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Some Unfriendly, Annoying Balls on the Desktop

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4.84 (43 votes)
3 Oct 2007
Some unfriendly, annoying balls on the desktop bouncing around and trying to catch the cursor - a mix of GDI+, transparent forms and bit of AI
Screenshot - balls.jpg


This program creates three balls on your desktop. If you move the cursor towards them, they move around and jump towards your cursor, trying to catch it. If they succeed, they will pull your cursor with them and you have to get rid of them by waiting or clicking around with your mouse.


First I wanted to create some sort of robot, which duplicates itself, and its children do that again, and again, and again... But as it did not work as expected, I created this out of the code I had so far - just to let you know why the project name is Replicator.

Using the Program

Just execute the program and see the balls bouncing around. Try to avoid them. To get rid of them after they catch you, just left-click a few times. If you want to close the program, right-click on one of them (e.g. when one catches you). The current state of the robot is presented by the filled circle in the middle. Red is Attack, blue is Follow, grey is Standby and black represents Inactive.

Using the Code

The graphical representation, as described further in my other articles, is done by a transparent Form. Each robot has its own dialog.

But the more interesting part is the movement/AI:

public void Loop() 
    while (!Disposing) 

As soon as the form is shown, a thread is created which processes the action part. The thread calls two methods as long as the robot is there. The first one is the Think() part. It "analyses" the current situation and decides what to do, where to walk, where to jump. The second one is the Act() part, which actually handles the physics (gravity, bouncing, movement).

public enum eBrain 

The Think() part uses a brain state eBrain to describe the current situation. In this case, Idle is used as a deciding part. It decides which brain state comes next depending on the distance to the target, and it is set when the current condition for the current brain state is no longer valid.

The actions taken by the brain are represented by the functions Walk(int x), Jump(int y) and Stand(). They just change the current velocity a bit and depend on being called on every tick, so that after some ticks, the expected movement is done.

The Act() part then moves the ball around and applies gravity, friction and other physical properties to it.

In Short

The AI is done here by a thread containing the AI and the physics, which calls the Think() part every time, which in turn causes the movement to be changed a little on every tick.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Germany Germany
No Biography provided

Comments and Discussions

Generalyou got my five.. Pin
shivamkalra4-Dec-09 15:10
membershivamkalra4-Dec-09 15:10 
Generalcool Pin
Mubi | www.mrmubi.com20-Jun-09 8:05
professionalMubi | www.mrmubi.com20-Jun-09 8:05 
General[Message Deleted] Pin
Danny Rodriguez26-Jan-08 17:10
memberDanny Rodriguez26-Jan-08 17:10 
GeneralA Blast!!! Pin
lost in transition 17-Oct-07 7:21
member lost in transition 17-Oct-07 7:21 
QuestionSTAThread Attribute Pin
Martin Surasky10-Oct-07 6:19
memberMartin Surasky10-Oct-07 6:19 
AnswerRe: STAThread Attribute Pin
]Metty[10-Oct-07 9:53
member]Metty[10-Oct-07 9:53 
GeneralInteresting.. Pin
Murat Firat9-Oct-07 8:25
memberMurat Firat9-Oct-07 8:25 
GeneralBrilliant ! Pin
Yclkvnc9-Oct-07 6:40
memberYclkvnc9-Oct-07 6:40 
GeneralCute Pin
BoneSoft9-Oct-07 4:45
groupBoneSoft9-Oct-07 4:45 
QuestionThat about multiplayer version? Pin
Chernichkin Stanislav9-Oct-07 1:28
memberChernichkin Stanislav9-Oct-07 1:28 
GeneralNoice Pin
Liqdfire8-Oct-07 9:07
memberLiqdfire8-Oct-07 9:07 
GeneralMy god, that is THE best application i ever ran Pin
Anthony Mushrow5-Oct-07 7:26
professionalAnthony Mushrow5-Oct-07 7:26 
JokeBug Pin
gore013-Oct-07 21:44
membergore013-Oct-07 21:44 
Jokelol Pin
Ben Daniel3-Oct-07 19:43
memberBen Daniel3-Oct-07 19:43 
GeneralRe: lol Pin
Paul_Williams10-Oct-07 0:54
groupPaul_Williams10-Oct-07 0:54 
GeneralMultiple monitors Pin
Lieutenant Frost3-Oct-07 6:57
memberLieutenant Frost3-Oct-07 6:57 
GeneralRe: Multiple monitors Pin
Lee Humphries3-Oct-07 14:45
professionalLee Humphries3-Oct-07 14:45 
GeneralRe: Multiple monitors Pin
dave.kelly3-Oct-07 21:04
professionaldave.kelly3-Oct-07 21:04 
GeneralNice piece of code and enjoyed playing it. Pin
shokisingh3-Oct-07 6:01
membershokisingh3-Oct-07 6:01 
Generallol Pin
Seishin#3-Oct-07 3:29
memberSeishin#3-Oct-07 3:29 
GeneralHa, thats cool Pin
Tom Lawrance3-Oct-07 3:21
professionalTom Lawrance3-Oct-07 3:21 
GeneralRe: Ha, thats cool Pin
Dwight Johnson9-Oct-07 3:19
memberDwight Johnson9-Oct-07 3:19 
GeneralRe: Ha, thats cool Pin
Tom Lawrance9-Oct-07 3:23
professionalTom Lawrance9-Oct-07 3:23 

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Posted 3 Oct 2007


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