
	Around the summer of 1984 I met a guy, in a campground in the
middle of California, who had an Atari 800.  He showed me many cool
things, among them a game called "Archon", a game called "Ballblazer",
and a game called "Behind Jaggi Lines".
	As it turns out, this latter game was an early version of a
Lucasfilm game that had leaked out to the Atari world.  The game was 
eventually released as "Resuce on Fractalus".  Lucasfilm developed a 
series of fairly groundbreaking Atari games in the early 80's, such as 
Ballblazer and Rescue, but my recollection is that it took several
years before C-64 versions of these games appeared.  Moreover it was
Epyx, and not Lucasfilm, which distributed (and presumably ported) 
these games.
	The "Jaggi" are the alien race in the game, and "Fractalus"
is the name of the planet.  The term "Jaggi" comes from the term
"jaggies", i.e. what you get with plain computer graphics -- the
designers felt that they were always fighting the jaggies, so it stuck.
"Fractalus" comes from the fact that the planet landscape is fractally
generated: instead of drawing the mountain/canyon sides as straight
lines, they are drawn using a "fractal line splitter", where you take
the midpoint of the line and displace it by a random amount, then
repeat on the remaining two lines, and so on.  These jaggie lines result 
in a jagged landscape, which is very effective-looking in my opinion.
	The game box and manual are really quite interesting -- there
are many photographs and composites in the manual, of the ship you
fly, of the landscape, and so on.  Sure, this is Lucasfilm we're talking 
about, but a drawing is surely easier than constructing a scale model.
Moreover, there is a long list of trademarks of the names used in the 
game (e.g. Jaggi and Fractalus).  One can only speculate that they had 
thoughts of the game going somewhere -- toys and plastic models, book 
serials, television, feature film?  Who knows!

About the 64 version
--------------------

	For some reason, there are at least two 64 versions of Rescue.
One version, presumably the later version, does not work on 128s
(it sets $D030), and has a disk loader which plays music while the
main program is loading.  My version works fine with my 128 and
has no IRQ-loader (although it has a nice fastloader).

	As you may know, there are several differences between the Atari
and Commodore 8-bits.  One difference is the raw speed difference: whereas 
a C64 runs at 1MHz, an Atari runs at around 1.7 MHz.  Once you factor in 
DMA delays and such the Atari still has a significant speed increase on
the 64, and Resuce was designed with that kind of speed in mind.  After
examining the code I believe that Epyx tried to compensate, but only
in some places and not others, and overall did a botched job.  Sorry
guys!
	If you've played the original, you probably noticed several
things, for example that lining up a shot on a bunker is pretty tough, 
and that it is very difficult to die in the game.  As with most games, 
there is a main loop, and there is an interrupt loop/sequence.  It turns 
out that they put the movement code -- the code which updates positions 
and velocities -- in the interrupt, and kept most everything else out.  
This means that no matter how slowly the display updates, you always move 
at a constant speed inside of the game.
	The first problem is that the display update is really slow!
You might move 10-20 times before the display finishes updating, so the
display never really represents the current game state.  This is why it 
is difficult to shoot at bunkers, for example.
	The second problem is that other stuff, most notably the code
which determines when an enemy should fire at you, is outside of the
IRQ loop.  With low frame rates, this means that enemies rarely shoot at
you and react slowly -- and it is very difficult to die!
	Finally, there is no limiter on the screen update code, which
means that when the screen updates really quickly -- like when you run 
the program at 20MHz -- you get a flicker.  That is, the code uses a 
double buffer, and it is the interrupt which displays the appropriate 
buffer.  But the display code is so fast that the back-buffer can be what 
is currently displayed on the screen, and you get to watch the code erase 
and draw into the buffer -- in other words, flicker.

	Naturally, all of this has been fixed up in this fix.

About this release
------------------

	I had a simple goal: to be able to use this program with my CMD
equipment, most notably my FD and my SCPU.  Later I also decided to
fix up some game-related things in the program -- velocities, turning 
rates, etc. -- to make it into the program it always should have been.

	This program isn't a "crack".  At least, I felt no desire to
conform to the usual cracker formula -- there is no cheesy intro or
vulgar trainer.  My goal was to keep the gaming experience as pure and 
close to original as possible.  If you want to see my name on a program, 
you can visit my web page and download one of my more substantive 
programming efforts.
	Moreover, I certainly don't condone piracy.  It doesn't take
much intelligence to understand the importance of supporting the few 
people and companies supporting the 64, so you ought to consider picking
up a copy of this program if you get the chance (besides, the manual
is really cool :).

	With that in mind, after extracting all of the relevant code,
I added a frame limiter to the main program, and adjusted the game 
constants related to movement -- you now move and turn faster.  The old 
constants were too slow at 20MHz, but too fast at 1Mhz!  I also added a 
highscore saver (the original uses a custom fastloader for disk i/o), 
and compressed the programs.  Finally, I changed the title screen text
to "Behind Jaggi Lines", to indicate the different program.  You may 
notice that "Rescue on Fractalus" still appears on the level-select 
screen, and there is a good reason for that -- the letters B, D, and J 
are not defined in that font!

	Of the three files in this archive, only "jaggi" is needed.
The other two files are the original intro and the highscore table.

	It's been a learning experience, and I believe the end result is 
a game that is much more fun and challenging, and is now the game it 
should have been.  I hope you enjoy it.

-Wyn 8/98
