Mercurial > sdl-ios-xcode
view include/SDL_syswm.h @ 942:41a59de7f2ed
Here are patches for SDL12 and SDL_mixer for 4 or 6 channel
surround sound on Linux using the Alsa driver. To use them, naturally
you need a sound card that will do 4 or 6 channels and probably also a
recent version of the Alsa drivers and library. Since the only SDL
output driver that knows about surround sound is the Alsa driver,
you���ll want to choose it, using:
export SDL_AUDIODRIVER=alsa
There are no syntactic changes to the programming API. No new
library calls, no differences in arguments.
There are two semantic changes:
(1) For library calls with number of channels as an argument, formerly
you could use only 1 or 2 for the number of channels. Now you
can also use 4 or 6.
(2) The two "left" and "right" arguments to Mix_SetPanning, for the
case of 4 or 6 channels, no longer simply control the volumes of
the left and right channels. Now the "left" argument is converted
to an angle and Mix_SetPosition is called, and the "right" argu-
ment is ignored.
With two exceptions, so far as I know, the modified SDL12 and
SDL_mixer work the same way as the original versions, when opened for
1 or 2 channel output. The two exceptions are bugs which I fixed.
Well, the first, anyway, is a bug for sure. When rate conversions up
or down by a factor of two are applied (in src/audio/SDL_audiocvt.c),
streams with different numbers of channels (that is, mono and stereo)
are treated the same way: either each sample is copied or every other
sample is omitted. This is ok for mono, but for stereo, it is frames
that should be copied or omitted, where by "frame" I mean a portion of
the stream containing one sample for each channel. (In the SDL source,
confusingly, sometimes frames are called "samples".) So for these
rate conversions, stereo streams have to be treated differently, and
they are, in my modified version.
The other problem that might be characterized as a bug arises
when SDL_mixer is passed a multichannel chunk which does not have an
integral number of frames. Due to the way the effect_position code
loops over frames, when the chunk ends with a partial frame, memory
outside the chunk buffer will be accessed. In the case of stereo,
it���s possible that because malloc may give more memory than requested,
this potential problem never actually causes a segment fault. I don���t
know. For 6 channel chunks, I do know, and it does cause segment
faults.
If SDL_mixer is passed defective chunks and this causes a segment
fault, arguably, that���s not a bug in SDL_mixer. Still, whether or not
it counts as a bug, it���s easy to protect against, so why not? I added
code in mixer.c to discard any partial frame at the end of a chunk.
Then what about when SDL or SDL_mixer is opened for 4 or 6 chan-
nel output? What happens with the parts of the current library
designed for stereo? I don���t know whether I���ve covered all the bases,
but I���ve tried:
(1) For playing 2 channel waves, or other cases where SDL knows it has
to match up a 2 channel source with a 4 or 6 channel output, I���ve
added code in SDL_audiocvt.c to make the necessary conversions.
(2) For playing midis using timidity, I���ve converted timidity to do 4
or 6 channel output, upon request.
(3) For playing mods using mikmod, I put ad hoc code in music.c to
convert the stereo output that mikmod produces to 4 or 6 chan-
nels. Obviously it would be better to change the mikmod code to
mix down into 4 or 6 channels, but I have a hard time following
the code in mikmod, so I didn���t do that.
(4) For playing mp3s, I put ad hoc code in smpeg to copy channels in
the case when 4 or 6 channel output is needed.
(5) There seems to be no problem with .ogg files - stereo .oggs can be
up converted as .wavs are.
(6) The effect_position code in SDL_mixer is now generalized to in-
clude the cases of 4 and 6 channel streams.
I���ve done a very limited amount of compatibility testing for some
of the games using SDL I happen to have. For details, see the file
TESTS.
I���ve put into a separate archive, Surround-SDL-testfiles.tgz, a
couple of 6 channel wave files for testing and a 6 channel ogg file.
If you have the right hardware and version of Alsa, you should be able
to play the wave files with the Alsa utility aplay (and hear all
channels, except maybe lfe, for chan-id.wav, since it���s rather faint).
Don���t expect aplay to give good sound, though. There���s something
wrong with the current version of aplay.
The canyon.ogg file is to test loading of 6 channel oggs. After
patching and compiling, you can play it with playmus. (My version of
ogg123 will not play it, and I had to patch mplayer to get it to play
6 channel oggs.)
Greg Lee <greg@ling.lll.hawaii.edu>
Thus, July 1, 2004
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sat, 21 Aug 2004 12:27:02 +0000 |
parents | 04a403e4ccf5 |
children | 8be85fa59cf3 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2004 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 /* Include file for SDL custom system window manager hooks */ #ifndef _SDL_syswm_h #define _SDL_syswm_h #include "SDL_version.h" #include "begin_code.h" /* Set up for C function definitions, even when using C++ */ #ifdef __cplusplus extern "C" { #endif /* Your application has access to a special type of event 'SDL_SYSWMEVENT', which contains window-manager specific information and arrives whenever an unhandled window event occurs. This event is ignored by default, but you can enable it with SDL_EventState() */ #ifdef SDL_PROTOTYPES_ONLY struct SDL_SysWMinfo; typedef struct SDL_SysWMinfo SDL_SysWMinfo; #else /* This is the structure for custom window manager events */ #if (defined(unix) || defined(__unix__) || defined(_AIX) || defined(__OpenBSD__)) && \ (!defined(DISABLE_X11) && !defined(__CYGWIN32__) && !defined(ENABLE_NANOX) && \ !defined(__QNXNTO__)) /* AIX is unix, of course, but the native compiler CSet doesn't define unix */ #include <X11/Xlib.h> #include <X11/Xatom.h> /* These are the various supported subsystems under UNIX */ typedef enum { SDL_SYSWM_X11 } SDL_SYSWM_TYPE; /* The UNIX custom event structure */ struct SDL_SysWMmsg { SDL_version version; SDL_SYSWM_TYPE subsystem; union { XEvent xevent; } event; }; /* The UNIX custom window manager information structure. When this structure is returned, it holds information about which low level system it is using, and will be one of SDL_SYSWM_TYPE. */ typedef struct SDL_SysWMinfo { SDL_version version; SDL_SYSWM_TYPE subsystem; union { struct { Display *display; /* The X11 display */ Window window; /* The X11 display window */ /* These locking functions should be called around any X11 functions using the display variable. They lock the event thread, so should not be called around event functions or from event filters. */ void (*lock_func)(void); void (*unlock_func)(void); /* Introduced in SDL 1.0.2 */ Window fswindow; /* The X11 fullscreen window */ Window wmwindow; /* The X11 managed input window */ } x11; } info; } SDL_SysWMinfo; #elif defined(ENABLE_NANOX) #include <microwin/nano-X.h> /* The generic custom event structure */ struct SDL_SysWMmsg { SDL_version version; int data; }; /* The windows custom window manager information structure */ typedef struct SDL_SysWMinfo { SDL_version version ; GR_WINDOW_ID window ; /* The display window */ } SDL_SysWMinfo; #elif defined(WIN32) #define WIN32_LEAN_AND_MEAN #include <windows.h> /* The windows custom event structure */ struct SDL_SysWMmsg { SDL_version version; HWND hwnd; /* The window for the message */ UINT msg; /* The type of message */ WPARAM wParam; /* WORD message parameter */ LPARAM lParam; /* LONG message parameter */ }; /* The windows custom window manager information structure */ typedef struct SDL_SysWMinfo { SDL_version version; HWND window; /* The Win32 display window */ HGLRC hglrc; /* The OpenGL context, if any */ } SDL_SysWMinfo; #elif defined(__riscos__) /* RISC OS custom event structure */ struct SDL_SysWMmsg { SDL_version version; int eventCode; /* The window for the message */ int pollBlock[64]; }; /* The RISCOS custom window manager information structure */ typedef struct SDL_SysWMinfo { SDL_version version; int wimpVersion; /* Wimp version running under */ int taskHandle; /* The RISCOS task handle */ int window; /* The RISCOS display window */ } SDL_SysWMinfo; #elif defined(__QNXNTO__) #include <sys/neutrino.h> #include <Ph.h> /* The QNX custom event structure */ struct SDL_SysWMmsg { SDL_version version; int data; }; /* The QNX custom window manager information structure */ typedef struct SDL_SysWMinfo { SDL_version version; int data; } SDL_SysWMinfo; #else /* The generic custom event structure */ struct SDL_SysWMmsg { SDL_version version; int data; }; /* The generic custom window manager information structure */ typedef struct SDL_SysWMinfo { SDL_version version; int data; } SDL_SysWMinfo; #endif /* OS type */ #endif /* SDL_PROTOTYPES_ONLY */ /* Function prototypes */ /* * This function gives you custom hooks into the window manager information. * It fills the structure pointed to by 'info' with custom information and * returns 1 if the function is implemented. If it's not implemented, or * the version member of the 'info' structure is invalid, it returns 0. */ extern DECLSPEC int SDLCALL SDL_GetWMInfo(SDL_SysWMinfo *info); /* Ends C function definitions when using C++ */ #ifdef __cplusplus } #endif #include "close_code.h" #endif /* _SDL_syswm_h */