WhatsNew
author Sam Lantinga <slouken@libsdl.org>
Fri, 29 Feb 2008 13:55:44 +0000
branchSDL-1.2
changeset 4139 568c9b3c0167
parent 4113 82dab719502e
child 4280 e1826b24ee8d
permissions -rw-r--r--
* Added configure option --enable-screensaver, to allow enabling the screensaver by default.
* Use XResetScreenSaver() instead of disabling screensaver entirely.

Full discussion summary from Erik on the SDL mailing list:

Current behaviour
=================

SDL changes the user's display power management settings without
permission from the user and without telling the user.

The interface that it uses to do so is DPMSDisable/DPMSEnable, which
should only ever be used by configuration utilities like KControl, never
by normal application programs, let alone by the libraries that they
use. Using an interface that is not at all intended for what SDL tries
to achieve means that it will not work as it should. Firstly, the power
management is completely disabled during the whole lifetime of the SDL
program, not only when it should be. Secondly, it makes SDL
non-reentrant, meaning that things will break when multiple SDL programs
are clients of the same X server simultaneously. Thirdly, no cleanup
mechanism ensures that the setting is restored if the client does not do
that (for example if it crashes).

In addition to that, this interface is broken on xorg,
[http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries
to do does not work at all on that implementation of the X Window
System. (The reason that the DPMSEnable works in KControl is that it
calls DPMSSetTimeout immediately after,
[http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]).


The problems that the current behaviour causes
==============================================
1. Information leak. When the user is away, someone might see what the
user has on the display when the user counts on the screensaver
preventing this. This does not even require physical access to the
workstation, it is enough to see it from a distance.
2. Draining battery. An SDL program that runs on a laptop will quickly
drain the battery while the user is away. The system will soon shut down
and require recharging before being usable again, while it should in
fact have consumed very little energy if the user's settings would have
been obeyed.
3. Wasting energy. Even if battery issues are not considered, energy as
such is wasted.
4. Display wear. The display may be worn out.


The problems that the current behaviour tries to solve
======================================================

1. Preventing screensaver while playing movies.
Many SDL applications are media players. They have reasons to prevent
screensavers from being activated while a movie is being played. When a
user clicks on the play button it can be interpreted as saying "play
this movie, but do not turn off the display while playing it, because I
will watch it even though I do not interact with the system".

2. Preventing screensaver when some input bypasses X.
Sometimes SDL uses input from another source than the X server, so
that the X server is bypassed. This obviously breaks the screensaver
handling. SDL tries to work around that.

3. Preventing screensaver when all input bypasses X.
There is something called Direct Graphics Access mode, where a
program takes control of both the display and the input devices from the
X server. This obviously means that the X server can not handle the
screensaver alone, since screensaver handling depends on input handling.
SDL does not do what it should to help the X server to handle the
screensaver. Nor does SDL take care of screeensaver handling itself. SDL
simply disables the screensaver completely.


How the problems should be solved
=================================

The correct way for an application program to prevent the screensaver
under X is to call XResetScreenSaver. This was recently discovered and
implemented by the mplayer developers,
[http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to
wrap this in an API call (SDL_ResetScreenSaver) and implement it for the
other video targets (if they do not have a corresponding call, SDL
should do what it takes on that particular target, for example sending
fake key events).

1. When a movie is played, the player should reset the screensaver when
the animation is advanced to a new frame. The same applies to anything
similar, like slideshows.

2. When the X server is handling input, it must handle all input
(keyboards, mice, gamepads, ...). This is necessary, not only to be able
to handle the screensaver, but also so that it can send the events to
the correct (the currently active) client. If there is an input device
that the X server can not handle for some reason (such as lack of Plug
and Play capability), the program that handles the device as a
workaround must simulate what would happen if the X server would have
handled the device, by calling XResetScreenSaver when input is received
from the device.

3. When the X server is not handling the input, it depends on the
program that does to call XResetScreenSaver whenever an input event
occurs. Alternatively the program must handle the screensaver countdown
internally and call XActivateScreenSaver.
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This is a list of API changes in SDL's version history.
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Version 1.0:
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1.2.13:
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	Added SDL_BUTTON_X1 and SDL_BUTTON_X2 constants.
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1.2.12:
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	Added SDL_VIDEO_ALLOW_SCREENSAVER to override SDL's disabling
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	of the screensaver on Mac OS X and X11.
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1.2.10:
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	If SDL_OpenAudio() is passed zero for the desired format
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	fields, the following environment variables will be used
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	to fill them in:
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		SDL_AUDIO_FREQUENCY
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		SDL_AUDIO_FORMAT
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		SDL_AUDIO_CHANNELS
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		SDL_AUDIO_SAMPLES
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	If an environment variable is not specified, it will be set
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	to a reasonable default value.
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	Added support for the SDL_VIDEO_FULLSCREEN_HEAD environment
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	variable, currently supported on X11 Xinerama configurations.
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	Added SDL_GL_SWAP_CONTROL to wait for vsync in OpenGL applications.
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	Added SDL_GL_ACCELERATED_VISUAL to guarantee hardware acceleration.
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	Added current_w and current_h to the SDL_VideoInfo structure,
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	which is set to the desktop resolution during video intialization,
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	and then set to the current resolution when a video mode is set.
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	SDL_SetVideoMode() now accepts 0 for width or height and will use
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	the current video mode (or the desktop mode if no mode has been set.)
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	Added SDL_GetKeyRepeat()
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	Added SDL_config.h, with defaults for various build environments.
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1.2.7:
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	Added CPU feature detection functions to SDL_cpuinfo.h:
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		SDL_HasRDTSC(), SDL_HasMMX(), SDL_Has3DNow(), SDL_HasSSE(),
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		SDL_HasAltiVec()
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	Added function to create RWops from const memory: SDL_RWFromConstMem()
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1.2.6:
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	Added SDL_LoadObject(), SDL_LoadFunction(), and SDL_UnloadObject()
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	Added SDL_GL_MULTISAMPLEBUFFERS and SDL_GL_MULTISAMPLESAMPLES for FSAA
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1.2.5:
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	Added SDL_BUTTON_WHEELUP (4) and SDL_BUTTON_WHEELDOWN (5)
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	Added SDL_GL_STEREO for stereoscopic OpenGL contexts
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1.2.0:
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	Added SDL_VIDEOEXPOSE event to signal that the screen needs to
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	be redrawn.  This is currently only delivered to OpenGL windows
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	on X11, though it may be delivered in the future when the video
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	memory is lost under DirectX.
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1.1.8:
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	You can pass SDL_NOFRAME to SDL_VideoMode() to create a window
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	that has no title bar or frame decoration.  Fullscreen video
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	modes automatically have this flag set.
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	Added a function to query the clipping rectangle for a surface:
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		void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect)
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	Added a function to query the current event filter:
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		SDL_EventFilter SDL_GetEventFilter(void)
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	If you pass -1 to SDL_ShowCursor(), it won't change the current
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	cursor visibility state, but will still return it.
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	SDL_LockSurface() and SDL_UnlockSurface() are recursive, meaning
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	you can nest them as deep as you want, as long as each lock call
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	has a matching unlock call.  The surface remains locked until the
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	last matching unlock call.
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	Note that you may not blit to or from a locked surface.
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1.1.7:
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	The SDL_SetGammaRamp() and SDL_GetGammaRamp() functions now take
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	arrays of Uint16 values instead of Uint8 values.  For the most part,
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	you can just take your old values and shift them up 8 bits to get
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	new correct values for your gamma ramps.
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	You can pass SDL_RLEACCEL in flags passed to SDL_ConvertSurface()
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        and SDL will try to RLE accelerate colorkey and alpha blits in the
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	resulting surface.
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1.1.6:
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	Added a function to return the thread ID of a specific thread:
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		Uint32 SDL_GetThreadID(SDL_Thread *thread)
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	If 'thread' is NULL, this function returns the id for this thread.
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1.1.5:
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	The YUV overlay structure has been changed to use an array of
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	pitches and pixels representing the planes of a YUV image, to
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	better enable hardware acceleration.  The YV12 and IYUV formats
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	each have three planes, corresponding to the Y, U, and V portions
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	of the image, while packed pixel YUV formats just have one plane.
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	For palettized mode (8bpp), the screen colormap is now split in
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	a physical and a logical palette. The physical palette determines
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	what colours the screen pixels will get when displayed, and the
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	logical palette controls the mapping from blits to/from the screen.
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	A new function, SDL_SetPalette() has been added to change
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	logical and physical palettes separately. SDL_SetColors() works
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	just as before, and is equivalent to calling SDL_SetPalette() with
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	a flag argument of (SDL_LOGPAL|SDL_PHYSPAL).
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	SDL_BlitSurface() no longer modifies the source rectangle, only the
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	destination rectangle. The width/height members of the destination
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	rectangle are ignored, only the position is used.
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	The old source clipping function SDL_SetClipping() has been replaced
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	with a more useful function to set the destination clipping rectangle:
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		SDL_bool SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect)
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	Added a function to see what subsystems have been initialized:
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		Uint32 SDL_WasInit(Uint32 flags)
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	The Big Alpha Flip: SDL now treats alpha as opacity like everybody
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	else, and not as transparency:
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	A new cpp symbol: SDL_ALPHA_OPAQUE is defined as 255
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	A new cpp symbol: SDL_ALPHA_TRANSPARENT is defined as 0
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	Values between 0 and 255 vary from fully transparent to fully opaque.
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	New functions:
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	SDL_DisplayFormatAlpha()
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	    Returns a surface converted to a format with alpha-channel
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	    that can be blit efficiently to the screen. (In other words,
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	    like SDL_DisplayFormat() but the resulting surface has
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	    an alpha channel.)  This is useful for surfaces with alpha.
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	SDL_MapRGBA()
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	    Works as SDL_MapRGB() but takes an additional alpha parameter.
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	SDL_GetRGBA()
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	    Works as SDL_GetRGB() but also returns the alpha value
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	    (SDL_ALPHA_OPAQUE for formats without an alpha channel)
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	Both SDL_GetRGB() and SDL_GetRGBA() now always return values in
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	the [0..255] interval. Previously, SDL_GetRGB() would return
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	(0xf8, 0xfc, 0xf8) for a completely white pixel in RGB565 format.
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	(N.B.: This is broken for bit fields < 3 bits.)
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	SDL_MapRGB() returns pixels in which the alpha channel is set opaque.
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	SDL_SetAlpha() can now be used for both setting the per-surface
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	alpha, using the new way of thinking of alpha, and also to enable
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	and disable per-pixel alpha blending for surfaces with an alpha
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	channel:
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		To disable alpha blending:
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			SDL_SetAlpha(surface, 0, 0);
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		To re-enable alpha blending:
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			SDL_SetAlpha(surface, SDL_SRCALPHA, 0);
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	Surfaces with an alpha channel have blending enabled by default.
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	SDL_SetAlpha() now accepts SDL_RLEACCEL as a flag, which requests
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	RLE acceleration of blits, just as like with SDL_SetColorKey().
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	This flag can be set for both surfaces with an alpha channel
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	and surfaces with an alpha value set by SDL_SetAlpha().
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	As always, RLE surfaces must be locked before pixel access is
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	allowed, and unlocked before any other SDL operations are done
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	on it.
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	The blit semantics for surfaces with and without alpha and colorkey
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	have now been defined:
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	RGBA->RGB:
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	    SDL_SRCALPHA set:
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		alpha-blend (using alpha-channel).
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		SDL_SRCCOLORKEY ignored.
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	    SDL_SRCALPHA not set:
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		copy RGB.
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		if SDL_SRCCOLORKEY set, only copy the pixels matching the
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		RGB values of the source colour key, ignoring alpha in the
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		comparison.
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	RGB->RGBA:
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	    SDL_SRCALPHA set:
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		alpha-blend (using the source per-surface alpha value);
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		set destination alpha to opaque.
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	    SDL_SRCALPHA not set:
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		copy RGB, set destination alpha to opaque.
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	    both:
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		if SDL_SRCCOLORKEY set, only copy the pixels matching the
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		source colour key.
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	RGBA->RGBA:
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	    SDL_SRCALPHA set:
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		alpha-blend (using the source alpha channel) the RGB values;
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		leave destination alpha untouched. [Note: is this correct?]
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		SDL_SRCCOLORKEY ignored.
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	    SDL_SRCALPHA not set:
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		copy all of RGBA to the destination.
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		if SDL_SRCCOLORKEY set, only copy the pixels matching the
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		RGB values of the source colour key, ignoring alpha in the
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		comparison.
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	RGB->RGB: 
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	    SDL_SRCALPHA set:
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		alpha-blend (using the source per-surface alpha value).
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	    SDL_SRCALPHA not set:
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		copy RGB.
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	    both:
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		if SDL_SRCCOLORKEY set, only copy the pixels matching the
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		source colour key.
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	As a special case, blits from surfaces with per-surface alpha
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	value of 128 (50% transparency) are optimised and much faster
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	than other alpha values. This does not apply to surfaces with
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	alpha channels (per-pixel alpha).
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	New functions for manipulating the gamma of the display have
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	been added:
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		int SDL_SetGamma(float red, float green, float blue);
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		int SDL_SetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
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		int SDL_GetGammaRamp(Uint8 *red, Uint8 *green, Uint8 *blue);
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	Gamma ramps are tables with 256 entries which map the screen color
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	components into actually displayed colors.  For an example of
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	implementing gamma correction and gamma fades, see test/testgamma.c
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	Gamma control is not supported on all hardware.
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1.1.4:
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	The size of the SDL_CDtrack structure changed from 8 to 12 bytes
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	as the size of the length member was extended to 32 bits.
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        You can now use SDL for 2D blitting with a GL mode by passing the
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	SDL_OPENGLBLIT flag to SDL_SetVideoMode().  You can specify 16 or
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	32 bpp, and the data in the framebuffer is put into the GL scene
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	when you call SDL_UpdateRects(), and the scene will be visible
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	when you call SDL_GL_SwapBuffers().
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	Run the "testgl" test program with the -logo command line option
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	to see an example of this blending of 2D and 3D in SDL.
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1.1.3:
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	Added SDL_FreeRW() to the API, to complement SDL_AllocRW()
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	Added resizable window support - just add SDL_RESIZABLE to the
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	SDL_SetVideoMode() flags, and then wait for SDL_VIDEORESIZE events.
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	See SDL_events.h for details on the new SDL_ResizeEvent structure.
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	Added condition variable support, based on mutexes and semaphores.
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		SDL_CreateCond()
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		SDL_DestroyCond()
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		SDL_CondSignal()
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		SDL_CondBroadcast()
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		SDL_CondWait()
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		SDL_CondTimedWait()
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	The new function prototypes are in SDL_mutex.h
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	Added counting semaphore support, based on the mutex primitive.
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		SDL_CreateSemaphore()
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		SDL_DestroySemaphore()
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		SDL_SemWait()
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		SDL_SemTryWait()
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		SDL_SemWaitTimeout()
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		SDL_SemPost()
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		SDL_SemValue()
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	The new function prototypes are in SDL_mutex.h
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	Added support for asynchronous blitting.  To take advantage of this,
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	you must set the SDL_ASYNCBLIT flag when setting the video mode and
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	creating surfaces that you want accelerated in this way.  You must
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	lock surfaces that have this flag set, and the lock will block until
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	any queued blits have completed.
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	Added YUV video overlay support.
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	The supported YUV formats are: YV12, IYUV, YUY2, UYVY, and YVYU.
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	This function creates an overlay surface:
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		SDL_CreateYUVOverlay()
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	You must lock and unlock the overlay to get access to the data:
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		SDL_LockYUVOverlay() SDL_UnlockYUVOverlay()
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	You can then display the overlay:
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		SDL_DisplayYUVOverlay()
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	You must free the overlay when you are done using it:
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		SDL_FreeYUVOverlay()
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	See SDL_video.h for the full function prototypes.
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	The joystick hat position constants have been changed:
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	Old constant            New constant
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	------------            ------------
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	     0                  SDL_HAT_CENTERED
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	     1                  SDL_HAT_UP
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	     2                  SDL_HAT_RIGHTUP
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	     3                  SDL_HAT_RIGHT
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	     4                  SDL_HAT_RIGHTDOWN
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	     5                  SDL_HAT_DOWN
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	     6                  SDL_HAT_LEFTDOWN
slouken@0
   296
	     7                  SDL_HAT_LEFT
slouken@0
   297
	     8                  SDL_HAT_LEFTUP
slouken@0
   298
	The new constants are bitmasks, so you can check for the
slouken@0
   299
	individual axes like this:
slouken@0
   300
		if ( hat_position & SDL_HAT_UP ) {
slouken@0
   301
		}
slouken@0
   302
	and you'll catch left-up, up, and right-up.
slouken@0
   303
slouken@0
   304
1.1.2:
slouken@0
   305
	Added multiple timer support:
slouken@0
   306
		SDL_AddTimer() and SDL_RemoveTimer()
slouken@0
   307
slouken@0
   308
	SDL_WM_SetIcon() now respects the icon colorkey if mask is NULL.
slouken@0
   309
slouken@0
   310
1.1.0:
slouken@0
   311
	Added initial OpenGL support.
slouken@0
   312
	First set GL attributes (such as RGB depth, alpha depth, etc.)
slouken@0
   313
		SDL_GL_SetAttribute()
slouken@0
   314
	Then call SDL_SetVideoMode() with the SDL_OPENGL flag.
slouken@0
   315
	Perform all of your normal GL drawing.
slouken@0
   316
	Finally swap the buffers with the new SDL function:
slouken@0
   317
		SDL_GL_SwapBuffers()
slouken@0
   318
	See the new 'testgl' test program for an example of using GL with SDL.
slouken@0
   319
slouken@0
   320
	You can load GL extension functions by using the function:
slouken@0
   321
		SDL_GL_LoadProcAddress()
slouken@0
   322
slouken@0
   323
	Added functions to initialize and cleanup specific SDL subsystems:
slouken@0
   324
		SDL_InitSubSystem() and SDL_QuitSubSystem()
slouken@0
   325
slouken@0
   326
	Added user-defined event type:
slouken@0
   327
		typedef struct {
slouken@0
   328
        		Uint8 type;
slouken@0
   329
        		int code;
slouken@0
   330
        		void *data1;
slouken@0
   331
        		void *data2;
slouken@0
   332
		} SDL_UserEvent;
slouken@0
   333
	This structure is in the "user" member of an SDL_Event.
slouken@0
   334
slouken@0
   335
	Added a function to push events into the event queue:
slouken@0
   336
		SDL_PushEvent()
slouken@0
   337
slouken@0
   338
	Example of using the new SDL user-defined events:
slouken@0
   339
	{
slouken@0
   340
		SDL_Event event;
slouken@0
   341
slouken@0
   342
		event.type = SDL_USEREVENT;
slouken@0
   343
		event.user.code = my_event_code;
slouken@0
   344
		event.user.data1 = significant_data;
slouken@0
   345
		event.user.data2 = 0;
slouken@0
   346
		SDL_PushEvent(&event);
slouken@0
   347
	}
slouken@0
   348
slouken@0
   349
	Added a function to get mouse deltas since last query:
slouken@0
   350
		SDL_GetRelativeMouseState()
slouken@0
   351
slouken@0
   352
	Added a boolean datatype to SDL_types.h:
slouken@0
   353
		SDL_bool = { SDL_TRUE, SDL_FALSE }
slouken@0
   354
slouken@0
   355
	Added a function to get the current audio status:
slouken@0
   356
		SDL_GetAudioState();
slouken@0
   357
	It returns one of:
slouken@0
   358
		SDL_AUDIO_STOPPED,
slouken@0
   359
		SDL_AUDIO_PLAYING,
slouken@0
   360
		SDL_AUDIO_PAUSED
slouken@0
   361
slouken@0
   362
	Added an AAlib driver (ASCII Art) - by Stephane Peter.
slouken@0
   363
slouken@0
   364
1.0.6:
slouken@0
   365
	The input grab state is reset after each call to SDL_SetVideoMode().
slouken@0
   366
	The input is grabbed by default in fullscreen mode, and ungrabbed in
slouken@0
   367
	windowed mode.  If you want to set input grab to a particular value,
slouken@0
   368
	you should set it after each call to SDL_SetVideoMode().
slouken@0
   369
slouken@0
   370
1.0.5:
slouken@0
   371
	Exposed SDL_AudioInit(), SDL_VideoInit()
slouken@0
   372
	Added SDL_AudioDriverName() and SDL_VideoDriverName()
slouken@0
   373
slouken@0
   374
	Added new window manager function:
slouken@0
   375
		SDL_WM_ToggleFullScreen()
slouken@0
   376
	This is currently implemented only on Linux
slouken@0
   377
slouken@0
   378
	The ALT-ENTER code has been removed - it's not appropriate for a
slouken@0
   379
	lib to bind keys when they aren't even emergency escape sequences.
slouken@0
   380
slouken@0
   381
	ALT-ENTER functionality can be implemented with the following code:
slouken@0
   382
slouken@0
   383
	int Handle_AltEnter(const SDL_Event *event)
slouken@0
   384
	{
slouken@0
   385
	    if ( event->type == SDL_KEYDOWN ) {
slouken@0
   386
	        if ( (event->key.keysym.sym == SDLK_RETURN) &&
slouken@0
   387
	             (event->key.keysym.mod & KMOD_ALT) ) {   
slouken@0
   388
	                SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
slouken@0
   389
	                return(0);
slouken@0
   390
	        }
slouken@0
   391
	    }
slouken@0
   392
	    return(1);
slouken@0
   393
	}
slouken@0
   394
	SDL_SetEventFilter(Handle_AltEnter);
slouken@0
   395
slouken@0
   396
1.0.3:
slouken@0
   397
	Under X11, if you grab the input and hide the mouse cursor,
slouken@0
   398
	the mouse will go into a "relative motion" mode where you
slouken@0
   399
	will always get relative motion events no matter how far in
slouken@0
   400
	each direction you move the mouse - relative motion is not
slouken@0
   401
	bounded by the edges of the window (though the absolute values
slouken@0
   402
	of the mouse positions are clamped by the size of the window).
slouken@0
   403
	The SVGAlib, framebuffer console, and DirectInput drivers all
slouken@0
   404
	have this behavior naturally, and the GDI and BWindow drivers
slouken@0
   405
	never go into "relative motion" mode.
slouken@0
   406
slouken@0
   407
1.0.2:
slouken@0
   408
	Added a function to enable keyboard repeat:
slouken@0
   409
		SDL_EnableKeyRepeat()
slouken@0
   410
slouken@0
   411
	Added a function to grab the mouse and keyboard input
slouken@0
   412
		SDL_WM_GrabInput()
slouken@0
   413
slouken@0
   414
	Added a function to iconify the window.
slouken@0
   415
		SDL_WM_IconifyWindow()
slouken@0
   416
	If this function succeeds, the application will receive an event
slouken@0
   417
	signaling SDL_APPACTIVE event 
slouken@0
   418
slouken@0
   419
1.0.1:
slouken@0
   420
	Added constants to SDL_audio.h for 16-bit native byte ordering:
slouken@0
   421
		AUDIO_U16SYS, AUDIO_S16SYS
slouken@0
   422
slouken@0
   423
1.0.0:
slouken@0
   424
	New public release
slouken@0
   425
slouken@0
   426
Version 0.11:
slouken@0
   427
slouken@0
   428
0.11.5:
slouken@0
   429
	A new function SDL_GetVideoSurface() has been added, and returns
slouken@0
   430
	a pointer to the current display surface.
slouken@0
   431
slouken@0
   432
	SDL_AllocSurface() has been renamed SDL_CreateRGBSurface(), and
slouken@0
   433
	a new function SDL_CreateRGBSurfaceFrom() has been added to allow
slouken@0
   434
	creating an SDL surface from an existing pixel data buffer.
slouken@0
   435
slouken@0
   436
	Added SDL_GetRGB() to the headers and documentation.
slouken@0
   437
slouken@0
   438
0.11.4:
slouken@0
   439
	SDL_SetLibraryPath() is no longer meaningful, and has been removed.
slouken@0
   440
slouken@0
   441
0.11.3:
slouken@0
   442
	A new flag for SDL_Init(), SDL_INIT_NOPARACHUTE, prevents SDL from
slouken@0
   443
	installing fatal signal handlers on operating systems that support
slouken@0
   444
	them.
slouken@0
   445
slouken@0
   446
Version 0.9:
slouken@0
   447
slouken@0
   448
0.9.15:
slouken@0
   449
	SDL_CreateColorCursor() has been removed.  Color cursors should
slouken@0
   450
	be implemented as sprites, blitted by the application when the
slouken@0
   451
	cursor moves.  To get smooth color cursor updates when the app
slouken@0
   452
	is busy, pass the SDL_INIT_EVENTTHREAD flag to SDL_Init().  This
slouken@0
   453
	allows you to handle the mouse motion in another thread from an
slouken@0
   454
	event filter function, but is currently only supported by Linux
slouken@0
   455
	and BeOS.  Note that you'll have to protect the display surface
slouken@0
   456
	from multi-threaded access by using mutexes if you do this.
slouken@0
   457
slouken@0
   458
	Thread-safe surface support has been removed from SDL.
slouken@0
   459
	This makes blitting somewhat faster, by removing SDL_MiddleBlit().
slouken@0
   460
	Code that used SDL_MiddleBlit() should use SDL_LowerBlit() instead.
slouken@0
   461
	You can make your surfaces thread-safe by allocating your own
slouken@0
   462
	mutex and making lock/unlock calls around accesses to your surface.
slouken@0
   463
slouken@0
   464
0.9.14:
slouken@0
   465
	SDL_GetMouseState() now takes pointers to int rather than Uint16.
slouken@0
   466
slouken@0
   467
	If you set the SDL_WINDOWID environment variable under UNIX X11,
slouken@0
   468
	SDL will use that as the main window instead of creating it's own.
slouken@0
   469
	This is an unsupported extension to SDL, and not portable at all.
slouken@0
   470
slouken@0
   471
0.9.13:
slouken@0
   472
	Added a function SDL_SetLibraryPath() which can be used to specify
slouken@0
   473
	the directory containing the SDL dynamic libraries.  This is useful
slouken@0
   474
	for commercial applications which ship with particular versions
slouken@0
   475
	of the libraries, and for security on multi-user systems.
slouken@0
   476
	If this function is not used, the default system directories are 
slouken@0
   477
	searched using the native dynamic object loading mechanism.
slouken@0
   478
slouken@0
   479
	In order to support C linkage under Visual C++, you must declare
slouken@0
   480
	main() without any return type:
slouken@0
   481
		main(int argc, char *argv[]) {
slouken@0
   482
			/* Do the program... */
slouken@0
   483
			return(0);
slouken@0
   484
		}
slouken@0
   485
	C++ programs should also return a value if compiled under VC++.
slouken@0
   486
slouken@0
   487
	The blit_endian member of the SDL_VideoInfo struct has been removed.
slouken@0
   488
slouken@0
   489
	SDL_SymToASCII() has been replaced with SDL_GetKeyName(), so there
slouken@0
   490
	is now no longer any function to translate a keysym to a character.
slouken@0
   491
slouken@0
   492
	The SDL_keysym structure has been extended with a 'scancode' and
slouken@0
   493
	'unicode' member.  The 'scancode' is a hardware specific scancode
slouken@0
   494
	for the key that was pressed, and may be 0.  The 'unicode' member
slouken@0
   495
	is a 16-bit UNICODE translation of the key that was pressed along
slouken@0
   496
	with any modifiers or compose keys that have been pressed.
slouken@0
   497
	If no UNICODE translation exists for the key, 'unicode' will be 0.
slouken@0
   498
slouken@0
   499
	Added a function SDL_EnableUNICODE() to enable/disable UNICODE
slouken@0
   500
	translation of character keypresses.  Translation defaults off.
slouken@0
   501
slouken@0
   502
	To convert existing code to use the new API, change code which
slouken@0
   503
	uses SDL_SymToASCII() to get the keyname to use SDL_GetKeyName(),
slouken@0
   504
	and change code which uses it to get the ASCII value of a sym to
slouken@0
   505
	use the 'unicode' member of the event keysym.
slouken@0
   506
slouken@0
   507
0.9.12:
slouken@0
   508
	There is partial support for 64-bit datatypes.  I don't recommend 
slouken@0
   509
	you use this if you have a choice, because 64-bit datatypes are not
slouken@0
   510
	supported on many platforms.  On platforms for which it is supported,
slouken@0
   511
	the SDL_HAS_64BIT_TYPE C preprocessor define will be enabled, and
slouken@0
   512
	you can use the Uint64 and Sint64 datatypes.
slouken@0
   513
slouken@0
   514
	Added functions to SDL_endian.h to support 64-bit datatypes:
slouken@0
   515
	    SDL_SwapLE64(), SDL_SwapBE64(),
slouken@0
   516
	    SDL_ReadLE64(), SDL_ReadBE64(), SDL_WriteLE64(), SDL_WriteBE64()
slouken@0
   517
slouken@0
   518
	A new member "len_ratio" has been added to the SDL_AudioCVT structure,
slouken@0
   519
	and allows you to determine either the original buffer length or the
slouken@0
   520
	converted buffer length, given the other.
slouken@0
   521
slouken@0
   522
	A new function SDL_FreeWAV() has been added to the API to free data
slouken@0
   523
	allocated by SDL_LoadWAV_RW().  This is necessary under Win32 since
slouken@0
   524
	the gcc compiled DLL uses a different heap than VC++ compiled apps.
slouken@0
   525
slouken@0
   526
	SDL now has initial support for international keyboards using the
slouken@0
   527
	Latin character set.
slouken@0
   528
	If a particular mapping is desired, you can set the DEFAULT_KEYBOARD
slouken@0
   529
	compile-time variable, or you can set the environment variable 
slouken@0
   530
	"SDL_KEYBOARD" to a string identifying the keyboard mapping you desire.
slouken@0
   531
	The valid values for these variables can be found in SDL_keyboard.c
slouken@0
   532
slouken@0
   533
	Full support for German and French keyboards under X11 is implemented.
slouken@0
   534
slouken@0
   535
0.9.11:
slouken@0
   536
	The THREADED_EVENTS compile-time define has been replaced with the
slouken@0
   537
	SDL_INIT_EVENTTHREAD flag.  If this flag is passed to SDL_Init(),
slouken@0
   538
	SDL will create a separate thread to perform input event handling.
slouken@0
   539
	If this flag is passed to SDL_Init(), and the OS doesn't support 
slouken@0
   540
	event handling in a separate thread, SDL_Init() will fail.
slouken@0
   541
	Be sure to add calls to SDL_Delay() in your main thread to allow
slouken@0
   542
	the OS to schedule your event thread, or it may starve, leading
slouken@0
   543
	to slow event delivery and/or dropped events.
slouken@0
   544
	Currently MacOS and Win32 do not support this flag, while BeOS 
slouken@0
   545
	and Linux do support it.  I recommend that your application only
slouken@0
   546
	use this flag if absolutely necessary.
slouken@0
   547
slouken@0
   548
	The SDL thread function passed to SDL_CreateThread() now returns a
slouken@0
   549
	status.  This status can be retrieved by passing a non-NULL pointer
slouken@0
   550
	as the 'status' argument to SDL_WaitThread().
slouken@0
   551
slouken@0
   552
	The volume parameter to SDL_MixAudio() has been increased in range
slouken@0
   553
	from (0-8) to (0-128)
slouken@0
   554
slouken@0
   555
	SDL now has a data source abstraction which can encompass a file,
slouken@0
   556
	an area of memory, or any custom object you can envision.  It uses
slouken@0
   557
	these abstractions, SDL_RWops, in the endian read/write functions,
slouken@0
   558
	and the built-in WAV and BMP file loaders.  This means you can load
slouken@0
   559
	WAV chunks from memory mapped files, compressed archives, network
slouken@0
   560
	pipes, or anything else that has a data read abstraction.
slouken@0
   561
slouken@0
   562
	There are three built-in data source abstractions:
slouken@0
   563
	    SDL_RWFromFile(), SDL_RWFromFP(), SDL_RWFromMem()
slouken@0
   564
	along with a generic data source allocation function:
slouken@0
   565
	    SDL_AllocRW()
slouken@0
   566
	These data sources can be used like stdio file pointers with the
slouken@0
   567
	following convenience functions:
slouken@0
   568
	    SDL_RWseek(), SDL_RWread(), SDL_RWwrite(), SDL_RWclose()
slouken@0
   569
	These functions are defined in the new header file "SDL_rwops.h"
slouken@0
   570
slouken@0
   571
	The endian swapping functions have been turned into macros for speed
slouken@0
   572
	and SDL_CalculateEndian() has been removed.  SDL_endian.h now defines
slouken@0
   573
	SDL_BYTEORDER as either SDL_BIG_ENDIAN or SDL_LIL_ENDIAN depending on
slouken@0
   574
	the endianness of the host system.
slouken@0
   575
slouken@0
   576
	The endian read/write functions now take an SDL_RWops pointer
slouken@0
   577
	instead of a stdio FILE pointer, to support the new data source
slouken@0
   578
	abstraction.
slouken@0
   579
slouken@0
   580
	The SDL_*LoadWAV() functions have been replaced with a single
slouken@0
   581
	SDL_LoadWAV_RW() function that takes a SDL_RWops pointer as it's
slouken@0
   582
	first parameter, and a flag whether or not to automatically 
slouken@0
   583
	free it as the second parameter.  SDL_LoadWAV() is a macro for
slouken@0
   584
	backward compatibility and convenience:
slouken@0
   585
	    SDL_LoadWAV_RW(SDL_RWFromFile("sample.wav", "rb"), 1, ...);
slouken@0
   586
slouken@0
   587
	The SDL_*LoadBMP()/SDL_*SaveBMP() functions have each been replaced
slouken@0
   588
	with a single function that takes a SDL_RWops pointer as it's
slouken@0
   589
	first parameter, and a flag whether or not to automatically 
slouken@0
   590
	free it as the second parameter.  SDL_LoadBMP() and SDL_SaveBMP()
slouken@0
   591
	are macros for backward compatibility and convenience:
slouken@0
   592
	    SDL_LoadBMP_RW(SDL_RWFromFile("sample.bmp", "rb"), 1, ...);
slouken@0
   593
	    SDL_SaveBMP_RW(SDL_RWFromFile("sample.bmp", "wb"), 1, ...);
slouken@0
   594
	Note that these functions use SDL_RWseek() extensively, and should
slouken@0
   595
	not be used on pipes or other non-seekable data sources.
slouken@0
   596
slouken@0
   597
0.9.10:
slouken@0
   598
	The Linux SDL_SysWMInfo and SDL_SysWMMsg structures have been 
slouken@0
   599
	extended to support multiple types of display drivers, as well as
slouken@0
   600
        safe access to the X11 display when THREADED_EVENTS is enabled.
slouken@0
   601
        The new structures are documented in the SDL_syswm.h header file.
slouken@0
   602
slouken@0
   603
	Thanks to John Elliott <jce@seasip.demon.co.uk>, the UK keyboard
slouken@0
   604
	should now work properly, as well as the "Windows" keys on US
slouken@0
   605
	keyboards.
slouken@0
   606
slouken@0
   607
	The Linux CD-ROM code now reads the CD-ROM devices from /etc/fstab
slouken@0
   608
	instead of trying to open each block device on the system.
slouken@0
   609
	The CD must be listed in /etc/fstab as using the iso9660 filesystem.
slouken@0
   610
slouken@0
   611
	On Linux, if you define THREADED_EVENTS at compile time, a separate
slouken@0
   612
	thread will be spawned to gather X events asynchronously from the
slouken@0
   613
	graphics updates.  This hasn't been extensively tested, but it does
slouken@0
   614
	provide a means of handling keyboard and mouse input in a separate
slouken@0
   615
	thread from the graphics thread.  (This is now enabled by default.)
slouken@0
   616
slouken@0
   617
	A special access function SDL_PeepEvents() allows you to manipulate
slouken@0
   618
	the event queue in a thread-safe manner, including peeking at events,
slouken@0
   619
	removing events of a specified type, and adding new events of arbitrary
slouken@0
   620
	type to the queue (use the new 'user' member of the SDL_Event type).
slouken@0
   621
slouken@0
   622
	If you use SDL_PeepEvents() to gather events, then the main graphics
slouken@0
   623
	thread needs to call SDL_PumpEvents() periodically to drive the event
slouken@0
   624
	loop and generate input events.  This is not necessary if SDL has been 
slouken@0
   625
	compiled with THREADED_EVENTS defined, but doesn't hurt.
slouken@0
   626
slouken@0
   627
	A new function SDL_ThreadID() returns the identifier associated with
slouken@0
   628
	the current thread.
slouken@0
   629
slouken@0
   630
0.9.9:
slouken@0
   631
	The AUDIO_STEREO format flag has been replaced with a new 'channels'
slouken@0
   632
	member of the SDL_AudioSpec structure.  The channels are 1 for mono
slouken@0
   633
	audio, and 2 for stereo audio.  In the future more channels may be
slouken@0
   634
	supported for 3D surround sound.
slouken@0
   635
slouken@0
   636
	The SDL_MixAudio() function now takes an additional volume parameter,
slouken@0
   637
	which should be set to SDL_MIX_MAXVOLUME for compatibility with the
slouken@0
   638
	original function.
slouken@0
   639
slouken@0
   640
	The CD-ROM functions which take a 'cdrom' parameter can now be
slouken@0
   641
	passed NULL, and will act on the last successfully opened CD-ROM.
slouken@0
   642
slouken@0
   643
0.9.8:
slouken@0
   644
	No changes, bugfixes only.
slouken@0
   645
	
slouken@0
   646
0.9.7:
slouken@0
   647
	No changes, bugfixes only.
slouken@0
   648
	
slouken@0
   649
0.9.6:
slouken@0
   650
	Added a fast rectangle fill function: SDL_FillRect()
slouken@0
   651
slouken@0
   652
	Addition of a useful function for getting info on the video hardware:
slouken@0
   653
	    const SDL_VideoInfo *SDL_GetVideoInfo(void)
slouken@0
   654
        This function replaces SDL_GetDisplayFormat().
slouken@0
   655
slouken@0
   656
	Initial support for double-buffering:
slouken@0
   657
	  Use the SDL_DOUBLEBUF flag in SDL_SetVideoMode()
slouken@0
   658
	  Update the screen with a new function: SDL_Flip()
slouken@0
   659
slouken@0
   660
	SDL_AllocSurface() takes two new flags:
slouken@0
   661
	SDL_SRCCOLORKEY means that the surface will be used for colorkey blits
slouken@0
   662
	  and if the hardware supports hardware acceleration of colorkey blits
slouken@0
   663
	  between two surfaces in video memory, to place the surface in video
slouken@0
   664
	  memory if possible, otherwise it will be placed in system memory.
slouken@0
   665
	SDL_SRCALPHA means that the surface will be used for alpha blits and
slouken@0
   666
	  if the hardware supports hardware acceleration of alpha blits between
slouken@0
   667
	  two surfaces in video memory, to place the surface in video memory
slouken@0
   668
	  if possible, otherwise it will be placed in system memory.
slouken@0
   669
	SDL_HWSURFACE now means that the surface will be created with the 
slouken@0
   670
	  same format as the display surface, since having surfaces in video
slouken@0
   671
	  memory is only useful for fast blitting to the screen, and you can't
slouken@0
   672
	  blit surfaces with different surface formats in video memory.
slouken@0
   673
slouken@0
   674
0.9.5:
slouken@0
   675
	You can now pass a NULL mask to SDL_WM_SetIcon(), and it will assume
slouken@0
   676
	that the icon consists of the entire image.
slouken@0
   677
slouken@0
   678
	SDL_LowerBlit() is back -- but don't use it on the display surface.
slouken@0
   679
	It is exactly the same as SDL_MiddleBlit(), but doesn't check for
slouken@0
   680
	thread safety.
slouken@0
   681
slouken@0
   682
	Added SDL_FPLoadBMP(), SDL_FPSaveBMP(), SDL_FPLoadWAV(), which take
slouken@0
   683
	a FILE pointer instead of a file name.
slouken@0
   684
slouken@0
   685
	Added CD-ROM audio control API:
slouken@0
   686
	    SDL_CDNumDrives()
slouken@0
   687
	    SDL_CDName()
slouken@0
   688
	    SDL_CDOpen()
slouken@0
   689
	    SDL_CDStatus()
slouken@0
   690
	    SDL_CDPlayTracks()
slouken@0
   691
	    SDL_CDPlay()
slouken@0
   692
	    SDL_CDPause()
slouken@0
   693
	    SDL_CDResume()
slouken@0
   694
	    SDL_CDStop()
slouken@0
   695
	    SDL_CDEject()
slouken@0
   696
	    SDL_CDClose()
slouken@0
   697
slouken@0
   698
0.9.4:
slouken@0
   699
	No changes, bugfixes only.
slouken@0
   700
slouken@0
   701
0.9.3:
slouken@0
   702
	Mouse motion event now includes relative motion information:
slouken@0
   703
	    Sint16 event->motion.xrel, Sint16 event->motion.yrel
slouken@0
   704
slouken@0
   705
	X11 keyrepeat handling can be disabled by defining IGNORE_X_KEYREPEAT
slouken@0
   706
	    (Add -DIGNORE_X_KEYREPEAT to CFLAGS line in obj/x11Makefile)
slouken@0
   707
slouken@0
   708
0.9.2:
slouken@0
   709
	No changes, bugfixes only.
slouken@0
   710
slouken@0
   711
0.9.1:
slouken@0
   712
	Removed SDL_MapSurface() and SDL_UnmapSurface() -- surfaces are now
slouken@0
   713
	automatically mapped on blit.
slouken@0
   714
slouken@0
   715
0.8.0:
slouken@0
   716
	SDL stable release