view src/audio/baudio/SDL_beaudio.cc @ 2364:e321b52dee8f gsoc2008_iphone

These files contain the audio support for iPhone. They are based on the CoreAudio audio driver for Mac OS X. The principle difference is that the iPhone doesn't seem to have a concept of audio devices ... it just has special units for audio in and audio out. Also had to change some functions to versions which seem to only exist on iPhone and will apparently exist in Mac OS X 10.6(!) There is currently no audio recording support -- my iPod Touch doesn't have a microphone to test this with.
author Holmes Futrell <hfutrell@umail.ucsb.edu>
date Fri, 18 Jul 2008 17:53:54 +0000
parents 866052b01ee5
children 99210400e8b9
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Allow access to the audio stream on BeOS */

#include <SoundPlayer.h>

#include "../../main/beos/SDL_BeApp.h"

extern "C"
{

#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "../SDL_sysaudio.h"
#include "../../thread/beos/SDL_systhread_c.h"
#include "SDL_beaudio.h"

}


/* !!! FIXME: have the callback call the higher level to avoid code dupe. */
/* The BeOS callback for handling the audio buffer */
static void
FillSound(void *device, void *stream, size_t len,
          const media_raw_audio_format & format)
{
    SDL_AudioDevice *audio = (SDL_AudioDevice *) device;

    /* Silence the buffer, since it's ours */
    SDL_memset(stream, audio->spec.silence, len);

    /* Only do soemthing if audio is enabled */
    if (!audio->enabled)
        return;

    if (!audio->paused) {
        if (audio->convert.needed) {
            SDL_mutexP(audio->mixer_lock);
            (*audio->spec.callback) (audio->spec.userdata,
                                     (Uint8 *) audio->convert.buf,
                                     audio->convert.len);
            SDL_mutexV(audio->mixer_lock);
            SDL_ConvertAudio(&audio->convert);
            SDL_memcpy(stream, audio->convert.buf, audio->convert.len_cvt);
        } else {
            SDL_mutexP(audio->mixer_lock);
            (*audio->spec.callback) (audio->spec.userdata,
                                     (Uint8 *) stream, len);
            SDL_mutexV(audio->mixer_lock);
        }
    }
}

static void
BEOSAUDIO_CloseDevice(_THIS)
{
    if (_this->hidden != NULL) {
        if (_this->hidden->audio_obj) {
            _this->hidden->audio_obj->Stop();
            delete _this->hidden->audio_obj;
            _this->hidden->audio_obj = NULL;
        }

        delete _this->hidden;
        _this->hidden = NULL;
    }
}

static int
BEOSAUDIO_OpenDevice(_THIS, const char *devname, int iscapture)
{
    int valid_datatype = 0;
    media_raw_audio_format format;
    SDL_AudioFormat test_format = SDL_FirstAudioFormat(_this->spec.format);

    /* Initialize all variables that we clean on shutdown */
    _this->hidden = new SDL_PrivateAudioData;
    if (_this->hidden == NULL) {
        SDL_OutOfMemory();
        return 0;
    }
    SDL_memset(_this->hidden, 0, (sizeof *_this->hidden));

    /* Parse the audio format and fill the Be raw audio format */
    SDL_memset(&format, '\0', sizeof(media_raw_audio_format));
    format.byte_order = B_MEDIA_LITTLE_ENDIAN;
    format.frame_rate = (float) _this->spec.freq;
    format.channel_count = _this->spec.channels;        /* !!! FIXME: support > 2? */
    while ((!valid_datatype) && (test_format)) {
        valid_datatype = 1;
        _this->spec.format = test_format;
        switch (test_format) {
        case AUDIO_S8:
            format.format = media_raw_audio_format::B_AUDIO_CHAR;
            break;

        case AUDIO_U8:
            format.format = media_raw_audio_format::B_AUDIO_UCHAR;
            break;

        case AUDIO_S16LSB:
            format.format = media_raw_audio_format::B_AUDIO_SHORT;
            break;

        case AUDIO_S16MSB:
            format.format = media_raw_audio_format::B_AUDIO_SHORT;
            format.byte_order = B_MEDIA_BIG_ENDIAN;
            break;

        case AUDIO_S32LSB:
            format.format = media_raw_audio_format::B_AUDIO_INT;
            break;

        case AUDIO_S32MSB:
            format.format = media_raw_audio_format::B_AUDIO_INT;
            format.byte_order = B_MEDIA_BIG_ENDIAN;
            break;

        case AUDIO_F32LSB:
            format.format = media_raw_audio_format::B_AUDIO_FLOAT;
            break;

        case AUDIO_F32MSB:
            format.format = media_raw_audio_format::B_AUDIO_FLOAT;
            format.byte_order = B_MEDIA_BIG_ENDIAN;
            break;

        default:
            valid_datatype = 0;
            test_format = SDL_NextAudioFormat();
            break;
        }
    }

    format.buffer_size = _this->spec.samples;

    if (!valid_datatype) {      /* shouldn't happen, but just in case... */
        BEOSAUDIO_CloseDevice(_this);
        SDL_SetError("Unsupported audio format");
        return 0;
    }

    /* Calculate the final parameters for this audio specification */
    SDL_CalculateAudioSpec(&_this->spec);

    /* Subscribe to the audio stream (creates a new thread) */
    sigset_t omask;
    SDL_MaskSignals(&omask);
    _this->hidden->audio_obj = new BSoundPlayer(&format, "SDL Audio",
                                                FillSound, NULL, _this);
    SDL_UnmaskSignals(&omask);

    if (_this->hidden->audio_obj->Start() == B_NO_ERROR) {
        _this->hidden->audio_obj->SetHasData(true);
    } else {
        BEOSAUDIO_CloseDevice(_this);
        SDL_SetError("Unable to start Be audio");
        return 0;
    }

    /* We're running! */
    return 1;
}

static void
BEOSAUDIO_Deinitialize(void)
{
    SDL_QuitBeApp();
}

static int
BEOSAUDIO_Init(SDL_AudioDriverImpl * impl)
{
    /* Initialize the Be Application, if it's not already started */
    if (SDL_InitBeApp() < 0) {
        return 0;
    }

    /* Set the function pointers */
    impl->OpenDevice = BEOSAUDIO_OpenDevice;
    impl->CloseDevice = BEOSAUDIO_CloseDevice;
    impl->Deinitialize = BEOSAUDIO_Deinitialize;
    impl->ProvidesOwnCallbackThread = 1;
    impl->OnlyHasDefaultOutputDevice = 1;

    return 1;
}

extern "C"
{
    extern AudioBootStrap BEOSAUDIO_bootstrap;
}
AudioBootStrap BEOSAUDIO_bootstrap = {
    "baudio", "BeOS BSoundPlayer", BEOSAUDIO_Init, 0
};

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