view src/audio/mme/SDL_mmeaudio.c @ 3818:49eadd6e8962 SDL-ryan-multiple-audio-device

Mangled ALSA dynamic loading...static loading will still work if you have the right libraries, but this is expected to break in general cases as we start dealing with different symbol versions, etc (but may work with, say, distro-specific packages, etc).
author Ryan C. Gordon <icculus@icculus.org>
date Fri, 06 Oct 2006 19:45:11 +0000
parents c8b3d3d13ed1
children 1806fd1acba4
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

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

/* Tru64 UNIX MME support */
#include <mme_api.h>

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "SDL_mmeaudio.h"

static BOOL inUse[NUM_BUFFERS];

/* Audio driver functions */
static int MME_OpenAudio(_THIS, SDL_AudioSpec * spec);
static void MME_WaitAudio(_THIS);
static Uint8 *MME_GetAudioBuf(_THIS);
static void MME_PlayAudio(_THIS);
static void MME_WaitDone(_THIS);
static void MME_CloseAudio(_THIS);

/* Audio driver bootstrap functions */
static int
Audio_Available(void)
{
    return (1);
}

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

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

/* Initialize all variables that we clean on shutdown */
    this = SDL_malloc(sizeof(SDL_AudioDevice));
    if (this) {
        SDL_memset(this, 0, (sizeof *this));
        this->hidden = 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 = MME_OpenAudio;
    this->WaitAudio = MME_WaitAudio;
    this->PlayAudio = MME_PlayAudio;
    this->GetAudioBuf = MME_GetAudioBuf;
    this->WaitDone = MME_WaitDone;
    this->CloseAudio = MME_CloseAudio;
    this->free = Audio_DeleteDevice;

    return this;
}

AudioBootStrap MMEAUDIO_bootstrap = {
    "waveout", "Tru64 MME WaveOut",
    Audio_Available, Audio_CreateDevice, 0
};

static void
SetMMerror(char *function, MMRESULT code)
{
    int len;
    char errbuf[MAXERRORLENGTH];

    SDL_snprintf(errbuf, SDL_arraysize(errbuf), "%s: ", function);
    len = SDL_strlen(errbuf);
    waveOutGetErrorText(code, errbuf + len, MAXERRORLENGTH - len);
    SDL_SetError("%s", errbuf);
}

static void CALLBACK
MME_CALLBACK(HWAVEOUT hwo,
             UINT uMsg, DWORD dwInstance, LPARAM dwParam1, LPARAM dwParam2)
{
    WAVEHDR *wp = (WAVEHDR *) dwParam1;

    if (uMsg == WOM_DONE)
        inUse[wp->dwUser] = FALSE;
}

static int
MME_OpenAudio(_THIS, SDL_AudioSpec * spec)
{
    MMRESULT result;
    int i;

    mixbuf = NULL;

    /* Set basic WAVE format parameters */
    shm = mmeAllocMem(sizeof(*shm));
    if (shm == NULL) {
        SDL_SetError("Out of memory: shm");
        return (-1);
    }
    shm->sound = 0;
    shm->wFmt.wf.wFormatTag = WAVE_FORMAT_PCM;

    /* Determine the audio parameters from the AudioSpec */
    switch (SDL_AUDIO_BITSIZE(spec->format)) {
    case 8:
        /* Unsigned 8 bit audio data */
        spec->format = AUDIO_U8;
        shm->wFmt.wBitsPerSample = 8;
        break;
    case 16:
        /* Signed 16 bit audio data */
        spec->format = AUDIO_S16;
        shm->wFmt.wBitsPerSample = 16;
        break;
    case 32:
        /* Signed 32 bit audio data */
        spec->format = AUDIO_S32;
        shm->wFmt.wBitsPerSample = 32;
        break;
    default:
        SDL_SetError("Unsupported audio format");
        return (-1);
    }

    /* !!! FIXME: Can this handle more than stereo? */
    shm->wFmt.wf.nChannels = spec->channels;
    shm->wFmt.wf.nSamplesPerSec = spec->freq;
    shm->wFmt.wf.nBlockAlign =
        shm->wFmt.wf.nChannels * shm->wFmt.wBitsPerSample / 8;
    shm->wFmt.wf.nAvgBytesPerSec =
        shm->wFmt.wf.nSamplesPerSec * shm->wFmt.wf.nBlockAlign;

    /* Check the buffer size -- minimum of 1/4 second (word aligned) */
    if (spec->samples < (spec->freq / 4))
        spec->samples = ((spec->freq / 4) + 3) & ~3;

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

    /* Open the audio device */
    result = waveOutOpen(&(shm->sound),
                         WAVE_MAPPER,
                         &(shm->wFmt.wf),
                         MME_CALLBACK,
                         NULL, (CALLBACK_FUNCTION | WAVE_OPEN_SHAREABLE));
    if (result != MMSYSERR_NOERROR) {
        SetMMerror("waveOutOpen()", result);
        return (-1);
    }

    /* Create the sound buffers */
    mixbuf = (Uint8 *) mmeAllocBuffer(NUM_BUFFERS * (spec->size));
    if (mixbuf == NULL) {
        SDL_SetError("Out of memory: mixbuf");
        return (-1);
    }

    for (i = 0; i < NUM_BUFFERS; i++) {
        shm->wHdr[i].lpData = &mixbuf[i * (spec->size)];
        shm->wHdr[i].dwBufferLength = spec->size;
        shm->wHdr[i].dwFlags = 0;
        shm->wHdr[i].dwUser = i;
        shm->wHdr[i].dwLoops = 0;       /* loop control counter */
        shm->wHdr[i].lpNext = NULL;     /* reserved for driver */
        shm->wHdr[i].reserved = 0;
        inUse[i] = FALSE;
    }
    next_buffer = 0;
    return 0;
}

static void
MME_WaitAudio(_THIS)
{
    while (inUse[next_buffer]) {
        mmeWaitForCallbacks();
        mmeProcessCallbacks();
    }
}

static Uint8 *
MME_GetAudioBuf(_THIS)
{
    Uint8 *retval;

    inUse[next_buffer] = TRUE;
    retval = (Uint8 *) (shm->wHdr[next_buffer].lpData);
    return retval;
}

static void
MME_PlayAudio(_THIS)
{
    /* Queue it up */
    waveOutWrite(shm->sound, &(shm->wHdr[next_buffer]), sizeof(WAVEHDR));
    next_buffer = (next_buffer + 1) % NUM_BUFFERS;
}

static void
MME_WaitDone(_THIS)
{
    MMRESULT result;
    int i;

    if (shm->sound) {
        for (i = 0; i < NUM_BUFFERS; i++)
            while (inUse[i]) {
                mmeWaitForCallbacks();
                mmeProcessCallbacks();
            }
        result = waveOutReset(shm->sound);
        if (result != MMSYSERR_NOERROR)
            SetMMerror("waveOutReset()", result);
        mmeProcessCallbacks();
    }
}

static void
MME_CloseAudio(_THIS)
{
    MMRESULT result;

    if (mixbuf) {
        result = mmeFreeBuffer(mixbuf);
        if (result != MMSYSERR_NOERROR)
            SetMMerror("mmeFreeBuffer", result);
        mixbuf = NULL;
    }

    if (shm) {
        if (shm->sound) {
            result = waveOutClose(shm->sound);
            if (result != MMSYSERR_NOERROR)
                SetMMerror("waveOutClose()", result);
            mmeProcessCallbacks();
        }
        result = mmeFreeMem(shm);
        if (result != MMSYSERR_NOERROR)
            SetMMerror("mmeFreeMem()", result);
        shm = NULL;
    }
}

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