bsnes/ruby/audio/ao.cpp

73 lines
1.8 KiB
C++

#include <ao/ao.h>
struct AudioAO : Audio {
AudioAO() { initialize(); }
~AudioAO() { terminate(); }
auto driver() -> string override { return "libao"; }
auto ready() -> bool override { return _ready; }
auto hasFrequencies() -> bool override { return true; }
auto availableFrequencies() -> vector<double> override {
return {44100.0, 48000.0, 96000.0};
}
auto setFrequency(double frequency) -> bool override {
if(frequency == Audio::frequency()) return true;
if(!Audio::setFrequency(frequency)) return false;
return initialize();
}
auto output(const double samples[]) -> void override {
uint32_t sample = 0;
sample |= (uint16_t)sclamp<16>(samples[0] * 32767.0) << 0;
sample |= (uint16_t)sclamp<16>(samples[1] * 32767.0) << 16;
ao_play(_interface, (char*)&sample, 4);
}
private:
auto initialize() -> bool {
terminate();
ao_initialize();
int driverID = ao_default_driver_id();
if(driverID < 0) return false;
ao_sample_format format;
format.bits = 16;
format.channels = 2;
format.rate = (uint)_frequency;
format.byte_format = AO_FMT_LITTLE;
format.matrix = nullptr;
ao_info* information = ao_driver_info(driverID);
if(!information) return false;
string device = information->short_name;
ao_option* options = nullptr;
if(device == "alsa") {
ao_append_option(&options, "buffer_time", "100000"); //100ms latency (default was 500ms)
}
_interface = ao_open_live(driverID, &format, options);
if(!_interface) return false;
return _ready = true;
}
auto terminate() -> void {
_ready = false;
if(_interface) {
ao_close(_interface);
_interface = nullptr;
}
ao_shutdown();
}
bool _ready = false;
ao_device* _interface = nullptr;
};