src/audio/arts/SDL_artsaudio.c
author Ryan C. Gordon <icculus@icculus.org>
Thu, 24 Aug 2006 12:10:46 +0000
changeset 1982 3b4ce57c6215
parent 1895 c121d94672cb
child 2049 5f6550e5184f
child 3798 c8b3d3d13ed1
permissions -rw-r--r--
First shot at new audio data types (int32 and float32). Notable changes: - Converters between types are autogenerated. Instead of making multiple passes over the data with seperate filters for endianess, size, signedness, etc, converting between data types is always one specialized filter. This simplifies SDL_BuildAudioCVT(), which otherwise had a million edge cases with the new types, and makes the actually conversions more CPU cache friendly. Left a stub for adding specific optimized versions of these routines (SSE/MMX/Altivec, assembler, etc) - Autogenerated converters are built by SDL/src/audio/sdlgenaudiocvt.pl. This does not need to be run unless tweaking the code, and thus doesn't need integration into the build system. - Went through all the drivers and tried to weed out all the "Uint16" references that are better specified with the new SDL_AudioFormat typedef. - Cleaned out a bunch of hardcoded bitwise magic numbers and replaced them with new SDL_AUDIO_* macros. - Added initial float32 and int32 support code. Theoretically, existing drivers will push these through converters to get the data they want to feed to the hardware. Still TODO: - Optimize and debug new converters. - Update the CoreAudio backend to accept float32 data directly. - Other backends, too? - SDL_LoadWAV() needs to be updated to support int32 and float32 .wav files (both of which exist and can be generated by 'sox' for testing purposes). - Update the mixer to handle new datatypes. - Optionally update SDL_sound and SDL_mixer, etc.

/*
    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 a raw mixing buffer */

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "../SDL_audiodev_c.h"
#include "SDL_artsaudio.h"

#ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC
#include "SDL_name.h"
#include "SDL_loadso.h"
#else
#define SDL_NAME(X)	X
#endif

/* The tag name used by artsc audio */
#define ARTS_DRIVER_NAME         "arts"

/* Audio driver functions */
static int ARTS_OpenAudio(_THIS, SDL_AudioSpec * spec);
static void ARTS_WaitAudio(_THIS);
static void ARTS_PlayAudio(_THIS);
static Uint8 *ARTS_GetAudioBuf(_THIS);
static void ARTS_CloseAudio(_THIS);

#ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC

static const char *arts_library = SDL_AUDIO_DRIVER_ARTS_DYNAMIC;
static void *arts_handle = NULL;
static int arts_loaded = 0;

static int (*SDL_NAME(arts_init)) (void);
static void (*SDL_NAME(arts_free)) (void);
static arts_stream_t(*SDL_NAME(arts_play_stream)) (int rate, int bits,
                                                   int channels,
                                                   const char *name);
static int (*SDL_NAME(arts_stream_set)) (arts_stream_t s,
                                         arts_parameter_t param, int value);
static int (*SDL_NAME(arts_stream_get)) (arts_stream_t s,
                                         arts_parameter_t param);
static int (*SDL_NAME(arts_write)) (arts_stream_t s, const void *buffer,
                                    int count);
static void (*SDL_NAME(arts_close_stream)) (arts_stream_t s);

static struct
{
    const char *name;
    void **func;
} arts_functions[] = {
    {
    "arts_init", (void **) &SDL_NAME(arts_init)}, {
    "arts_free", (void **) &SDL_NAME(arts_free)}, {
    "arts_play_stream", (void **) &SDL_NAME(arts_play_stream)}, {
    "arts_stream_set", (void **) &SDL_NAME(arts_stream_set)}, {
    "arts_stream_get", (void **) &SDL_NAME(arts_stream_get)}, {
    "arts_write", (void **) &SDL_NAME(arts_write)}, {
"arts_close_stream", (void **) &SDL_NAME(arts_close_stream)},};

static void
UnloadARTSLibrary()
{
    if (arts_loaded) {
        SDL_UnloadObject(arts_handle);
        arts_handle = NULL;
        arts_loaded = 0;
    }
}

static int
LoadARTSLibrary(void)
{
    int i, retval = -1;

    arts_handle = SDL_LoadObject(arts_library);
    if (arts_handle) {
        arts_loaded = 1;
        retval = 0;
        for (i = 0; i < SDL_arraysize(arts_functions); ++i) {
            *arts_functions[i].func =
                SDL_LoadFunction(arts_handle, arts_functions[i].name);
            if (!*arts_functions[i].func) {
                retval = -1;
                UnloadARTSLibrary();
                break;
            }
        }
    }
    return retval;
}

#else

static void
UnloadARTSLibrary()
{
    return;
}

static int
LoadARTSLibrary(void)
{
    return 0;
}

#endif /* SDL_AUDIO_DRIVER_ARTS_DYNAMIC */

/* Audio driver bootstrap functions */

static int
Audio_Available(void)
{
    int available = 0;

    if (LoadARTSLibrary() < 0) {
        return available;
    }
    if (SDL_NAME(arts_init) () == 0) {
#define ARTS_CRASH_HACK         /* Play a stream so aRts doesn't crash */
#ifdef ARTS_CRASH_HACK
        arts_stream_t stream2;
        stream2 = SDL_NAME(arts_play_stream) (44100, 16, 2, "SDL");
        SDL_NAME(arts_write) (stream2, "", 0);
        SDL_NAME(arts_close_stream) (stream2);
#endif
        available = 1;
        SDL_NAME(arts_free) ();
    }
    UnloadARTSLibrary();

    return available;
}

static void
Audio_DeleteDevice(SDL_AudioDevice * device)
{
    SDL_free(device->hidden);
    SDL_free(device);
    UnloadARTSLibrary();
}

static SDL_AudioDevice *
Audio_CreateDevice(int devindex)
{
    SDL_AudioDevice *this;

    /* Initialize all variables that we clean on shutdown */
    LoadARTSLibrary();
    this = (SDL_AudioDevice *) SDL_malloc(sizeof(SDL_AudioDevice));
    if (this) {
        SDL_memset(this, 0, (sizeof *this));
        this->hidden = (struct SDL_PrivateAudioData *)
            SDL_malloc((sizeof *this->hidden));
    }
    if ((this == NULL) || (this->hidden == NULL)) {
        SDL_OutOfMemory();
        if (this) {
            SDL_free(this);
        }
        return (0);
    }
    SDL_memset(this->hidden, 0, (sizeof *this->hidden));
    stream = 0;

    /* Set the function pointers */
    this->OpenAudio = ARTS_OpenAudio;
    this->WaitAudio = ARTS_WaitAudio;
    this->PlayAudio = ARTS_PlayAudio;
    this->GetAudioBuf = ARTS_GetAudioBuf;
    this->CloseAudio = ARTS_CloseAudio;

    this->free = Audio_DeleteDevice;

    return this;
}

AudioBootStrap ARTS_bootstrap = {
    ARTS_DRIVER_NAME, "Analog Realtime Synthesizer",
    Audio_Available, Audio_CreateDevice
};

/* This function waits until it is possible to write a full sound buffer */
static void
ARTS_WaitAudio(_THIS)
{
    Sint32 ticks;

    /* Check to see if the thread-parent process is still alive */
    {
        static int cnt = 0;
        /* Note that this only works with thread implementations 
           that use a different process id for each thread.
         */
        if (parent && (((++cnt) % 10) == 0)) {  /* Check every 10 loops */
            if (kill(parent, 0) < 0) {
                this->enabled = 0;
            }
        }
    }

    /* Use timer for general audio synchronization */
    ticks = ((Sint32) (next_frame - SDL_GetTicks())) - FUDGE_TICKS;
    if (ticks > 0) {
        SDL_Delay(ticks);
    }
}

static void
ARTS_PlayAudio(_THIS)
{
    int written;

    /* Write the audio data */
    written = SDL_NAME(arts_write) (stream, mixbuf, mixlen);

    /* If timer synchronization is enabled, set the next write frame */
    if (frame_ticks) {
        next_frame += frame_ticks;
    }

    /* If we couldn't write, assume fatal error for now */
    if (written < 0) {
        this->enabled = 0;
    }
#ifdef DEBUG_AUDIO
    fprintf(stderr, "Wrote %d bytes of audio data\n", written);
#endif
}

static Uint8 *
ARTS_GetAudioBuf(_THIS)
{
    return (mixbuf);
}

static void
ARTS_CloseAudio(_THIS)
{
    if (mixbuf != NULL) {
        SDL_FreeAudioMem(mixbuf);
        mixbuf = NULL;
    }
    if (stream) {
        SDL_NAME(arts_close_stream) (stream);
        stream = 0;
    }
    SDL_NAME(arts_free) ();
}

static int
ARTS_OpenAudio(_THIS, SDL_AudioSpec * spec)
{
    int bits, frag_spec;
    SDL_AudioFormat test_format, format;

    /* Reset the timer synchronization flag */
    frame_ticks = 0.0;

    mixbuf = NULL;

    /* Try for a closest match on audio format */
    format = 0;
    bits = 0;
    for (test_format = SDL_FirstAudioFormat(spec->format);
         !format && test_format;) {
#ifdef DEBUG_AUDIO
        fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
#endif
        switch (test_format) {
        case AUDIO_U8:
            bits = 8;
            format = 1;
            break;
        case AUDIO_S16LSB:
            bits = 16;
            format = 1;
            break;
        default:
            format = 0;
            break;
        }
        if (!format) {
            test_format = SDL_NextAudioFormat();
        }
    }
    if (format == 0) {
        SDL_SetError("Couldn't find any hardware audio formats");
        return (-1);
    }
    spec->format = test_format;

    if (SDL_NAME(arts_init) () != 0) {
        SDL_SetError("Unable to initialize ARTS");
        return (-1);
    }
    stream =
        SDL_NAME(arts_play_stream) (spec->freq, bits, spec->channels, "SDL");

    /* Calculate the final parameters for this audio specification */
    SDL_CalculateAudioSpec(spec);

    /* Determine the power of two of the fragment size */
    for (frag_spec = 0; (0x01 << frag_spec) < spec->size; ++frag_spec);
    if ((0x01 << frag_spec) != spec->size) {
        SDL_SetError("Fragment size must be a power of two");
        return (-1);
    }
    frag_spec |= 0x00020000;    /* two fragments, for low latency */

#ifdef ARTS_P_PACKET_SETTINGS
    SDL_NAME(arts_stream_set) (stream, ARTS_P_PACKET_SETTINGS, frag_spec);
#else
    SDL_NAME(arts_stream_set) (stream, ARTS_P_PACKET_SIZE,
                               frag_spec & 0xffff);
    SDL_NAME(arts_stream_set) (stream, ARTS_P_PACKET_COUNT, frag_spec >> 16);
#endif
    spec->size = SDL_NAME(arts_stream_get) (stream, ARTS_P_PACKET_SIZE);

    /* Allocate mixing buffer */
    mixlen = spec->size;
    mixbuf = (Uint8 *) SDL_AllocAudioMem(mixlen);
    if (mixbuf == NULL) {
        return (-1);
    }
    SDL_memset(mixbuf, spec->silence, spec->size);

    /* Get the parent process id (we're the parent of the audio thread) */
    parent = getpid();

    /* We're ready to rock and roll. :-) */
    return (0);
}

/* vi: set ts=4 sw=4 expandtab: */