snes9x/gtk/src/gtk_sound_driver_portaudio.cpp

/*****************************************************************************\
     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 "gtk_s9x.h"
#include "gtk_sound_driver_portaudio.h"

static inline int
frames_to_bytes (int frames)
{
    return frames * 4;
}

static void
port_audio_samples_available_callback (void *data)
{
    ((S9xPortAudioSoundDriver *) data)->samples_available ();
}

S9xPortAudioSoundDriver::S9xPortAudioSoundDriver()
{
    audio_stream = NULL;
    sound_buffer = NULL;
    sound_buffer_size = 0;
}

void
S9xPortAudioSoundDriver::init ()
{
    PaError err;

    err = Pa_Initialize ();

    if (err != paNoError)
        fprintf (stderr,
                 "Couldn't initialize PortAudio: %s\n",
                 Pa_GetErrorText (err));
}

void
S9xPortAudioSoundDriver::terminate ()
{
    stop ();

    S9xSetSamplesAvailableCallback (NULL, NULL);

    Pa_Terminate ();

    if (sound_buffer)
    {
        free (sound_buffer);
        sound_buffer = NULL;
    }
}

void
S9xPortAudioSoundDriver::start ()
{
    PaError err;

    if (audio_stream != NULL && !(gui_config->mute_sound))
    {
        if ((Pa_IsStreamActive (audio_stream)))
            return;

        err = Pa_StartStream (audio_stream);

        if (err != paNoError)
        {
            fprintf (stderr, "Error: %s\n", Pa_GetErrorText (err));
        }
    }
}

void
S9xPortAudioSoundDriver::stop ()
{
    if (audio_stream != NULL)
    {
        Pa_StopStream (audio_stream);
    }
}

bool S9xPortAudioSoundDriver::open_device()
{
    PaStreamParameters  param;
    const PaDeviceInfo  *device_info;
    const PaHostApiInfo *hostapi_info;
    PaError             err = paNoError;

    if (audio_stream != NULL)
    {
        printf ("Shutting down sound for reset\n");
        err = Pa_CloseStream (audio_stream);

        if (err != paNoError)
        {
            fprintf (stderr,
                     "Couldn't reset audio stream.\nError: %s\n",
                     Pa_GetErrorText (err));
            return true;
        }

        audio_stream = NULL;
    }

    param.channelCount = 2;
    param.sampleFormat = paInt16;
    param.hostApiSpecificStreamInfo = NULL;

    printf ("PortAudio sound driver initializing...\n");

    for (int i = 0; i < Pa_GetHostApiCount (); i++)
    {
        printf ("    --> ");

        hostapi_info = Pa_GetHostApiInfo (i);
        if (!hostapi_info)
        {
            printf ("Host API #%d has no info\n", i);
            err = paNotInitialized;
            continue;
        }

        device_info = Pa_GetDeviceInfo (hostapi_info->defaultOutputDevice);
        if (!device_info)
        {
            printf ("(%s)...No device info available.\n", hostapi_info->name);
            err = paNotInitialized;
            continue;
        }

        param.device = hostapi_info->defaultOutputDevice;
        param.suggestedLatency = gui_config->sound_buffer_size * 0.001;

        printf ("(%s : %s, latency %dms)...",
                hostapi_info->name,
                device_info->name,
                (int) (param.suggestedLatency * 1000.0));

        fflush (stdout);

        err = Pa_OpenStream (&audio_stream,
                             NULL,
                             &param,
                             Settings.SoundPlaybackRate,
                             0,
                             paNoFlag,
                             NULL,
                             NULL);

        int frames = Pa_GetStreamWriteAvailable (audio_stream);
        output_buffer_size = frames_to_bytes (frames);

        if (err == paNoError)
        {
            printf ("OK\n");
            break;
        }
        else
        {
            printf ("Failed (%s)\n",
                    Pa_GetErrorText (err));
        }
    }

    if (err != paNoError || Pa_GetHostApiCount () < 1)
    {
        fprintf (stderr,
                 "Couldn't initialize sound\n");
        return false;
    }

    S9xSetSamplesAvailableCallback (port_audio_samples_available_callback, this);

    fflush (stdout);
    fflush (stderr);

    return true;
}

void
S9xPortAudioSoundDriver::samples_available ()
{
    int frames;
    int bytes;

    frames = Pa_GetStreamWriteAvailable (audio_stream);

    if (Settings.DynamicRateControl)
    {
        S9xUpdateDynamicRate (frames_to_bytes (frames), output_buffer_size);
    }

    S9xFinalizeSamples ();

    if (Settings.DynamicRateControl)
    {
        // Using rate control, we should always keep the emulator's sound buffers empty to
        // maintain an accurate measurement.
        if (frames < (S9xGetSampleCount () >> 1))
        {
            S9xClearSamples ();
            return;
        }
    }

    frames = MIN (frames, S9xGetSampleCount () >> 1);
    bytes = frames_to_bytes (frames);

    if (sound_buffer_size < bytes || sound_buffer == NULL)
    {
        sound_buffer = (uint8 *) realloc (sound_buffer, bytes);
        sound_buffer_size = bytes;
    }

    S9xMixSamples (sound_buffer, frames << 1);

    Pa_WriteStream (audio_stream, sound_buffer, frames);
}