Method Beeper

test/browser/test_sdl2_audio_beep.cpp:52–84

void audio_callback(void*, Uint8*, int);

Beeper::Beeper(int frequency_, int numChannels_, int sdlAudioFormat_) {
  phase = 0.0;
  mutedChannel = 1;

  SDL_AudioSpec desiredSpec;

  desiredSpec.freq = frequency_;
  desiredSpec.format = sdlAudioFormat_;
  desiredSpec.channels = numChannels_;
  desiredSpec.samples = 1024; // This is samples per channel.
  desiredSpec.callback = audio_callback;
  desiredSpec.userdata = this;

  SDL_AudioSpec obtainedSpec;

  // you might want to look for errors here
  SDL_OpenAudio(&desiredSpec, &obtainedSpec);

  // In this test, we require *exactly* the identical SDL result that we provide, since we test
  // all various configurations individually.
  if (obtainedSpec.freq != desiredSpec.freq || obtainedSpec.format != desiredSpec.format
    || obtainedSpec.channels != desiredSpec.channels || obtainedSpec.samples != desiredSpec.samples) {
    SDL_CloseAudio();
    throw std::runtime_error("Failed to initialize desired SDL_OpenAudio!");
  }

  frequency = obtainedSpec.freq;
  numChannels = obtainedSpec.channels;
  sdlAudioFormat = obtainedSpec.format;

  // Immediately start producing audio.
  SDL_PauseAudio(0);
}

Beeper::~Beeper() {
  SDL_CloseAudio();