view src/video/Xext/extensions/xf86dga.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 585a7e1285ae
children 0c105755b110
line wrap: on
line source

/*
   Copyright (c) 1999  XFree86 Inc
*/
/* $XFree86: xc/include/extensions/xf86dga.h,v 3.21 2001/08/01 00:44:36 tsi Exp $ */

#ifndef _XF86DGA_H_
#define _XF86DGA_H_

#include <X11/Xfuncproto.h>
#include <XFree86/extensions/xf86dga1.h>
#include "SDL_name.h"

#define X_XDGAQueryVersion		0

/* 1 through 9 are in xf86dga1.h */

/* 10 and 11 are reserved to avoid conflicts with rogue DGA extensions */

#define X_XDGAQueryModes		12
#define X_XDGASetMode			13
#define X_XDGASetViewport		14
#define X_XDGAInstallColormap		15
#define X_XDGASelectInput		16
#define X_XDGAFillRectangle		17
#define X_XDGACopyArea			18
#define X_XDGACopyTransparentArea	19
#define X_XDGAGetViewportStatus		20
#define X_XDGASync			21
#define X_XDGAOpenFramebuffer		22
#define X_XDGACloseFramebuffer		23
#define X_XDGASetClientVersion		24
#define X_XDGAChangePixmapMode		25
#define X_XDGACreateColormap		26


#define XDGAConcurrentAccess	0x00000001
#define XDGASolidFillRect	0x00000002
#define XDGABlitRect		0x00000004
#define XDGABlitTransRect	0x00000008
#define XDGAPixmap    		0x00000010

#define XDGAInterlaced          0x00010000
#define XDGADoublescan          0x00020000

#define XDGAFlipImmediate	0x00000001
#define XDGAFlipRetrace		0x00000002

#define XDGANeedRoot		0x00000001

#define XF86DGANumberEvents		7

#define XDGAPixmapModeLarge		0
#define XDGAPixmapModeSmall		1

#define XF86DGAClientNotLocal		0
#define XF86DGANoDirectVideoMode	1
#define XF86DGAScreenNotActive		2
#define XF86DGADirectNotActivated	3
#define XF86DGAOperationNotSupported	4
#define XF86DGANumberErrors		(XF86DGAOperationNotSupported + 1)


typedef struct {
   int num;		/* A unique identifier for the mode (num > 0) */
   char *name;		/* name of mode given in the XF86Config */
   float verticalRefresh;
   int flags;		/* DGA_CONCURRENT_ACCESS, etc... */
   int imageWidth;	/* linear accessible portion (pixels) */
   int imageHeight;
   int pixmapWidth;	/* Xlib accessible portion (pixels) */
   int pixmapHeight;	/* both fields ignored if no concurrent access */
   int bytesPerScanline; 
   int byteOrder;	/* MSBFirst, LSBFirst */
   int depth;		
   int bitsPerPixel;
   unsigned long redMask;
   unsigned long greenMask;
   unsigned long blueMask;
   short visualClass;
   int viewportWidth;
   int viewportHeight;
   int xViewportStep;	/* viewport position granularity */
   int yViewportStep;
   int maxViewportX;	/* max viewport origin */
   int maxViewportY;
   int viewportFlags;	/* types of page flipping possible */
   int reserved1;
   int reserved2;
} SDL_NAME(XDGAMode);


typedef struct {
   SDL_NAME(XDGAMode) mode;
   unsigned char *data;
   Pixmap pixmap;
} SDL_NAME(XDGADevice);


#ifndef _XF86DGA_SERVER_
_XFUNCPROTOBEGIN

typedef struct {
   int type;
   unsigned long serial;
   Display *display;
   int screen;
   Time time;
   unsigned int state;
   unsigned int button;
} SDL_NAME(XDGAButtonEvent);

typedef struct {
   int type;
   unsigned long serial;
   Display *display;
   int screen;
   Time time;
   unsigned int state;
   unsigned int keycode;
} SDL_NAME(XDGAKeyEvent);

typedef struct {
   int type;
   unsigned long serial;
   Display *display;
   int screen;
   Time time;
   unsigned int state;
   int dx;
   int dy;
} SDL_NAME(XDGAMotionEvent);

typedef union {
  int type;
  SDL_NAME(XDGAButtonEvent) xbutton;
  SDL_NAME(XDGAKeyEvent)	  xkey;
  SDL_NAME(XDGAMotionEvent) xmotion;
  long		  pad[24];
} SDL_NAME(XDGAEvent);

Bool SDL_NAME(XDGAQueryExtension)(
    Display 	*dpy,
    int 	*eventBase,
    int 	*erroBase
);

Bool SDL_NAME(XDGAQueryVersion)(
    Display 	*dpy,
    int 	*majorVersion,
    int 	*minorVersion
);

SDL_NAME(XDGAMode)* SDL_NAME(XDGAQueryModes)(
    Display	*dpy,
    int 	screen,
    int		*num
);

SDL_NAME(XDGADevice)* SDL_NAME(XDGASetMode)(
    Display	*dpy,
    int		screen,
    int		mode
);

Bool SDL_NAME(XDGAOpenFramebuffer)(
    Display	*dpy,
    int 	screen
);

void SDL_NAME(XDGACloseFramebuffer)(
    Display	*dpy,
    int		screen
);

void SDL_NAME(XDGASetViewport)(
    Display	*dpy,
    int		screen,
    int		x,
    int		y,
    int		flags
);

void SDL_NAME(XDGAInstallColormap)(
    Display	*dpy,
    int		screen,
    Colormap	cmap
);

Colormap SDL_NAME(XDGACreateColormap)(
    Display	*dpy,
    int 	screen,
    SDL_NAME(XDGADevice)  *device,
    int 	alloc
);

void SDL_NAME(XDGASelectInput)(
    Display	*dpy,
    int		screen,
    long	event_mask
);

void SDL_NAME(XDGAFillRectangle)(
    Display	*dpy,
    int		screen,
    int		x,
    int		y,
    unsigned int	width,
    unsigned int	height,
    unsigned long	color
);


void SDL_NAME(XDGACopyArea)(
    Display	*dpy,
    int		screen,
    int		srcx,
    int		srcy,
    unsigned int	width,
    unsigned int	height,
    int		dstx,
    int		dsty
);


void SDL_NAME(XDGACopyTransparentArea)(
    Display	*dpy,
    int		screen,
    int		srcx,
    int		srcy,
    unsigned int	width,
    unsigned int	height,
    int		dstx,
    int		dsty,
    unsigned long key
);

int SDL_NAME(XDGAGetViewportStatus)(
    Display	*dpy,
    int		screen
);
   
void SDL_NAME(XDGASync)(
    Display	*dpy,
    int		screen
);

Bool SDL_NAME(XDGASetClientVersion)(
    Display	*dpy
);

void SDL_NAME(XDGAChangePixmapMode)(
    Display 	*dpy,
    int		screen,
    int		*x,
    int		*y,
    int		mode
);


void SDL_NAME(XDGAKeyEventToXKeyEvent)(SDL_NAME(XDGAKeyEvent)* dk, XKeyEvent* xk);


_XFUNCPROTOEND
#endif /* _XF86DGA_SERVER_ */
#endif /* _XF86DGA_H_ */