute() override
Unmute the sound system.
void mute() override
Mute the sound system.
~SDLSoundDriver() override
unsigned getFrequency() const override
Returns the actual sample frequency.
SDLSoundDriver(const SDLSoundDriver &)=delete
unsigned getSamples() const override
Get the number of samples that should be created 'per fragment'.
bool isThrottled() const
Ask if throttling is enabled.
constexpr vecN< N, T > min(const vecN< N, T > &x, const vecN< N, T > &y)
void sleep(uint64_t us)
Sleep for the specified amount of time (in us).
This file implemented 3 utility functions:
constexpr void fill(ForwardRange &&range, const T &value)
auto copy(InputRange &&range, OutputIter out)
constexpr auto subspan(Range &&range, size_t offset, size_t count=std::dynamic_extent)