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Member Since 20 Jul 2007
Offline Last Active Nov 22 2014 03:48 PM

Topics I've Started

[SDLNet] Server does not receive incoming connection from client

25 October 2014 - 02:40 PM

I am making a simple Client-Server application.

For now, I am trying to create a server and a client, and make the client connect to the server. When this is done, the server should print a message.


-- Server --



-- Client --



First I run the server.

Then I run the client, it prints but the server does not seem to receive the connection request by the client. No errors are printed however (really strange...)


If I try to change the IP that the client connects to to the local IP of the pc the server is running (192.168.x.y) or to localhost I get "Couldn't connect to remote host" from the client... But why? Shouldn't these work in the same way as


What troubles me is that with the client seems to connect to the server (no errors by the client) but the server never receives the request. Maybe it's blocked by a firewall or am I doing something really wrong?

Having a phone interview with a game company

01 September 2014 - 02:15 PM



I am having a technical phone interview (about 30 minutes).


To prepare for it, I am going to:

  • Refresh my C++ knowledge (virtual functions, templates, operator overloading etc)
  • Revisit some of my old game projects so I will be able to answer questions about projects I have made
  • Study some algorithms (but what kind of algorithms), 3D math (dot/cross product)


The job title is "Junior Programmer".


What kinds of questions should I expect? It's a technical interview so I hope there won't be any stupid questions.

What else would you recommend to study for the interview?


Thank you,


[Flocking] How to improve performance?

12 April 2014 - 04:18 PM

I'm doing a simulation of flying birds for my thesis.


I am using the usual steering behaviors: Cohesion, Separation, Velocity Match and Obstacle Avoidance (to avoid terrain).

The program is written in C# and uses Unity3D. I have disabled physics for the boids.


I'm also using alglib to calculate K-nearest neighbors using AKNN. alglib uses k-d trees for this.


So here are the fps I get:

100 boids = 60 fps

200 boids = 35 fps

300 boids = 23 fps

500 boids = 13 fps

1000 boids = 5 fps


As the number of boids increases, performance degrades rapidly. I'd like to do something to improve it, but sadly I am using the free version of unity3D, which does not have a profiler.


Is the performance I'm getting good? I haven't found results online for this.

Should I find another library instead of alglib?


By the way, you can see the program online here. Requires unity3d plugin.

[Flocking] Avoid many "sub-flocks" in Cohesion

05 April 2014 - 08:20 AM

Hi, I am developing a simulation of flocking for my thesis.


I am using Unity3D and C#.


For fast calculation of K-nearest neighbors I use the alglib library, which provides methods for it (uses a K-D tree). It also supports approximate knn for faster results, which is what I'm using since I don't need 100% accuracy.



In my tests I have 500 boids (birds) flying around. They are spawned near to each other so they form a swarm. However, after some seconds, this big swarm begins to break into smaller ones. I'm 99% certain that this is because for Cohesion's a-knn I use 30 for k, which means take into account the 30 "closest" (not really the 30 closest since I'm using aknn).


This has the effect that I described above - many small swarms of about 30 boids each, which is very logical since each boid considers a neighborhood of 30 closest boids for Cohesion).




When I change the k for Cohesion to bigger numbers (e.g 100) less swarms are formed. If I set k to 500 only one is formed. But this has a very big downside.

For k = 30, I get ~20 fps

For k = 500, I get ~3 fps

[a-knn epsilon is 50.0 for both)


Is there a solution to this? I'd like less swarms but better performance.

Is alglib slow? I couldn't find something else... I'm not doing anything special in my code, just the usual behaviors - Cohesion, Separation and Velocity Match. And one more, Cohesion to an anchor object so the flock will follow a path I want.


Thanks in advance.



Review my portfolio

15 March 2014 - 10:39 PM



In June I will be finishing my studies in University and I would like to work in the games industry.

So I made a portfolio site (not on my own, using another website that has the tools to do so) and put stuff I made in it.


I would appreciate your opinions, critiques or anything else I can improve :)




Thank you.