view src/audio/windib/SDL_dibaudio.c @ 3798:c8b3d3d13ed1 SDL-ryan-multiple-audio-device

Audio bootstraps can now specify that a driver is only to be used if explicitly requested (for things like the "disk" driver that is always available but you would never want to default to using). Trimmed out code that can be handled by stubs in the core. The "dummy" driver is pretty damned small now. :)
author Ryan C. Gordon <icculus@icculus.org>
date Wed, 04 Oct 2006 21:27:53 +0000
parents a5d0758f88d8
children 3479f939987c
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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 a raw mixing buffer */

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <mmsystem.h>

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "SDL_dibaudio.h"
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
#include "win_ce_semaphore.h"
#endif


/* Audio driver functions */
static int DIB_OpenAudio(_THIS, SDL_AudioSpec * spec);
static void DIB_ThreadInit(_THIS);
static void DIB_WaitAudio(_THIS);
static Uint8 *DIB_GetAudioBuf(_THIS);
static void DIB_PlayAudio(_THIS);
static void DIB_WaitDone(_THIS);
static void DIB_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 = DIB_OpenAudio;
    this->ThreadInit = DIB_ThreadInit;
    this->WaitAudio = DIB_WaitAudio;
    this->PlayAudio = DIB_PlayAudio;
    this->GetAudioBuf = DIB_GetAudioBuf;
    this->WaitDone = DIB_WaitDone;
    this->CloseAudio = DIB_CloseAudio;

    this->free = Audio_DeleteDevice;

    return this;
}

AudioBootStrap WAVEOUT_bootstrap = {
    "waveout", "Win95/98/NT/2000 WaveOut",
    Audio_Available, Audio_CreateDevice, 0
};


/* The Win32 callback for filling the WAVE device */
static void CALLBACK
FillSound(HWAVEOUT hwo, UINT uMsg, DWORD_PTR dwInstance,
          DWORD dwParam1, DWORD dwParam2)
{
    SDL_AudioDevice *this = (SDL_AudioDevice *) dwInstance;

    /* Only service "buffer done playing" messages */
    if (uMsg != WOM_DONE)
        return;

    /* Signal that we are done playing a buffer */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    ReleaseSemaphoreCE(audio_sem, 1, NULL);
#else
    ReleaseSemaphore(audio_sem, 1, NULL);
#endif
}

static void
SetMMerror(char *function, MMRESULT code)
{
    size_t len;
    char errbuf[MAXERRORLENGTH];
#ifdef _WIN32_WCE
    wchar_t werrbuf[MAXERRORLENGTH];
#endif

    SDL_snprintf(errbuf, SDL_arraysize(errbuf), "%s: ", function);
    len = SDL_strlen(errbuf);

#ifdef _WIN32_WCE
    /* UNICODE version */
    waveOutGetErrorText(code, werrbuf, MAXERRORLENGTH - len);
    WideCharToMultiByte(CP_ACP, 0, werrbuf, -1, errbuf + len,
                        MAXERRORLENGTH - len, NULL, NULL);
#else
    waveOutGetErrorText(code, errbuf + len, (UINT) (MAXERRORLENGTH - len));
#endif

    SDL_SetError("%s", errbuf);
}

/* Set high priority for the audio thread */
static void
DIB_ThreadInit(_THIS)
{
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
}

void
DIB_WaitAudio(_THIS)
{
    /* Wait for an audio chunk to finish */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    WaitForSemaphoreCE(audio_sem, INFINITE);
#else
    WaitForSingleObject(audio_sem, INFINITE);
#endif
}

Uint8 *
DIB_GetAudioBuf(_THIS)
{
    Uint8 *retval;

    retval = (Uint8 *) (wavebuf[next_buffer].lpData);
    return retval;
}

void
DIB_PlayAudio(_THIS)
{
    /* Queue it up */
    waveOutWrite(sound, &wavebuf[next_buffer], sizeof(wavebuf[0]));
    next_buffer = (next_buffer + 1) % NUM_BUFFERS;
}

void
DIB_WaitDone(_THIS)
{
    int i, left;

    do {
        left = NUM_BUFFERS;
        for (i = 0; i < NUM_BUFFERS; ++i) {
            if (wavebuf[i].dwFlags & WHDR_DONE) {
                --left;
            }
        }
        if (left > 0) {
            SDL_Delay(100);
        }
    }
    while (left > 0);
}

void
DIB_CloseAudio(_THIS)
{
    int i;

    /* Close up audio */
    if (audio_sem) {
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
        CloseSynchHandle(audio_sem);
#else
        CloseHandle(audio_sem);
#endif
    }
    if (sound) {
        waveOutClose(sound);
    }

    /* Clean up mixing buffers */
    for (i = 0; i < NUM_BUFFERS; ++i) {
        if (wavebuf[i].dwUser != 0xFFFF) {
            waveOutUnprepareHeader(sound, &wavebuf[i], sizeof(wavebuf[i]));
            wavebuf[i].dwUser = 0xFFFF;
        }
    }
    /* Free raw mixing buffer */
    if (mixbuf != NULL) {
        SDL_free(mixbuf);
        mixbuf = NULL;
    }
}

int
DIB_OpenAudio(_THIS, SDL_AudioSpec * spec)
{
    MMRESULT result;
    int i;
    WAVEFORMATEX waveformat;

    /* Initialize the wavebuf structures for closing */
    sound = NULL;
    audio_sem = NULL;
    for (i = 0; i < NUM_BUFFERS; ++i)
        wavebuf[i].dwUser = 0xFFFF;
    mixbuf = NULL;

    /* Set basic WAVE format parameters */
    SDL_memset(&waveformat, 0, sizeof(waveformat));
    waveformat.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;
        waveformat.wBitsPerSample = 8;
        break;
    case 16:
        /* Signed 16 bit audio data */
        spec->format = AUDIO_S16;
        waveformat.wBitsPerSample = 16;
        break;
    case 32:
        /* Signed 32 bit audio data */
        spec->format = AUDIO_S32;
        waveformat.wBitsPerSample = 32;
        break;
    default:
        SDL_SetError("Unsupported audio format");
        return (-1);
    }
    waveformat.nChannels = spec->channels;
    waveformat.nSamplesPerSec = spec->freq;
    waveformat.nBlockAlign =
        waveformat.nChannels * (waveformat.wBitsPerSample / 8);
    waveformat.nAvgBytesPerSec =
        waveformat.nSamplesPerSec * waveformat.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(&sound, WAVE_MAPPER, &waveformat,
                         (DWORD_PTR) FillSound, (DWORD_PTR) this,
                         CALLBACK_FUNCTION);
    if (result != MMSYSERR_NOERROR) {
        SetMMerror("waveOutOpen()", result);
        return (-1);
    }
#ifdef SOUND_DEBUG
    /* Check the sound device we retrieved */
    {
        WAVEOUTCAPS caps;

        result = waveOutGetDevCaps((UINT) sound, &caps, sizeof(caps));
        if (result != MMSYSERR_NOERROR) {
            SetMMerror("waveOutGetDevCaps()", result);
            return (-1);
        }
        printf("Audio device: %s\n", caps.szPname);
    }
#endif

    /* Create the audio buffer semaphore */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    audio_sem = CreateSemaphoreCE(NULL, NUM_BUFFERS - 1, NUM_BUFFERS, NULL);
#else
    audio_sem = CreateSemaphore(NULL, NUM_BUFFERS - 1, NUM_BUFFERS, NULL);
#endif
    if (audio_sem == NULL) {
        SDL_SetError("Couldn't create semaphore");
        return (-1);
    }

    /* Create the sound buffers */
    mixbuf = (Uint8 *) SDL_malloc(NUM_BUFFERS * spec->size);
    if (mixbuf == NULL) {
        SDL_SetError("Out of memory");
        return (-1);
    }
    for (i = 0; i < NUM_BUFFERS; ++i) {
        SDL_memset(&wavebuf[i], 0, sizeof(wavebuf[i]));
        wavebuf[i].lpData = (LPSTR) & mixbuf[i * spec->size];
        wavebuf[i].dwBufferLength = spec->size;
        wavebuf[i].dwFlags = WHDR_DONE;
        result = waveOutPrepareHeader(sound, &wavebuf[i], sizeof(wavebuf[i]));
        if (result != MMSYSERR_NOERROR) {
            SetMMerror("waveOutPrepareHeader()", result);
            return (-1);
        }
    }

    /* Ready to go! */
    next_buffer = 0;
    return (0);
}

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