January 11, 2012

Last week I started working on a small, yet powerful visualization tool for animations or more generally spoken for any multi-body simulations. It is based on skeletal animation and magic and is called MeshUp!.

The frames for the skeleton are defined in a JSON file (thanks to jsoncpp this was relatively easy to implement). In the same file meshes can be attached to the frames (e.g. some random monkey head to the “Head” frame, etc.) and are then moved with the head bone.

The meshes themselves are Wavefront OBJ files that can be exported by nearly every 3d content creation package. I wrote the importer in about 2 hours which surprised me. I feared that to be a lot more of a hassle.

Furthermore it finally made me play around with Quaternions a bit more. Turns out that they are not as hard and are actually quite efficient. Before that I used some matrix calculations for the rotations but with the Quaternions I basically have the same usage but about 10% performance gain (not that it would matter, but it surprised me a little). The biggest problems I had, was that in my computer animation reference book a formula for a conversion had a typo. Thanks to test driven development this was easy to debug and will not occur in the future! Yay!

Oh, also it is coordinate system agnostic. Meaning you can use whatever angle convention you like! ZYX Euler? Sure! YZX Euler? Why not? Just define the proper coordinate system and rotation order in the model file and that’s it!

I published MeshUp! at bitbucket account. You can download the source at:

So far I havent’t decided on a license. Any suggestions?



Premature code and binary LEAKED*!

April 9, 2010

The worst possible happened: the source code an even a buggy windows version version of my asteroids clone leaked to the internet! It took me quite long to finally get it run under windows and now that hard work simply pops up in the internet… I don’t know what to say. I fear it is probably an evil German hacker, just like in the 2003 leak of the Half-life 2 source. Tough times, I’d say…

Apart from that I am actually quite happy to get it finally run on windows. On the way there I ran into quite a few obstacles. I tried to use portable tools and libraries (CMake, freetype, OpenGL, SDL, libpng, boost), however getting them compiled and correctly linked in Visual Studio Express 2008 took quite some time. I also used a few precompiler #defines that were not supported by the Microsoft compiler (e.g. used __func__ instead of __FUNCTION__). There also was a critical bug that would make my game crash under Windows but not under GNU/Linux which was caused of improper initialization of a variable. The biggest hassle in the end was however getting it compiled so that it can be run on a computer on which it wasn’t compiled as there are some dependancies on the redistributable runtime libraries of Visual C++. I hope this is solved in the uploaded binary.

When you look at the asteroids.rc file you can mess around with some variables of the game (such as ship acceleration, maximum speed, etc.) and also set the controls the way you like it (so far only keyboard). Oh and there is also a very basic console (to access it press F8) with which you can run simple commands such as the ones in the asteroids.rc file.

For those who want to have a look at it here are the official links to the “leaked” versions ;D:

Known issues so far:

explosion of an innocent ship

(buggy) explosion of an innocent ship

*too bad 1st of april has been already 9 days ago