You can access the PDF from here and the source (OpenOffice Writer document) here. If you find it useful or would like an item added, feel free to leave a comment.

This was supposed to be a very literal copy of Master of Orion that you could play online with up to 15 other players on one map. Yet now I have something different in mind and I also have a different approach. It will only be a hobby project and I don’t plan to get immediate results, I want it to progress and evolve in my mind until I’m at a point where I can start writing code. Writing the code should be just handcraft at that point as I have most of the skills and knowledge to develop such a game.

What I’m doing now is writing a design document. The design will be highly influenced by the Foundation Series, one of the greatest science fiction series ever written. The first version of the design document can be found here. I still want the game to have a Master of Orion look and feel to it and it will certainly be a 4X type of game but I want different factions to be completely different (comparable to the different races in Starcraft) in the way they are played. I would like to see a “First Foundation” faction that relies on technology, economy and firepower and a “Second Foundation” faction that relies solely on the power of their minds, e.g. mind control. More about that can be found int the design document. A third faction is also possible but I have no concrete ideas about that yet. As the game design and the game itself progresses I will occasional write articles about it here on this blog.

Another caveat I found is also related to array indexes. When using a Matlab function that takes as parameters matrix indexes you might think of creating an mwArray of type mxUINT32_CLASS. Wrong. You have to pass indices – as strange as it sounds – as doubles so you should use mxDOUBLE_CLASS.

One custom Matlab function I wanted to use in C++ took as an argument a cell array. A cell array is an array containing other arrays. In Matlab you create a cell array like this:

a = magic(5);
b = ones(3);
z{1} = a;
z{2} = b;

If you look at z now you will get something like this:

z =
[5x5 double] [3x3 double]

An array of arrays. Easy. Well if you want to construct a cell array in C++ you have to do something like this:

mwArray a(5, 5, mxDOUBLE_CLASS);
mwArray b(3, 3, mxINT16_CLASS);
mwArray z(1, 2, mxCELL_CLASS);
z.Get(1,1).Set(a); // Sets z(1) = a
z.Get(1,2).Set(b); // Sets z(2) = b

You can find the description on this page.
If you get used to those little quirks however the Matlab Compiler is a very powerful tool to include your crazy Matlab scripts in a stand alone C++ application. One of the next things I would like to investigate are free (open source) Matlab Compiler alternatives such as the Octave C++ integration and compiler.

I wanted to show multiple threads communicating and synchronizing with each other. I’ve read the argument that something like multithreading concerns only the implementation of a system and can thus be ignored when modeling. I agree with the argument however there will come a time in the development phase of a system when one needs to think about multithreading and one wants to sketch out how the system facilitates multiple threads to be efficient. And for that I have not found good tool within UML.

So I searched for examples of diagrams that visualize multithreading. The collage shows 4 different diagrams I found rather interesting. The first one is from this page about a traffic simulator written in Java (orignal image). It shows different threads and how they signal each other. It’s simple yet quite clear what is going an. The second image is taken from a CodeProject documentation about a genetic library (original image). It sort of uses UML symbols but it’s not clear what happens at the fork and join points. The way I figure it, those symbols inside the threads are supposed to be branches not forks. The third image is also from a CodeProject page – this time it’s a how-to about avoiding an exception when using multiple threads (original image). It reminds me of a sequence diagram. There are no blocking states in the diagram and I figure in this particular application the threads are non-blocking so diagram fits the application perfectly. The fourth diagram I liked the most. It’s from the Multithreaded Programming with ThreadMentor tutorial (original image) and has special symbols for sending signals and waiting for signals.

So I gave it a try myself and tried to model a simple controller and worker thread scenario based on the last of the example diagrams I found. The gray boxes and circle represent a signaling concept where one thread can send a signal and the other thread waits until it receives the signal. I also included a shared variable that handles the task shutdown. One thread can set the variable and the other branches depending on that variable. I am not happy yet with this particular part of the image. If anyone has a better idea or pointer to resources on that topic feel free to leave a comment.

7-Zip is an open source file archiver with a high compression ratio. It supports all common archive types. Avast is a free (for personal use) anti virus kit, that protects my system from all those nasty pieces of software out there. Cygwin is an ingenious collection of tools that provides a Linux-like environment for Windows. You can use it with puttycyg to get a very easy to use Linux-like shell with all the tools you miss so badly on Windows. And for those good old DOS games you miss so much there’s DOSBox, the x86 emulator with DOS. Check out a number of old free but totally awesome games you can play on the DOSBox here. For file-transfers there’s FileZilla for FTP and for SFTP there’s WinSCP. And of course there’s everybody’s favorite browsers Firefox and Opera for browsing and ‘being connected’. From what I hear Opera 10 will be out any day now. For my document viewing, editing and creation needs I heavily rely on Texmaker, MiKTeX, GSview and of course OpenOffice.org.

For image creation I just love Inkscape. It has to be one of the greatest open source tools ever created. For graph creation I use gnuplot also I have to say I have been using the graphing tools of MATLAB a lot lately due to ease of use. For text and code editing I use either Notepad++ or Vim. It depends on my mood really. To communicate online I use mostly the cute pidgin universal chat client but I also sometimes log on to IRC using mIRC. For all my media and entertainment needs I have the great and famous VLC media player of course but I tend to use Winamp for audio playback. To download torrent files I use µTorrent and to connect to remote servers I use PuTTY.

I use XAMPP for web development and the ingenious VirtualBox x86 virtualization software for testing on different systems. When my harddrives are a cluttered mess I use WinDirStat to get a hold of the chaos and clean it up. And recently I accidentally deleted files from the SD-Card of my mobile phone and was able to recover them instantly using the awesome Photorec data recovery software.

That’s it for my list. I hope someone out there will find this list useful.

I admit the graph is a bit ambiguous and it would be much better to count the number of links in blog posts that link to the respective product. But let’s just assume that the graph is an accurate representation of the buzz those products created.

So Wolfram. I like what they did but have a couple of problems with it. For one I feel like they kind of not understood what it is all about these days. They ignore collaboration, wisdom of the crowd, free knowledge and all that good stuff we have today. But they don’t want that, they want scientific accuracy and control over their content. That’s fine I think but I would have loved to see all those smart people to contribute to a project like Wikipedia or freebase. And maybe they could have dedicated some of their enormous brainpower to finally getting NLP off the ground to provide a nice interface to all the information out there and to establish some ground rules about how we should do NLP.

Bing, well – pretty pictures. That’s really all it is for me personally. The name is certainly better than their Live Search thing but I don’t like the interface at all.

And then for Google Wave: I really hope this product will not succeed and will not revolutionize anything. It’s in the first few minutes of the demo why it would be very scary to have Wave around. Lars Rasmussen says that E-Mail is bad because it’s peer to peer, not very comfortable and whatnot. So he proposes to put the Wave (i.e. Google) in the middle of all that communication. Scary.

What’s really awesome is Google Squared. It’s by no means perfect – still a lot of rough edges – but has a lot of potential. I hope to see some serious work done on that thing and maybe an API for us developers to play with and create new things.

I didn’t have such a tool but it sounded like a fun challenge and I thought that such a tool might also help all the people who run into trouble when trying to create a spanning tree for their graphs. So I created walruscsv – a command line tool written in C++ that reads a CSV and outputs a LibSea graph file that can be visualized with Walrus. The CSV file hast to contain a link in each row and consist of 2 columns. The first column in each row represents the first node of the link and the second column the second node of the link. It automatically generates an arbitrary spanning tree.

A sample CSV file containing the links node1<->node2, node1<->node3, node3<->node4 could look like this:

node1,node2
node1,node3
node3,node4

Although Walrus is only capable of visualizing one network at a time walruscsv can handle multiple networks in one CSV file. It creates an arbitrary node and connects a node of each network to that node enabling Walrus to visualize the data. Currently the tool creates an arbitrary spanning tree so it’s not weighted and therefore not minimal.

Walruscsv reads the name of the CSV file to process as the first command line parameter passed to it. It is released under a non restrictive open source license so in addition to binaries the source code is provided. To compile it using the GNU C++ compiler simply type:

g++ wlink.cpp main.cpp wtree.cpp -o walrus.exe

You can use the program by typing

walrus.exe testfile1.csv

whereas testfile1.csv is the CSV file containing the graphs you want to visualize. Bloodshed Dev-C++ can also be used to compile the code and although I didn’t try it it should also work with C++ compilers from Microsoft (e.g. using Visual Studio). Here are the files:

Source code (the source code released to the public domain)
Test files (a collection of test CSV files)
Win32 binary
Debian x86 64bit binary

If you’re having trouble using or compiling the tool or if you have suggestions or comments of if you find a bug feel free to contact me or leave a comment.

Looks like the Chrome buzz easily surpassed the Firefox3 release buzz. Quite impressive. Unfortunately blogpulse’s trend tool allows users only to look 6 months into the past. It would be very interesting to have events such as the release of Internet Explorer 7 or the announcement of Safari for Windows on that graph too.

I wrote a script that creates a pixel tile based map from a random height map and created 6 pixel tiles for the different heights. I wanted water, a beach, nice grasslands and icy mountains. To generate the height map I used Matlab. I tried a couple of different techniques and finally ended up using a perlin noise algorithm.

I also experimented with a simple Gaussian distribution random number generator and tried to fit the numbers to my needs. However it turned out to be ‘too’ noisy as I was aiming for continents and large mountain ranges. The Gaussian distribution however gave me only small islands. I tried to smooth it with different filters which made it a little better but I realized the numbers where fundamentally different from what I wanted.

The image on the left is created with Gaussian distribution, the second has a 7×7 Gaussian blur filter applied 3 times and the third one is created with Perlin noise. Go ahead and click on the images to view the full size version. They are quite large so they might take a second to load. I got the matlab code for the Perlin noise generator from Christopher Wellons’ blog post about Noise Fractals and Clouds. He wrote it for GNU Octave, a tool which I have to try out yet. To use it in Matlab only a slight modification was necessary:

function s = perlin (m)
  s = zeros(m);                                    % output image
  w = m;                                 % width of current layer
  i = 0;                                             % iterations

  while w > 3
    i = i + 1;
    d = interp2(randn(w), i-1, 'spline');
    s = s + i * d(1:m, 1:m);
    w = w - ceil(w/2 - 1);
  end
end

Now this looks quite inconspicuous but there’s quite something to those 11 lines of code. The interp2() function recursively expands the matrix returned by rand(w) i-1 times with spline interpolation. This contains the frequency of the the function and the i in the following line represents the amplitude. Quite elegant really! The only thing to criticize about this code is probably that it can’t exploit the fact that Perlin noise can create continuous noise resulting in an infinite world. To do that I guess you need a seeded random number generator. Matlab let’s you save and restore the state of the generator with:

s = randn('state');          %save state to s
randn('state',s);            %restore state from s

which might enable you to accomplish just that. And finally here’s a PHP script that let’s you generate a map based on a height map in a CSV File (sample file). Be warned though: PHP is a very bad choice to do these kinds of things and the script is therefore very slow. A ZIP file containing the PHP script, the test data and the 6 separate pixel tiles can be downloaded from here.

There’s a great old space strategy game called “Ascendancy” (download and play with DosBox). One unique feature of the game is the intriguing 3D map of the universe. It’s from 1995 and now in 2008 such a 3D map can easily be implemented. But I like browser based games so the challenge was to implement the thing inside the browser. Turns out that’s also not very complicated when using the canvas tag supported by Firefox, Safari (Webkit) and Opera browsers. Here’s a warning for Internet Explorer users: the prototype won’t work very well. I’m using Google’s Explorercanvas – it emulates canvas-tag behavior but it is therefor very slow. So please consider using one of the afore mentioned browsers to test it.

Go ahead and start the prototype.

A random universe is created and rotates around the y-axis. You may change the continuous rotation axis, activate and deactivate starlanes, change the number of stars, change the size of stars, change the number of starlanes and change the rotation speed. You can also rotate the universe by moving the mouse over one of the arrows in the small coordinate system on the right. Additionally you can select stars by clicking on them. This works best when the stars are not moving and when they are not too small. Here’s an image of the whole thing:

It should work reasonably well depending on the number of elements displayed and your hardware specifications. I found that Opera renders the universe a tad faster than Firefox. I’m using Prototype and the Script.aculo.us slider to help out with the Javascript and the user interface.

Three things I still have to iron out: 1) dragging the universe with the mouse 2) zooming and 3) the depth is not correct. This is visible when rendering large stars. Stars are always drawn in the same order and a star actually behind another one could be drawn in front of it. But that’s hardly visible when using smaller stars so I think it’s alright for now.

The code is released under a non restrictive open source license. The source code is fairly well documented (use tab size of 2). Have fun.

Update: A friend of mine pointed out that the prototype reminded her of a lottery drawing. I don’t think she’s very much into space and science fiction mumbo jumbo or computer games for that matter but she’s got a point. Galaxies don’t look like that! So I added a spiral galaxy generator to the prototype. The code is based on a very good article called “Making Galaxies”. I added the calculation of the third dimension so that the height of the galaxy disk is small in the center and high at the edge.

In spiral galaxy mode you need a lot of stars to actually see a nice galaxy (say 600). The starsize should also be reduced. In case you feel like playing around with the galaxy generator, here’s the testscript I used: galaxy.html.