WhatsNew
author Sam Lantinga <slouken@libsdl.org>
Wed, 06 Mar 2002 05:20:11 +0000
changeset 294 d2d48e10f370
parent 292 eadc0746dfaf
child 296 fab1ddc4d7bf
permissions -rw-r--r--
Added a new header file: SDL_loadso.h
It contains the following functions:
SDL_LoadObject(), SDL_LoadFunction(), SDL_UnloadObject()
The UNIX esd and arts audio code use these to dynamically load
their respective audio libraries.
     1 
     2 This is a list of API changes in SDL's version history.
     3 
     4 Version 1.0:
     5 
     6 1.2.4:
     7 	Added a new header file: SDL_loadso.h
     8 	It contains the following functions:
     9 		SDL_LoadObject(), SDL_LoadFunction(), SDL_UnloadObject()
    10 	The UNIX esd and arts audio code use these to dynamically load
    11 	their respective audio libraries.
    12 
    13 	Added SDL_LockRect() and SDL_UnlockRect() to lock a portion of a
    14 	surface.  This may be more efficient than a full lock if you are
    15 	using a hardware surface and plan to make a few changes to small
    16 	areas in the surface.
    17 
    18 1.2.0:
    19 	Added SDL_VIDEOEXPOSE event to signal that the screen needs to
    20 	be redrawn.  This is currently only delivered to OpenGL windows
    21 	on X11, though it may be delivered in the future when the video
    22 	memory is lost under DirectX.
    23 
    24 1.1.8:
    25 	You can pass SDL_NOFRAME to SDL_VideoMode() to create a window
    26 	that has no title bar or frame decoration.  Fullscreen video
    27 	modes automatically have this flag set.
    28 
    29 	Added a function to query the clipping rectangle for a surface:
    30 		void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect)
    31 
    32 	Added a function to query the current event filter:
    33 		SDL_EventFilter SDL_GetEventFilter(void)
    34 
    35 	If you pass -1 to SDL_ShowCursor(), it won't change the current
    36 	cursor visibility state, but will still return it.
    37 
    38 	SDL_LockSurface() and SDL_UnlockSurface() are recursive, meaning
    39 	you can nest them as deep as you want, as long as each lock call
    40 	has a matching unlock call.  The surface remains locked until the
    41 	last matching unlock call.
    42 
    43 	Note that you may not blit to or from a locked surface.
    44 
    45 1.1.7:
    46 	The SDL_SetGammaRamp() and SDL_GetGammaRamp() functions now take
    47 	arrays of Uint16 values instead of Uint8 values.  For the most part,
    48 	you can just take your old values and shift them up 8 bits to get
    49 	new correct values for your gamma ramps.
    50 
    51 	You can pass SDL_RLEACCEL in flags passed to SDL_ConvertSurface()
    52         and SDL will try to RLE accelerate colorkey and alpha blits in the
    53 	resulting surface.
    54 
    55 1.1.6:
    56 	Added a function to return the thread ID of a specific thread:
    57 		Uint32 SDL_GetThreadID(SDL_Thread *thread)
    58 	If 'thread' is NULL, this function returns the id for this thread.
    59 
    60 1.1.5:
    61 	The YUV overlay structure has been changed to use an array of
    62 	pitches and pixels representing the planes of a YUV image, to
    63 	better enable hardware acceleration.  The YV12 and IYUV formats
    64 	each have three planes, corresponding to the Y, U, and V portions
    65 	of the image, while packed pixel YUV formats just have one plane.
    66 
    67 	For palettized mode (8bpp), the screen colormap is now split in
    68 	a physical and a logical palette. The physical palette determines
    69 	what colours the screen pixels will get when displayed, and the
    70 	logical palette controls the mapping from blits to/from the screen.
    71 	A new function, SDL_SetPalette() has been added to change
    72 	logical and physical palettes separately. SDL_SetColors() works
    73 	just as before, and is equivalent to calling SDL_SetPalette() with
    74 	a flag argument of (SDL_LOGPAL|SDL_PHYSPAL).
    75 
    76 	SDL_BlitSurface() no longer modifies the source rectangle, only the
    77 	destination rectangle. The width/height members of the destination
    78 	rectangle are ignored, only the position is used.
    79 
    80 	The old source clipping function SDL_SetClipping() has been replaced
    81 	with a more useful function to set the destination clipping rectangle:
    82 		SDL_bool SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect)
    83 		
    84 	Added a function to see what subsystems have been initialized:
    85 		Uint32 SDL_WasInit(Uint32 flags)
    86 
    87 	The Big Alpha Flip: SDL now treats alpha as opacity like everybody
    88 	else, and not as transparency:
    89 
    90 	A new cpp symbol: SDL_ALPHA_OPAQUE is defined as 255
    91 	A new cpp symbol: SDL_ALPHA_TRANSPARENT is defined as 0
    92 	Values between 0 and 255 vary from fully transparent to fully opaque.
    93 
    94 	New functions:
    95 	SDL_DisplayFormatAlpha()
    96 	    Returns a surface converted to a format with alpha-channel
    97 	    that can be blit efficiently to the screen. (In other words,
    98 	    like SDL_DisplayFormat() but the resulting surface has
    99 	    an alpha channel.)  This is useful for surfaces with alpha.
   100 	SDL_MapRGBA()
   101 	    Works as SDL_MapRGB() but takes an additional alpha parameter.
   102 	SDL_GetRGBA()
   103 	    Works as SDL_GetRGB() but also returns the alpha value
   104 	    (SDL_ALPHA_OPAQUE for formats without an alpha channel)
   105 
   106 	Both SDL_GetRGB() and SDL_GetRGBA() now always return values in
   107 	the [0..255] interval. Previously, SDL_GetRGB() would return
   108 	(0xf8, 0xfc, 0xf8) for a completely white pixel in RGB565 format.
   109 	(N.B.: This is broken for bit fields < 3 bits.)
   110 
   111 	SDL_MapRGB() returns pixels in which the alpha channel is set opaque.
   112 
   113 	SDL_SetAlpha() can now be used for both setting the per-surface
   114 	alpha, using the new way of thinking of alpha, and also to enable
   115 	and disable per-pixel alpha blending for surfaces with an alpha
   116 	channel:
   117 		To disable alpha blending:
   118 			SDL_SetAlpha(surface, 0, 0);
   119 		To re-enable alpha blending:
   120 			SDL_SetAlpha(surface, SDL_SRCALPHA, 0);
   121 	Surfaces with an alpha channel have blending enabled by default.
   122 
   123 	SDL_SetAlpha() now accepts SDL_RLEACCEL as a flag, which requests
   124 	RLE acceleration of blits, just as like with SDL_SetColorKey().
   125 	This flag can be set for both surfaces with an alpha channel
   126 	and surfaces with an alpha value set by SDL_SetAlpha().
   127 	As always, RLE surfaces must be locked before pixel access is
   128 	allowed, and unlocked before any other SDL operations are done
   129 	on it.
   130 
   131 	The blit semantics for surfaces with and without alpha and colorkey
   132 	have now been defined:
   133 
   134 	RGBA->RGB:
   135 	    SDL_SRCALPHA set:
   136 		alpha-blend (using alpha-channel).
   137 		SDL_SRCCOLORKEY ignored.
   138 	    SDL_SRCALPHA not set:
   139 		copy RGB.
   140 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   141 		RGB values of the source colour key, ignoring alpha in the
   142 		comparison.
   143 
   144 	RGB->RGBA:
   145 	    SDL_SRCALPHA set:
   146 		alpha-blend (using the source per-surface alpha value);
   147 		set destination alpha to opaque.
   148 	    SDL_SRCALPHA not set:
   149 		copy RGB, set destination alpha to opaque.
   150 	    both:
   151 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   152 		source colour key.
   153 
   154 	RGBA->RGBA:
   155 	    SDL_SRCALPHA set:
   156 		alpha-blend (using the source alpha channel) the RGB values;
   157 		leave destination alpha untouched. [Note: is this correct?]
   158 		SDL_SRCCOLORKEY ignored.
   159 	    SDL_SRCALPHA not set:
   160 		copy all of RGBA to the destination.
   161 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   162 		RGB values of the source colour key, ignoring alpha in the
   163 		comparison.
   164 
   165 	RGB->RGB: 
   166 	    SDL_SRCALPHA set:
   167 		alpha-blend (using the source per-surface alpha value).
   168 	    SDL_SRCALPHA not set:
   169 		copy RGB.
   170 	    both:
   171 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   172 		source colour key.
   173 
   174 	As a special case, blits from surfaces with per-surface alpha
   175 	value of 128 (50% transparency) are optimised and much faster
   176 	than other alpha values. This does not apply to surfaces with
   177 	alpha channels (per-pixel alpha).
   178 
   179 	New functions for manipulating the gamma of the display have
   180 	been added:
   181 		int SDL_SetGamma(float red, float green, float blue);
   182 		int SDL_SetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   183 		int SDL_GetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   184 	Gamma ramps are tables with 256 entries which map the screen color
   185 	components into actually displayed colors.  For an example of
   186 	implementing gamma correction and gamma fades, see test/testgamma.c
   187 	Gamma control is not supported on all hardware.
   188 
   189 1.1.4:
   190 	The size of the SDL_CDtrack structure changed from 8 to 12 bytes
   191 	as the size of the length member was extended to 32 bits.
   192 
   193         You can now use SDL for 2D blitting with a GL mode by passing the
   194 	SDL_OPENGLBLIT flag to SDL_SetVideoMode().  You can specify 16 or
   195 	32 bpp, and the data in the framebuffer is put into the GL scene
   196 	when you call SDL_UpdateRects(), and the scene will be visible
   197 	when you call SDL_GL_SwapBuffers().
   198 
   199 	Run the "testgl" test program with the -logo command line option
   200 	to see an example of this blending of 2D and 3D in SDL.
   201 
   202 1.1.3:
   203 	Added SDL_FreeRW() to the API, to complement SDL_AllocRW()
   204 
   205 	Added resizable window support - just add SDL_RESIZABLE to the
   206 	SDL_SetVideoMode() flags, and then wait for SDL_VIDEORESIZE events.
   207 	See SDL_events.h for details on the new SDL_ResizeEvent structure.
   208 
   209 	Added condition variable support, based on mutexes and semaphores.
   210 		SDL_CreateCond()
   211 		SDL_DestroyCond()
   212 		SDL_CondSignal()
   213 		SDL_CondBroadcast()
   214 		SDL_CondWait()
   215 		SDL_CondTimedWait()
   216 	The new function prototypes are in SDL_mutex.h
   217 
   218 	Added counting semaphore support, based on the mutex primitive.
   219 		SDL_CreateSemaphore()
   220 		SDL_DestroySemaphore()
   221 		SDL_SemWait()
   222 		SDL_SemTryWait()
   223 		SDL_SemWaitTimeout()
   224 		SDL_SemPost()
   225 		SDL_SemValue()
   226 	The new function prototypes are in SDL_mutex.h
   227 
   228 	Added support for asynchronous blitting.  To take advantage of this,
   229 	you must set the SDL_ASYNCBLIT flag when setting the video mode and
   230 	creating surfaces that you want accelerated in this way.  You must
   231 	lock surfaces that have this flag set, and the lock will block until
   232 	any queued blits have completed.
   233 
   234 	Added YUV video overlay support.
   235 	The supported YUV formats are: YV12, IYUV, YUY2, UYVY, and YVYU.
   236 	This function creates an overlay surface:
   237 		SDL_CreateYUVOverlay()
   238 	You must lock and unlock the overlay to get access to the data:
   239 		SDL_LockYUVOverlay() SDL_UnlockYUVOverlay()
   240 	You can then display the overlay:
   241 		SDL_DisplayYUVOverlay()
   242 	You must free the overlay when you are done using it:
   243 		SDL_FreeYUVOverlay()
   244 	See SDL_video.h for the full function prototypes.
   245 
   246 	The joystick hat position constants have been changed:
   247 	Old constant            New constant
   248 	------------            ------------
   249 	     0                  SDL_HAT_CENTERED
   250 	     1                  SDL_HAT_UP
   251 	     2                  SDL_HAT_RIGHTUP
   252 	     3                  SDL_HAT_RIGHT
   253 	     4                  SDL_HAT_RIGHTDOWN
   254 	     5                  SDL_HAT_DOWN
   255 	     6                  SDL_HAT_LEFTDOWN
   256 	     7                  SDL_HAT_LEFT
   257 	     8                  SDL_HAT_LEFTUP
   258 	The new constants are bitmasks, so you can check for the
   259 	individual axes like this:
   260 		if ( hat_position & SDL_HAT_UP ) {
   261 		}
   262 	and you'll catch left-up, up, and right-up.
   263 
   264 1.1.2:
   265 	Added multiple timer support:
   266 		SDL_AddTimer() and SDL_RemoveTimer()
   267 
   268 	SDL_WM_SetIcon() now respects the icon colorkey if mask is NULL.
   269 
   270 1.1.0:
   271 	Added initial OpenGL support.
   272 	First set GL attributes (such as RGB depth, alpha depth, etc.)
   273 		SDL_GL_SetAttribute()
   274 	Then call SDL_SetVideoMode() with the SDL_OPENGL flag.
   275 	Perform all of your normal GL drawing.
   276 	Finally swap the buffers with the new SDL function:
   277 		SDL_GL_SwapBuffers()
   278 	See the new 'testgl' test program for an example of using GL with SDL.
   279 
   280 	You can load GL extension functions by using the function:
   281 		SDL_GL_LoadProcAddress()
   282 
   283 	Added functions to initialize and cleanup specific SDL subsystems:
   284 		SDL_InitSubSystem() and SDL_QuitSubSystem()
   285 
   286 	Added user-defined event type:
   287 		typedef struct {
   288         		Uint8 type;
   289         		int code;
   290         		void *data1;
   291         		void *data2;
   292 		} SDL_UserEvent;
   293 	This structure is in the "user" member of an SDL_Event.
   294 
   295 	Added a function to push events into the event queue:
   296 		SDL_PushEvent()
   297 
   298 	Example of using the new SDL user-defined events:
   299 	{
   300 		SDL_Event event;
   301 
   302 		event.type = SDL_USEREVENT;
   303 		event.user.code = my_event_code;
   304 		event.user.data1 = significant_data;
   305 		event.user.data2 = 0;
   306 		SDL_PushEvent(&event);
   307 	}
   308 
   309 	Added a function to get mouse deltas since last query:
   310 		SDL_GetRelativeMouseState()
   311 
   312 	Added a boolean datatype to SDL_types.h:
   313 		SDL_bool = { SDL_TRUE, SDL_FALSE }
   314 
   315 	Added a function to get the current audio status:
   316 		SDL_GetAudioState();
   317 	It returns one of:
   318 		SDL_AUDIO_STOPPED,
   319 		SDL_AUDIO_PLAYING,
   320 		SDL_AUDIO_PAUSED
   321 
   322 	Added an AAlib driver (ASCII Art) - by Stephane Peter.
   323 
   324 1.0.6:
   325 	The input grab state is reset after each call to SDL_SetVideoMode().
   326 	The input is grabbed by default in fullscreen mode, and ungrabbed in
   327 	windowed mode.  If you want to set input grab to a particular value,
   328 	you should set it after each call to SDL_SetVideoMode().
   329 
   330 1.0.5:
   331 	Exposed SDL_AudioInit(), SDL_VideoInit()
   332 	Added SDL_AudioDriverName() and SDL_VideoDriverName()
   333 
   334 	Added new window manager function:
   335 		SDL_WM_ToggleFullScreen()
   336 	This is currently implemented only on Linux
   337 
   338 	The ALT-ENTER code has been removed - it's not appropriate for a
   339 	lib to bind keys when they aren't even emergency escape sequences.
   340 
   341 	ALT-ENTER functionality can be implemented with the following code:
   342 
   343 	int Handle_AltEnter(const SDL_Event *event)
   344 	{
   345 	    if ( event->type == SDL_KEYDOWN ) {
   346 	        if ( (event->key.keysym.sym == SDLK_RETURN) &&
   347 	             (event->key.keysym.mod & KMOD_ALT) ) {   
   348 	                SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
   349 	                return(0);
   350 	        }
   351 	    }
   352 	    return(1);
   353 	}
   354 	SDL_SetEventFilter(Handle_AltEnter);
   355 
   356 1.0.3:
   357 	Under X11, if you grab the input and hide the mouse cursor,
   358 	the mouse will go into a "relative motion" mode where you
   359 	will always get relative motion events no matter how far in
   360 	each direction you move the mouse - relative motion is not
   361 	bounded by the edges of the window (though the absolute values
   362 	of the mouse positions are clamped by the size of the window).
   363 	The SVGAlib, framebuffer console, and DirectInput drivers all
   364 	have this behavior naturally, and the GDI and BWindow drivers
   365 	never go into "relative motion" mode.
   366 
   367 1.0.2:
   368 	Added a function to enable keyboard repeat:
   369 		SDL_EnableKeyRepeat()
   370 
   371 	Added a function to grab the mouse and keyboard input
   372 		SDL_WM_GrabInput()
   373 
   374 	Added a function to iconify the window.
   375 		SDL_WM_IconifyWindow()
   376 	If this function succeeds, the application will receive an event
   377 	signaling SDL_APPACTIVE event 
   378 
   379 1.0.1:
   380 	Added constants to SDL_audio.h for 16-bit native byte ordering:
   381 		AUDIO_U16SYS, AUDIO_S16SYS
   382 
   383 1.0.0:
   384 	New public release
   385 
   386 Version 0.11:
   387 
   388 0.11.5:
   389 	A new function SDL_GetVideoSurface() has been added, and returns
   390 	a pointer to the current display surface.
   391 
   392 	SDL_AllocSurface() has been renamed SDL_CreateRGBSurface(), and
   393 	a new function SDL_CreateRGBSurfaceFrom() has been added to allow
   394 	creating an SDL surface from an existing pixel data buffer.
   395 
   396 	Added SDL_GetRGB() to the headers and documentation.
   397 
   398 0.11.4:
   399 	SDL_SetLibraryPath() is no longer meaningful, and has been removed.
   400 
   401 0.11.3:
   402 	A new flag for SDL_Init(), SDL_INIT_NOPARACHUTE, prevents SDL from
   403 	installing fatal signal handlers on operating systems that support
   404 	them.
   405 
   406 Version 0.9:
   407 
   408 0.9.15:
   409 	SDL_CreateColorCursor() has been removed.  Color cursors should
   410 	be implemented as sprites, blitted by the application when the
   411 	cursor moves.  To get smooth color cursor updates when the app
   412 	is busy, pass the SDL_INIT_EVENTTHREAD flag to SDL_Init().  This
   413 	allows you to handle the mouse motion in another thread from an
   414 	event filter function, but is currently only supported by Linux
   415 	and BeOS.  Note that you'll have to protect the display surface
   416 	from multi-threaded access by using mutexes if you do this.
   417 
   418 	Thread-safe surface support has been removed from SDL.
   419 	This makes blitting somewhat faster, by removing SDL_MiddleBlit().
   420 	Code that used SDL_MiddleBlit() should use SDL_LowerBlit() instead.
   421 	You can make your surfaces thread-safe by allocating your own
   422 	mutex and making lock/unlock calls around accesses to your surface.
   423 
   424 0.9.14:
   425 	SDL_GetMouseState() now takes pointers to int rather than Uint16.
   426 
   427 	If you set the SDL_WINDOWID environment variable under UNIX X11,
   428 	SDL will use that as the main window instead of creating it's own.
   429 	This is an unsupported extension to SDL, and not portable at all.
   430 
   431 0.9.13:
   432 	Added a function SDL_SetLibraryPath() which can be used to specify
   433 	the directory containing the SDL dynamic libraries.  This is useful
   434 	for commercial applications which ship with particular versions
   435 	of the libraries, and for security on multi-user systems.
   436 	If this function is not used, the default system directories are 
   437 	searched using the native dynamic object loading mechanism.
   438 
   439 	In order to support C linkage under Visual C++, you must declare
   440 	main() without any return type:
   441 		main(int argc, char *argv[]) {
   442 			/* Do the program... */
   443 			return(0);
   444 		}
   445 	C++ programs should also return a value if compiled under VC++.
   446 
   447 	The blit_endian member of the SDL_VideoInfo struct has been removed.
   448 
   449 	SDL_SymToASCII() has been replaced with SDL_GetKeyName(), so there
   450 	is now no longer any function to translate a keysym to a character.
   451 
   452 	The SDL_keysym structure has been extended with a 'scancode' and
   453 	'unicode' member.  The 'scancode' is a hardware specific scancode
   454 	for the key that was pressed, and may be 0.  The 'unicode' member
   455 	is a 16-bit UNICODE translation of the key that was pressed along
   456 	with any modifiers or compose keys that have been pressed.
   457 	If no UNICODE translation exists for the key, 'unicode' will be 0.
   458 
   459 	Added a function SDL_EnableUNICODE() to enable/disable UNICODE
   460 	translation of character keypresses.  Translation defaults off.
   461 
   462 	To convert existing code to use the new API, change code which
   463 	uses SDL_SymToASCII() to get the keyname to use SDL_GetKeyName(),
   464 	and change code which uses it to get the ASCII value of a sym to
   465 	use the 'unicode' member of the event keysym.
   466 
   467 0.9.12:
   468 	There is partial support for 64-bit datatypes.  I don't recommend 
   469 	you use this if you have a choice, because 64-bit datatypes are not
   470 	supported on many platforms.  On platforms for which it is supported,
   471 	the SDL_HAS_64BIT_TYPE C preprocessor define will be enabled, and
   472 	you can use the Uint64 and Sint64 datatypes.
   473 
   474 	Added functions to SDL_endian.h to support 64-bit datatypes:
   475 	    SDL_SwapLE64(), SDL_SwapBE64(),
   476 	    SDL_ReadLE64(), SDL_ReadBE64(), SDL_WriteLE64(), SDL_WriteBE64()
   477 
   478 	A new member "len_ratio" has been added to the SDL_AudioCVT structure,
   479 	and allows you to determine either the original buffer length or the
   480 	converted buffer length, given the other.
   481 
   482 	A new function SDL_FreeWAV() has been added to the API to free data
   483 	allocated by SDL_LoadWAV_RW().  This is necessary under Win32 since
   484 	the gcc compiled DLL uses a different heap than VC++ compiled apps.
   485 
   486 	SDL now has initial support for international keyboards using the
   487 	Latin character set.
   488 	If a particular mapping is desired, you can set the DEFAULT_KEYBOARD
   489 	compile-time variable, or you can set the environment variable 
   490 	"SDL_KEYBOARD" to a string identifying the keyboard mapping you desire.
   491 	The valid values for these variables can be found in SDL_keyboard.c
   492 
   493 	Full support for German and French keyboards under X11 is implemented.
   494 
   495 0.9.11:
   496 	The THREADED_EVENTS compile-time define has been replaced with the
   497 	SDL_INIT_EVENTTHREAD flag.  If this flag is passed to SDL_Init(),
   498 	SDL will create a separate thread to perform input event handling.
   499 	If this flag is passed to SDL_Init(), and the OS doesn't support 
   500 	event handling in a separate thread, SDL_Init() will fail.
   501 	Be sure to add calls to SDL_Delay() in your main thread to allow
   502 	the OS to schedule your event thread, or it may starve, leading
   503 	to slow event delivery and/or dropped events.
   504 	Currently MacOS and Win32 do not support this flag, while BeOS 
   505 	and Linux do support it.  I recommend that your application only
   506 	use this flag if absolutely necessary.
   507 
   508 	The SDL thread function passed to SDL_CreateThread() now returns a
   509 	status.  This status can be retrieved by passing a non-NULL pointer
   510 	as the 'status' argument to SDL_WaitThread().
   511 
   512 	The volume parameter to SDL_MixAudio() has been increased in range
   513 	from (0-8) to (0-128)
   514 
   515 	SDL now has a data source abstraction which can encompass a file,
   516 	an area of memory, or any custom object you can envision.  It uses
   517 	these abstractions, SDL_RWops, in the endian read/write functions,
   518 	and the built-in WAV and BMP file loaders.  This means you can load
   519 	WAV chunks from memory mapped files, compressed archives, network
   520 	pipes, or anything else that has a data read abstraction.
   521 
   522 	There are three built-in data source abstractions:
   523 	    SDL_RWFromFile(), SDL_RWFromFP(), SDL_RWFromMem()
   524 	along with a generic data source allocation function:
   525 	    SDL_AllocRW()
   526 	These data sources can be used like stdio file pointers with the
   527 	following convenience functions:
   528 	    SDL_RWseek(), SDL_RWread(), SDL_RWwrite(), SDL_RWclose()
   529 	These functions are defined in the new header file "SDL_rwops.h"
   530 
   531 	The endian swapping functions have been turned into macros for speed
   532 	and SDL_CalculateEndian() has been removed.  SDL_endian.h now defines
   533 	SDL_BYTEORDER as either SDL_BIG_ENDIAN or SDL_LIL_ENDIAN depending on
   534 	the endianness of the host system.
   535 
   536 	The endian read/write functions now take an SDL_RWops pointer
   537 	instead of a stdio FILE pointer, to support the new data source
   538 	abstraction.
   539 
   540 	The SDL_*LoadWAV() functions have been replaced with a single
   541 	SDL_LoadWAV_RW() function that takes a SDL_RWops pointer as it's
   542 	first parameter, and a flag whether or not to automatically 
   543 	free it as the second parameter.  SDL_LoadWAV() is a macro for
   544 	backward compatibility and convenience:
   545 	    SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
   546 
   547 	The SDL_*LoadBMP()/SDL_*SaveBMP() functions have each been replaced
   548 	with a single function that takes a SDL_RWops pointer as it's
   549 	first parameter, and a flag whether or not to automatically 
   550 	free it as the second parameter.  SDL_LoadBMP() and SDL_SaveBMP()
   551 	are macros for backward compatibility and convenience:
   552 	    SDL_LoadBMP_RW(SDL_RWFromFile("sample.bmp", "rb"), 1, ...);
   553 	    SDL_SaveBMP_RW(SDL_RWFromFile("sample.bmp", "wb"), 1, ...);
   554 	Note that these functions use SDL_RWseek() extensively, and should
   555 	not be used on pipes or other non-seekable data sources.
   556 
   557 0.9.10:
   558 	The Linux SDL_SysWMInfo and SDL_SysWMMsg structures have been 
   559 	extended to support multiple types of display drivers, as well as
   560         safe access to the X11 display when THREADED_EVENTS is enabled.
   561         The new structures are documented in the SDL_syswm.h header file.
   562 
   563 	Thanks to John Elliott <jce@seasip.demon.co.uk>, the UK keyboard
   564 	should now work properly, as well as the "Windows" keys on US
   565 	keyboards.
   566 
   567 	The Linux CD-ROM code now reads the CD-ROM devices from /etc/fstab
   568 	instead of trying to open each block device on the system.
   569 	The CD must be listed in /etc/fstab as using the iso9660 filesystem.
   570 
   571 	On Linux, if you define THREADED_EVENTS at compile time, a separate
   572 	thread will be spawned to gather X events asynchronously from the
   573 	graphics updates.  This hasn't been extensively tested, but it does
   574 	provide a means of handling keyboard and mouse input in a separate
   575 	thread from the graphics thread.  (This is now enabled by default.)
   576 
   577 	A special access function SDL_PeepEvents() allows you to manipulate
   578 	the event queue in a thread-safe manner, including peeking at events,
   579 	removing events of a specified type, and adding new events of arbitrary
   580 	type to the queue (use the new 'user' member of the SDL_Event type).
   581 
   582 	If you use SDL_PeepEvents() to gather events, then the main graphics
   583 	thread needs to call SDL_PumpEvents() periodically to drive the event
   584 	loop and generate input events.  This is not necessary if SDL has been 
   585 	compiled with THREADED_EVENTS defined, but doesn't hurt.
   586 
   587 	A new function SDL_ThreadID() returns the identifier associated with
   588 	the current thread.
   589 
   590 0.9.9:
   591 	The AUDIO_STEREO format flag has been replaced with a new 'channels'
   592 	member of the SDL_AudioSpec structure.  The channels are 1 for mono
   593 	audio, and 2 for stereo audio.  In the future more channels may be
   594 	supported for 3D surround sound.
   595 
   596 	The SDL_MixAudio() function now takes an additional volume parameter,
   597 	which should be set to SDL_MIX_MAXVOLUME for compatibility with the
   598 	original function.
   599 
   600 	The CD-ROM functions which take a 'cdrom' parameter can now be
   601 	passed NULL, and will act on the last successfully opened CD-ROM.
   602 
   603 0.9.8:
   604 	No changes, bugfixes only.
   605 	
   606 0.9.7:
   607 	No changes, bugfixes only.
   608 	
   609 0.9.6:
   610 	Added a fast rectangle fill function: SDL_FillRect()
   611 
   612 	Addition of a useful function for getting info on the video hardware:
   613 	    const SDL_VideoInfo *SDL_GetVideoInfo(void)
   614         This function replaces SDL_GetDisplayFormat().
   615 
   616 	Initial support for double-buffering:
   617 	  Use the SDL_DOUBLEBUF flag in SDL_SetVideoMode()
   618 	  Update the screen with a new function: SDL_Flip()
   619 
   620 	SDL_AllocSurface() takes two new flags:
   621 	SDL_SRCCOLORKEY means that the surface will be used for colorkey blits
   622 	  and if the hardware supports hardware acceleration of colorkey blits
   623 	  between two surfaces in video memory, to place the surface in video
   624 	  memory if possible, otherwise it will be placed in system memory.
   625 	SDL_SRCALPHA means that the surface will be used for alpha blits and
   626 	  if the hardware supports hardware acceleration of alpha blits between
   627 	  two surfaces in video memory, to place the surface in video memory
   628 	  if possible, otherwise it will be placed in system memory.
   629 	SDL_HWSURFACE now means that the surface will be created with the 
   630 	  same format as the display surface, since having surfaces in video
   631 	  memory is only useful for fast blitting to the screen, and you can't
   632 	  blit surfaces with different surface formats in video memory.
   633 
   634 0.9.5:
   635 	You can now pass a NULL mask to SDL_WM_SetIcon(), and it will assume
   636 	that the icon consists of the entire image.
   637 
   638 	SDL_LowerBlit() is back -- but don't use it on the display surface.
   639 	It is exactly the same as SDL_MiddleBlit(), but doesn't check for
   640 	thread safety.
   641 
   642 	Added SDL_FPLoadBMP(), SDL_FPSaveBMP(), SDL_FPLoadWAV(), which take
   643 	a FILE pointer instead of a file name.
   644 
   645 	Added CD-ROM audio control API:
   646 	    SDL_CDNumDrives()
   647 	    SDL_CDName()
   648 	    SDL_CDOpen()
   649 	    SDL_CDStatus()
   650 	    SDL_CDPlayTracks()
   651 	    SDL_CDPlay()
   652 	    SDL_CDPause()
   653 	    SDL_CDResume()
   654 	    SDL_CDStop()
   655 	    SDL_CDEject()
   656 	    SDL_CDClose()
   657 
   658 0.9.4:
   659 	No changes, bugfixes only.
   660 
   661 0.9.3:
   662 	Mouse motion event now includes relative motion information:
   663 	    Sint16 event->motion.xrel, Sint16 event->motion.yrel
   664 
   665 	X11 keyrepeat handling can be disabled by defining IGNORE_X_KEYREPEAT
   666 	    (Add -DIGNORE_X_KEYREPEAT to CFLAGS line in obj/x11Makefile)
   667 
   668 0.9.2:
   669 	No changes, bugfixes only.
   670 
   671 0.9.1:
   672 	Removed SDL_MapSurface() and SDL_UnmapSurface() -- surfaces are now
   673 	automatically mapped on blit.
   674 
   675 0.8.0:
   676 	SDL stable release