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Man Pages

Manual Reference Pages  -  FLYING (1)


flying - pool/snooker/carrom/hockey/curling simulator


     Pool, Snooker, Cannon
     Additional Key-Controls


flying [-options ...]


flying was actually meant to be a test program to implement some classes to control flying objects on the screen. After the classes were implemented there was the need of some real tests and a game of billard was just the first idea. By now, many subgame-classes are already more or less completely defined. They can either be selected by the options or by making a link to the original with a special name. Unfortunately having so many subclasses means that the classes themselves can’t be too complicated. (There’s just too less time in the world :( ) Therefore the games don’t have any rules yet. This means you have to play fair and watch your opponent.

Anyway, the main thing was animation and controlling and that works fine, especially with the -deluxe version of pool-billard. Since the main intention was to get an excellent billard game, I will mainly describe the pool-version in the following pages. The other subgames are similar to control (and there are no special rules anyway).


The flying package contains many subgames, that are more or less in an experimental stage. Here is a tiny summary of version 6

    Pool, Snooker, Cannon

As already mentioned above, pool is the most comprehensive subgame, especially due to the deluxe version. It is very playable even though spin is not implemented. Rules will have to be added in later revision.


Very similar to pool, just with another background (and more friction)


experimental air-hockey implementation (see option -in2 to set the display for the input-pointer for the second player), which is worth looking at because of the unconventional control mechanism. The players have to select one of the big discs before they can play.


experimental curling implementation, which is even more worth to look at because of the control: Hold the left button to take one curl. Move it in the right direction and let it go...


The pointer (or pointers) run fully simultaenously and are like the hand of the players. At every time it’s possible to pick one of the objects to select it as the cue-object (It should better be the cueball, if you don’t want to lose some friends). After you have aimed in the desired direction there are 2 ways to play the ball:
easy: Press and hold down the left button to increase the strength of your shot. Release the button to shoot. There is a maximum power! If you hold down the button too long, you will just make a very poor shot as a penalty.
tricky: You might notice on that the queue stays on the table for a moment. This is a problem, if you are very close to the cushion. Then, the cueball might hits the queue again. Therefor you can alternatively gather power by pressing the right pointer button and shot by simultaenously pressing the left button. When you release the left button after the shot, the queue is removed from the table and you can therefore remove it earlier.
After shooting, you can only wait and see what will happen. By the way, there actually are some tiny rules implemented. The billard classes know, that cueballs shouldn’t stay in the pocket after a shot. When they are back on the table, you can roll them to the position you like by using the right pointer button.

By the way, if you picked the wrong ball as the cue-object, you can get rid of it by just clicking the right button once.

To overcome the hurdle of the mouse resolution, you can use the middle pointer button for fine adjustments. With that help, you can actually position the mouse in fractions of pixels. To make shoting a thrill, you’ve got to release the button again for shoting. (The fraction is stored in that case)


left select cueball
introduce easy shot
pick ball from pocket
middle fine adjustment via interpixel motion
right deselect cueball
introduce tricky shot
move ball

    Additional Key-Controls

SPACE reset game
Q,Esc quit game
R restart game
^L redraw screen



-size n window size
-root full screen (the default)
  don’t use OverrideRedirect for the background window, when the -root option is used.
  don’t grab the server, when problems with the colormap occur.
-display name
  the output-display (default is contents of $DISPLAY)
-in1 name
  name of the main display for input (default is: same as the output display)
-in2 name
  name of a second input display. If given, a second pointer object will be installed in the program and can be controlled by the pointer of the given display. (The pointer will get invisible on that display as it is grabbed anything)

As for every display connection, you have to make sure that all displays are accessible from your host. (by using xhost ...)

-sound a subprocess is started, which gives some clicks when balls hit together, but the smooth motion gets distorted in that way, at least on my workstation.


-deluxe a special version of the pool with animated balls by using hundreds of precalculated pixmaps. The construction of the pixmaps at game start is very time consuming. Therefore the computed pixmaps are cached in files fly*-*.dta in a special data-directory (usually just /tmp) for reusability.
-tv since the deluxe-option is default, this can be used to switch back to the set of TV-balls.
-ft n sets the size of the table in pool-billard to n foot. The value should be in a range of 6 to 9 feet. If not given, the size is selected randomly, except in the deluxe-version, where it default to 8 feet. This was done because every size would need other pixmaps for the balls.


-mode n selects the update mode for the animation in the deluxe version of pool. There are 3 (internal) different implementations of the ball animation, which depend on the implementation of some specific routines of the x-server. Since mode 2 is usually the fastest one, it is turned on by default.
-chkmode runs a small benchmark with the available update modes. If a mode other than the second is the fastest on the current machine, you should use the mode-option to select it.
-time s stop process after s seconds
-demo demonstration (without pockets). By the way, there are some tiny meters on the bottom of the screen (when using the full screen and the binary was compiled with statistic features), which have the following meanings:
rate: shows the number of cycles per second. A cycle means the loop for doing collision detection and recomputing the corrent position of all objects.
moves: show the number of ball moves, that were neccessary in one seconds. If all objects are moving, this would be <object number> x <rate>
offset: if shown, it tells you, how much the real time has gone ahead of the current internal calculation time. It should never light up during the game, except probably at the first shot into the triangle.
  the collision calculation is done only in those moments, when a collision takes place. In the intermediate time, only the motion graphics are updated as fast as possible. The switch disables that intermediate calculation to get measures for the speed of the collision calculation. (Good combinations to check the speed of your machine would be: -demo -maxspeed -time 10)
-presets shows the current internal values of static variables on stdout. The values can be dynamically altered by setting them in the file presets.txt with the same syntax as in this output.
There are many additional debugging options, when the executable was compiled for debugging. They are shown when no argument or -h is given at the commandline. You can try flying -pool -deluxe Intro (if you’re lucky) to see the some information about the pixmap-usage.


presets.txt file to overwrite internal static values
fly*-*.dta files containing the pixmaps for the ball animation in deluxe-pool. They are created automatically when they are missing.


X(1), xhost(1)


As I told, this is a very uncompleted version without any rules, but you can perfectly play billard, so why worrying ...

The friction is not exactly integrated in the computations, since that would have cost too much performance. Instead the objects move without friction for a given amount of time. Then their speed is re-adjusted. When the granularity gets smaller, the friction gets more exact. But that works against a caching-mechanism and therefore would extremely increase computation time, if many objects are on the table.

Spin is not implemented

There seem to be problems, when moving objects directly with the pointer (like in hockey or curling or with the right button in billard) when the host is not fast enough. At least I can not use it on my 386.

There are some minor problems when drawing static parts of the screen. Sometimes they are misplaced for 1 pixel, e.g. there is a one pixel gap below the line representing the pocket

There is a problem in the start-shot of carrom. Due to the weight of the striker, the other stones might get pushed so close together, that the collision detection will fail and objects will overlap (or the algorithm gets stuck in a loop, only to be escaped by entering ’q’). Sorry for that.

Usually, the program needs it’s private colormap. To get a nicer appearance, a black OverrideRedirect window is placed above everything else when the -root option is given. This confuses some window managers and a struggle for the colormap begins. If anythings else fails, flying will grab the server and installs the map on it’s own ...


Copyright 1995, Helmut Hoenig, Mettmann/Bad Camberg

email (for any comments):
smail (for gifts):
  Helmut Hoenig
Hopfenstrasse 8a
65520 Bad Camberg

By the way, I am collecting banknotes! If you want to join into my collection, get any bill of your country, sign it on the backside and send it to me so I will pin it on my world map. (Don’t forget the exact location for the pin :-) But you can also just send me a picture postcard ...


Permission to use, copy, modify, and distribute this software for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies.

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X Version 11 FLYING (6) 18 July 1995

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