view src/audio/baudio/SDL_beaudio.cc @ 4001:6831b8723a85 SDL-1.2

Don't initialize the audio buffer passed to the application's audio callback, since they are expected to entirely fill it with data or silence. For legacy apps that might expect the buffer to already have silence and thus may not fill the buffer in the callback, there's an environment variable to expose the old behaviour. Fixes Bugzilla #416.
author Ryan C. Gordon <icculus@icculus.org>
date Thu, 05 Jul 2007 02:24:36 +0000
parents 5b5e549382b3
children a1b03ba2fcd0
line wrap: on
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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 the audio stream on BeOS */

#include <SoundPlayer.h>

#include "../../main/beos/SDL_BeApp.h"

extern "C" {

#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "../SDL_sysaudio.h"
#include "../../thread/beos/SDL_systhread_c.h"
#include "SDL_beaudio.h"


/* Audio driver functions */
static int BE_OpenAudio(_THIS, SDL_AudioSpec *spec);
static void BE_WaitAudio(_THIS);
static void BE_PlayAudio(_THIS);
static Uint8 *BE_GetAudioBuf(_THIS);
static void BE_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 *device;

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

	/* Set the function pointers */
	device->OpenAudio = BE_OpenAudio;
	device->WaitAudio = BE_WaitAudio;
	device->PlayAudio = BE_PlayAudio;
	device->GetAudioBuf = BE_GetAudioBuf;
	device->CloseAudio = BE_CloseAudio;

	device->free = Audio_DeleteDevice;

	return device;
}

AudioBootStrap BAUDIO_bootstrap = {
	"baudio", "BeOS BSoundPlayer",
	Audio_Available, Audio_CreateDevice
};

/* The BeOS callback for handling the audio buffer */
static void FillSound(void *device, void *stream, size_t len, 
					const media_raw_audio_format &format)
{
	SDL_AudioDevice *audio = (SDL_AudioDevice *)device;

	/* Silence the buffer, since it's ours */
	SDL_memset(stream, audio->spec.silence, len);

	/* Only do soemthing if audio is enabled */
	if ( ! audio->enabled )
		return;

	if ( ! audio->paused ) {
		if ( audio->convert.needed ) {
			SDL_mutexP(audio->mixer_lock);
			(*audio->spec.callback)(audio->spec.userdata,
				(Uint8 *)audio->convert.buf,audio->convert.len);
			SDL_mutexV(audio->mixer_lock);
			SDL_ConvertAudio(&audio->convert);
			SDL_memcpy(stream,audio->convert.buf,audio->convert.len_cvt);
		} else {
			SDL_mutexP(audio->mixer_lock);
			(*audio->spec.callback)(audio->spec.userdata,
						(Uint8 *)stream, len);
			SDL_mutexV(audio->mixer_lock);
		}
	}
	return;
}

/* Dummy functions -- we don't use thread-based audio */
void BE_WaitAudio(_THIS)
{
	return;
}
void BE_PlayAudio(_THIS)
{
	return;
}
Uint8 *BE_GetAudioBuf(_THIS)
{
	return(NULL);
}

void BE_CloseAudio(_THIS)
{
	if ( audio_obj ) {
		audio_obj->Stop();
		delete audio_obj;
		audio_obj = NULL;
	}

	/* Quit the Be Application, if there's nothing left to do */
	SDL_QuitBeApp();
}

int BE_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
    int valid_datatype = 0;
    media_raw_audio_format format;
    Uint16 test_format = SDL_FirstAudioFormat(spec->format);

    /* Parse the audio format and fill the Be raw audio format */
    memset(&format, '\0', sizeof (media_raw_audio_format));
    format.byte_order = B_MEDIA_LITTLE_ENDIAN;
    format.frame_rate = (float) spec->freq;
    format.channel_count = spec->channels;  /* !!! FIXME: support > 2? */
    while ((!valid_datatype) && (test_format)) {
        valid_datatype = 1;
        spec->format = test_format;
        switch (test_format) {
            case AUDIO_S8:
                format.format = media_raw_audio_format::B_AUDIO_CHAR;
                break;

            case AUDIO_U8:
                format.format = media_raw_audio_format::B_AUDIO_UCHAR;
                break;

            case AUDIO_S16LSB:
                format.format = media_raw_audio_format::B_AUDIO_SHORT;
                break;

            case AUDIO_S16MSB:
                format.format = media_raw_audio_format::B_AUDIO_SHORT;
                format.byte_order = B_MEDIA_BIG_ENDIAN;
                break;

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

    if (!valid_datatype) { /* shouldn't happen, but just in case... */
        SDL_SetError("Unsupported audio format");
        return (-1);
    }

    /* Initialize the Be Application, if it's not already started */
    if (SDL_InitBeApp() < 0) {
        return (-1);
    }

    format.buffer_size = spec->samples;

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

	/* Subscribe to the audio stream (creates a new thread) */
	{ sigset_t omask;
		SDL_MaskSignals(&omask);
		audio_obj = new BSoundPlayer(&format, "SDL Audio", FillSound,
		                                                 NULL, _this);
		SDL_UnmaskSignals(&omask);
	}
	if ( audio_obj->Start() == B_NO_ERROR ) {
		audio_obj->SetHasData(true);
	} else {
		SDL_SetError("Unable to start Be audio");
		return(-1);
	}

	/* We're running! */
	return(1);
}

};	/* Extern C */