view src/audio/mme/SDL_mmeaudio.c @ 3469:8c5fb2a3b11d

RenderReadPixels and RenderWritePixels functions work with back buffer now and all asynchronous operations are flushed before reading or writing to backbuffer. Thanks Sam for clarification of this.
author Mike Gorchak <lestat@i.com.ua>
date Sat, 21 Nov 2009 06:17:50 +0000
parents 99210400e8b9
children f7b03b6838cb
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 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];

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_OpenDevice(_THIS, const char *devname, int iscapture)
{
    int valid_format = 0;
    MMRESULT result;
    Uint8 *mixbuf = NULL;
    int i;

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

    /* Set basic WAVE format parameters */
    this->hidden->shm = mmeAllocMem(sizeof(*this->hidden->shm));
    if (this->hidden->shm == NULL) {
        MME_CloseDevice(this);
        SDL_OutOfMemory();
        return 0;
    }

    SDL_memset(this->hidden->shm, '\0', sizeof(*this->hidden->shm));
    this->hidden->shm->sound = 0;
    this->hidden->shm->wFmt.wf.wFormatTag = WAVE_FORMAT_PCM;

    /* Determine the audio parameters from the AudioSpec */
    /* Try for a closest match on audio format */
    for (test_format = SDL_FirstAudioFormat(this->spec.format);
         !valid_format && test_format;) {
        valid_format = 1;
        switch (test_format) {
        case AUDIO_U8:
        case AUDIO_S16:
        case AUDIO_S32:
            break;
        default:
            valid_format = 0;
            test_format = SDL_NextAudioFormat();
        }
    }

    if (!valid_format) {
        MME_CloseDevice(this);
        SDL_SetError("Unsupported audio format");
        return 0;
    }

    this->spec.format = test_format;
    this->hidden->shm->wFmt.wBitsPerSample = SDL_AUDIO_BITSIZE(test_format);

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

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

    /* Update the fragment size as size in bytes */
    SDL_CalculateAudioSpec(&this->spec);

    /* Open the audio device */
    result = waveOutOpen(&(this->hidden->shm->sound),
                         WAVE_MAPPER,
                         &(this->hidden->shm->wFmt.wf),
                         MME_Callback,
                         NULL, (CALLBACK_FUNCTION | WAVE_OPEN_SHAREABLE));
    if (result != MMSYSERR_NOERROR) {
        MME_CloseDevice(this);
        SetMMerror("waveOutOpen()", result);
        return 0;
    }

    /* Create the sound buffers */
    mixbuf = (Uint8 *) mmeAllocBuffer(NUM_BUFFERS * (this->spec.size));
    if (mixbuf == NULL) {
        MME_CloseDevice(this);
        SDL_OutOfMemory();
        return 0;
    }
    this->hidden->mixbuf = mixbuf;

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

    return 1;
}

static void
MME_WaitDevice(_THIS)
{
    while (inUse[this->hidden->next_buffer]) {
        mmeWaitForCallbacks();
        mmeProcessCallbacks();
    }
}

static Uint8 *
MME_GetDeviceBuf(_THIS)
{
    void *retval = this->hidden->shm->wHdr[this->hidden->next_buffer].lpData;
    inUse[this->hidden->next_buffer] = TRUE;
    return (Uint8 *) retval;
}

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

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

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

static void
MME_CloseDevice(_THIS)
{
    if (this->hidden != NULL) {
        MMRESULT result;

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

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

        SDL_free(this->hidden);
        this->hidden = NULL;
    }
}

static int
MME_Init(SDL_AudioDriverImpl * impl)
{
    /* Set the function pointers */
    impl->OpenDevice = MME_OpenDevice;
    impl->WaitDevice = MME_WaitDevice;
    impl->WaitDone = MME_WaitDone;
    impl->PlayDevice = MME_PlayDevice;
    impl->GetDeviceBuf = MME_GetDeviceBuf;
    impl->CloseDevice = MME_CloseDevice;
    impl->OnlyHasDefaultOutputDevice = 1;

    return 1;
}

/* !!! FIXME: Windows "windib" driver is called waveout, too */
AudioBootStrap MMEAUDIO_bootstrap = {
    "waveout", "Tru64 MME WaveOut", MME_Init, 0
};

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