SDL environment variables
=========================

last updated: 27 Sept 2001

The following applies to the CVS SDL (the 1.2 branch). This is unofficial,
and the semantics may vary, and some variables might go away.

AUDIODEV
	The audio device to use, if SDL_PATH_DSP isn't set.

SDL_AUDIODRIVER
	Selects the audio driver for SDL to use. Possible values, in the
	order they are tried if this variable is not set:

	openbsd	   (OpenBSD)
	dsp	   (OSS /dev/dsp: Linux, Solaris, BSD etc)
	alsa	   (Linux)
	audio	   (Unix style /dev/audio: SunOS, Solaris etc)
	AL	   (Irix)
	artsc	   (ARTS audio daemon)
	esd	   (esound audio daemon)
	nas	   (NAS audio daemon)
	dma	   (OSS /dev/dsp, using DMA)
	dsound	   (Win32 DirectX)
	waveout	   (Win32 WaveOut)
	baudio	   (BeOS)
	sndmgr	   (MacOS SoundManager)
	paud	   (AIX)
	AHI	   (Amiga)
	disk	   (all; output to file)

SDL_CDROM
	A colon-separated list of CD-ROM devices to use, in addition to
	the standard devices (typically /dev/cdrom, platform-dependant).

SDL_DEBUG
	If set, causes every call to SDL_SetError() to also print an
	error message on stderr.

SDL_DISKAUDIOFILE
	The name of the output file for the "disk" audio driver. If not
	set, the name "sdlaudio.raw" is used.

SDL_DISKAUDIODELAY
	For the "disk" audio driver, how long to wait (in ms) before writing
	a full sound buffer. The default is 150 ms.

SDL_DSP_NOSELECT
	For some audio drivers (alsa, paud, dma and dsp), don't use
	select() but a timed method instead. May cure some audio problems,
	or cause others.

SDL_ELO_MIN_X
SDL_ELO_MIN_Y
SDL_ELO_MAX_X
SDL_ELO_MAX_Y
	Calibration values for the fbcon driver, for the Elographics
        touchscreen controller. Default values are 400, 500, 3670, 3540
        respectively.

SDL_FBACCEL
	If set to 0, disable hardware acceleration in the linux fbcon driver.

SDL_FBDEV
	Frame buffer device to use in the linux fbcon driver, instead of
	/dev/fb0

SDL_FULLSCREEN_UPDATE
	In the ps2gs driver, sets the SDL_ASYNCBLIT flag on the display
	surface.

SDL_JOYSTICK_DEVICE
	Joystick device to use in the linux joystick driver, in addition
	to the usual: /dev/js*, /dev/input/event*, /dev/input/js*

SDL_LINUX_JOYSTICK
	Special joystick configuration string for linux. The format is
	"name numaxes numhats numballs"
	where name is the name string of the joystick (possibly in single
	quotes), and the rest are the number of axes, hats and balls
	respectively.

SDL_MOUSE_RELATIVE
	If set to 0, do not use mouse relative mode in X11. The default is
	to use it if the mouse is hidden and input is grabbed.

SDL_MOUSEDEV
	The mouse device to use for the linux fbcon driver. If not set,
	SDL first tries to use GPM in repeater mode, then various other
	devices (/dev/pcaux, /dev/adbmouse, /dev/mouse etc).

SDL_MOUSEDEV_IMPS2
	If set, SDL will not try to auto-detect	the IMPS/2 protocol of
	a PS/2 mouse but use it right away. For the fbcon and ps2gs drivers.

SDL_MOUSEDRV
	For the linux fbcon driver: if set to ELO, use the ELO touchscreen
	controller as a pointer device

SDL_NO_RAWKBD
	For the libvga driver: If set, do not attempt to put the keyboard
	in raw mode.

SDL_NOMOUSE
	If set, the linux fbcon driver will not use a mouse at all.

SDL_PATH_DSP
	The audio device to use. If not set, SDL tries AUDIODEV and then
	a platform-dependent default value (/dev/audio on Solaris,
	/dev/dsp on Linux etc).

SDL_VIDEODRIVER
	Selectes the video driver for SDL to use. Possible values, in the
        order they are tried if this variable is not set:

	x11
	dga		(the XFree86 DGA2)
	nanox		(Linux)
	fbcon		(Linux)
	directfb	(Linux)
	ps2gs		(Playstation 2)
	ggi
	vgl		(BSD)
	svgalib		(Linux)
	aalib
	directx		(Win32)
	windib		(Win32)
	bwindow		(BeOS)
	toolbox		(MacOS Classic)
	DSp		(MacOS Classic)
	Quartz		(MacOS X)
	CGX		(Amiga)
	photon		(QNX)
	epoc		(Epoc)
	dummy

SDL_VIDEO_CENTERED
	If set, tries to center the SDL window when running in X11 windowed
	mode, or using the CyberGrafix driver.

SDL_VIDEO_GL_DRIVER
	The openGL driver (shared library) to use for X11. Default is
	libGL.so.1

SDL_VIDEO_X11_DGAMOUSE
	With XFree86, enables use of DGA mouse if set.

SDL_VIDEO_X11_MOUSEACCEL
	For X11, sets the mouse acceleration. The value should be a string
	on the form: n/d/t
	where n and d are the acceleration numerator/denumerators (so
	mouse movement is accelerated by n/d), and t is the threshold
	above which acceleration applies (counted as number of pixels
	the mouse moves at once).

SDL_VIDEO_X11_NODIRECTCOLOR
	If set, don't attempt to use DirectColor visuals even if they are
	present. (SDL will use them otherwise for gamma correction).
	This is needed with older X servers when using the XVideo extension.

SDL_VIDEO_X11_VISUALID
	ID of an X11 visual to use, overriding SDL's default visual selection
	algorithm. It can be in decimal or in hex (prefixed by 0x).

SDL_VIDEO_YUV_DIRECT
	If set, display YUV overlay directly on the video surface if possible,
	instead of on the surface passed to SDL_CreateYUVOverlay().

SDL_VIDEO_YUV_HWACCEL
	If not set or set to a nonzero value, SDL will attempt to use
	hardware YUV acceleration for video playback.

SDL_WINDOWID
	For X11 or Win32, contains the ID number of the window to be used by
	SDL instead of creating its own window. Either in decimal or
	in hex (prefixed by 0x).

