"ic-gravitation cave" screen saver   v.1.3
evaluation

- Gravitational engine and dos on-screen simulation created by
Mathias Burmeister, (c) 1994;

- Interaction and reflection engine, further graphic development and
windows programming by Evgenij Barsoukov, (c) 1998

All questions to --------> root@bars.kiev.ua

# Contents

1.What is "ic-gravitation cave"?
2. Why this program was made?
3. Installation
4. Obtaining registered version
5. Interested in the source code?

## ---------->What is "ic-gravitation cave"?

- It is a physically correct 3d simulation of stars movement under force of
gravitational attraction.Different from the objects you can see out of your window in a clear night, stars in "cave" don't have much space to move around (they are restricted by the walls of the cave),so they collide just like billiard-balls (also physically correct). Situation is actually near the one just after the big-bang.

## --------->Why this program was made?

-In fact, the initial idea was from Mathias Burmeister. He actually made the gravitational
simulation with point-bodies and nice 3d graphic. I was fascinated when he showed it to me! But the system had problems - on screen balls had certain diameter, whereas in mathematics they were only dimensionless points, and did not see each other (did not collide). I was attracted by the challenge to make the multy-body system to work "cooperatively" and pseudo-simultaneously. Thanks to courtesy of Mathias, I got his code and his blessing to do with it whatever I want. So I could continue the work on the program and finally succeed in creating a pseudo-simultaneous simulation engine, where gravitation bodies are also geometrical bodies interacting with each other. Also some niceties in the graphics were introduced.
This screen-saver is the first  application of this engine, aiming to demonstrate it's physical "real-word" correctness. Apart from its physical and mathematical attraction, I also find the spectacle happening on the screen  simply.... beautiful. That is why the screen-saver is put to public domain:

1) to introduce the physically strict simulation engine to anybody who would be interested in
cooperation to implement it in games (like billiard etc.) or educational software (to visualize the molecules dynamics for example). For example, you can check _visually_ Maxwell-Bolzman distribution of kinetic energies.

2) just to share my fascination by the world of physics, unveiling itself on the screen. It is
always out there around us but we usually can not see it with our eyes.

## ---------------->Installation

Simply copy the *.scr file to your windows directory, and choose the ic-cave screen saver as your default.

Options:

- You can change the delay in program operation in "settings". I usually use "slow" setting, as it shows the "planets" behavior most clearly, saves computer resources and don't tire the eyes. But fast movement has also its own beauty.

- You click ON  "show frame" to see the boundaries of the box where the balls
are flying around.

Btw this program is rather resource-intensive (lots of mathematics is going on). It requires pentium 100 at least, k6/200 is just right, and 16-bit color or higher. It will look rather nasty when dithered down to 4 and 8-bit color, sorry.

Hot-keys:

There is a hot-key which saves the whole beautiful screen-picture to a bmp-file
called tmp.bmp (in desktop directory). The free-version users have to find
this hot-key. Try - it is not difficult! :-) Registered users will get a version where
the key is documented together with other features.

## ---------->Registration

I have a couple more niceties in stock, which I reserved for these, who want to support my work with 10\$. You know, hardware and compilers cost money... If you register you will receive to e-mail address you specify a registered version of the program (its radical advantages described later on).

Now, here is an unusual offer - you can get a credit by me! If you send me an non anonymous e-mail, to evgen@camd1.kkpcr.re.kr (check current address at http://members.tripod.com/~Sudy_Zhenja/ )
***********
after receiving the registered version as attachment you _will_ send me during next 1 week (by stamp on  envelope) 10\$ cash or check  - I will believe you on your word_ and  _immediatelly_ send  you the registered version as  attachment. I will also send you a separate e-mail with my current post address.
************
Evgeni Barsukov
Shin-Song Dong 209-11 #202
Yuseong-Gu
Taejeon 305345
S.Korea

The registered version can do in addition:

### -save a screen-shot at any moment by pushing a hot-key.

You know, sometimes the screens arising are just overwhelmingly spectacular - and remember, they will _never_ come back again! Initial positions, masses and colors are chosen randomly by use of good random number generator. Not to mention, that the mathematics of this system is "cryptographically strong", which means that after some time of work even very small difference in initial conditions results in _very_ different scenery.

### -design your own stars constellations.

In registered version you can edit the resource file, where all initial conditions are specified
(masses, radius, number of bodies, colors). It is a lot of fan creating your own spectacular worlds, with white heavy dwarf stars, sun-systems with fancy multy-lunar planets - I really can spend a lot of time doing that and then watching development of my creations.

This is obviously necessary if you have many of your "custom-created" worlds.

This is good if you want to watch the development of some stellar system not only until you hit some key to do some work on your computer, but continuously. If you put-on this check-box, each time you terminate the screen-saver the positions are saved, and next time it will start with it and continue development as if nothing happened in between.

## ----------->Interested in the source code?

Contact me by e-mail, I am interested on cooperation in further development based on
existing engine.

Best regards,
Evgenij

--------->
current fastest e-mail:
evgen@camd1.kkpcr.re.kr
permanent e-mail:
root@bars.kiev.ua