Mercurial > sdl-ios-xcode
view src/hermes/HeadX86.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 | c94b390687d2 |
| children | bb5ace455586 |
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/* Header definitions for the x86 routines for the HERMES library Copyright (c) 1998 Christian Nentwich (brn@eleet.mcb.at) This source code is licensed under the GNU LGPL Please refer to the file COPYING.LIB contained in the distribution for licensing conditions */ #ifndef __HERMES_HEAD_X86__ #define __HERMES_HEAD_X86__ #ifdef X86_ASSEMBLER /* If you can't stand IFDEFS, then close your eyes now, please :) */ /* Ok, we start with normal function definitions */ #ifdef __cplusplus extern "C" { #endif void STACKCALL ConvertX86(HermesConverterInterface *); void STACKCALL ClearX86_32(HermesClearInterface *); void STACKCALL ClearX86_24(HermesClearInterface *); void STACKCALL ClearX86_16(HermesClearInterface *); void STACKCALL ClearX86_8(HermesClearInterface *); int STACKCALL Hermes_X86_CPU(); void ConvertX86p32_32BGR888(); void ConvertX86p32_32RGBA888(); void ConvertX86p32_32BGRA888(); void ConvertX86p32_24RGB888(); void ConvertX86p32_24BGR888(); void ConvertX86p32_16RGB565(); void ConvertX86p32_16BGR565(); void ConvertX86p32_16RGB555(); void ConvertX86p32_16BGR555(); void ConvertX86p32_8RGB332(); void ConvertX86p16_32RGB888(); void ConvertX86p16_32BGR888(); void ConvertX86p16_32RGBA888(); void ConvertX86p16_32BGRA888(); void ConvertX86p16_24RGB888(); void ConvertX86p16_24BGR888(); void ConvertX86p16_16BGR565(); void ConvertX86p16_16RGB555(); void ConvertX86p16_16BGR555(); void ConvertX86p16_8RGB332(); void CopyX86p_4byte(); void CopyX86p_3byte(); void CopyX86p_2byte(); void CopyX86p_1byte(); void ConvertX86pI8_32(); void ConvertX86pI8_24(); void ConvertX86pI8_16(); extern int ConvertX86p16_32RGB888_LUT_X86[512]; extern int ConvertX86p16_32BGR888_LUT_X86[512]; extern int ConvertX86p16_32RGBA888_LUT_X86[512]; extern int ConvertX86p16_32BGRA888_LUT_X86[512]; #ifdef __cplusplus } #endif /* Now fix up the ELF underscore problem */ #if defined(__ELF__) && defined(__GNUC__) #ifdef __cplusplus extern "C" { #endif int Hermes_X86_CPU() __attribute__ ((alias ("_Hermes_X86_CPU"))); void ConvertX86(HermesConverterInterface *) __attribute__ ((alias ("_ConvertX86"))); #if 0 void ClearX86_32(HermesClearInterface *) __attribute__ ((alias ("_ClearX86_32"))); void ClearX86_24(HermesClearInterface *) __attribute__ ((alias ("_ClearX86_24"))); void ClearX86_16(HermesClearInterface *) __attribute__ ((alias ("_ClearX86_16"))); void ClearX86_8(HermesClearInterface *) __attribute__ ((alias ("_ClearX86_8"))); #endif void ConvertX86p32_32BGR888() __attribute__ ((alias ("_ConvertX86p32_32BGR888"))); void ConvertX86p32_32RGBA888() __attribute__ ((alias ("_ConvertX86p32_32RGBA888"))); void ConvertX86p32_32BGRA888() __attribute__ ((alias ("_ConvertX86p32_32BGRA888"))); void ConvertX86p32_24RGB888() __attribute__ ((alias ("_ConvertX86p32_24RGB888"))); void ConvertX86p32_24BGR888() __attribute__ ((alias ("_ConvertX86p32_24BGR888"))); void ConvertX86p32_16RGB565() __attribute__ ((alias ("_ConvertX86p32_16RGB565"))); void ConvertX86p32_16BGR565() __attribute__ ((alias ("_ConvertX86p32_16BGR565"))); void ConvertX86p32_16RGB555() __attribute__ ((alias ("_ConvertX86p32_16RGB555"))); void ConvertX86p32_16BGR555() __attribute__ ((alias ("_ConvertX86p32_16BGR555"))); void ConvertX86p32_8RGB332() __attribute__ ((alias ("_ConvertX86p32_8RGB332"))); #if 0 void ConvertX86p16_32RGB888() __attribute__ ((alias ("_ConvertX86p16_32RGB888"))); void ConvertX86p16_32BGR888() __attribute__ ((alias ("_ConvertX86p16_32BGR888"))); void ConvertX86p16_32RGBA888() __attribute__ ((alias ("_ConvertX86p16_32RGBA888"))); void ConvertX86p16_32BGRA888() __attribute__ ((alias ("_ConvertX86p16_32BGRA888"))); void ConvertX86p16_24RGB888() __attribute__ ((alias ("_ConvertX86p16_24RGB888"))); void ConvertX86p16_24BGR888() __attribute__ ((alias ("_ConvertX86p16_24BGR888"))); #endif void ConvertX86p16_16BGR565() __attribute__ ((alias ("_ConvertX86p16_16BGR565"))); void ConvertX86p16_16RGB555() __attribute__ ((alias ("_ConvertX86p16_16RGB555"))); void ConvertX86p16_16BGR555() __attribute__ ((alias ("_ConvertX86p16_16BGR555"))); void ConvertX86p16_8RGB332() __attribute__ ((alias ("_ConvertX86p16_8RGB332"))); #if 0 void CopyX86p_4byte() __attribute__ ((alias ("_CopyX86p_4byte"))); void CopyX86p_3byte() __attribute__ ((alias ("_CopyX86p_3byte"))); void CopyX86p_2byte() __attribute__ ((alias ("_CopyX86p_2byte"))); void CopyX86p_1byte() __attribute__ ((alias ("_CopyX86p_1byte"))); void ConvertX86pI8_32() __attribute__ ((alias ("_ConvertX86pI8_32"))); void ConvertX86pI8_24() __attribute__ ((alias ("_ConvertX86pI8_24"))); void ConvertX86pI8_16() __attribute__ ((alias ("_ConvertX86pI8_16"))); extern int ConvertX86p16_32RGB888_LUT_X86[512] __attribute__ ((alias ("_ConvertX86p16_32RGB888_LUT_X86"))); extern int ConvertX86p16_32BGR888_LUT_X86[512] __attribute__ ((alias ("_ConvertX86p16_32BGR888_LUT_X86"))); extern int ConvertX86p16_32RGBA888_LUT_X86[512] __attribute__ ((alias ("_ConvertX86p16_32RGBA888_LUT_X86"))); extern int ConvertX86p16_32BGRA888_LUT_X86[512] __attribute__ ((alias ("_ConvertX86p16_32BGRA888_LUT_X86"))); #endif #ifdef __cplusplus } #endif #endif /* ELF & GNU */ /* Make it run with WATCOM C */ #ifdef __WATCOMC__ #pragma warning 601 9 #pragma aux Hermes_X86_CPU "_*" #pragma aux ConvertX86 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearX86_32 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearX86_24 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearX86_16 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearX86_8 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ConvertX86p32_32BGR888 "_*" #pragma aux ConvertX86p32_32RGBA888 "_*" #pragma aux ConvertX86p32_32BGRA888 "_*" #pragma aux ConvertX86p32_24RGB888 "_*" #pragma aux ConvertX86p32_24BGR888 "_*" #pragma aux ConvertX86p32_16RGB565 "_*" #pragma aux ConvertX86p32_16BGR565 "_*" #pragma aux ConvertX86p32_16RGB555 "_*" #pragma aux ConvertX86p32_16BGR555 "_*" #pragma aux ConvertX86p32_8RGB332 "_*" #pragma aux ConvertX86p16_32RGB888 "_*" #pragma aux ConvertX86p16_32BGR888 "_*" #pragma aux ConvertX86p16_32RGBA888 "_*" #pragma aux ConvertX86p16_32BGRA888 "_*" #pragma aux ConvertX86p16_24RGB888 "_*" #pragma aux ConvertX86p16_24BGR888 "_*" #pragma aux ConvertX86p16_16BGR565 "_*" #pragma aux ConvertX86p16_16RGB555 "_*" #pragma aux ConvertX86p16_16BGR555 "_*" #pragma aux ConvertX86p16_8RGB332 "_*" #pragma aux CopyX86p_4byte "_*" #pragma aux CopyX86p_3byte "_*" #pragma aux CopyX86p_2byte "_*" #pragma aux CopyX86p_1byte "_*" #pragma aux ConvertX86pI8_32 "_*" #pragma aux ConvertX86pI8_24 "_*" #pragma aux ConvertX86pI8_16 "_*" #pragma aux ConvertX86p16_32RGB888_LUT_X86 "_*" #pragma aux ConvertX86p16_32BGR888_LUT_X86 "_*" #pragma aux ConvertX86p16_32RGBA888_LUT_X86 "_*" #pragma aux ConvertX86p16_32BGRA888_LUT_X86 "_*" #endif /* __WATCOMC__ */ #endif /* X86_ASSEMBLER */ #endif