Mercurial > sdl-ios-xcode
view src/audio/baudio/SDL_beaudio.cc @ 765:4c2ba6161939
Editors Note: The original patch was modified to use SDL_Delay() instead of
nanosleep because nanosleep may not be portable to all systems
using SDL with the ALSA backend. This may be a moot point with
the switch to blocking writes anyway...
Date: Sat, 27 Dec 2003 21:47:36 +0100
From: Michel Daenzer
To: Debian Bug Tracking System
Subject: [SDL] Bug#225252: [PATCH] ALSA fixes
Package: libsdl1.2debian-all
Version: 1.2.6-2
Severity: normal
Tags: patch
For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with
SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU
usage, interrupted sound and stuttering in some games here. Taking a nanosleep
whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more
efficient to use blocking mode for the actual sound playback. Feedback from the
SDL and ALSA lists appreciated.
The patch also fixes the default ALSA device to be used.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 04 Jan 2004 15:40:50 +0000 |
parents | e8157fcb3114 |
children | c9b51268668f |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997 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 */ #ifdef SAVE_RCSID static char rcsid = "@(#) $Id$"; #endif /* Allow access to the audio stream on BeOS */ #include <stdlib.h> #include <stdio.h> #include <string.h> #include <SoundPlayer.h> #include "SDL_BeApp.h" extern "C" { #include "SDL_audio.h" #include "SDL_audio_c.h" #include "SDL_sysaudio.h" #include "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) { free(device->hidden); free(device); } static SDL_AudioDevice *Audio_CreateDevice(int devindex) { SDL_AudioDevice *device; /* Initialize all variables that we clean on shutdown */ device = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice)); if ( device ) { memset(device, 0, (sizeof *device)); device->hidden = (struct SDL_PrivateAudioData *) malloc((sizeof *device->hidden)); } if ( (device == NULL) || (device->hidden == NULL) ) { SDL_OutOfMemory(); if ( device ) { free(device); } return(0); } 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 */ 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); 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) { media_raw_audio_format format; /* Initialize the Be Application, if it's not already started */ if ( SDL_InitBeApp() < 0 ) { return(-1); } /* Parse the audio format and fill the Be raw audio format */ format.frame_rate = (float)spec->freq; format.channel_count = spec->channels; switch (spec->format&~0x1000) { case AUDIO_S8: /* Signed 8-bit audio unsupported, convert to U8 */ spec->format = AUDIO_U8; case AUDIO_U8: format.format = media_raw_audio_format::B_AUDIO_UCHAR; format.byte_order = 0; break; case AUDIO_U16: /* Unsigned 16-bit audio unsupported, convert to S16 */ spec->format ^= 0x8000; case AUDIO_S16: format.format = media_raw_audio_format::B_AUDIO_SHORT; if ( spec->format & 0x1000 ) { format.byte_order = 1; /* Big endian */ } else { format.byte_order = 2; /* Little endian */ } break; } 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 */