WhatsNew
author Sam Lantinga <slouken@libsdl.org>
Thu, 19 Jan 2006 05:34:24 +0000
changeset 1249 e6a82dcdce09
parent 781 67176351a1b8
child 1507 1ff64ad478b2
permissions -rw-r--r--
*** empty log message ***
     1 
     2 This is a list of API changes in SDL's version history.
     3 
     4 Version 1.0:
     5 
     6 1.2.7:
     7 	Added CPU feature detection functions to SDL_cpuinfo.h:
     8 		SDL_HasRDTSC(), SDL_HasMMX(), SDL_Has3DNow(), SDL_HasSSE(),
     9 		SDL_HasAltiVec()
    10 	Added function to create RWops from const memory: SDL_RWFromConstMem()
    11 
    12 1.2.6:
    13 	Added SDL_LoadObject(), SDL_LoadFunction(), and SDL_UnloadObject()
    14 
    15 	Added SDL_GL_MULTISAMPLEBUFFERS and SDL_GL_MULTISAMPLESAMPLES for FSAA
    16 
    17 1.2.5:
    18 	Added SDL_BUTTON_WHEELUP (4) and SDL_BUTTON_WHEELDOWN (5)
    19 
    20 	Added SDL_GL_STEREO for stereoscopic OpenGL contexts
    21 
    22 1.2.0:
    23 	Added SDL_VIDEOEXPOSE event to signal that the screen needs to
    24 	be redrawn.  This is currently only delivered to OpenGL windows
    25 	on X11, though it may be delivered in the future when the video
    26 	memory is lost under DirectX.
    27 
    28 1.1.8:
    29 	You can pass SDL_NOFRAME to SDL_VideoMode() to create a window
    30 	that has no title bar or frame decoration.  Fullscreen video
    31 	modes automatically have this flag set.
    32 
    33 	Added a function to query the clipping rectangle for a surface:
    34 		void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect)
    35 
    36 	Added a function to query the current event filter:
    37 		SDL_EventFilter SDL_GetEventFilter(void)
    38 
    39 	If you pass -1 to SDL_ShowCursor(), it won't change the current
    40 	cursor visibility state, but will still return it.
    41 
    42 	SDL_LockSurface() and SDL_UnlockSurface() are recursive, meaning
    43 	you can nest them as deep as you want, as long as each lock call
    44 	has a matching unlock call.  The surface remains locked until the
    45 	last matching unlock call.
    46 
    47 	Note that you may not blit to or from a locked surface.
    48 
    49 1.1.7:
    50 	The SDL_SetGammaRamp() and SDL_GetGammaRamp() functions now take
    51 	arrays of Uint16 values instead of Uint8 values.  For the most part,
    52 	you can just take your old values and shift them up 8 bits to get
    53 	new correct values for your gamma ramps.
    54 
    55 	You can pass SDL_RLEACCEL in flags passed to SDL_ConvertSurface()
    56         and SDL will try to RLE accelerate colorkey and alpha blits in the
    57 	resulting surface.
    58 
    59 1.1.6:
    60 	Added a function to return the thread ID of a specific thread:
    61 		Uint32 SDL_GetThreadID(SDL_Thread *thread)
    62 	If 'thread' is NULL, this function returns the id for this thread.
    63 
    64 1.1.5:
    65 	The YUV overlay structure has been changed to use an array of
    66 	pitches and pixels representing the planes of a YUV image, to
    67 	better enable hardware acceleration.  The YV12 and IYUV formats
    68 	each have three planes, corresponding to the Y, U, and V portions
    69 	of the image, while packed pixel YUV formats just have one plane.
    70 
    71 	For palettized mode (8bpp), the screen colormap is now split in
    72 	a physical and a logical palette. The physical palette determines
    73 	what colours the screen pixels will get when displayed, and the
    74 	logical palette controls the mapping from blits to/from the screen.
    75 	A new function, SDL_SetPalette() has been added to change
    76 	logical and physical palettes separately. SDL_SetColors() works
    77 	just as before, and is equivalent to calling SDL_SetPalette() with
    78 	a flag argument of (SDL_LOGPAL|SDL_PHYSPAL).
    79 
    80 	SDL_BlitSurface() no longer modifies the source rectangle, only the
    81 	destination rectangle. The width/height members of the destination
    82 	rectangle are ignored, only the position is used.
    83 
    84 	The old source clipping function SDL_SetClipping() has been replaced
    85 	with a more useful function to set the destination clipping rectangle:
    86 		SDL_bool SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect)
    87 		
    88 	Added a function to see what subsystems have been initialized:
    89 		Uint32 SDL_WasInit(Uint32 flags)
    90 
    91 	The Big Alpha Flip: SDL now treats alpha as opacity like everybody
    92 	else, and not as transparency:
    93 
    94 	A new cpp symbol: SDL_ALPHA_OPAQUE is defined as 255
    95 	A new cpp symbol: SDL_ALPHA_TRANSPARENT is defined as 0
    96 	Values between 0 and 255 vary from fully transparent to fully opaque.
    97 
    98 	New functions:
    99 	SDL_DisplayFormatAlpha()
   100 	    Returns a surface converted to a format with alpha-channel
   101 	    that can be blit efficiently to the screen. (In other words,
   102 	    like SDL_DisplayFormat() but the resulting surface has
   103 	    an alpha channel.)  This is useful for surfaces with alpha.
   104 	SDL_MapRGBA()
   105 	    Works as SDL_MapRGB() but takes an additional alpha parameter.
   106 	SDL_GetRGBA()
   107 	    Works as SDL_GetRGB() but also returns the alpha value
   108 	    (SDL_ALPHA_OPAQUE for formats without an alpha channel)
   109 
   110 	Both SDL_GetRGB() and SDL_GetRGBA() now always return values in
   111 	the [0..255] interval. Previously, SDL_GetRGB() would return
   112 	(0xf8, 0xfc, 0xf8) for a completely white pixel in RGB565 format.
   113 	(N.B.: This is broken for bit fields < 3 bits.)
   114 
   115 	SDL_MapRGB() returns pixels in which the alpha channel is set opaque.
   116 
   117 	SDL_SetAlpha() can now be used for both setting the per-surface
   118 	alpha, using the new way of thinking of alpha, and also to enable
   119 	and disable per-pixel alpha blending for surfaces with an alpha
   120 	channel:
   121 		To disable alpha blending:
   122 			SDL_SetAlpha(surface, 0, 0);
   123 		To re-enable alpha blending:
   124 			SDL_SetAlpha(surface, SDL_SRCALPHA, 0);
   125 	Surfaces with an alpha channel have blending enabled by default.
   126 
   127 	SDL_SetAlpha() now accepts SDL_RLEACCEL as a flag, which requests
   128 	RLE acceleration of blits, just as like with SDL_SetColorKey().
   129 	This flag can be set for both surfaces with an alpha channel
   130 	and surfaces with an alpha value set by SDL_SetAlpha().
   131 	As always, RLE surfaces must be locked before pixel access is
   132 	allowed, and unlocked before any other SDL operations are done
   133 	on it.
   134 
   135 	The blit semantics for surfaces with and without alpha and colorkey
   136 	have now been defined:
   137 
   138 	RGBA->RGB:
   139 	    SDL_SRCALPHA set:
   140 		alpha-blend (using alpha-channel).
   141 		SDL_SRCCOLORKEY ignored.
   142 	    SDL_SRCALPHA not set:
   143 		copy RGB.
   144 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   145 		RGB values of the source colour key, ignoring alpha in the
   146 		comparison.
   147 
   148 	RGB->RGBA:
   149 	    SDL_SRCALPHA set:
   150 		alpha-blend (using the source per-surface alpha value);
   151 		set destination alpha to opaque.
   152 	    SDL_SRCALPHA not set:
   153 		copy RGB, set destination alpha to opaque.
   154 	    both:
   155 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   156 		source colour key.
   157 
   158 	RGBA->RGBA:
   159 	    SDL_SRCALPHA set:
   160 		alpha-blend (using the source alpha channel) the RGB values;
   161 		leave destination alpha untouched. [Note: is this correct?]
   162 		SDL_SRCCOLORKEY ignored.
   163 	    SDL_SRCALPHA not set:
   164 		copy all of RGBA to the destination.
   165 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   166 		RGB values of the source colour key, ignoring alpha in the
   167 		comparison.
   168 
   169 	RGB->RGB: 
   170 	    SDL_SRCALPHA set:
   171 		alpha-blend (using the source per-surface alpha value).
   172 	    SDL_SRCALPHA not set:
   173 		copy RGB.
   174 	    both:
   175 		if SDL_SRCCOLORKEY set, only copy the pixels matching the
   176 		source colour key.
   177 
   178 	As a special case, blits from surfaces with per-surface alpha
   179 	value of 128 (50% transparency) are optimised and much faster
   180 	than other alpha values. This does not apply to surfaces with
   181 	alpha channels (per-pixel alpha).
   182 
   183 	New functions for manipulating the gamma of the display have
   184 	been added:
   185 		int SDL_SetGamma(float red, float green, float blue);
   186 		int SDL_SetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   187 		int SDL_GetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
   188 	Gamma ramps are tables with 256 entries which map the screen color
   189 	components into actually displayed colors.  For an example of
   190 	implementing gamma correction and gamma fades, see test/testgamma.c
   191 	Gamma control is not supported on all hardware.
   192 
   193 1.1.4:
   194 	The size of the SDL_CDtrack structure changed from 8 to 12 bytes
   195 	as the size of the length member was extended to 32 bits.
   196 
   197         You can now use SDL for 2D blitting with a GL mode by passing the
   198 	SDL_OPENGLBLIT flag to SDL_SetVideoMode().  You can specify 16 or
   199 	32 bpp, and the data in the framebuffer is put into the GL scene
   200 	when you call SDL_UpdateRects(), and the scene will be visible
   201 	when you call SDL_GL_SwapBuffers().
   202 
   203 	Run the "testgl" test program with the -logo command line option
   204 	to see an example of this blending of 2D and 3D in SDL.
   205 
   206 1.1.3:
   207 	Added SDL_FreeRW() to the API, to complement SDL_AllocRW()
   208 
   209 	Added resizable window support - just add SDL_RESIZABLE to the
   210 	SDL_SetVideoMode() flags, and then wait for SDL_VIDEORESIZE events.
   211 	See SDL_events.h for details on the new SDL_ResizeEvent structure.
   212 
   213 	Added condition variable support, based on mutexes and semaphores.
   214 		SDL_CreateCond()
   215 		SDL_DestroyCond()
   216 		SDL_CondSignal()
   217 		SDL_CondBroadcast()
   218 		SDL_CondWait()
   219 		SDL_CondTimedWait()
   220 	The new function prototypes are in SDL_mutex.h
   221 
   222 	Added counting semaphore support, based on the mutex primitive.
   223 		SDL_CreateSemaphore()
   224 		SDL_DestroySemaphore()
   225 		SDL_SemWait()
   226 		SDL_SemTryWait()
   227 		SDL_SemWaitTimeout()
   228 		SDL_SemPost()
   229 		SDL_SemValue()
   230 	The new function prototypes are in SDL_mutex.h
   231 
   232 	Added support for asynchronous blitting.  To take advantage of this,
   233 	you must set the SDL_ASYNCBLIT flag when setting the video mode and
   234 	creating surfaces that you want accelerated in this way.  You must
   235 	lock surfaces that have this flag set, and the lock will block until
   236 	any queued blits have completed.
   237 
   238 	Added YUV video overlay support.
   239 	The supported YUV formats are: YV12, IYUV, YUY2, UYVY, and YVYU.
   240 	This function creates an overlay surface:
   241 		SDL_CreateYUVOverlay()
   242 	You must lock and unlock the overlay to get access to the data:
   243 		SDL_LockYUVOverlay() SDL_UnlockYUVOverlay()
   244 	You can then display the overlay:
   245 		SDL_DisplayYUVOverlay()
   246 	You must free the overlay when you are done using it:
   247 		SDL_FreeYUVOverlay()
   248 	See SDL_video.h for the full function prototypes.
   249 
   250 	The joystick hat position constants have been changed:
   251 	Old constant            New constant
   252 	------------            ------------
   253 	     0                  SDL_HAT_CENTERED
   254 	     1                  SDL_HAT_UP
   255 	     2                  SDL_HAT_RIGHTUP
   256 	     3                  SDL_HAT_RIGHT
   257 	     4                  SDL_HAT_RIGHTDOWN
   258 	     5                  SDL_HAT_DOWN
   259 	     6                  SDL_HAT_LEFTDOWN
   260 	     7                  SDL_HAT_LEFT
   261 	     8                  SDL_HAT_LEFTUP
   262 	The new constants are bitmasks, so you can check for the
   263 	individual axes like this:
   264 		if ( hat_position & SDL_HAT_UP ) {
   265 		}
   266 	and you'll catch left-up, up, and right-up.
   267 
   268 1.1.2:
   269 	Added multiple timer support:
   270 		SDL_AddTimer() and SDL_RemoveTimer()
   271 
   272 	SDL_WM_SetIcon() now respects the icon colorkey if mask is NULL.
   273 
   274 1.1.0:
   275 	Added initial OpenGL support.
   276 	First set GL attributes (such as RGB depth, alpha depth, etc.)
   277 		SDL_GL_SetAttribute()
   278 	Then call SDL_SetVideoMode() with the SDL_OPENGL flag.
   279 	Perform all of your normal GL drawing.
   280 	Finally swap the buffers with the new SDL function:
   281 		SDL_GL_SwapBuffers()
   282 	See the new 'testgl' test program for an example of using GL with SDL.
   283 
   284 	You can load GL extension functions by using the function:
   285 		SDL_GL_LoadProcAddress()
   286 
   287 	Added functions to initialize and cleanup specific SDL subsystems:
   288 		SDL_InitSubSystem() and SDL_QuitSubSystem()
   289 
   290 	Added user-defined event type:
   291 		typedef struct {
   292         		Uint8 type;
   293         		int code;
   294         		void *data1;
   295         		void *data2;
   296 		} SDL_UserEvent;
   297 	This structure is in the "user" member of an SDL_Event.
   298 
   299 	Added a function to push events into the event queue:
   300 		SDL_PushEvent()
   301 
   302 	Example of using the new SDL user-defined events:
   303 	{
   304 		SDL_Event event;
   305 
   306 		event.type = SDL_USEREVENT;
   307 		event.user.code = my_event_code;
   308 		event.user.data1 = significant_data;
   309 		event.user.data2 = 0;
   310 		SDL_PushEvent(&event);
   311 	}
   312 
   313 	Added a function to get mouse deltas since last query:
   314 		SDL_GetRelativeMouseState()
   315 
   316 	Added a boolean datatype to SDL_types.h:
   317 		SDL_bool = { SDL_TRUE, SDL_FALSE }
   318 
   319 	Added a function to get the current audio status:
   320 		SDL_GetAudioState();
   321 	It returns one of:
   322 		SDL_AUDIO_STOPPED,
   323 		SDL_AUDIO_PLAYING,
   324 		SDL_AUDIO_PAUSED
   325 
   326 	Added an AAlib driver (ASCII Art) - by Stephane Peter.
   327 
   328 1.0.6:
   329 	The input grab state is reset after each call to SDL_SetVideoMode().
   330 	The input is grabbed by default in fullscreen mode, and ungrabbed in
   331 	windowed mode.  If you want to set input grab to a particular value,
   332 	you should set it after each call to SDL_SetVideoMode().
   333 
   334 1.0.5:
   335 	Exposed SDL_AudioInit(), SDL_VideoInit()
   336 	Added SDL_AudioDriverName() and SDL_VideoDriverName()
   337 
   338 	Added new window manager function:
   339 		SDL_WM_ToggleFullScreen()
   340 	This is currently implemented only on Linux
   341 
   342 	The ALT-ENTER code has been removed - it's not appropriate for a
   343 	lib to bind keys when they aren't even emergency escape sequences.
   344 
   345 	ALT-ENTER functionality can be implemented with the following code:
   346 
   347 	int Handle_AltEnter(const SDL_Event *event)
   348 	{
   349 	    if ( event->type == SDL_KEYDOWN ) {
   350 	        if ( (event->key.keysym.sym == SDLK_RETURN) &&
   351 	             (event->key.keysym.mod & KMOD_ALT) ) {   
   352 	                SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
   353 	                return(0);
   354 	        }
   355 	    }
   356 	    return(1);
   357 	}
   358 	SDL_SetEventFilter(Handle_AltEnter);
   359 
   360 1.0.3:
   361 	Under X11, if you grab the input and hide the mouse cursor,
   362 	the mouse will go into a "relative motion" mode where you
   363 	will always get relative motion events no matter how far in
   364 	each direction you move the mouse - relative motion is not
   365 	bounded by the edges of the window (though the absolute values
   366 	of the mouse positions are clamped by the size of the window).
   367 	The SVGAlib, framebuffer console, and DirectInput drivers all
   368 	have this behavior naturally, and the GDI and BWindow drivers
   369 	never go into "relative motion" mode.
   370 
   371 1.0.2:
   372 	Added a function to enable keyboard repeat:
   373 		SDL_EnableKeyRepeat()
   374 
   375 	Added a function to grab the mouse and keyboard input
   376 		SDL_WM_GrabInput()
   377 
   378 	Added a function to iconify the window.
   379 		SDL_WM_IconifyWindow()
   380 	If this function succeeds, the application will receive an event
   381 	signaling SDL_APPACTIVE event 
   382 
   383 1.0.1:
   384 	Added constants to SDL_audio.h for 16-bit native byte ordering:
   385 		AUDIO_U16SYS, AUDIO_S16SYS
   386 
   387 1.0.0:
   388 	New public release
   389 
   390 Version 0.11:
   391 
   392 0.11.5:
   393 	A new function SDL_GetVideoSurface() has been added, and returns
   394 	a pointer to the current display surface.
   395 
   396 	SDL_AllocSurface() has been renamed SDL_CreateRGBSurface(), and
   397 	a new function SDL_CreateRGBSurfaceFrom() has been added to allow
   398 	creating an SDL surface from an existing pixel data buffer.
   399 
   400 	Added SDL_GetRGB() to the headers and documentation.
   401 
   402 0.11.4:
   403 	SDL_SetLibraryPath() is no longer meaningful, and has been removed.
   404 
   405 0.11.3:
   406 	A new flag for SDL_Init(), SDL_INIT_NOPARACHUTE, prevents SDL from
   407 	installing fatal signal handlers on operating systems that support
   408 	them.
   409 
   410 Version 0.9:
   411 
   412 0.9.15:
   413 	SDL_CreateColorCursor() has been removed.  Color cursors should
   414 	be implemented as sprites, blitted by the application when the
   415 	cursor moves.  To get smooth color cursor updates when the app
   416 	is busy, pass the SDL_INIT_EVENTTHREAD flag to SDL_Init().  This
   417 	allows you to handle the mouse motion in another thread from an
   418 	event filter function, but is currently only supported by Linux
   419 	and BeOS.  Note that you'll have to protect the display surface
   420 	from multi-threaded access by using mutexes if you do this.
   421 
   422 	Thread-safe surface support has been removed from SDL.
   423 	This makes blitting somewhat faster, by removing SDL_MiddleBlit().
   424 	Code that used SDL_MiddleBlit() should use SDL_LowerBlit() instead.
   425 	You can make your surfaces thread-safe by allocating your own
   426 	mutex and making lock/unlock calls around accesses to your surface.
   427 
   428 0.9.14:
   429 	SDL_GetMouseState() now takes pointers to int rather than Uint16.
   430 
   431 	If you set the SDL_WINDOWID environment variable under UNIX X11,
   432 	SDL will use that as the main window instead of creating it's own.
   433 	This is an unsupported extension to SDL, and not portable at all.
   434 
   435 0.9.13:
   436 	Added a function SDL_SetLibraryPath() which can be used to specify
   437 	the directory containing the SDL dynamic libraries.  This is useful
   438 	for commercial applications which ship with particular versions
   439 	of the libraries, and for security on multi-user systems.
   440 	If this function is not used, the default system directories are 
   441 	searched using the native dynamic object loading mechanism.
   442 
   443 	In order to support C linkage under Visual C++, you must declare
   444 	main() without any return type:
   445 		main(int argc, char *argv[]) {
   446 			/* Do the program... */
   447 			return(0);
   448 		}
   449 	C++ programs should also return a value if compiled under VC++.
   450 
   451 	The blit_endian member of the SDL_VideoInfo struct has been removed.
   452 
   453 	SDL_SymToASCII() has been replaced with SDL_GetKeyName(), so there
   454 	is now no longer any function to translate a keysym to a character.
   455 
   456 	The SDL_keysym structure has been extended with a 'scancode' and
   457 	'unicode' member.  The 'scancode' is a hardware specific scancode
   458 	for the key that was pressed, and may be 0.  The 'unicode' member
   459 	is a 16-bit UNICODE translation of the key that was pressed along
   460 	with any modifiers or compose keys that have been pressed.
   461 	If no UNICODE translation exists for the key, 'unicode' will be 0.
   462 
   463 	Added a function SDL_EnableUNICODE() to enable/disable UNICODE
   464 	translation of character keypresses.  Translation defaults off.
   465 
   466 	To convert existing code to use the new API, change code which
   467 	uses SDL_SymToASCII() to get the keyname to use SDL_GetKeyName(),
   468 	and change code which uses it to get the ASCII value of a sym to
   469 	use the 'unicode' member of the event keysym.
   470 
   471 0.9.12:
   472 	There is partial support for 64-bit datatypes.  I don't recommend 
   473 	you use this if you have a choice, because 64-bit datatypes are not
   474 	supported on many platforms.  On platforms for which it is supported,
   475 	the SDL_HAS_64BIT_TYPE C preprocessor define will be enabled, and
   476 	you can use the Uint64 and Sint64 datatypes.
   477 
   478 	Added functions to SDL_endian.h to support 64-bit datatypes:
   479 	    SDL_SwapLE64(), SDL_SwapBE64(),
   480 	    SDL_ReadLE64(), SDL_ReadBE64(), SDL_WriteLE64(), SDL_WriteBE64()
   481 
   482 	A new member "len_ratio" has been added to the SDL_AudioCVT structure,
   483 	and allows you to determine either the original buffer length or the
   484 	converted buffer length, given the other.
   485 
   486 	A new function SDL_FreeWAV() has been added to the API to free data
   487 	allocated by SDL_LoadWAV_RW().  This is necessary under Win32 since
   488 	the gcc compiled DLL uses a different heap than VC++ compiled apps.
   489 
   490 	SDL now has initial support for international keyboards using the
   491 	Latin character set.
   492 	If a particular mapping is desired, you can set the DEFAULT_KEYBOARD
   493 	compile-time variable, or you can set the environment variable 
   494 	"SDL_KEYBOARD" to a string identifying the keyboard mapping you desire.
   495 	The valid values for these variables can be found in SDL_keyboard.c
   496 
   497 	Full support for German and French keyboards under X11 is implemented.
   498 
   499 0.9.11:
   500 	The THREADED_EVENTS compile-time define has been replaced with the
   501 	SDL_INIT_EVENTTHREAD flag.  If this flag is passed to SDL_Init(),
   502 	SDL will create a separate thread to perform input event handling.
   503 	If this flag is passed to SDL_Init(), and the OS doesn't support 
   504 	event handling in a separate thread, SDL_Init() will fail.
   505 	Be sure to add calls to SDL_Delay() in your main thread to allow
   506 	the OS to schedule your event thread, or it may starve, leading
   507 	to slow event delivery and/or dropped events.
   508 	Currently MacOS and Win32 do not support this flag, while BeOS 
   509 	and Linux do support it.  I recommend that your application only
   510 	use this flag if absolutely necessary.
   511 
   512 	The SDL thread function passed to SDL_CreateThread() now returns a
   513 	status.  This status can be retrieved by passing a non-NULL pointer
   514 	as the 'status' argument to SDL_WaitThread().
   515 
   516 	The volume parameter to SDL_MixAudio() has been increased in range
   517 	from (0-8) to (0-128)
   518 
   519 	SDL now has a data source abstraction which can encompass a file,
   520 	an area of memory, or any custom object you can envision.  It uses
   521 	these abstractions, SDL_RWops, in the endian read/write functions,
   522 	and the built-in WAV and BMP file loaders.  This means you can load
   523 	WAV chunks from memory mapped files, compressed archives, network
   524 	pipes, or anything else that has a data read abstraction.
   525 
   526 	There are three built-in data source abstractions:
   527 	    SDL_RWFromFile(), SDL_RWFromFP(), SDL_RWFromMem()
   528 	along with a generic data source allocation function:
   529 	    SDL_AllocRW()
   530 	These data sources can be used like stdio file pointers with the
   531 	following convenience functions:
   532 	    SDL_RWseek(), SDL_RWread(), SDL_RWwrite(), SDL_RWclose()
   533 	These functions are defined in the new header file "SDL_rwops.h"
   534 
   535 	The endian swapping functions have been turned into macros for speed
   536 	and SDL_CalculateEndian() has been removed.  SDL_endian.h now defines
   537 	SDL_BYTEORDER as either SDL_BIG_ENDIAN or SDL_LIL_ENDIAN depending on
   538 	the endianness of the host system.
   539 
   540 	The endian read/write functions now take an SDL_RWops pointer
   541 	instead of a stdio FILE pointer, to support the new data source
   542 	abstraction.
   543 
   544 	The SDL_*LoadWAV() functions have been replaced with a single
   545 	SDL_LoadWAV_RW() function that takes a SDL_RWops pointer as it's
   546 	first parameter, and a flag whether or not to automatically 
   547 	free it as the second parameter.  SDL_LoadWAV() is a macro for
   548 	backward compatibility and convenience:
   549 	    SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
   550 
   551 	The SDL_*LoadBMP()/SDL_*SaveBMP() functions have each been replaced
   552 	with a single function that takes a SDL_RWops pointer as it's
   553 	first parameter, and a flag whether or not to automatically 
   554 	free it as the second parameter.  SDL_LoadBMP() and SDL_SaveBMP()
   555 	are macros for backward compatibility and convenience:
   556 	    SDL_LoadBMP_RW(SDL_RWFromFile("sample.bmp", "rb"), 1, ...);
   557 	    SDL_SaveBMP_RW(SDL_RWFromFile("sample.bmp", "wb"), 1, ...);
   558 	Note that these functions use SDL_RWseek() extensively, and should
   559 	not be used on pipes or other non-seekable data sources.
   560 
   561 0.9.10:
   562 	The Linux SDL_SysWMInfo and SDL_SysWMMsg structures have been 
   563 	extended to support multiple types of display drivers, as well as
   564         safe access to the X11 display when THREADED_EVENTS is enabled.
   565         The new structures are documented in the SDL_syswm.h header file.
   566 
   567 	Thanks to John Elliott <jce@seasip.demon.co.uk>, the UK keyboard
   568 	should now work properly, as well as the "Windows" keys on US
   569 	keyboards.
   570 
   571 	The Linux CD-ROM code now reads the CD-ROM devices from /etc/fstab
   572 	instead of trying to open each block device on the system.
   573 	The CD must be listed in /etc/fstab as using the iso9660 filesystem.
   574 
   575 	On Linux, if you define THREADED_EVENTS at compile time, a separate
   576 	thread will be spawned to gather X events asynchronously from the
   577 	graphics updates.  This hasn't been extensively tested, but it does
   578 	provide a means of handling keyboard and mouse input in a separate
   579 	thread from the graphics thread.  (This is now enabled by default.)
   580 
   581 	A special access function SDL_PeepEvents() allows you to manipulate
   582 	the event queue in a thread-safe manner, including peeking at events,
   583 	removing events of a specified type, and adding new events of arbitrary
   584 	type to the queue (use the new 'user' member of the SDL_Event type).
   585 
   586 	If you use SDL_PeepEvents() to gather events, then the main graphics
   587 	thread needs to call SDL_PumpEvents() periodically to drive the event
   588 	loop and generate input events.  This is not necessary if SDL has been 
   589 	compiled with THREADED_EVENTS defined, but doesn't hurt.
   590 
   591 	A new function SDL_ThreadID() returns the identifier associated with
   592 	the current thread.
   593 
   594 0.9.9:
   595 	The AUDIO_STEREO format flag has been replaced with a new 'channels'
   596 	member of the SDL_AudioSpec structure.  The channels are 1 for mono
   597 	audio, and 2 for stereo audio.  In the future more channels may be
   598 	supported for 3D surround sound.
   599 
   600 	The SDL_MixAudio() function now takes an additional volume parameter,
   601 	which should be set to SDL_MIX_MAXVOLUME for compatibility with the
   602 	original function.
   603 
   604 	The CD-ROM functions which take a 'cdrom' parameter can now be
   605 	passed NULL, and will act on the last successfully opened CD-ROM.
   606 
   607 0.9.8:
   608 	No changes, bugfixes only.
   609 	
   610 0.9.7:
   611 	No changes, bugfixes only.
   612 	
   613 0.9.6:
   614 	Added a fast rectangle fill function: SDL_FillRect()
   615 
   616 	Addition of a useful function for getting info on the video hardware:
   617 	    const SDL_VideoInfo *SDL_GetVideoInfo(void)
   618         This function replaces SDL_GetDisplayFormat().
   619 
   620 	Initial support for double-buffering:
   621 	  Use the SDL_DOUBLEBUF flag in SDL_SetVideoMode()
   622 	  Update the screen with a new function: SDL_Flip()
   623 
   624 	SDL_AllocSurface() takes two new flags:
   625 	SDL_SRCCOLORKEY means that the surface will be used for colorkey blits
   626 	  and if the hardware supports hardware acceleration of colorkey blits
   627 	  between two surfaces in video memory, to place the surface in video
   628 	  memory if possible, otherwise it will be placed in system memory.
   629 	SDL_SRCALPHA means that the surface will be used for alpha blits and
   630 	  if the hardware supports hardware acceleration of alpha blits between
   631 	  two surfaces in video memory, to place the surface in video memory
   632 	  if possible, otherwise it will be placed in system memory.
   633 	SDL_HWSURFACE now means that the surface will be created with the 
   634 	  same format as the display surface, since having surfaces in video
   635 	  memory is only useful for fast blitting to the screen, and you can't
   636 	  blit surfaces with different surface formats in video memory.
   637 
   638 0.9.5:
   639 	You can now pass a NULL mask to SDL_WM_SetIcon(), and it will assume
   640 	that the icon consists of the entire image.
   641 
   642 	SDL_LowerBlit() is back -- but don't use it on the display surface.
   643 	It is exactly the same as SDL_MiddleBlit(), but doesn't check for
   644 	thread safety.
   645 
   646 	Added SDL_FPLoadBMP(), SDL_FPSaveBMP(), SDL_FPLoadWAV(), which take
   647 	a FILE pointer instead of a file name.
   648 
   649 	Added CD-ROM audio control API:
   650 	    SDL_CDNumDrives()
   651 	    SDL_CDName()
   652 	    SDL_CDOpen()
   653 	    SDL_CDStatus()
   654 	    SDL_CDPlayTracks()
   655 	    SDL_CDPlay()
   656 	    SDL_CDPause()
   657 	    SDL_CDResume()
   658 	    SDL_CDStop()
   659 	    SDL_CDEject()
   660 	    SDL_CDClose()
   661 
   662 0.9.4:
   663 	No changes, bugfixes only.
   664 
   665 0.9.3:
   666 	Mouse motion event now includes relative motion information:
   667 	    Sint16 event->motion.xrel, Sint16 event->motion.yrel
   668 
   669 	X11 keyrepeat handling can be disabled by defining IGNORE_X_KEYREPEAT
   670 	    (Add -DIGNORE_X_KEYREPEAT to CFLAGS line in obj/x11Makefile)
   671 
   672 0.9.2:
   673 	No changes, bugfixes only.
   674 
   675 0.9.1:
   676 	Removed SDL_MapSurface() and SDL_UnmapSurface() -- surfaces are now
   677 	automatically mapped on blit.
   678 
   679 0.8.0:
   680 	SDL stable release