WhatsNew
author Sam Lantinga <slouken@libsdl.org>
Tue, 09 May 2006 08:52:54 +0000
changeset 1794 5605a9820134
parent 1765 c2c6ff414ef5
child 1895 c121d94672cb
child 3960 f5daa62ce1c4
permissions -rw-r--r--
Fixed bug #137

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