6.1 Notes on Video Modes, "Standard" and Otherwise
Alas, in this day of Windows, video adapter manufacturers do not have
much incentive to support DOS video modes. Fractint can support any
video modes included in your board's VESA video bios. Many otherwise
good boards do not include the higher resolution modes in their bios
even though those modes are supported in the manufacturer's Windows
driver.
Fractint users are particularly fond of the 1600x1200 mode. If you want
to use this mode, make sure your video board supports it. Some boards
that have given good results are boards from STB, various versions of
Matrox Millennium, and boards from several manufacturers using Nvidia
Riva chip sets.
Using high resolution video modes poses a second challenge for fractint
users. That is that the VESA standard does not have standard settings
for this mode, so you will have to edit the fractint.cfg file to support
your board. You can run the program makefcfg.exe that comes with
fractint to generate entries for your fractint.cfg file.
Finally, even if your video board VESA Bios supports high resolution
video modes, it probably doesn't come with a utility that allows you to
set the vertical refresh. If the vertical refresh is set for 60 Hz or
less, you may see flicker and be subject to headaches. Fortunately,
there is a wonderful freeware utility by Rob Muller that allows you to
control the vertical refresh for any VESA video mode. Of course your
monitor still needs to be able to support higher rates -- software can't
help that. To get Rob's unirefresh program, email Rob at
r.muller@student.utwente.nl or check out
http://home.student.utwente.nl/r.muller/unirefresh
True to the spirit of public-domain programming, Fractint makes only a
limited attempt to verify that your video adapter can run in the mode
you specify, or even that an adapter is present, before writing to it.
So if you use the "video=" command line parameter, check it before using
a new version of Fractint - the old key combo may now call an
ultraviolet holographic mode.
EGA
Fractint assumes that every EGA adapter has a full 256K of memory (and
can therefore display 640 x 350 x 16 colors), but does nothing to verify
that fact before slinging pixels.
"TWEAKED" VGA MODES
The IBM VGA adapter is a highly programmable device, and can be set up
to display many video-mode combinations beyond those "officially"
supported by the IBM BIOS. E.g. 320x400x256 and 360x480x256 (the latter
is one of our favorites). These video modes are perfectly legal, but
temporarily reprogram the adapter (IBM or fully register-compatible) in
a non-standard manner that the BIOS does not recognize.
Fractint also contains code that sets up the IBM (or any truly register-
compatible) VGA adapter for several extended modes such as 704x528,
736x552, 768x576, and 800x600. It does this by programming the VGA
controller to use the fastest dot-clock on the IBM adapter (28.322 MHz),
throwing more pixels, and reducing the refresh rate to make up for it.
These modes push many monitors beyond their rated specs, in terms of
both resolution and refresh rate. Signs that your monitor is having
problems with a particular "tweaked" mode include:
o vertical or horizontal overscan (displaying dots beyond the edges of
your visible CRT area)
o flickering (caused by a too-slow refresh rate)
o vertical roll or total garbage on the screen (your monitor simply
can't keep up, or is attempting to "force" the image into a pre-set
mode that doesn't fit).
We have successfully tested the modes up to 768x576 on an IBM PS/2 Model
80 connected to IBM 8513, IBM 8514, NEC Multisync II, and Zenith 1490
monitors (all of which exhibit some overscan and flicker at the highest
rates), and have tested 800x600 mode on the NEC Multisync II (although
it took some twiddling of the vertical-size control).
SUPER-EGA AND SUPER-VGA MODES
Since version 12.0, we've used both John Bridges' SuperVGA Autodetecting
logic *and* VESA adapter detection, so that many brand-specific SuperVGA
modes have been combined into single video mode selection entries.
There is now exactly one entry for SuperVGA 640x480x256 mode, for
instance.
If Fractint's automatic SuperVGA/VESA detection logic guesses wrong, and
you know which SuperVGA chipset your video adapter uses, you can use the
"adapter=" command-line option to force Fractint to assume the presence
of a specific SuperVGA Chipset - see Video Parameters (p. 134) for
details.
8514/A MODES
The IBM 8514/A modes (640x480 and 1024x768) default to using the
hardware registers. If an error occurs when trying to open the adapter,
an attempt will be made to use IBM's software interface, and requires
the preloading of IBM's HDILOAD TSR utility.
The Adex 1280x1024 modes were written for and tested on an Adex
Corporation 8514/A using a Brooktree DAC. The ATI GU 800x600x256 and
1280x1024x16 modes require a ROM bios version of 1.3 or higher for
800x600 and 1.4 or higher for 1280x1024.
There are two sets of 8514/A modes: full sets (640x480, 800x600,
1024x768, 1280x1024) which cover the entire screen and do NOT have a
border color (so that you cannot tell when you are "paused" in a color-
cycling mode), and partial sets (632x474, 792x594, 1016x762, 1272x1018)
with small border areas which do turn white when you are paused in
color-cycling mode. Also, while these modes are declared to be 256-
color, if you do not have your 8514/A adapter loaded with its full
complement of memory you will actually be in 16-color mode. The hardware
register 16-color modes have not been tested.
If your 8514/A adapter is not truly register compatible and Fractint
does not detect this, use of the adapter interface can be forced by
using afi=y or afi=8514 in your SSTOOLS.INI file.
Finally, because IBM's adapter interface does not handle drawing single
pixels very well (we have to draw a 1x1 pixel "box"), generating the
zoom box when using the interface is excruciatingly slow. Still, it
works!
XGA MODES
The XGA adapter is supported using the VESA/SuperVGA Autodetect modes -
the XGA looks like just another SuperVGA adapter to Fractint. The
supported XGA modes are 640x480x256, 1024x768x16, 1024x768x256,
800x600x16, and 800x600x256. Note that the 1024x768x256 mode requires a
full 1MB of adapter memory, the 1024x768 modes require a high-rez
monitor, and the 800x600 modes require a multisynching monitor such as
the NEC 2A.
TARGA MODES
TARGA support for Fractint is provided courtesy of Joe McLain and has
been enhanced with the help of Bruce Goren and Richard Biddle. To use a
TARGA board with Fractint, you must define two DOS environment
variables, "TARGA" and "TARGASET". The definition of these variables is
standardized by Truevision; if you have a TARGA board you probably
already have added "SET" statements for these variables to your
AUTOEXEC.BAT file. Be aware that there are a LOT of possible TARGA
configurations, and a LOT of opportunities for a TARGA board and a VGA
or EGA board to interfere with each other, and we may not have all of
them smoothed away yet. Also, the TARGA boards have an entirely
different color-map scheme than the VGA cards, and at the moment they
cannot be run through the color-cycling menu. The "MAP=" argument (see
Color Parameters (p. 128)), however, works with both TARGA and VGA
boards and enables you to redefine the default color maps with either
board.
TARGA+ MODES
To use the special modes supported for TARGA+ adapters, the TARGAP.SYS
device driver has to be loaded, and the TPLUS.DAT file (included with
Fractint) must be in the same directory as Fractint. The video modes
with names containing "True Color Autodetect" can be used with the
Targa+. You might want to use the command line parameters "tplus=",
"noninterlaced=", "maxcolorres=", and "pixelzoom=" (see Video Parameters
(p. 134)) in your SSTOOLS.INI file to modify Fractint's use of the
adapter.