WhatsNew
author Sam Lantinga <slouken@libsdl.org>
Fri, 06 Jul 2007 09:15:43 +0000
branchSDL-1.2
changeset 4009 1146681dbb74
parent 3960 f5daa62ce1c4
child 4011 f5794774970d
permissions -rw-r--r--
Fixed bug #382

Added horizontal scrolling support: SDL_BUTTON_WHEELLEFT (6) and SDL_BUTTON_WHEELRIGHT (7)
     1 
     2 This is a list of API changes in SDL's version history.
     3 
     4 Version 1.0:
     5 
     6 1.2.12:
     7 	Added SDL_VIDEO_ALLOW_SCREENSAVER to override SDL's disabling
     8 	of the screensaver on Mac OS X and X11.
     9 
    10 	Added SDL_BUTTON_WHEELLEFT (6) and SDL_BUTTON_WHEELRIGHT (7)
    11 
    12 1.2.10:
    13 	If SDL_OpenAudio() is passed zero for the desired format
    14 	fields, the following environment variables will be used
    15 	to fill them in:
    16 		SDL_AUDIO_FREQUENCY
    17 		SDL_AUDIO_FORMAT
    18 		SDL_AUDIO_CHANNELS
    19 		SDL_AUDIO_SAMPLES
    20 	If an environment variable is not specified, it will be set
    21 	to a reasonable default value.
    22 
    23 	Added support for the SDL_VIDEO_FULLSCREEN_HEAD environment
    24 	variable, currently supported on X11 Xinerama configurations.
    25 
    26 	Added SDL_GL_SWAP_CONTROL to wait for vsync in OpenGL applications.
    27 
    28 	Added SDL_GL_ACCELERATED_VISUAL to guarantee hardware acceleration.
    29 
    30 	Added current_w and current_h to the SDL_VideoInfo structure,
    31 	which is set to the desktop resolution during video intialization,
    32 	and then set to the current resolution when a video mode is set.
    33 
    34 	SDL_SetVideoMode() now accepts 0 for width or height and will use
    35 	the current video mode (or the desktop mode if no mode has been set.)
    36 
    37 	Added SDL_GetKeyRepeat()
    38 
    39 	Added SDL_config.h, with defaults for various build environments.
    40 
    41 1.2.7:
    42 	Added CPU feature detection functions to SDL_cpuinfo.h:
    43 		SDL_HasRDTSC(), SDL_HasMMX(), SDL_Has3DNow(), SDL_HasSSE(),
    44 		SDL_HasAltiVec()
    45 	Added function to create RWops from const memory: SDL_RWFromConstMem()
    46 
    47 1.2.6:
    48 	Added SDL_LoadObject(), SDL_LoadFunction(), and SDL_UnloadObject()
    49 
    50 	Added SDL_GL_MULTISAMPLEBUFFERS and SDL_GL_MULTISAMPLESAMPLES for FSAA
    51 
    52 1.2.5:
    53 	Added SDL_BUTTON_WHEELUP (4) and SDL_BUTTON_WHEELDOWN (5)
    54 
    55 	Added SDL_GL_STEREO for stereoscopic OpenGL contexts
    56 
    57 1.2.0:
    58 	Added SDL_VIDEOEXPOSE event to signal that the screen needs to
    59 	be redrawn.  This is currently only delivered to OpenGL windows
    60 	on X11, though it may be delivered in the future when the video
    61 	memory is lost under DirectX.
    62 
    63 1.1.8:
    64 	You can pass SDL_NOFRAME to SDL_VideoMode() to create a window
    65 	that has no title bar or frame decoration.  Fullscreen video
    66 	modes automatically have this flag set.
    67 
    68 	Added a function to query the clipping rectangle for a surface:
    69 		void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect)
    70 
    71 	Added a function to query the current event filter:
    72 		SDL_EventFilter SDL_GetEventFilter(void)
    73 
    74 	If you pass -1 to SDL_ShowCursor(), it won't change the current
    75 	cursor visibility state, but will still return it.
    76 
    77 	SDL_LockSurface() and SDL_UnlockSurface() are recursive, meaning
    78 	you can nest them as deep as you want, as long as each lock call
    79 	has a matching unlock call.  The surface remains locked until the
    80 	last matching unlock call.
    81 
    82 	Note that you may not blit to or from a locked surface.
    83 
    84 1.1.7:
    85 	The SDL_SetGammaRamp() and SDL_GetGammaRamp() functions now take
    86 	arrays of Uint16 values instead of Uint8 values.  For the most part,
    87 	you can just take your old values and shift them up 8 bits to get
    88 	new correct values for your gamma ramps.
    89 
    90 	You can pass SDL_RLEACCEL in flags passed to SDL_ConvertSurface()
    91         and SDL will try to RLE accelerate colorkey and alpha blits in the
    92 	resulting surface.
    93 
    94 1.1.6:
    95 	Added a function to return the thread ID of a specific thread:
    96 		Uint32 SDL_GetThreadID(SDL_Thread *thread)
    97 	If 'thread' is NULL, this function returns the id for this thread.
    98 
    99 1.1.5:
   100 	The YUV overlay structure has been changed to use an array of
   101 	pitches and pixels representing the planes of a YUV image, to
   102 	better enable hardware acceleration.  The YV12 and IYUV formats
   103 	each have three planes, corresponding to the Y, U, and V portions
   104 	of the image, while packed pixel YUV formats just have one plane.
   105 
   106 	For palettized mode (8bpp), the screen colormap is now split in
   107 	a physical and a logical palette. The physical palette determines
   108 	what colours the screen pixels will get when displayed, and the
   109 	logical palette controls the mapping from blits to/from the screen.
   110 	A new function, SDL_SetPalette() has been added to change
   111 	logical and physical palettes separately. SDL_SetColors() works
   112 	just as before, and is equivalent to calling SDL_SetPalette() with
   113 	a flag argument of (SDL_LOGPAL|SDL_PHYSPAL).
   114 
   115 	SDL_BlitSurface() no longer modifies the source rectangle, only the
   116 	destination rectangle. The width/height members of the destination
   117 	rectangle are ignored, only the position is used.
   118 
   119 	The old source clipping function SDL_SetClipping() has been replaced
   120 	with a more useful function to set the destination clipping rectangle:
   121 		SDL_bool SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect)
   122 		
   123 	Added a function to see what subsystems have been initialized:
   124 		Uint32 SDL_WasInit(Uint32 flags)
   125 
   126 	The Big Alpha Flip: SDL now treats alpha as opacity like everybody
   127 	else, and not as transparency:
   128 
   129 	A new cpp symbol: SDL_ALPHA_OPAQUE is defined as 255
   130 	A new cpp symbol: SDL_ALPHA_TRANSPARENT is defined as 0
   131 	Values between 0 and 255 vary from fully transparent to fully opaque.
   132 
   133 	New functions:
   134 	SDL_DisplayFormatAlpha()
   135 	    Returns a surface converted to a format with alpha-channel
   136 	    that can be blit efficiently to the screen. (In other words,
   137 	    like SDL_DisplayFormat() but the resulting surface has
   138 	    an alpha channel.)  This is useful for surfaces with alpha.
   139 	SDL_MapRGBA()
   140 	    Works as SDL_MapRGB() but takes an additional alpha parameter.
   141 	SDL_GetRGBA()
   142 	    Works as SDL_GetRGB() but also returns the alpha value
   143 	    (SDL_ALPHA_OPAQUE for formats without an alpha channel)
   144 
   145 	Both SDL_GetRGB() and SDL_GetRGBA() now always return values in
   146 	the [0..255] interval. Previously, SDL_GetRGB() would return
   147 	(0xf8, 0xfc, 0xf8) for a completely white pixel in RGB565 format.
   148 	(N.B.: This is broken for bit fields < 3 bits.)
   149 
   150 	SDL_MapRGB() returns pixels in which the alpha channel is set opaque.
   151 
   152 	SDL_SetAlpha() can now be used for both setting the per-surface
   153 	alpha, using the new way of thinking of alpha, and also to enable
   154 	and disable per-pixel alpha blending for surfaces with an alpha
   155 	channel:
   156 		To disable alpha blending:
   157 			SDL_SetAlpha(surface, 0, 0);
   158 		To re-enable alpha blending:
   159 			SDL_SetAlpha(surface, SDL_SRCALPHA, 0);
   160 	Surfaces with an alpha channel have blending enabled by default.
   161 
   162 	SDL_SetAlpha() now accepts SDL_RLEACCEL as a flag, which requests
   163 	RLE acceleration of blits, just as like with SDL_SetColorKey().
   164 	This flag can be set for both surfaces with an alpha channel
   165 	and surfaces with an alpha value set by SDL_SetAlpha().
   166 	As always, RLE surfaces must be locked before pixel access is
   167 	allowed, and unlocked before any other SDL operations are done
   168 	on it.
   169 
   170 	The blit semantics for surfaces with and without alpha and colorkey
   171 	have now been defined:
   172 
   173 	RGBA->RGB:
   174 	    SDL_SRCALPHA set:
   175 		alpha-blend (using alpha-channel).
   176 		SDL_SRCCOLORKEY ignored.
   177 	    SDL_SRCALPHA not set:
   178 		copy RGB.
   179 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   180 		RGB values of the source colour key, ignoring alpha in the
   181 		comparison.
   182 
   183 	RGB->RGBA:
   184 	    SDL_SRCALPHA set:
   185 		alpha-blend (using the source per-surface alpha value);
   186 		set destination alpha to opaque.
   187 	    SDL_SRCALPHA not set:
   188 		copy RGB, set destination alpha to opaque.
   189 	    both:
   190 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   191 		source colour key.
   192 
   193 	RGBA->RGBA:
   194 	    SDL_SRCALPHA set:
   195 		alpha-blend (using the source alpha channel) the RGB values;
   196 		leave destination alpha untouched. [Note: is this correct?]
   197 		SDL_SRCCOLORKEY ignored.
   198 	    SDL_SRCALPHA not set:
   199 		copy all of RGBA to the destination.
   200 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   201 		RGB values of the source colour key, ignoring alpha in the
   202 		comparison.
   203 
   204 	RGB->RGB: 
   205 	    SDL_SRCALPHA set:
   206 		alpha-blend (using the source per-surface alpha value).
   207 	    SDL_SRCALPHA not set:
   208 		copy RGB.
   209 	    both:
   210 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   211 		source colour key.
   212 
   213 	As a special case, blits from surfaces with per-surface alpha
   214 	value of 128 (50% transparency) are optimised and much faster
   215 	than other alpha values. This does not apply to surfaces with
   216 	alpha channels (per-pixel alpha).
   217 
   218 	New functions for manipulating the gamma of the display have
   219 	been added:
   220 		int SDL_SetGamma(float red, float green, float blue);
   221 		int SDL_SetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   222 		int SDL_GetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   223 	Gamma ramps are tables with 256 entries which map the screen color
   224 	components into actually displayed colors.  For an example of
   225 	implementing gamma correction and gamma fades, see test/testgamma.c
   226 	Gamma control is not supported on all hardware.
   227 
   228 1.1.4:
   229 	The size of the SDL_CDtrack structure changed from 8 to 12 bytes
   230 	as the size of the length member was extended to 32 bits.
   231 
   232         You can now use SDL for 2D blitting with a GL mode by passing the
   233 	SDL_OPENGLBLIT flag to SDL_SetVideoMode().  You can specify 16 or
   234 	32 bpp, and the data in the framebuffer is put into the GL scene
   235 	when you call SDL_UpdateRects(), and the scene will be visible
   236 	when you call SDL_GL_SwapBuffers().
   237 
   238 	Run the "testgl" test program with the -logo command line option
   239 	to see an example of this blending of 2D and 3D in SDL.
   240 
   241 1.1.3:
   242 	Added SDL_FreeRW() to the API, to complement SDL_AllocRW()
   243 
   244 	Added resizable window support - just add SDL_RESIZABLE to the
   245 	SDL_SetVideoMode() flags, and then wait for SDL_VIDEORESIZE events.
   246 	See SDL_events.h for details on the new SDL_ResizeEvent structure.
   247 
   248 	Added condition variable support, based on mutexes and semaphores.
   249 		SDL_CreateCond()
   250 		SDL_DestroyCond()
   251 		SDL_CondSignal()
   252 		SDL_CondBroadcast()
   253 		SDL_CondWait()
   254 		SDL_CondTimedWait()
   255 	The new function prototypes are in SDL_mutex.h
   256 
   257 	Added counting semaphore support, based on the mutex primitive.
   258 		SDL_CreateSemaphore()
   259 		SDL_DestroySemaphore()
   260 		SDL_SemWait()
   261 		SDL_SemTryWait()
   262 		SDL_SemWaitTimeout()
   263 		SDL_SemPost()
   264 		SDL_SemValue()
   265 	The new function prototypes are in SDL_mutex.h
   266 
   267 	Added support for asynchronous blitting.  To take advantage of this,
   268 	you must set the SDL_ASYNCBLIT flag when setting the video mode and
   269 	creating surfaces that you want accelerated in this way.  You must
   270 	lock surfaces that have this flag set, and the lock will block until
   271 	any queued blits have completed.
   272 
   273 	Added YUV video overlay support.
   274 	The supported YUV formats are: YV12, IYUV, YUY2, UYVY, and YVYU.
   275 	This function creates an overlay surface:
   276 		SDL_CreateYUVOverlay()
   277 	You must lock and unlock the overlay to get access to the data:
   278 		SDL_LockYUVOverlay() SDL_UnlockYUVOverlay()
   279 	You can then display the overlay:
   280 		SDL_DisplayYUVOverlay()
   281 	You must free the overlay when you are done using it:
   282 		SDL_FreeYUVOverlay()
   283 	See SDL_video.h for the full function prototypes.
   284 
   285 	The joystick hat position constants have been changed:
   286 	Old constant            New constant
   287 	------------            ------------
   288 	     0                  SDL_HAT_CENTERED
   289 	     1                  SDL_HAT_UP
   290 	     2                  SDL_HAT_RIGHTUP
   291 	     3                  SDL_HAT_RIGHT
   292 	     4                  SDL_HAT_RIGHTDOWN
   293 	     5                  SDL_HAT_DOWN
   294 	     6                  SDL_HAT_LEFTDOWN
   295 	     7                  SDL_HAT_LEFT
   296 	     8                  SDL_HAT_LEFTUP
   297 	The new constants are bitmasks, so you can check for the
   298 	individual axes like this:
   299 		if ( hat_position & SDL_HAT_UP ) {
   300 		}
   301 	and you'll catch left-up, up, and right-up.
   302 
   303 1.1.2:
   304 	Added multiple timer support:
   305 		SDL_AddTimer() and SDL_RemoveTimer()
   306 
   307 	SDL_WM_SetIcon() now respects the icon colorkey if mask is NULL.
   308 
   309 1.1.0:
   310 	Added initial OpenGL support.
   311 	First set GL attributes (such as RGB depth, alpha depth, etc.)
   312 		SDL_GL_SetAttribute()
   313 	Then call SDL_SetVideoMode() with the SDL_OPENGL flag.
   314 	Perform all of your normal GL drawing.
   315 	Finally swap the buffers with the new SDL function:
   316 		SDL_GL_SwapBuffers()
   317 	See the new 'testgl' test program for an example of using GL with SDL.
   318 
   319 	You can load GL extension functions by using the function:
   320 		SDL_GL_LoadProcAddress()
   321 
   322 	Added functions to initialize and cleanup specific SDL subsystems:
   323 		SDL_InitSubSystem() and SDL_QuitSubSystem()
   324 
   325 	Added user-defined event type:
   326 		typedef struct {
   327         		Uint8 type;
   328         		int code;
   329         		void *data1;
   330         		void *data2;
   331 		} SDL_UserEvent;
   332 	This structure is in the "user" member of an SDL_Event.
   333 
   334 	Added a function to push events into the event queue:
   335 		SDL_PushEvent()
   336 
   337 	Example of using the new SDL user-defined events:
   338 	{
   339 		SDL_Event event;
   340 
   341 		event.type = SDL_USEREVENT;
   342 		event.user.code = my_event_code;
   343 		event.user.data1 = significant_data;
   344 		event.user.data2 = 0;
   345 		SDL_PushEvent(&event);
   346 	}
   347 
   348 	Added a function to get mouse deltas since last query:
   349 		SDL_GetRelativeMouseState()
   350 
   351 	Added a boolean datatype to SDL_types.h:
   352 		SDL_bool = { SDL_TRUE, SDL_FALSE }
   353 
   354 	Added a function to get the current audio status:
   355 		SDL_GetAudioState();
   356 	It returns one of:
   357 		SDL_AUDIO_STOPPED,
   358 		SDL_AUDIO_PLAYING,
   359 		SDL_AUDIO_PAUSED
   360 
   361 	Added an AAlib driver (ASCII Art) - by Stephane Peter.
   362 
   363 1.0.6:
   364 	The input grab state is reset after each call to SDL_SetVideoMode().
   365 	The input is grabbed by default in fullscreen mode, and ungrabbed in
   366 	windowed mode.  If you want to set input grab to a particular value,
   367 	you should set it after each call to SDL_SetVideoMode().
   368 
   369 1.0.5:
   370 	Exposed SDL_AudioInit(), SDL_VideoInit()
   371 	Added SDL_AudioDriverName() and SDL_VideoDriverName()
   372 
   373 	Added new window manager function:
   374 		SDL_WM_ToggleFullScreen()
   375 	This is currently implemented only on Linux
   376 
   377 	The ALT-ENTER code has been removed - it's not appropriate for a
   378 	lib to bind keys when they aren't even emergency escape sequences.
   379 
   380 	ALT-ENTER functionality can be implemented with the following code:
   381 
   382 	int Handle_AltEnter(const SDL_Event *event)
   383 	{
   384 	    if ( event->type == SDL_KEYDOWN ) {
   385 	        if ( (event->key.keysym.sym == SDLK_RETURN) &&
   386 	             (event->key.keysym.mod & KMOD_ALT) ) {   
   387 	                SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
   388 	                return(0);
   389 	        }
   390 	    }
   391 	    return(1);
   392 	}
   393 	SDL_SetEventFilter(Handle_AltEnter);
   394 
   395 1.0.3:
   396 	Under X11, if you grab the input and hide the mouse cursor,
   397 	the mouse will go into a "relative motion" mode where you
   398 	will always get relative motion events no matter how far in
   399 	each direction you move the mouse - relative motion is not
   400 	bounded by the edges of the window (though the absolute values
   401 	of the mouse positions are clamped by the size of the window).
   402 	The SVGAlib, framebuffer console, and DirectInput drivers all
   403 	have this behavior naturally, and the GDI and BWindow drivers
   404 	never go into "relative motion" mode.
   405 
   406 1.0.2:
   407 	Added a function to enable keyboard repeat:
   408 		SDL_EnableKeyRepeat()
   409 
   410 	Added a function to grab the mouse and keyboard input
   411 		SDL_WM_GrabInput()
   412 
   413 	Added a function to iconify the window.
   414 		SDL_WM_IconifyWindow()
   415 	If this function succeeds, the application will receive an event
   416 	signaling SDL_APPACTIVE event 
   417 
   418 1.0.1:
   419 	Added constants to SDL_audio.h for 16-bit native byte ordering:
   420 		AUDIO_U16SYS, AUDIO_S16SYS
   421 
   422 1.0.0:
   423 	New public release
   424 
   425 Version 0.11:
   426 
   427 0.11.5:
   428 	A new function SDL_GetVideoSurface() has been added, and returns
   429 	a pointer to the current display surface.
   430 
   431 	SDL_AllocSurface() has been renamed SDL_CreateRGBSurface(), and
   432 	a new function SDL_CreateRGBSurfaceFrom() has been added to allow
   433 	creating an SDL surface from an existing pixel data buffer.
   434 
   435 	Added SDL_GetRGB() to the headers and documentation.
   436 
   437 0.11.4:
   438 	SDL_SetLibraryPath() is no longer meaningful, and has been removed.
   439 
   440 0.11.3:
   441 	A new flag for SDL_Init(), SDL_INIT_NOPARACHUTE, prevents SDL from
   442 	installing fatal signal handlers on operating systems that support
   443 	them.
   444 
   445 Version 0.9:
   446 
   447 0.9.15:
   448 	SDL_CreateColorCursor() has been removed.  Color cursors should
   449 	be implemented as sprites, blitted by the application when the
   450 	cursor moves.  To get smooth color cursor updates when the app
   451 	is busy, pass the SDL_INIT_EVENTTHREAD flag to SDL_Init().  This
   452 	allows you to handle the mouse motion in another thread from an
   453 	event filter function, but is currently only supported by Linux
   454 	and BeOS.  Note that you'll have to protect the display surface
   455 	from multi-threaded access by using mutexes if you do this.
   456 
   457 	Thread-safe surface support has been removed from SDL.
   458 	This makes blitting somewhat faster, by removing SDL_MiddleBlit().
   459 	Code that used SDL_MiddleBlit() should use SDL_LowerBlit() instead.
   460 	You can make your surfaces thread-safe by allocating your own
   461 	mutex and making lock/unlock calls around accesses to your surface.
   462 
   463 0.9.14:
   464 	SDL_GetMouseState() now takes pointers to int rather than Uint16.
   465 
   466 	If you set the SDL_WINDOWID environment variable under UNIX X11,
   467 	SDL will use that as the main window instead of creating it's own.
   468 	This is an unsupported extension to SDL, and not portable at all.
   469 
   470 0.9.13:
   471 	Added a function SDL_SetLibraryPath() which can be used to specify
   472 	the directory containing the SDL dynamic libraries.  This is useful
   473 	for commercial applications which ship with particular versions
   474 	of the libraries, and for security on multi-user systems.
   475 	If this function is not used, the default system directories are 
   476 	searched using the native dynamic object loading mechanism.
   477 
   478 	In order to support C linkage under Visual C++, you must declare
   479 	main() without any return type:
   480 		main(int argc, char *argv[]) {
   481 			/* Do the program... */
   482 			return(0);
   483 		}
   484 	C++ programs should also return a value if compiled under VC++.
   485 
   486 	The blit_endian member of the SDL_VideoInfo struct has been removed.
   487 
   488 	SDL_SymToASCII() has been replaced with SDL_GetKeyName(), so there
   489 	is now no longer any function to translate a keysym to a character.
   490 
   491 	The SDL_keysym structure has been extended with a 'scancode' and
   492 	'unicode' member.  The 'scancode' is a hardware specific scancode
   493 	for the key that was pressed, and may be 0.  The 'unicode' member
   494 	is a 16-bit UNICODE translation of the key that was pressed along
   495 	with any modifiers or compose keys that have been pressed.
   496 	If no UNICODE translation exists for the key, 'unicode' will be 0.
   497 
   498 	Added a function SDL_EnableUNICODE() to enable/disable UNICODE
   499 	translation of character keypresses.  Translation defaults off.
   500 
   501 	To convert existing code to use the new API, change code which
   502 	uses SDL_SymToASCII() to get the keyname to use SDL_GetKeyName(),
   503 	and change code which uses it to get the ASCII value of a sym to
   504 	use the 'unicode' member of the event keysym.
   505 
   506 0.9.12:
   507 	There is partial support for 64-bit datatypes.  I don't recommend 
   508 	you use this if you have a choice, because 64-bit datatypes are not
   509 	supported on many platforms.  On platforms for which it is supported,
   510 	the SDL_HAS_64BIT_TYPE C preprocessor define will be enabled, and
   511 	you can use the Uint64 and Sint64 datatypes.
   512 
   513 	Added functions to SDL_endian.h to support 64-bit datatypes:
   514 	    SDL_SwapLE64(), SDL_SwapBE64(),
   515 	    SDL_ReadLE64(), SDL_ReadBE64(), SDL_WriteLE64(), SDL_WriteBE64()
   516 
   517 	A new member "len_ratio" has been added to the SDL_AudioCVT structure,
   518 	and allows you to determine either the original buffer length or the
   519 	converted buffer length, given the other.
   520 
   521 	A new function SDL_FreeWAV() has been added to the API to free data
   522 	allocated by SDL_LoadWAV_RW().  This is necessary under Win32 since
   523 	the gcc compiled DLL uses a different heap than VC++ compiled apps.
   524 
   525 	SDL now has initial support for international keyboards using the
   526 	Latin character set.
   527 	If a particular mapping is desired, you can set the DEFAULT_KEYBOARD
   528 	compile-time variable, or you can set the environment variable 
   529 	"SDL_KEYBOARD" to a string identifying the keyboard mapping you desire.
   530 	The valid values for these variables can be found in SDL_keyboard.c
   531 
   532 	Full support for German and French keyboards under X11 is implemented.
   533 
   534 0.9.11:
   535 	The THREADED_EVENTS compile-time define has been replaced with the
   536 	SDL_INIT_EVENTTHREAD flag.  If this flag is passed to SDL_Init(),
   537 	SDL will create a separate thread to perform input event handling.
   538 	If this flag is passed to SDL_Init(), and the OS doesn't support 
   539 	event handling in a separate thread, SDL_Init() will fail.
   540 	Be sure to add calls to SDL_Delay() in your main thread to allow
   541 	the OS to schedule your event thread, or it may starve, leading
   542 	to slow event delivery and/or dropped events.
   543 	Currently MacOS and Win32 do not support this flag, while BeOS 
   544 	and Linux do support it.  I recommend that your application only
   545 	use this flag if absolutely necessary.
   546 
   547 	The SDL thread function passed to SDL_CreateThread() now returns a
   548 	status.  This status can be retrieved by passing a non-NULL pointer
   549 	as the 'status' argument to SDL_WaitThread().
   550 
   551 	The volume parameter to SDL_MixAudio() has been increased in range
   552 	from (0-8) to (0-128)
   553 
   554 	SDL now has a data source abstraction which can encompass a file,
   555 	an area of memory, or any custom object you can envision.  It uses
   556 	these abstractions, SDL_RWops, in the endian read/write functions,
   557 	and the built-in WAV and BMP file loaders.  This means you can load
   558 	WAV chunks from memory mapped files, compressed archives, network
   559 	pipes, or anything else that has a data read abstraction.
   560 
   561 	There are three built-in data source abstractions:
   562 	    SDL_RWFromFile(), SDL_RWFromFP(), SDL_RWFromMem()
   563 	along with a generic data source allocation function:
   564 	    SDL_AllocRW()
   565 	These data sources can be used like stdio file pointers with the
   566 	following convenience functions:
   567 	    SDL_RWseek(), SDL_RWread(), SDL_RWwrite(), SDL_RWclose()
   568 	These functions are defined in the new header file "SDL_rwops.h"
   569 
   570 	The endian swapping functions have been turned into macros for speed
   571 	and SDL_CalculateEndian() has been removed.  SDL_endian.h now defines
   572 	SDL_BYTEORDER as either SDL_BIG_ENDIAN or SDL_LIL_ENDIAN depending on
   573 	the endianness of the host system.
   574 
   575 	The endian read/write functions now take an SDL_RWops pointer
   576 	instead of a stdio FILE pointer, to support the new data source
   577 	abstraction.
   578 
   579 	The SDL_*LoadWAV() functions have been replaced with a single
   580 	SDL_LoadWAV_RW() function that takes a SDL_RWops pointer as it's
   581 	first parameter, and a flag whether or not to automatically 
   582 	free it as the second parameter.  SDL_LoadWAV() is a macro for
   583 	backward compatibility and convenience:
   584 	    SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
   585 
   586 	The SDL_*LoadBMP()/SDL_*SaveBMP() functions have each been replaced
   587 	with a single function that takes a SDL_RWops pointer as it's
   588 	first parameter, and a flag whether or not to automatically 
   589 	free it as the second parameter.  SDL_LoadBMP() and SDL_SaveBMP()
   590 	are macros for backward compatibility and convenience:
   591 	    SDL_LoadBMP_RW(SDL_RWFromFile("sample.bmp", "rb"), 1, ...);
   592 	    SDL_SaveBMP_RW(SDL_RWFromFile("sample.bmp", "wb"), 1, ...);
   593 	Note that these functions use SDL_RWseek() extensively, and should
   594 	not be used on pipes or other non-seekable data sources.
   595 
   596 0.9.10:
   597 	The Linux SDL_SysWMInfo and SDL_SysWMMsg structures have been 
   598 	extended to support multiple types of display drivers, as well as
   599         safe access to the X11 display when THREADED_EVENTS is enabled.
   600         The new structures are documented in the SDL_syswm.h header file.
   601 
   602 	Thanks to John Elliott <jce@seasip.demon.co.uk>, the UK keyboard
   603 	should now work properly, as well as the "Windows" keys on US
   604 	keyboards.
   605 
   606 	The Linux CD-ROM code now reads the CD-ROM devices from /etc/fstab
   607 	instead of trying to open each block device on the system.
   608 	The CD must be listed in /etc/fstab as using the iso9660 filesystem.
   609 
   610 	On Linux, if you define THREADED_EVENTS at compile time, a separate
   611 	thread will be spawned to gather X events asynchronously from the
   612 	graphics updates.  This hasn't been extensively tested, but it does
   613 	provide a means of handling keyboard and mouse input in a separate
   614 	thread from the graphics thread.  (This is now enabled by default.)
   615 
   616 	A special access function SDL_PeepEvents() allows you to manipulate
   617 	the event queue in a thread-safe manner, including peeking at events,
   618 	removing events of a specified type, and adding new events of arbitrary
   619 	type to the queue (use the new 'user' member of the SDL_Event type).
   620 
   621 	If you use SDL_PeepEvents() to gather events, then the main graphics
   622 	thread needs to call SDL_PumpEvents() periodically to drive the event
   623 	loop and generate input events.  This is not necessary if SDL has been 
   624 	compiled with THREADED_EVENTS defined, but doesn't hurt.
   625 
   626 	A new function SDL_ThreadID() returns the identifier associated with
   627 	the current thread.
   628 
   629 0.9.9:
   630 	The AUDIO_STEREO format flag has been replaced with a new 'channels'
   631 	member of the SDL_AudioSpec structure.  The channels are 1 for mono
   632 	audio, and 2 for stereo audio.  In the future more channels may be
   633 	supported for 3D surround sound.
   634 
   635 	The SDL_MixAudio() function now takes an additional volume parameter,
   636 	which should be set to SDL_MIX_MAXVOLUME for compatibility with the
   637 	original function.
   638 
   639 	The CD-ROM functions which take a 'cdrom' parameter can now be
   640 	passed NULL, and will act on the last successfully opened CD-ROM.
   641 
   642 0.9.8:
   643 	No changes, bugfixes only.
   644 	
   645 0.9.7:
   646 	No changes, bugfixes only.
   647 	
   648 0.9.6:
   649 	Added a fast rectangle fill function: SDL_FillRect()
   650 
   651 	Addition of a useful function for getting info on the video hardware:
   652 	    const SDL_VideoInfo *SDL_GetVideoInfo(void)
   653         This function replaces SDL_GetDisplayFormat().
   654 
   655 	Initial support for double-buffering:
   656 	  Use the SDL_DOUBLEBUF flag in SDL_SetVideoMode()
   657 	  Update the screen with a new function: SDL_Flip()
   658 
   659 	SDL_AllocSurface() takes two new flags:
   660 	SDL_SRCCOLORKEY means that the surface will be used for colorkey blits
   661 	  and if the hardware supports hardware acceleration of colorkey blits
   662 	  between two surfaces in video memory, to place the surface in video
   663 	  memory if possible, otherwise it will be placed in system memory.
   664 	SDL_SRCALPHA means that the surface will be used for alpha blits and
   665 	  if the hardware supports hardware acceleration of alpha blits between
   666 	  two surfaces in video memory, to place the surface in video memory
   667 	  if possible, otherwise it will be placed in system memory.
   668 	SDL_HWSURFACE now means that the surface will be created with the 
   669 	  same format as the display surface, since having surfaces in video
   670 	  memory is only useful for fast blitting to the screen, and you can't
   671 	  blit surfaces with different surface formats in video memory.
   672 
   673 0.9.5:
   674 	You can now pass a NULL mask to SDL_WM_SetIcon(), and it will assume
   675 	that the icon consists of the entire image.
   676 
   677 	SDL_LowerBlit() is back -- but don't use it on the display surface.
   678 	It is exactly the same as SDL_MiddleBlit(), but doesn't check for
   679 	thread safety.
   680 
   681 	Added SDL_FPLoadBMP(), SDL_FPSaveBMP(), SDL_FPLoadWAV(), which take
   682 	a FILE pointer instead of a file name.
   683 
   684 	Added CD-ROM audio control API:
   685 	    SDL_CDNumDrives()
   686 	    SDL_CDName()
   687 	    SDL_CDOpen()
   688 	    SDL_CDStatus()
   689 	    SDL_CDPlayTracks()
   690 	    SDL_CDPlay()
   691 	    SDL_CDPause()
   692 	    SDL_CDResume()
   693 	    SDL_CDStop()
   694 	    SDL_CDEject()
   695 	    SDL_CDClose()
   696 
   697 0.9.4:
   698 	No changes, bugfixes only.
   699 
   700 0.9.3:
   701 	Mouse motion event now includes relative motion information:
   702 	    Sint16 event->motion.xrel, Sint16 event->motion.yrel
   703 
   704 	X11 keyrepeat handling can be disabled by defining IGNORE_X_KEYREPEAT
   705 	    (Add -DIGNORE_X_KEYREPEAT to CFLAGS line in obj/x11Makefile)
   706 
   707 0.9.2:
   708 	No changes, bugfixes only.
   709 
   710 0.9.1:
   711 	Removed SDL_MapSurface() and SDL_UnmapSurface() -- surfaces are now
   712 	automatically mapped on blit.
   713 
   714 0.8.0:
   715 	SDL stable release