Mercurial > sdl-ios-xcode
view src/events/SDL_active.c @ 4216:5b99971a27b4 SDL-1.2
Fixed bug #698
Hans de Goede 2009-02-13 01:10:52 PST
Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst
others), the sound of SDL using apps (like a simple playmus call) has been
crackling.
While looking in to fixing this I noticed that the current pulseaudio code in
SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events
and ipc, given that SDL already has its own thread for audio handling this is
clearly suboptimal, leading to unnecessary context switching IPC, etc. Also
pa_simple does not allow one to implement the WaitAudio() callback for SDL
audiodrivers properly.
Given that my work is mostly a rewrite (although some original pieces remain)
I'm attaching the new .c and .h file, as that is easier to review then the huge
diff.
Let me know if you also want the diff.
This new version has the following features:
-no longer use an additional thread next to the SDL sound thread
-do not crackle with glitch free audio
-when used with a newer pulse, which does glitch free audio, the total latency
is
the same as with the alsa driver
-proper WaitAudio() implementation, saving another mixlen worth of latency
-adds a WaitDone() implementation
This patch has been written in consultancy with Lennart Poetering (the
pulseaudio author) and has been reviewed by him for correct use of the pa API.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 21 Sep 2009 09:27:08 +0000 |
parents | a1b03ba2fcd0 |
children | 052dc40d917f |
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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 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" /* Application focus/iconification handling code for SDL */ #include "SDL_events.h" #include "SDL_events_c.h" /* These are static for our active event handling code */ static Uint8 SDL_appstate = 0; /* Public functions */ int SDL_AppActiveInit(void) { /* Start completely active */ SDL_appstate = (SDL_APPACTIVE|SDL_APPINPUTFOCUS|SDL_APPMOUSEFOCUS); /* That's it! */ return(0); } void SDL_AppActiveQuit(void) { } Uint8 SDL_GetAppState(void) { return(SDL_appstate); } /* This is global for SDL_eventloop.c */ int SDL_PrivateAppActive(Uint8 gain, Uint8 state) { int posted; Uint8 new_state; /* Modify the current state with the given mask */ if ( gain ) { new_state = (SDL_appstate | state); } else { new_state = (SDL_appstate & ~state); } /* Drop events that don't change state */ if ( new_state == SDL_appstate ) { return(0); } /* Update internal active state */ SDL_appstate = new_state; /* Post the event, if desired */ posted = 0; if ( SDL_ProcessEvents[SDL_ACTIVEEVENT] == SDL_ENABLE ) { SDL_Event event; SDL_memset(&event, 0, sizeof(event)); event.type = SDL_ACTIVEEVENT; event.active.gain = gain; event.active.state = state; if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) { posted = 1; SDL_PushEvent(&event); } } /* If we lost keyboard focus, post key-up events */ if ( (state & SDL_APPINPUTFOCUS) && !gain ) { SDL_ResetKeyboard(); } return(posted); }