NAME
svgalib - a low level graphics library for linux
TABLE OF CONTENTS
0. Introduction
1. Installation
2. How to use svgalib
3. Description of svgalib functions
4. Overview of supported SVGA chipsets and modes
5. Detailed comments on certain device drivers
6. Goals
7. References (location of latest version, apps etc.)
8. Known bugs
0. INTRODUCTION
This is a low level graphics library for Linux, originally based on
VGAlib 1.2 by Tommy Frandsen. VGAlib supported a number of standard VGA
graphics modes, as well as Tseng ET4000 high resolution 256-color
modes. As of now, support for many more chipsets has been added. See
section 4 Overview of supported SVGA chipsets and modes
It supports transparent virtual console switching, that is, you can
switch consoles to and from text and graphics mode consoles using
alt-[function key]. Also, svgalib corrects most of VGAlib’s textmode
corruption behaviour by catching SIGSEGV, SIGFPE, SIGILL, and other
fatal signals and ensuring that a program is running in the currently
visible virtual console before setting a graphics mode.
Note right here that SIGUSR1 and SIGUSR2 are used to manage console
switching internally in svgalib. You can not use them in your
programs. If your program needs to use one of those signals, svgalib
can be compiled to use other signals, by editing libvga.h
This version includes code to hunt for a free virtual console on its
own in case you are not starting the program from one (but instead over
a network or modem login, from within screen(1) or an xterm(1)).
Provided there is a free console, this succeeds if you are root or if
the svgalib calling user own the current console. This is to avoid
people not using the console being able to fiddle with it. On graceful
exit the program returns to the console from which it was started.
Otherwise it remains in text mode at the VC which svgalib allocated to
allow you to see any error messages. In any case, any I/O the svgalib
makes in text mode (after calling vga_init(3)) will also take place at
this new console.
Alas, some games misuse their suid root privilege and run as full root
process. svgalib cannot detect this and allows Joe Blow User to open a
new VC on the console. If this annoys you, ROOT_VC_SHORTCUT in
Makefile.cfg allows you to disable allocating a new VC for root (except
when he owns the current console) when you compile svgalib. This is the
default.
When the library is used by a program at run-time, first the chipset is
detected and the appropriate driver is used. This means that a graphics
program will work on any card that is supported by svgalib, if the mode
it uses is supported by the chipset driver for that card. The library
is upwardly compatible with VGAlib.
The set of drawing functions provided by svgalib itself is limited
(unchanged from VGAlib) and unoptimized; you can however use
vga_setpage(3) and vga_getgraphmem(3) (which points to the 64K VGA
framebuffer) in a program or graphics library. A fast external
framebuffer graphics library for linear and banked 1, 2, 3 and 4 bytes
per pixel modes is included (it also indirectly supports planar VGA
modes). It is documented in vgagl(7).
One obvious application of the library is a picture viewer. Several are
available, along with animation viewers. See the 7. References at the
end of this document.
I have added a simple VGA textmode font restoration utility
(restorefont(1)) which may help if you suffer from XFree86 textmode
font corruption. It can also be used to change the textmode font. It
comes with some other textmode utilities: restoretextmode(1) (which
saves/restores textmode registers), restorepalette(1), and the script
textmode(1). If you run the savetextmode(1) script to save textmode
information to /tmp, you’ll be able to restore textmode by running the
textmode(1) script.
1. INSTALLATION
Installation is easy in general but there are many options and things
you should keep in mind. This document however assumes that svgalib is
already installed.
If you need information on installation see 0-INSTALL which comes with
the svgalib distribution.
However, even after installation of the library you might need to
configure svgalib using the file /etc/vga/libvga.config. Checkout
section 4 Overview of supported SVGA chipsets and modes and
libvga.config(5) for information.
2. HOW TO USE SVGALIB
For basic svgalib usage (no mouse, no raw keyboard) add #include
<vga.h> at the beginning your program. Use vga_init(3) as your first
svgalib call. This will give up root privileges right after
initialization, making setuid-root binaries relatively safe.
The function vga_getdefaultmode(3) checks the environment variable
SVGALIB_DEFAULT_MODE for a default mode, and returns the corresponding
mode number. The environment string can either be a mode number or a
mode name as in (G640x480x2, G640x480x16, G640x480x256 , G640x480x32K,
G640x480x64K, G640x480x16M). As an example, to set the default
graphics mode to 640x480, 256 colors, use:
export SVGALIB_DEFAULT_MODE=G640x480x256
on the bash(1) command line. If a program needs just a linear VGA/SVGA
resolution (as required by vgagl(7)), only modes where bytesperpixel in
the vga_modeinfo structure returned by vga_getmodeinfo(3) is greater or
equal to 1 should be accepted (this is 0 for tweaked planar 256-color
VGA modes).
Use vga_setmode(graphicsmode) to set a graphics mode. Use
vga_setmode(TEXT) to restore textmode before program exit.
Programs that use svgalib must #include<vga.h>; if they also use the
external graphics library vgagl(7), you must also #include<vgagl.h>.
Linking must be done with -lvga (and -lvgagl before -lvga, if vgagl(7)
is used). You can save binary space by removing the unused chipset
drivers in Makefile.cfg if you only use specific chipsets. However this
reduces the flexibility of svgalib and has a significant effect only
when you use the static libraries. You should better use the shared
libraries and these will load only the really used parts anyway.
Functions in the vgagl(7) library have the prefix gl_. Please see
vgagl(7) for details.
There are demos with sources available which will also help to get you
started, in recommended order of interest: vgatest(6), keytest(6),
mousetest(6), eventtest(6), forktest(6), bg_test(6), scrolltest(6),
speedtest(6), fun(6), spin(6), testlinear(6), lineart(6), testgl(6),
accel(6), testaccel(6), plane(6), and wrapdemo(6).
Debugging your programs will turn out to be rather difficult, because
the svgalib application can not restore textmode when it returns to the
debugger.
Happy are the users with a serial terminal, X-station, or another way
to log into the machine from network. These can use
textmode </dev/ttyN
on the console where the program runs and continue.
However, the vga_flip(3) function allows you to switch to textmode by
entering a call to it blindly into your debugger when your program
stops in graphics mode. vga_flip(3) is not very robust though. You
shall not call it when svgalib is not yet initialized or in textmode.
Before continuing your program, you must then call vga_flip(3) again to
return to graphics mode. If the program will not make any screen
accesses or svgalib calls before it returns to the debugger, you can
omit that, of course.
This will only work if your program and the debugger run in the same
virtual linux console.
3. DESCRIPTION OF SVGALIB FUNCTIONS
Each function has its own section 3 manual page. For a list of vgagl
functions see vgagl(7).
Initialization
vga_init(3)
- initialize svgalib library.
vga_disabledriverreport(3)
- makes svgalib not emit any startup messages.
vga_claimvideomemory(3)
- declare the amount of video memory used.
vga_safety_fork(3)
- start a parallel process to restore the console at a crash.
vga_setchipset(3)
- force chipset.
vga_setchipsetandfeatures(3)
- force chipset and optional parameters.
Inquire hardware configuration
vga_getmousetype(3)
- returns the mouse type configured.
vga_getcurrentchipset(3)
- returns the current SVGA chipset.
vga_getmonitortype(3)
- returns the monitor type configured.
Setting video modes
vga_setmode(3)
- sets a video mode.
vga_setdisplaystart(3)
- set the display start address.
vga_setlogicalwidth(3)
- set the logical scanline width.
vga_setlinearaddressing(3)
- switch to linear addressing mode.
vga_setmodeX(3)
- try to set Mode X-like memory organization .
vga_ext_set(3)
- set and query several extended features.
vga_screenoff(3), vga_screenon(3)
- turn generation of the video signal on or off.
Get video mode information
vga_getxdim(3), vga_getydim(3), vga_getcolors(3)
- return the current screen resolution.
vga_white(3)
- return the color white in the current screen resolution.
vga_getcurrentmode(3)
- returns the current video mode.
vga_hasmode(3)
- returns if a video mode is supported.
vga_getmodeinfo(3)
- returns pointer to mode information structure for a mode.
vga_getdefaultmode(3)
- returns the default graphics mode number.
vga_lastmodenumber(3)
- returns the last video mode number.
vga_getmodename(3)
- return a name for the given video mode.
vga_getmodenumber(3)
- return a number for the given video mode.
Drawing primitives
vga_clear(3)
- clear the screen.
vga_setcolor(3)
- set the current color.
vga_setrgbcolor(3)
- set the current color.
vga_setegacolor(3)
- set the current color.
vga_drawpixel(3)
- draw a pixel on the screen.
vga_drawscanline(3)
- draw a horizontal line of pixels.
vga_drawscansegment(3)
- draw a horizontal line of pixels.
vga_drawline(3)
- draw a line on the screen.
vga_getpixel(3)
- get a pixels value from the screen.
vga_getscansegment(3)
- get a list of consecutive pixel values.
vga_waitretrace(3)
- wait for vertical retrace.
Basic (non raw) keyboard I/O
vga_getch(3)
- wait for a key.
vga_getkey(3)
- read a character from the keyboard without waiting.
vga_waitevent(3)
- wait for various I/O events.
Direct VGA memory access
vga_setpage(3)
- set the 64K SVGA page number.
vga_setreadpage(3)
- set the 64K SVGA page number.
vga_setwritepage(3)
- set the 64K SVGA page number.
vga_getgraphmem(3)
- returns the address of the VGA memory.
vga_copytoplanar256(3)
- copy linear pixmap into Mode X video memory.
vga_copytoplanar16(3)
- copy linear pixmap into VGA 16 color mode video memory.
vga_copytoplane(3)
- copy linear pixmap to some planes of VGA 16 color mode video
memory.
Manage color lookup tables
vga_setpalette(3)
- set a color in the color lookup table.
vga_getpalette(3)
- get a color in the color lookup table.
vga_setpalvec(3)
- sets colors in the color lookup table.
vga_getpalvec(3)
- gets colors from the color lookup table.
Mouse handling
vga_setmousesupport(3)
- enable mouse support.
mouse_init(3), mouse_init_return_fd(3)
- specifically initialize a mouse.
mouse_close(3)
- explicitly close a mouse.
mouse_update(3)
- updates the mouse state.
mouse_waitforupdate(3)
- wait for an mouse update.
mouse_setscale(3)
- sets a mouse scale factor.
mouse_setwrap(3)
- set what happens at the mouse boundaries.
mouse_setxrange(3), mouse_setyrange(3)
- define the boundaries for the mouse cursor.
mouse_getx(3), mouse_gety(3), mouse_getbutton(3)
- query the mouse state.
mouse_setposition(3)
- set the current mouse position.
mouse_getposition_6d(3), mouse_setposition_6d(3), mouse_setrange_6d(3)
- provide an interface to 3d mice.
mouse_seteventhandler(3), mouse_setdefaulteventhandler(3)
- set a mouse event handler.
Raw keyboard handling
keyboard_init(3), keyboard_init_return_fd(3)
- initialize the keyboard to raw mode.
keyboard_close(3)
- return the keyboard to normal operation from raw mode.
keyboard_update(3), keyboard_waitforupdate(3)
- process raw keyboard events.
keyboard_translatekeys(3)
- modify scancode mappings in raw keyboard mode.
keyboard_keypressed(3)
- check if a key is pressed when in raw keyboard mode.
keyboard_getstate(3)
- get a pointer to a buffer holding the state of all keys in raw
keyboard mode.
keyboard_clearstate(3)
- reset the state of all keys when in raw keyboard mode.
keyboard_seteventhandler(3), keyboard_setdefaulteventhandler(3)
- define an event handler for keyboard events in raw mode.
Joystick handling
joystick_init(3)
- initialize and calibrate joysticks.
joystick_close(3)
- close a joystick device.
joystick_update(3)
- query and process joystick state changes.
joystick_sethandler(3), joystick_setdefaulthandler(3)
- define own joystick even handler.
joystick_getnumaxes(3), joystick_getnumbuttons(3)
- query the capabilities of a joystick.
joystick_getaxis(3), joystick_getbutton(3)
- query the state of a joystick.
joystick_button1|2|3|4(3), joystick_getb1|2|3|4(3), joystick_x|y|z(3),
joystick_getx|y|z(3)
- convenience macros to query the joystick position.
Accelerator interface (new style)
vga_accel(3)
- calls the graphics accelerator.
Accelerator interface (old style)
vga_bitblt(3)
- copy pixmap on screen using an accelerator.
vga_fillblt(3)
- fill rectangular area in video memory with a single color.
vga_hlinelistblt(3)
- draw horizontal scan lines.
vga_imageblt(3)
- copy a rectangular pixmap from system memory to video memory.
vga_blitwait(3)
- wait for any accelerator operation to finish.
Controlling VC switches
vga_lockvc(3)
- disables virtual console switching for safety.
vga_unlockvc(3)
- re-enables virtual console switching.
vga_oktowrite(3)
- indicates whether the program has direct access to the SVGA.
vga_runinbackground(3)
- enable running of the program while there is no VGA access.
vga_runinbackground_version(3)
- returns the version of the current background support.
Debugging aids
vga_dumpregs(3)
- dump the contents of the SVGA registers.
vga_gettextfont(3), vga_puttextfont(3)
- get/set the font used in text mode.
vga_gettextmoderegs(3), vga_settextmoderegs(3)
- get/set the vga state used in text mode.
vga_flip(3)
- toggle between text and graphics mode.
vga_setflipchar(3)
- set the character causing a vga_flip().
4. OVERVIEW OF SUPPORTED SVGA CHIPSETS AND MODES
VGA and compatibles
320x200x256, and the series of 16-color and non-standard planar 256
color modes supported by VGAlib, as well as 720x348x2.
ALI2301
Supports 640x480x256, 800x600x256, 1024x768x256 SVGA modes
AT3D (AT25)
Also known as Promotion at25. Popular as the 2D part of a voodoo rush
card. As of this writing there are a few known problems with this
driver. Read below.
ARK Logic ARK1000PV/2000PV
Full support, limited RAMDAC support. Only ARK1000PV tested. Supports
Clocks and Ramdac lines in config file.
ATI SVGA (VGA Wonder and friends)
This is no real driver. I do not support any new modes. However it
saves additional card setup and thus allows use of the plain VGA modes
even when you are using non standard text modes. It is possible to
enforce use of this driver even on ATI Mach32 but not very useful.
ATI Mach32
The driver by Michael Weller supports all ATI BIOS-defined modes and
more... It hits the best out of your card. Some modes may not have
nice default timings but it uses the ATI’s EEPROM for custom config or
allows to specify modes in libvga.config(5). Some problems may occur
with quite some third party cards (usually on board) Mach32 based
controllers as they do not completely conform to the Mach32 data
sheets. Check out svgalib.mach32(7) (and libvga.config(5)).
ATI Mach64 (rage)
A driver for ATi Mach64 based cards with internal DAC.
Chips and Technologies chipsets 65525, 65535, 65546, 65548, 65550, and
65554 (usually in laptops).
This server was written using the SVGALIB patch from Sergio and Angelo
Masci as a starting point. This version of the code resembled the XFree
server code that was used up to XFree 3.1.2. As such it was incapable
of programming the clocks, using linear addressing, Hi-Color, True-
Color modes or the hardware acceleration. All of these features have
since been added to the code. The 64200 and 64300 chips are
unsupported, however these chips are very similar to the 6554x chips
which are supported.
Cirrus Logic GD542x/3x
All the modes, including 256 color, 32K/64K color, 16M color (3 bytes
per pixel) and 32-bit pixel 16M color modes (5434). Some bitblt
functions are supported. The driver doesn’t work with mode dumps, but
uses a SVGA abstraction with mode timings like the X drivers.
Genoa(?) GVGA6400 cards.
Supported.
Hercules Stingray 64/Video
Is supported as an ARK2000PV
NV3 driver for the Riva128.
This driver was written by Matan Ziv-Av and is derived from the XFree86
driver by David J. Mckay. It lacks 24bit modes (can the card do them at
all?), acceleration support and pageflipping in threeDKit is broken.
Oak Technologies OTI-037/67/77/87
Driver by Christopher Wiles; includes 32K color modes for OTI-087.
S3
The driver is not complete, but should work on a number of
cards/RAMDACs, and 640x480x256 should work on most card. The best
support is for a 801/805 with AT&T20C490-compatible RAMDAC, and S3-864
+ SDAC. All 256/32K/64K/16M works for them (within the bounds of video
memory & ramdac restrictions).
The supported cards include S3 Virge and S3 Trio64 cards.
None of the acceleration function is supported yet.
The chip level code should work with the 964/868/968, but most likely
the card they come on would use an unsupported ramdac/clock chip.
Support for these chips is slowly being added.
Clocks and Ramdac lines in libvga.config(5) supported.
The maximum pixel clock (in MHz) of the ramdac can be set using a
Dacspeed line in the config file. A reasonable default is assumed if
the Dacspeed line is omitted. Clocks should be the same as in XFree86.
Supported ramdac IDs: Sierra32K, SC15025, SDAC, GenDAC, ATT20C490,
ATT20C498, IBMRGB52x.
Example:
Clocks 25.175 28.3 40 70 50 75 36 44.9 0 118 77 31.5 110 65 72 93.5
Ramdac att20c490
DacSpeed 85
Also supported, at least in combination with the SC15025/26A ramdac, is
the ICD 2061A clock chip. Since it cannot be autodetected you need to
define it in the config file using a Clockchip line. As there is no way
to read the current settings out of the 2061, you have the option to
specify the frequency used when switching back to text mode as second
argument in the Clockchip line.
This is especially required if your text mode is an 132 column mode,
since these modes use a clock from the clock chip, while 80 column
modes use a fixed clock of 25 MHz. The text mode frequency defaults to
40 MHz, if omitted.
Example:
ClockChip icd2061a 40.0
Trident TVGA 8900C/9000 (and possibly also 8800CS/8900A/B) and also TVGA
9440
Derived from tvgalib by Toomas Losin. TVGA 9440 support by ARK
<ark@lhq.com, root@ark.dyn.ml.or>.
Supports 640x480x256, 800x600x256, 1024x768x256 (interlaced and non-
interlaced) Might be useful to add 16-color modes (for those equipped
with a 512K TVGA9000) for the 8900 and 9000 cards.
320x200x{32K, 64K, 16M}, 640x480x{256, 32K, 64K, 16M}, 800x600x{256,
32K, 64K, 16M}, 1024x768x{16, 256}, 800x600x{16, 256, 32K, 64K} modes
are supported for the TVGA 9440.
Autodetection can be forced with a:
chipset TVGA memory flags
line in the config file.
memory is the amount of VGA memory in KB, flags is composed of three
bits:
bit2 = false, bit1 = false
force 8900.
bit2 = false, bit1 = true
force 9440.
bit2 = true, bit1 = false
force 9680.
bit0 = true
force noninterlaced.
bit0 = false
force interlaced which only matters on 8900’s with at
least 1M since there is no 512K interlaced mode on the
8900 or any of the other cards.
Tseng ET4000/ET4000W32(i/p)
Derived from VGAlib; not the same register values. ET4000 register
values are not compatible; see svgalib.et4000(7).
Make sure the colors are right in hicolor mode; the vgatest program
should draw the same color bars for 256 and hicolor modes (the DAC type
is defined at compilation in et4000.regs or the dynamic registers
file). ET4000/W32 based cards usually have an AT&T or Sierra 15025/6
DAC. With recent W32p based cards, you might have some luck with the
AT&T DAC type. If the high resolution modes don’t work, you can try
dumping the registers in DOS using the program in the et4000/ directory
and putting them in a file (/etc/vga/libvga.et4000 is parsed at runtime
if DYNAMIC is defined in Makefile.cfg at compilation (this is
default)).
Supported modes are 640x480x256, 800x600x256, 1024x768x256,
640x480x32K, 800x600x32K, 640x480x16M, etc.
Reports of ET4000/W32i/p functionality are welcome.
There may be a problem with the way the hicolor DAC register is
handled; dumped registers may use one of two timing methods, with the
value written to the register for a particular DAC for a hicolor mode
(in vgahico.c) being correct for just one of the these methods. As a
consequence some dumped resolutions may work while others don’t.
Tseng ET6000
Most modes of which the card is capable are supported. The 8 15 16 24
and 32 bit modes are supported.
The ET6000 has a built in DAC and there is no problem coming from that
area. The ET6000 is capable of acceleration, but this as well as
sprites are not yet implemented in the driver.
The driver now uses modelines in libvga.config for user defined modes.
It is sometimes useful to add a modeline for a resolution which does
not display well. For example, the G400x600 is too far to the right of
the screen using standard modes. This is corrected by including in
libvga.config the line
Modeline "400x600@72" 25.000 400 440 488 520 600 639 644 666
More examples are given below.
This driver was provided by Don Secrest.
VESA
Please read README.vesa and README.lrmi in doc subdirectory of the
standard distribution.
Go figure! I turned off autodetection in the release, as a broken bios
will be called too, maybe crashing the machine. Enforce VESA mode by
putting a chipset VESA in the end of your libvga.config(5).
Note that it will leave protected mode and call the cards bios opening
the door to many hazards.
5. DETAILED COMMENTS ON CERTAIN DEVICE DRIVERS
This section contains detailed information by the authors on certain
chipsets.
AT3D (AT25)
Also known as Promotion at25. Popular as the 2D part of a voodoo rush
card.
I have written a driver for this chipset, based on the XF86 driver for
this chipset.
The programs that work with this driver include all the programs in the
demos directory, zgv and dvisvga (tmview).
I believe it should be easy to make it work on AT24, AT6422.
ATI Mach32
Please see svgalib.mach32(7).
ATI Mach64
The rage.c driver works only on mach64 based cards with internal DAC.
The driver might misdetect the base frequency the card uses, so if when
setting any svgalib modes the screen blanks, or complains about out of
bound frequencies, or the display is unsynced, then try adding the
option RageDoubleClock to the config file.
Chips and Technologies chipsets 65525, 65535, 65546, 65548, 65550, and
65554 (usually in laptops).
Please see svgalib.chips(7).
Tseng ET4000/ET4000W32(i/p)
Please see svgalib.et4000(7).
Tseng ET6000
I have only 2 Mbytes of memory on my ET6000 card, so I am not able to
get all possible modes running. I haven’t even tried to do all of the
modes which I am capable of doing, but I am confident that I can manage
more modes when I have time. I have enough modes working to make the
card useful, so I felt it was worth while to add the driver to svgalib
now.
Linear graphics is working on this card, both with and without
BACKGROUND enabled, and vga_runinbackground works.
I decided it was best to quit working on more modes and try to get
acceleration and sprites working.
My et6000 card is on a PCI bus. The card will run on a vesa bus, but
since I don’t have one on my machine I couldn’t develop vesa bus
handling. I quit if the bus is a vesa bus.
I check for an et6000 card, which can be unequivocally identified. The
et4000 driver does not properly identify et4000 cards. It thinks the
et6000 card is an et4000, but can only run it in vga modes.
I have found the following four modelines to be useful in libvga.config
or in ~/.svgalibrc for proper display of some modes.
Modeline "512x384@79" 25.175 512 560 592 640 384 428 436 494
Modeline "400x300@72" 25.000 400 456 472 520 300 319 332 350
DOUBLESCAN
Modeline "512x480@71" 25.175 512 584 600 656 480 500 510 550
Modeline "400x600@72" 25.000 400 440 488 520 600 639 644 666
Don Secrest <secrest@uiuc.edu> Aug 21, 1999
Oak Technologies OTI-037/67/77/87
First a few comments of me (Michael Weller <eowmob@exp-math.uni-
essen.de>):
As of this writing (1.2.8) fixes were made to the oak driver by Frodo
Looijaard <frodol@dds.nl> to reenable OTI-067 support. It is unknown
right now if they might have broken OTI-087 support. The author of the
’87 support Christopher Wiles <wileyc@moscow.com> owns no longer an
OTI-087 card and can thus no longer give optimal support to this
driver. Thus you might be better off contacting me or Frodo for
questions. If you are a knowledgeable OTI-087 user and experience
problems you are welcome to provide fixes. No user of a OTI-087 is
currently known to me, so if you are able to fix problems with the
driver please do so (and contact me) as noone else can.
Michael.
Now back to the original Oak information:
The original OTI driver, which supported the OTI-067/77 at 640x480x256,
has been augmented with the following features:
1) Supported resolutions/colors have been expanded to 640x480x32K,
800x600x256/32K, 1024x768x256, and 1280x1024x16.
2) The OTI-087 (all variants) is now supported. Video memory is
correctly recognized.
The driver as it exists now is somewhat schizoid. As the ’87
incorporates a completely different set of extended registers, I found
it necessary to split its routines from the others. Further, I did not
have access to either a ’67 or a ’77 for testing the new resolutions.
If using them causes your monitor/video card to fry, your dog to bite
you, and so forth, I warned you. The driver works on my ’87, and
that’s all I guarantee. Period.
Heh. Now, if someone wants to try them out ... let me know if they
work.
New from last release:
32K modes now work for 640x480 and 800x600. I found that the Sierra
DAC information in VGADOC3.ZIP is, well, wrong. But, then again, the
information for the ’87 was wrong also.
64K modes do not work. I can’t even get Oak’s BIOS to enter those
modes.
I have included a 1280x1024x16 mode, but I haven’t tested it. My
monitor can’t handle that resolution. According to the documentation,
with 2 megs the ’87 should be able to do an interlaced 1280x1024x256
... again, I couldn’t get the BIOS to do the mode. I haven’t 2 megs
anyway, so there it sits.
I have included routines for entering and leaving linear mode. They
should work, but they don’t. It looks like a pointer to the frame
buffer is not being passed to SVGALIB. I’ve been fighting with this
one for a month. If anyone wants to play with this, let me know if it
can be make to work. I’ve got exams that I need to pass.
Tidbit: I pulled the extended register info out of the video BIOS.
When the information thus obtained failed to work, I procured the
OTI-087 data book. It appears that Oak’s video BIOS sets various modes
incorrectly (e.g. setting 8-bit color as 4, wrong dot clock
frequencies, etc.). Sort of makes me wonder ...
Christopher M. Wiles (a0017097@wsuaix.csc.wsu.edu)
12 September 1994
6. GOALS
I think the ability to use a VGA/SVGA graphics resolution in one
virtual console, and being able to switch to any other virtual
console and back makes a fairly useful implementation of graphics modes
in the Linux console.
Programs that use svgalib must be setuid root. I don’t know how
desirable it is to have this changed; direct port access can hardly be
done without. Root privileges can now be given up right after
initialization. I noticed some unimplemented stuff in the kernel header
files that may be useful, although doing all register I/O via the
kernel would incur a significant context-switching overhead. An
alternative might be to have a pseudo /dev/vga device that yields the
required permissions when opened, the device being readable by programs
in group vga.
It is important that textmode is restored properly and reliably; it is
fairly reliable at the moment, but fast console switching back and
forth between two consoles running graphics can give problems. Wild
virtual console switching also sometimes corrupts the contents of the
textmode screen buffer (not the textmode registers or font). Also if a
program crashes it may write into the area where the saved textmode
registers are stored, causing textmode not be restored correctly. It
would be a good idea to somehow store this information in a ’safe’ area
(say a kernel buffer). Note that the vga_safety_fork(3) thing has the
same idea.
Currently, programs that are in graphics mode are suspended while not
in the current virtual console. Would it be a good idea to let them run
in the background, virtualizing framebuffer actions (this should not be
too hard for linear banked SVGA modes)? It would be nice to have, say,
a raytracer with a real-time display run in the background (although
just using a separate real-time viewing program is much more elegant).
Anyone wanting to rewrite it all in a cleaner way (something with
loadable kernel modules shouldn’t hurt performance with linear
framebuffer/vgagl type applications) is encouraged.
Also, if anyone feels really strongly about a low-resource and
truecolor supporting graphical window environment with cut-and-paste, I
believe it would be surprisingly little work to come up with a simple
but very useful client-server system with shmem, the most useful
applications being fairly trivial to write (e.g. shell window, bitmap
viewer). And many X apps would port trivially.
This is old information, please be sure to read svgalib.faq(7) if you
are interested in further goals.
7. REFERENCES
The latest version of svgalib can be found on sunsite.unc.edu in
/pub/Linux/libs/graphics or tsx-11.mit.edu in /pub/linux/sources/libs
as svgalib-X.X.X.tar.gz. As of this writing the latest version is
svgalib-1.4.1.tar.gz. There are countless mirrors of these ftp servers
in the world. Certainly a server close to you will carry it.
The original VGAlib is on tsx-11.mit.edu,
pub/linux/sources/libs/vgalib12.tar.Z. tvgalib-1.0.tar.Z is in the
same directory.
SLS has long been distributing an old version of VGAlib. Slackware
keeps a fairly up-to-date version of svgalib, but it may be installed
in different directories from what svgalib likes to do by default. The
current svgalib install tries to remove most of this. It also removes
/usr/bin/setmclk and /usr/bin/convfont, which is a security risk if
setuid-root. Actually the recent makefiles try to do a really good job
to cleanup the mess which some distributions make.
If you want to recompile the a.out shared library, you will need the
DLL ’tools’ package (found on tsx-11.mit.edu, GCC dir). To make it
work with recent ELF compiler’s you actually need to hand patch it. You
should probably not try to compile it. Compiling the ELF library is
deadly simple.
And here is a list of other references which is horribly outdated.
There are many more svgalib applications as well as the directories
might have changed. However, these will give you a start point and
names to hunt for on CD’s or in ftp archives.
Viewers (in /pub/Linux/apps/graphics/viewers on sunsite.unc.edu):
spic Picture viewer; JPG/PPM/GIF; truecolor; scrolling.
zgv Full-featured viewer with nice file selector.
see-jpeg
Shows picture as it is being built up.
mpeg-linux
svgalib port of the Berkeley MPEG decoder (mpeg_play); it also
includes an X binary.
flip FLI/FLC player (supports SVGA-resolution).
Games (in /pub/Linux/games on sunsite.unc.edu):
bdash B*lderdash clone with sound.
sasteroids
Very smooth arcade asteroids game.
yatzy Neat mouse controlled dice game.
vga_cardgames
Collection of graphical card games.
vga_gamespack
Connect4, othello and mines.
wt Free state-of-the-art Doom-like engine.
Maelstrom
A very nice asteroids style game port from Mac.
Koules A game. (I’ve no idea what it looks like)
Docs
In the vga directory of the SIMTEL MSDOS collection, there is a package
called vgadoc3 which is a collection of VGA/SVGA register information.
The XFree86 driver sources distributed with the link-kit may be
helpful.
Miscellaneous
There’s an alternative RAW-mode keyboard library by Russell Marks for
use with svgalib on sunsite.unc.edu.
LIBGRX, the extensive framebuffer library by Csaba Biegl distributed
with DJGPP, has been ported to Linux. Contact Hartmut Schirmer
(phc27@rz.uni-kiel.d400.de, subject prefix "HARTMUT:"). A more up-to-
date port by Daniel Jackson (djackson@icomp.intel.com) is on
sunsite.unc.edu.
The vgalib ghostscript device driver sources can be found on
sunsite.unc.edu, /pub/Linux/apps/graphics. Ghostscript patches from
Slackware: ftp.cdrom.com, /pub/linux/misc. gnuplot patches are on
sunsite.unc.edu.
Mitch D’Souza has written font functions that work in 16 color modes
and can use VGA textmode (codepage format) fonts; these can be found in
his g3fax package in sunsite.unc.edu. These functions may go into a
later version of svgalib.
8. KNOWN BUGS
This section is most probably outdated, none of these problems are no
longer reported.
Using a 132 column textmode may cause graphics modes to fail. Try using
something like 80x28.
The console switching doesn’t preserve some registers that may be used
to draw in planar VGA modes.
Wild console switching can cause the text screen to be corrupted,
especially when switching between two graphics consoles.
On ET4000, having run XFree86 may cause high resolution modes to fail
(this is more XFree86’s fault).
The Trident probing routine in the XFree86 server may cause standard
VGA modes to fail after exiting X on a Cirrus. Try putting a ’Chipset’
line in your Xconfig to avoid the Trident probe, or use the link kit to
build a server without the Trident driver. Saving and restoring the
textmode registers with savetextmode/textmode (restoretextmode) should
also work. [Note: svgalib now resets the particular extended register,
but only if the Cirrus driver is used (i.e. the chipset is not forced
to VGA)] [This is fixed in XFree86 v2.1]
Some Paradise VGA cards may not work even in standard VGA modes. Can
anyone confirm this?
Piping data into a graphics program has problems. I am not sure why. A
pity, since zcatting a 5Mb FLC file into flip on a 4Mb machine would be
fun.
The tseng3.exe DOS program include as source in the svgalib
distribution doesn’t recognize any modes on some ET4000 cards. Also
ET4000 cards with a Acumos/Cirrus DAC may only work correctly in 64K
color mode.
FILES
/etc/vga/libvga.config
/etc/vga/libvga.et4000
SEE ALSO
svgalib.et4000(7), svgalib.chips(7), svgalib.mach32(7), vgagl(7),
libvga.config(5), 3d(6), accel(6), bg_test(6), eventtest(6),
forktest(6), fun(6), keytest(6), lineart(5), mousetest(6), joytest(6),
mjoytest(6), scrolltest(6), speedtest(6), spin(6), testaccel(6),
testgl(6), testlinear(6), vgatest(6), plane(6), wrapdemo(6),
convfont(1), dumpreg(1), fix132x43(1), restorefont(1),
restorepalette(1), restoretextmode(1), runx(1), savetextmode(1),
setmclk(1), textmode(1), mach32info(1).
AUTHOR
There are many authors of svgalib. This page was edited by Michael
Weller <eowmob@exp-math.uni-essen.de>. The original documentation and
most of svgalib was done by Harm Hanemaayer <H.Hanemaayer@inter.nl.net>
though.