============================== FracBlank 1.8 ==============================
===========================================================================
A screen blanker to be used with Kickstart 2.x, written by Olaf `Olsen'
Barthel. © Copyright 1991 by Olaf `Olsen' Barthel, Giftware, all rights
reserved.
No guarantee of any kind is made that the program(s) described in this
document are 100% reliable. You use this material on your own risk.
================================= Purpose ================================
===========================================================================
FracBlank is yet another custom screen blanker created to live in symbiosis
with Kickstart 2.x and the Commodities Exchange toolkit, similar to the
`Blanker' program to be found in Tools/Commodities, just more wonderful.
Apart from the usual job (turning the screen black after a given period
of time to prevent the phosphorus of your monitor from burning in) it will
draw some neat patterns while mouse and keyboard are inactive. Instead of
bouncing polygons, the Amiga logo, the Boing! ball or other assorted items
around the screen, real plane fractals (yes, real fractals) will be drawn.
The algorithm employed comes from the September 1986 issue of Scientific
American; some of you who are familiar with OpenWindows Version 2 (such as
running on the Sun4) will know it from the popular `xlock' program. The
patterns created may remind you of spiders' webs, lace or even the
Chladnian patterns formed by grains of sand strewn across a vibrating
surface. I haven't seen an implementation of this algorithm on the Amiga
yet, so it was time to program it ;-)
============================== Installation ===============================
===========================================================================
I have provided two versions of `FracBlank', one has been compiled with
standard Motorola FFP support (this one will run on any Amiga which has
Kickstart 2.x installed), the other one will only work on Amiga computers
which have an MC68020/030 and an FPU68881/882 (or MC68040) installed
(namely the A3000/T/UX line of computers).
Drop the approriate file into your WbStartup drawer or add the line `run
>nil: <nil: fracblank' to your `s:user-startup' file.
There are a number of command line switches available which also
correspond to tooltype entries to be changed/created by selecting the
approriate icon and choosing the Workbench item `Information...':
CX_PRIORITY...... The Cx priority to assign this tool to. You may want to
change this value if there is more than one Commodity
tool running to use the same key sequences as
`FracBlank'. The one which has the higher priority
assigned will receive the keystrokes first.
CX_POPKEY........ The keys to press to open the `FracBlank' control panel.
The control panel allows you to set the hotkeys, adjust
the timeouts, to select the hotkeys and to terminate the
program.
CX_POPUP......... This is a boolean switch which determines whether
`FracBlank' is to open the control panel on startup or to
remain quiet. Place `yes' here to open it.
BLANKSCREEN...... The keys to depress to force the screen blanker to become
active. If the blanker is already active, pressing these
keys will cause the pattern to change.
MONO............. There are two display modes available for the patterns to
be drawn: high resolution monochrome mode and low
resolution multicolour mode. Place `yes' here to select
high resolution monochrome mode.
CYCLE............ In multicolour mode the program can either use a fixed 32
colours palette, or a dynamically changing 75 colours
palette. Place `yes' here to use the 75 colours palette.
SCREENTIMEOUT.... The number of seconds to wait before the screen blanker
is activated. This period of time must elapse without
any mouse movements or keys being pressed. If the value
placed here is zero, screen blanking will be disabled.
You may either enter the number of seconds (60, 120,
etc.) or provide a string of the format mm:ss (11:30,
12:25, etc.).
PATTERNTIMEOUT... While the screen blanker is running, the number of
seconds to wait before changing the fractal pattern. If
the value placed here is zero, a single pattern will
remain.
You may either enter the number of seconds (60, 120,
etc.) or provide a string of the format mm:ss (11:30,
12:25, etc.).
Running `FracBlank' twice will cause it to open the control panel; to
terminate `FracBlank' send it a ^E signal (such as by `break 3 e' with
`FracBlank' running as CLI task 3) or conjure up the control panel and
press the `Quit' gadget.
==================== Author's Request & Gift-Ware fee =====================
===========================================================================
By releasing this program and the accompanying source code as Gift-Ware I
do not place any obligations on you, feel free to share this program with
your friends (and enemies) to study and to learn from it. But, should you
feel the need to make any contributions, send them to:
Olaf Barthel
Brabeckstrasse 35
D-3000 Hannover 71
Federal Republic of Germany
(If you don't have an idea about what to contribute: I am still looking
for old Infocom adventure games, since they are no longer available in
Germany)
I may also answer questions asked via electronic mail. My email
addresses are:
Z-Net: O.BARTHEL@A-Link-H
Usenet: o.barthel@a-link-h.zer.sub.org
cbmvax.commodore.com!cbmehq!sourcery!olsen
The entire FracBlank package may be noncommercially redistributed,
provided that the package is always distributed in its complete form. A
small copy fee for media costs is okay but any kind of commercial
distribution is strictly forbidden!
Comments and suggestions how to improve this program are generally
appreciated!
=============== Revision history (most recent change first) ===============
===========================================================================
1.8 Numerous bug fixes and some enhancements.
1.7 Removed sprite blanker code, replaced it by a user copper list.
1.6 Added cycle gadget.
1.5 Added multicolour mode.
1.4 The sprite pointer used to pop up randomly now and then; the
interrupt server has been rewritten to turn off the sprite DMA
twice instead of only once.
1.3 Added VBlank interrupt server (disables sprites), idea turned up by
Adam Keith Levin's `Disabling Sprite DMA From a Vertical Blank
Interrupt' article published in AmigaMail November/December 1989.
1.2 First public release.
1.1,1.0 Before written history.
