src/audio/dmedia/SDL_irixaudio.c

/*
    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 <errno.h>
#include "SDL_config.h"

/* Allow access to a raw mixing buffer (For IRIX 6.5 and higher) */
/* patch for IRIX 5 by Georg Schwarz 18/07/2004 */

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "SDL_irixaudio.h"


#ifndef AL_RESOURCE             /* as a test whether we use the old IRIX audio libraries */
#define OLD_IRIX_AUDIO
#define alClosePort(x) ALcloseport(x)
#define alFreeConfig(x) ALfreeconfig(x)
#define alGetFillable(x) ALgetfillable(x)
#define alNewConfig() ALnewconfig()
#define alOpenPort(x,y,z) ALopenport(x,y,z)
#define alSetChannels(x,y) ALsetchannels(x,y)
#define alSetQueueSize(x,y) ALsetqueuesize(x,y)
#define alSetSampFmt(x,y) ALsetsampfmt(x,y)
#define alSetWidth(x,y) ALsetwidth(x,y)
#endif

/* Audio driver functions */
static int AL_OpenAudio(_THIS, SDL_AudioSpec * spec);
static void AL_WaitAudio(_THIS);
static void AL_PlayAudio(_THIS);
static Uint8 *AL_GetAudioBuf(_THIS);
static void AL_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int
Audio_Available(void)
{
    return 1;
}

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

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

    /* Initialize all variables that we clean on shutdown */
    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));

    /* Set the function pointers */
    this->OpenAudio = AL_OpenAudio;
    this->WaitAudio = AL_WaitAudio;
    this->PlayAudio = AL_PlayAudio;
    this->GetAudioBuf = AL_GetAudioBuf;
    this->CloseAudio = AL_CloseAudio;

    this->free = Audio_DeleteDevice;

    return this;
}

AudioBootStrap DMEDIA_bootstrap = {
    "AL", "IRIX DMedia audio",
    Audio_Available, Audio_CreateDevice
};


void static
AL_WaitAudio(_THIS)
{
    Sint32 timeleft;

    timeleft = this->spec.samples - alGetFillable(audio_port);
    if (timeleft > 0) {
        timeleft /= (this->spec.freq / 1000);
        SDL_Delay((Uint32) timeleft);
    }
}

static void
AL_PlayAudio(_THIS)
{
    /* Write the audio data out */
    if (alWriteFrames(audio_port, mixbuf, this->spec.samples) < 0) {
        /* Assume fatal error, for now */
        this->enabled = 0;
    }
}

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

static void
AL_CloseAudio(_THIS)
{
    if (mixbuf != NULL) {
        SDL_FreeAudioMem(mixbuf);
        mixbuf = NULL;
    }
    if (audio_port != NULL) {
        alClosePort(audio_port);
        audio_port = NULL;
    }
}

static int
AL_OpenAudio(_THIS, SDL_AudioSpec * spec)
{
    SDL_AudioFormat test_format = SDL_FirstAudioFormat(spec->format);
    long width = 0;
    long fmt = 0;
    int valid = 0;

#ifdef OLD_IRIX_AUDIO
    {
        long audio_param[2];
        audio_param[0] = AL_OUTPUT_RATE;
        audio_param[1] = spec->freq;
        valid = (ALsetparams(AL_DEFAULT_DEVICE, audio_param, 2) < 0);
    }
#else
    {
        ALpv audio_param;
        audio_param.param = AL_RATE;
        audio_param.value.i = spec->freq;
        valid = (alSetParams(AL_DEFAULT_OUTPUT, &audio_param, 1) < 0);
    }
#endif

    while ((!valid) && (test_format)) {
        valid = 1;
        spec->format = test_format;

        switch (test_format) {
            case AUDIO_S8:
                width = AL_SAMPLE_8;
                fmt = AL_SAMPFMT_TWOSCOMP;
                break;

            case AUDIO_S16SYS:
                width = AL_SAMPLE_16;
                fmt = AL_SAMPFMT_TWOSCOMP;
                break;

            case AUDIO_F32SYS:
                width = 0;  /* not used here... */
                fmt = AL_SAMPFMT_FLOAT;
                break;

            /* Docs say there is int24, but not int32.... */

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

        if (valid) {
            ALconfig audio_config = alNewConfig();
            valid = 0;
            if (audio_config) {
                if (alSetChannels(audio_config, spec->channels) < 0) {
                    if (spec->channels > 2) {  /* can't handle > stereo? */
                        spec->channels = 2;  /* try again below. */
                    }
                }

                if ((alSetSampFmt(audio_config, fmt) >= 0) &&
                    ((!width) || (alSetWidth(audio_config, width) >= 0)) &&
                    (alSetQueueSize(audio_config, spec->samples * 2) >= 0) &&
                    (alSetChannels(audio_config, spec->channels) >= 0)) {

                    audio_port = alOpenPort("SDL audio", "w", audio_config);
                    if (audio_port == NULL) {
                        /* docs say AL_BAD_CHANNELS happens here, too. */
                        int err = oserror();
                        if (err == AL_BAD_CHANNELS) {
                            spec->channels = 2;
                            alSetChannels(audio_config, spec->channels);
                            audio_port = alOpenPort("SDL audio", "w",
                                                    audio_config);
                        }
                    }

                    if (audio_port != NULL) {
                        valid = 1;
                    }
                }

                alFreeConfig(audio_config);
            }
        }
    }

    if (!valid) {
        SDL_SetError("Unsupported audio format");
        return (-1);
    }

    /* Update the fragment size as size in bytes */
    SDL_CalculateAudioSpec(spec);

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

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

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