WhatsNew
author Sam Lantinga <slouken@libsdl.org>
Thu, 27 Apr 2006 09:09:48 +0000
branchSDL-1.3
changeset 1656 96c2f89cc7e1
parent 1545 8d9bb0cf2c2a
child 1659 14717b52abc0
permissions -rw-r--r--
SDL-trunk-1.3-merge-1
     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 	Added SDL_GL_SWAP_CONTROL to wait for vsync in OpenGL applications.
     8 
     9 	Added SDL_GL_ACCELERATED_VISUAL to guarantee hardware acceleration.
    10 
    11 	Added current_w and current_h to the SDL_VideoInfo structure,
    12 	which is set to the desktop resolution during video intialization,
    13 	and then set to the current resolution when a video mode is set.
    14 
    15 	SDL_SetVideoMode() now accepts 0 for width or height and will use
    16 	the current video mode (or the desktop mode if no mode has been set.)
    17 
    18 	Added SDL_GetKeyRepeat()
    19 
    20 	Added SDL_config.h, with defaults for various build environments.
    21 
    22 1.2.7:
    23 	Added CPU feature detection functions to SDL_cpuinfo.h:
    24 		SDL_HasRDTSC(), SDL_HasMMX(), SDL_Has3DNow(), SDL_HasSSE(),
    25 		SDL_HasAltiVec()
    26 	Added function to create RWops from const memory: SDL_RWFromConstMem()
    27 
    28 1.2.6:
    29 	Added SDL_LoadObject(), SDL_LoadFunction(), and SDL_UnloadObject()
    30 
    31 	Added SDL_GL_MULTISAMPLEBUFFERS and SDL_GL_MULTISAMPLESAMPLES for FSAA
    32 
    33 1.2.5:
    34 	Added SDL_BUTTON_WHEELUP (4) and SDL_BUTTON_WHEELDOWN (5)
    35 
    36 	Added SDL_GL_STEREO for stereoscopic OpenGL contexts
    37 
    38 1.2.0:
    39 	Added SDL_VIDEOEXPOSE event to signal that the screen needs to
    40 	be redrawn.  This is currently only delivered to OpenGL windows
    41 	on X11, though it may be delivered in the future when the video
    42 	memory is lost under DirectX.
    43 
    44 1.1.8:
    45 	You can pass SDL_NOFRAME to SDL_VideoMode() to create a window
    46 	that has no title bar or frame decoration.  Fullscreen video
    47 	modes automatically have this flag set.
    48 
    49 	Added a function to query the clipping rectangle for a surface:
    50 		void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect)
    51 
    52 	Added a function to query the current event filter:
    53 		SDL_EventFilter SDL_GetEventFilter(void)
    54 
    55 	If you pass -1 to SDL_ShowCursor(), it won't change the current
    56 	cursor visibility state, but will still return it.
    57 
    58 	SDL_LockSurface() and SDL_UnlockSurface() are recursive, meaning
    59 	you can nest them as deep as you want, as long as each lock call
    60 	has a matching unlock call.  The surface remains locked until the
    61 	last matching unlock call.
    62 
    63 	Note that you may not blit to or from a locked surface.
    64 
    65 1.1.7:
    66 	The SDL_SetGammaRamp() and SDL_GetGammaRamp() functions now take
    67 	arrays of Uint16 values instead of Uint8 values.  For the most part,
    68 	you can just take your old values and shift them up 8 bits to get
    69 	new correct values for your gamma ramps.
    70 
    71 	You can pass SDL_RLEACCEL in flags passed to SDL_ConvertSurface()
    72         and SDL will try to RLE accelerate colorkey and alpha blits in the
    73 	resulting surface.
    74 
    75 1.1.6:
    76 	Added a function to return the thread ID of a specific thread:
    77 		Uint32 SDL_GetThreadID(SDL_Thread *thread)
    78 	If 'thread' is NULL, this function returns the id for this thread.
    79 
    80 1.1.5:
    81 	The YUV overlay structure has been changed to use an array of
    82 	pitches and pixels representing the planes of a YUV image, to
    83 	better enable hardware acceleration.  The YV12 and IYUV formats
    84 	each have three planes, corresponding to the Y, U, and V portions
    85 	of the image, while packed pixel YUV formats just have one plane.
    86 
    87 	For palettized mode (8bpp), the screen colormap is now split in
    88 	a physical and a logical palette. The physical palette determines
    89 	what colours the screen pixels will get when displayed, and the
    90 	logical palette controls the mapping from blits to/from the screen.
    91 	A new function, SDL_SetPalette() has been added to change
    92 	logical and physical palettes separately. SDL_SetColors() works
    93 	just as before, and is equivalent to calling SDL_SetPalette() with
    94 	a flag argument of (SDL_LOGPAL|SDL_PHYSPAL).
    95 
    96 	SDL_BlitSurface() no longer modifies the source rectangle, only the
    97 	destination rectangle. The width/height members of the destination
    98 	rectangle are ignored, only the position is used.
    99 
   100 	The old source clipping function SDL_SetClipping() has been replaced
   101 	with a more useful function to set the destination clipping rectangle:
   102 		SDL_bool SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect)
   103 		
   104 	Added a function to see what subsystems have been initialized:
   105 		Uint32 SDL_WasInit(Uint32 flags)
   106 
   107 	The Big Alpha Flip: SDL now treats alpha as opacity like everybody
   108 	else, and not as transparency:
   109 
   110 	A new cpp symbol: SDL_ALPHA_OPAQUE is defined as 255
   111 	A new cpp symbol: SDL_ALPHA_TRANSPARENT is defined as 0
   112 	Values between 0 and 255 vary from fully transparent to fully opaque.
   113 
   114 	New functions:
   115 	SDL_DisplayFormatAlpha()
   116 	    Returns a surface converted to a format with alpha-channel
   117 	    that can be blit efficiently to the screen. (In other words,
   118 	    like SDL_DisplayFormat() but the resulting surface has
   119 	    an alpha channel.)  This is useful for surfaces with alpha.
   120 	SDL_MapRGBA()
   121 	    Works as SDL_MapRGB() but takes an additional alpha parameter.
   122 	SDL_GetRGBA()
   123 	    Works as SDL_GetRGB() but also returns the alpha value
   124 	    (SDL_ALPHA_OPAQUE for formats without an alpha channel)
   125 
   126 	Both SDL_GetRGB() and SDL_GetRGBA() now always return values in
   127 	the [0..255] interval. Previously, SDL_GetRGB() would return
   128 	(0xf8, 0xfc, 0xf8) for a completely white pixel in RGB565 format.
   129 	(N.B.: This is broken for bit fields < 3 bits.)
   130 
   131 	SDL_MapRGB() returns pixels in which the alpha channel is set opaque.
   132 
   133 	SDL_SetAlpha() can now be used for both setting the per-surface
   134 	alpha, using the new way of thinking of alpha, and also to enable
   135 	and disable per-pixel alpha blending for surfaces with an alpha
   136 	channel:
   137 		To disable alpha blending:
   138 			SDL_SetAlpha(surface, 0, 0);
   139 		To re-enable alpha blending:
   140 			SDL_SetAlpha(surface, SDL_SRCALPHA, 0);
   141 	Surfaces with an alpha channel have blending enabled by default.
   142 
   143 	SDL_SetAlpha() now accepts SDL_RLEACCEL as a flag, which requests
   144 	RLE acceleration of blits, just as like with SDL_SetColorKey().
   145 	This flag can be set for both surfaces with an alpha channel
   146 	and surfaces with an alpha value set by SDL_SetAlpha().
   147 	As always, RLE surfaces must be locked before pixel access is
   148 	allowed, and unlocked before any other SDL operations are done
   149 	on it.
   150 
   151 	The blit semantics for surfaces with and without alpha and colorkey
   152 	have now been defined:
   153 
   154 	RGBA->RGB:
   155 	    SDL_SRCALPHA set:
   156 		alpha-blend (using alpha-channel).
   157 		SDL_SRCCOLORKEY ignored.
   158 	    SDL_SRCALPHA not set:
   159 		copy RGB.
   160 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   161 		RGB values of the source colour key, ignoring alpha in the
   162 		comparison.
   163 
   164 	RGB->RGBA:
   165 	    SDL_SRCALPHA set:
   166 		alpha-blend (using the source per-surface alpha value);
   167 		set destination alpha to opaque.
   168 	    SDL_SRCALPHA not set:
   169 		copy RGB, set destination alpha to opaque.
   170 	    both:
   171 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   172 		source colour key.
   173 
   174 	RGBA->RGBA:
   175 	    SDL_SRCALPHA set:
   176 		alpha-blend (using the source alpha channel) the RGB values;
   177 		leave destination alpha untouched. [Note: is this correct?]
   178 		SDL_SRCCOLORKEY ignored.
   179 	    SDL_SRCALPHA not set:
   180 		copy all of RGBA to the destination.
   181 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   182 		RGB values of the source colour key, ignoring alpha in the
   183 		comparison.
   184 
   185 	RGB->RGB: 
   186 	    SDL_SRCALPHA set:
   187 		alpha-blend (using the source per-surface alpha value).
   188 	    SDL_SRCALPHA not set:
   189 		copy RGB.
   190 	    both:
   191 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   192 		source colour key.
   193 
   194 	As a special case, blits from surfaces with per-surface alpha
   195 	value of 128 (50% transparency) are optimised and much faster
   196 	than other alpha values. This does not apply to surfaces with
   197 	alpha channels (per-pixel alpha).
   198 
   199 	New functions for manipulating the gamma of the display have
   200 	been added:
   201 		int SDL_SetGamma(float red, float green, float blue);
   202 		int SDL_SetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   203 		int SDL_GetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   204 	Gamma ramps are tables with 256 entries which map the screen color
   205 	components into actually displayed colors.  For an example of
   206 	implementing gamma correction and gamma fades, see test/testgamma.c
   207 	Gamma control is not supported on all hardware.
   208 
   209 1.1.4:
   210 	The size of the SDL_CDtrack structure changed from 8 to 12 bytes
   211 	as the size of the length member was extended to 32 bits.
   212 
   213         You can now use SDL for 2D blitting with a GL mode by passing the
   214 	SDL_OPENGLBLIT flag to SDL_SetVideoMode().  You can specify 16 or
   215 	32 bpp, and the data in the framebuffer is put into the GL scene
   216 	when you call SDL_UpdateRects(), and the scene will be visible
   217 	when you call SDL_GL_SwapBuffers().
   218 
   219 	Run the "testgl" test program with the -logo command line option
   220 	to see an example of this blending of 2D and 3D in SDL.
   221 
   222 1.1.3:
   223 	Added SDL_FreeRW() to the API, to complement SDL_AllocRW()
   224 
   225 	Added resizable window support - just add SDL_RESIZABLE to the
   226 	SDL_SetVideoMode() flags, and then wait for SDL_VIDEORESIZE events.
   227 	See SDL_events.h for details on the new SDL_ResizeEvent structure.
   228 
   229 	Added condition variable support, based on mutexes and semaphores.
   230 		SDL_CreateCond()
   231 		SDL_DestroyCond()
   232 		SDL_CondSignal()
   233 		SDL_CondBroadcast()
   234 		SDL_CondWait()
   235 		SDL_CondTimedWait()
   236 	The new function prototypes are in SDL_mutex.h
   237 
   238 	Added counting semaphore support, based on the mutex primitive.
   239 		SDL_CreateSemaphore()
   240 		SDL_DestroySemaphore()
   241 		SDL_SemWait()
   242 		SDL_SemTryWait()
   243 		SDL_SemWaitTimeout()
   244 		SDL_SemPost()
   245 		SDL_SemValue()
   246 	The new function prototypes are in SDL_mutex.h
   247 
   248 	Added support for asynchronous blitting.  To take advantage of this,
   249 	you must set the SDL_ASYNCBLIT flag when setting the video mode and
   250 	creating surfaces that you want accelerated in this way.  You must
   251 	lock surfaces that have this flag set, and the lock will block until
   252 	any queued blits have completed.
   253 
   254 	Added YUV video overlay support.
   255 	The supported YUV formats are: YV12, IYUV, YUY2, UYVY, and YVYU.
   256 	This function creates an overlay surface:
   257 		SDL_CreateYUVOverlay()
   258 	You must lock and unlock the overlay to get access to the data:
   259 		SDL_LockYUVOverlay() SDL_UnlockYUVOverlay()
   260 	You can then display the overlay:
   261 		SDL_DisplayYUVOverlay()
   262 	You must free the overlay when you are done using it:
   263 		SDL_FreeYUVOverlay()
   264 	See SDL_video.h for the full function prototypes.
   265 
   266 	The joystick hat position constants have been changed:
   267 	Old constant            New constant
   268 	------------            ------------
   269 	     0                  SDL_HAT_CENTERED
   270 	     1                  SDL_HAT_UP
   271 	     2                  SDL_HAT_RIGHTUP
   272 	     3                  SDL_HAT_RIGHT
   273 	     4                  SDL_HAT_RIGHTDOWN
   274 	     5                  SDL_HAT_DOWN
   275 	     6                  SDL_HAT_LEFTDOWN
   276 	     7                  SDL_HAT_LEFT
   277 	     8                  SDL_HAT_LEFTUP
   278 	The new constants are bitmasks, so you can check for the
   279 	individual axes like this:
   280 		if ( hat_position & SDL_HAT_UP ) {
   281 		}
   282 	and you'll catch left-up, up, and right-up.
   283 
   284 1.1.2:
   285 	Added multiple timer support:
   286 		SDL_AddTimer() and SDL_RemoveTimer()
   287 
   288 	SDL_WM_SetIcon() now respects the icon colorkey if mask is NULL.
   289 
   290 1.1.0:
   291 	Added initial OpenGL support.
   292 	First set GL attributes (such as RGB depth, alpha depth, etc.)
   293 		SDL_GL_SetAttribute()
   294 	Then call SDL_SetVideoMode() with the SDL_OPENGL flag.
   295 	Perform all of your normal GL drawing.
   296 	Finally swap the buffers with the new SDL function:
   297 		SDL_GL_SwapBuffers()
   298 	See the new 'testgl' test program for an example of using GL with SDL.
   299 
   300 	You can load GL extension functions by using the function:
   301 		SDL_GL_LoadProcAddress()
   302 
   303 	Added functions to initialize and cleanup specific SDL subsystems:
   304 		SDL_InitSubSystem() and SDL_QuitSubSystem()
   305 
   306 	Added user-defined event type:
   307 		typedef struct {
   308         		Uint8 type;
   309         		int code;
   310         		void *data1;
   311         		void *data2;
   312 		} SDL_UserEvent;
   313 	This structure is in the "user" member of an SDL_Event.
   314 
   315 	Added a function to push events into the event queue:
   316 		SDL_PushEvent()
   317 
   318 	Example of using the new SDL user-defined events:
   319 	{
   320 		SDL_Event event;
   321 
   322 		event.type = SDL_USEREVENT;
   323 		event.user.code = my_event_code;
   324 		event.user.data1 = significant_data;
   325 		event.user.data2 = 0;
   326 		SDL_PushEvent(&event);
   327 	}
   328 
   329 	Added a function to get mouse deltas since last query:
   330 		SDL_GetRelativeMouseState()
   331 
   332 	Added a boolean datatype to SDL_types.h:
   333 		SDL_bool = { SDL_TRUE, SDL_FALSE }
   334 
   335 	Added a function to get the current audio status:
   336 		SDL_GetAudioState();
   337 	It returns one of:
   338 		SDL_AUDIO_STOPPED,
   339 		SDL_AUDIO_PLAYING,
   340 		SDL_AUDIO_PAUSED
   341 
   342 	Added an AAlib driver (ASCII Art) - by Stephane Peter.
   343 
   344 1.0.6:
   345 	The input grab state is reset after each call to SDL_SetVideoMode().
   346 	The input is grabbed by default in fullscreen mode, and ungrabbed in
   347 	windowed mode.  If you want to set input grab to a particular value,
   348 	you should set it after each call to SDL_SetVideoMode().
   349 
   350 1.0.5:
   351 	Exposed SDL_AudioInit(), SDL_VideoInit()
   352 	Added SDL_AudioDriverName() and SDL_VideoDriverName()
   353 
   354 	Added new window manager function:
   355 		SDL_WM_ToggleFullScreen()
   356 	This is currently implemented only on Linux
   357 
   358 	The ALT-ENTER code has been removed - it's not appropriate for a
   359 	lib to bind keys when they aren't even emergency escape sequences.
   360 
   361 	ALT-ENTER functionality can be implemented with the following code:
   362 
   363 	int Handle_AltEnter(const SDL_Event *event)
   364 	{
   365 	    if ( event->type == SDL_KEYDOWN ) {
   366 	        if ( (event->key.keysym.sym == SDLK_RETURN) &&
   367 	             (event->key.keysym.mod & KMOD_ALT) ) {   
   368 	                SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
   369 	                return(0);
   370 	        }
   371 	    }
   372 	    return(1);
   373 	}
   374 	SDL_SetEventFilter(Handle_AltEnter);
   375 
   376 1.0.3:
   377 	Under X11, if you grab the input and hide the mouse cursor,
   378 	the mouse will go into a "relative motion" mode where you
   379 	will always get relative motion events no matter how far in
   380 	each direction you move the mouse - relative motion is not
   381 	bounded by the edges of the window (though the absolute values
   382 	of the mouse positions are clamped by the size of the window).
   383 	The SVGAlib, framebuffer console, and DirectInput drivers all
   384 	have this behavior naturally, and the GDI and BWindow drivers
   385 	never go into "relative motion" mode.
   386 
   387 1.0.2:
   388 	Added a function to enable keyboard repeat:
   389 		SDL_EnableKeyRepeat()
   390 
   391 	Added a function to grab the mouse and keyboard input
   392 		SDL_WM_GrabInput()
   393 
   394 	Added a function to iconify the window.
   395 		SDL_WM_IconifyWindow()
   396 	If this function succeeds, the application will receive an event
   397 	signaling SDL_APPACTIVE event 
   398 
   399 1.0.1:
   400 	Added constants to SDL_audio.h for 16-bit native byte ordering:
   401 		AUDIO_U16SYS, AUDIO_S16SYS
   402 
   403 1.0.0:
   404 	New public release
   405 
   406 Version 0.11:
   407 
   408 0.11.5:
   409 	A new function SDL_GetVideoSurface() has been added, and returns
   410 	a pointer to the current display surface.
   411 
   412 	SDL_AllocSurface() has been renamed SDL_CreateRGBSurface(), and
   413 	a new function SDL_CreateRGBSurfaceFrom() has been added to allow
   414 	creating an SDL surface from an existing pixel data buffer.
   415 
   416 	Added SDL_GetRGB() to the headers and documentation.
   417 
   418 0.11.4:
   419 	SDL_SetLibraryPath() is no longer meaningful, and has been removed.
   420 
   421 0.11.3:
   422 	A new flag for SDL_Init(), SDL_INIT_NOPARACHUTE, prevents SDL from
   423 	installing fatal signal handlers on operating systems that support
   424 	them.
   425 
   426 Version 0.9:
   427 
   428 0.9.15:
   429 	SDL_CreateColorCursor() has been removed.  Color cursors should
   430 	be implemented as sprites, blitted by the application when the
   431 	cursor moves.  To get smooth color cursor updates when the app
   432 	is busy, pass the SDL_INIT_EVENTTHREAD flag to SDL_Init().  This
   433 	allows you to handle the mouse motion in another thread from an
   434 	event filter function, but is currently only supported by Linux
   435 	and BeOS.  Note that you'll have to protect the display surface
   436 	from multi-threaded access by using mutexes if you do this.
   437 
   438 	Thread-safe surface support has been removed from SDL.
   439 	This makes blitting somewhat faster, by removing SDL_MiddleBlit().
   440 	Code that used SDL_MiddleBlit() should use SDL_LowerBlit() instead.
   441 	You can make your surfaces thread-safe by allocating your own
   442 	mutex and making lock/unlock calls around accesses to your surface.
   443 
   444 0.9.14:
   445 	SDL_GetMouseState() now takes pointers to int rather than Uint16.
   446 
   447 	If you set the SDL_WINDOWID environment variable under UNIX X11,
   448 	SDL will use that as the main window instead of creating it's own.
   449 	This is an unsupported extension to SDL, and not portable at all.
   450 
   451 0.9.13:
   452 	Added a function SDL_SetLibraryPath() which can be used to specify
   453 	the directory containing the SDL dynamic libraries.  This is useful
   454 	for commercial applications which ship with particular versions
   455 	of the libraries, and for security on multi-user systems.
   456 	If this function is not used, the default system directories are 
   457 	searched using the native dynamic object loading mechanism.
   458 
   459 	In order to support C linkage under Visual C++, you must declare
   460 	main() without any return type:
   461 		main(int argc, char *argv[]) {
   462 			/* Do the program... */
   463 			return(0);
   464 		}
   465 	C++ programs should also return a value if compiled under VC++.
   466 
   467 	The blit_endian member of the SDL_VideoInfo struct has been removed.
   468 
   469 	SDL_SymToASCII() has been replaced with SDL_GetKeyName(), so there
   470 	is now no longer any function to translate a keysym to a character.
   471 
   472 	The SDL_keysym structure has been extended with a 'scancode' and
   473 	'unicode' member.  The 'scancode' is a hardware specific scancode
   474 	for the key that was pressed, and may be 0.  The 'unicode' member
   475 	is a 16-bit UNICODE translation of the key that was pressed along
   476 	with any modifiers or compose keys that have been pressed.
   477 	If no UNICODE translation exists for the key, 'unicode' will be 0.
   478 
   479 	Added a function SDL_EnableUNICODE() to enable/disable UNICODE
   480 	translation of character keypresses.  Translation defaults off.
   481 
   482 	To convert existing code to use the new API, change code which
   483 	uses SDL_SymToASCII() to get the keyname to use SDL_GetKeyName(),
   484 	and change code which uses it to get the ASCII value of a sym to
   485 	use the 'unicode' member of the event keysym.
   486 
   487 0.9.12:
   488 	There is partial support for 64-bit datatypes.  I don't recommend 
   489 	you use this if you have a choice, because 64-bit datatypes are not
   490 	supported on many platforms.  On platforms for which it is supported,
   491 	the SDL_HAS_64BIT_TYPE C preprocessor define will be enabled, and
   492 	you can use the Uint64 and Sint64 datatypes.
   493 
   494 	Added functions to SDL_endian.h to support 64-bit datatypes:
   495 	    SDL_SwapLE64(), SDL_SwapBE64(),
   496 	    SDL_ReadLE64(), SDL_ReadBE64(), SDL_WriteLE64(), SDL_WriteBE64()
   497 
   498 	A new member "len_ratio" has been added to the SDL_AudioCVT structure,
   499 	and allows you to determine either the original buffer length or the
   500 	converted buffer length, given the other.
   501 
   502 	A new function SDL_FreeWAV() has been added to the API to free data
   503 	allocated by SDL_LoadWAV_RW().  This is necessary under Win32 since
   504 	the gcc compiled DLL uses a different heap than VC++ compiled apps.
   505 
   506 	SDL now has initial support for international keyboards using the
   507 	Latin character set.
   508 	If a particular mapping is desired, you can set the DEFAULT_KEYBOARD
   509 	compile-time variable, or you can set the environment variable 
   510 	"SDL_KEYBOARD" to a string identifying the keyboard mapping you desire.
   511 	The valid values for these variables can be found in SDL_keyboard.c
   512 
   513 	Full support for German and French keyboards under X11 is implemented.
   514 
   515 0.9.11:
   516 	The THREADED_EVENTS compile-time define has been replaced with the
   517 	SDL_INIT_EVENTTHREAD flag.  If this flag is passed to SDL_Init(),
   518 	SDL will create a separate thread to perform input event handling.
   519 	If this flag is passed to SDL_Init(), and the OS doesn't support 
   520 	event handling in a separate thread, SDL_Init() will fail.
   521 	Be sure to add calls to SDL_Delay() in your main thread to allow
   522 	the OS to schedule your event thread, or it may starve, leading
   523 	to slow event delivery and/or dropped events.
   524 	Currently MacOS and Win32 do not support this flag, while BeOS 
   525 	and Linux do support it.  I recommend that your application only
   526 	use this flag if absolutely necessary.
   527 
   528 	The SDL thread function passed to SDL_CreateThread() now returns a
   529 	status.  This status can be retrieved by passing a non-NULL pointer
   530 	as the 'status' argument to SDL_WaitThread().
   531 
   532 	The volume parameter to SDL_MixAudio() has been increased in range
   533 	from (0-8) to (0-128)
   534 
   535 	SDL now has a data source abstraction which can encompass a file,
   536 	an area of memory, or any custom object you can envision.  It uses
   537 	these abstractions, SDL_RWops, in the endian read/write functions,
   538 	and the built-in WAV and BMP file loaders.  This means you can load
   539 	WAV chunks from memory mapped files, compressed archives, network
   540 	pipes, or anything else that has a data read abstraction.
   541 
   542 	There are three built-in data source abstractions:
   543 	    SDL_RWFromFile(), SDL_RWFromFP(), SDL_RWFromMem()
   544 	along with a generic data source allocation function:
   545 	    SDL_AllocRW()
   546 	These data sources can be used like stdio file pointers with the
   547 	following convenience functions:
   548 	    SDL_RWseek(), SDL_RWread(), SDL_RWwrite(), SDL_RWclose()
   549 	These functions are defined in the new header file "SDL_rwops.h"
   550 
   551 	The endian swapping functions have been turned into macros for speed
   552 	and SDL_CalculateEndian() has been removed.  SDL_endian.h now defines
   553 	SDL_BYTEORDER as either SDL_BIG_ENDIAN or SDL_LIL_ENDIAN depending on
   554 	the endianness of the host system.
   555 
   556 	The endian read/write functions now take an SDL_RWops pointer
   557 	instead of a stdio FILE pointer, to support the new data source
   558 	abstraction.
   559 
   560 	The SDL_*LoadWAV() functions have been replaced with a single
   561 	SDL_LoadWAV_RW() function that takes a SDL_RWops pointer as it's
   562 	first parameter, and a flag whether or not to automatically 
   563 	free it as the second parameter.  SDL_LoadWAV() is a macro for
   564 	backward compatibility and convenience:
   565 	    SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
   566 
   567 	The SDL_*LoadBMP()/SDL_*SaveBMP() functions have each been replaced
   568 	with a single function that takes a SDL_RWops pointer as it's
   569 	first parameter, and a flag whether or not to automatically 
   570 	free it as the second parameter.  SDL_LoadBMP() and SDL_SaveBMP()
   571 	are macros for backward compatibility and convenience:
   572 	    SDL_LoadBMP_RW(SDL_RWFromFile("sample.bmp", "rb"), 1, ...);
   573 	    SDL_SaveBMP_RW(SDL_RWFromFile("sample.bmp", "wb"), 1, ...);
   574 	Note that these functions use SDL_RWseek() extensively, and should
   575 	not be used on pipes or other non-seekable data sources.
   576 
   577 0.9.10:
   578 	The Linux SDL_SysWMInfo and SDL_SysWMMsg structures have been 
   579 	extended to support multiple types of display drivers, as well as
   580         safe access to the X11 display when THREADED_EVENTS is enabled.
   581         The new structures are documented in the SDL_syswm.h header file.
   582 
   583 	Thanks to John Elliott <jce@seasip.demon.co.uk>, the UK keyboard
   584 	should now work properly, as well as the "Windows" keys on US
   585 	keyboards.
   586 
   587 	The Linux CD-ROM code now reads the CD-ROM devices from /etc/fstab
   588 	instead of trying to open each block device on the system.
   589 	The CD must be listed in /etc/fstab as using the iso9660 filesystem.
   590 
   591 	On Linux, if you define THREADED_EVENTS at compile time, a separate
   592 	thread will be spawned to gather X events asynchronously from the
   593 	graphics updates.  This hasn't been extensively tested, but it does
   594 	provide a means of handling keyboard and mouse input in a separate
   595 	thread from the graphics thread.  (This is now enabled by default.)
   596 
   597 	A special access function SDL_PeepEvents() allows you to manipulate
   598 	the event queue in a thread-safe manner, including peeking at events,
   599 	removing events of a specified type, and adding new events of arbitrary
   600 	type to the queue (use the new 'user' member of the SDL_Event type).
   601 
   602 	If you use SDL_PeepEvents() to gather events, then the main graphics
   603 	thread needs to call SDL_PumpEvents() periodically to drive the event
   604 	loop and generate input events.  This is not necessary if SDL has been 
   605 	compiled with THREADED_EVENTS defined, but doesn't hurt.
   606 
   607 	A new function SDL_ThreadID() returns the identifier associated with
   608 	the current thread.
   609 
   610 0.9.9:
   611 	The AUDIO_STEREO format flag has been replaced with a new 'channels'
   612 	member of the SDL_AudioSpec structure.  The channels are 1 for mono
   613 	audio, and 2 for stereo audio.  In the future more channels may be
   614 	supported for 3D surround sound.
   615 
   616 	The SDL_MixAudio() function now takes an additional volume parameter,
   617 	which should be set to SDL_MIX_MAXVOLUME for compatibility with the
   618 	original function.
   619 
   620 	The CD-ROM functions which take a 'cdrom' parameter can now be
   621 	passed NULL, and will act on the last successfully opened CD-ROM.
   622 
   623 0.9.8:
   624 	No changes, bugfixes only.
   625 	
   626 0.9.7:
   627 	No changes, bugfixes only.
   628 	
   629 0.9.6:
   630 	Added a fast rectangle fill function: SDL_FillRect()
   631 
   632 	Addition of a useful function for getting info on the video hardware:
   633 	    const SDL_VideoInfo *SDL_GetVideoInfo(void)
   634         This function replaces SDL_GetDisplayFormat().
   635 
   636 	Initial support for double-buffering:
   637 	  Use the SDL_DOUBLEBUF flag in SDL_SetVideoMode()
   638 	  Update the screen with a new function: SDL_Flip()
   639 
   640 	SDL_AllocSurface() takes two new flags:
   641 	SDL_SRCCOLORKEY means that the surface will be used for colorkey blits
   642 	  and if the hardware supports hardware acceleration of colorkey blits
   643 	  between two surfaces in video memory, to place the surface in video
   644 	  memory if possible, otherwise it will be placed in system memory.
   645 	SDL_SRCALPHA means that the surface will be used for alpha blits and
   646 	  if the hardware supports hardware acceleration of alpha blits between
   647 	  two surfaces in video memory, to place the surface in video memory
   648 	  if possible, otherwise it will be placed in system memory.
   649 	SDL_HWSURFACE now means that the surface will be created with the 
   650 	  same format as the display surface, since having surfaces in video
   651 	  memory is only useful for fast blitting to the screen, and you can't
   652 	  blit surfaces with different surface formats in video memory.
   653 
   654 0.9.5:
   655 	You can now pass a NULL mask to SDL_WM_SetIcon(), and it will assume
   656 	that the icon consists of the entire image.
   657 
   658 	SDL_LowerBlit() is back -- but don't use it on the display surface.
   659 	It is exactly the same as SDL_MiddleBlit(), but doesn't check for
   660 	thread safety.
   661 
   662 	Added SDL_FPLoadBMP(), SDL_FPSaveBMP(), SDL_FPLoadWAV(), which take
   663 	a FILE pointer instead of a file name.
   664 
   665 	Added CD-ROM audio control API:
   666 	    SDL_CDNumDrives()
   667 	    SDL_CDName()
   668 	    SDL_CDOpen()
   669 	    SDL_CDStatus()
   670 	    SDL_CDPlayTracks()
   671 	    SDL_CDPlay()
   672 	    SDL_CDPause()
   673 	    SDL_CDResume()
   674 	    SDL_CDStop()
   675 	    SDL_CDEject()
   676 	    SDL_CDClose()
   677 
   678 0.9.4:
   679 	No changes, bugfixes only.
   680 
   681 0.9.3:
   682 	Mouse motion event now includes relative motion information:
   683 	    Sint16 event->motion.xrel, Sint16 event->motion.yrel
   684 
   685 	X11 keyrepeat handling can be disabled by defining IGNORE_X_KEYREPEAT
   686 	    (Add -DIGNORE_X_KEYREPEAT to CFLAGS line in obj/x11Makefile)
   687 
   688 0.9.2:
   689 	No changes, bugfixes only.
   690 
   691 0.9.1:
   692 	Removed SDL_MapSurface() and SDL_UnmapSurface() -- surfaces are now
   693 	automatically mapped on blit.
   694 
   695 0.8.0:
   696 	SDL stable release