snes9x/common/audio/s9x_sound_driver_sdl.cpp

110 lines
2.6 KiB
C++

/*****************************************************************************\
Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
This file is licensed under the Snes9x License.
For further information, consult the LICENSE file in the root directory.
\*****************************************************************************/
#include "s9x_sound_driver_sdl.hpp"
#include "SDL_audio.h"
bool S9xSDLSoundDriver::write_samples(int16_t *data, int samples)
{
bool retval = true;
auto empty = buffer.space_empty();
if (samples > empty)
{
retval = false;
buffer.dump(buffer.buffer_size / 2 - empty);
}
buffer.push(data, samples);
return retval;
}
void S9xSDLSoundDriver::mix(unsigned char *output, int bytes)
{
if (buffer.avail() >= bytes >> 1)
buffer.read((int16_t *)output, bytes >> 1);
else
{
buffer.read((int16_t *)output, buffer.avail());
buffer.add_silence(buffer.buffer_size / 2);
}
}
S9xSDLSoundDriver::S9xSDLSoundDriver()
{
}
S9xSDLSoundDriver::~S9xSDLSoundDriver()
{
deinit();
}
void S9xSDLSoundDriver::init()
{
SDL_InitSubSystem(SDL_INIT_AUDIO);
stop();
}
void S9xSDLSoundDriver::deinit()
{
stop();
SDL_CloseAudio();
SDL_QuitSubSystem(SDL_INIT_AUDIO);
}
void S9xSDLSoundDriver::start()
{
SDL_PauseAudio(0);
}
void S9xSDLSoundDriver::stop()
{
SDL_PauseAudio(1);
}
bool S9xSDLSoundDriver::open_device(int playback_rate, int buffer_size)
{
audiospec = {};
audiospec.freq = playback_rate;
audiospec.channels = 2;
audiospec.format = AUDIO_S16SYS;
audiospec.samples = audiospec.freq * buffer_size / 8 / 1000; // 1/8th buffer per callback
audiospec.callback = [](void *userdata, uint8_t *stream, int len) {
((S9xSDLSoundDriver *)userdata)->mix((unsigned char *)stream, len);
};
audiospec.userdata = this;
printf("SDL sound driver initializing...\n");
printf(" --> (Frequency: %dhz, Latency: %dms)...",
audiospec.freq,
(audiospec.samples * 1000 / audiospec.freq));
if (SDL_OpenAudio(&audiospec, NULL) < 0)
{
printf("Failed\n");
return false;
}
printf("OK\n");
if (buffer_size < 32)
buffer_size = 32;
buffer.resize(buffer_size * 4 * audiospec.freq / 1000);
return true;
}
int S9xSDLSoundDriver::space_free()
{
auto space_empty = buffer.space_empty();
return space_empty;
}
std::pair<int, int> S9xSDLSoundDriver::buffer_level()
{
std::pair<int, int> level = { buffer.space_empty(), buffer.buffer_size };
return level;
}