Google Summer of Code 2011

Say hello and be welcomed to our introduction page for the Google Summer of Code 2011 (GSoC).

If you do not know what GSoC is you may want to visit the project's homepage. But if you do so you probably want to know more about OpenClonk.

Note: OpenClonk was not accepted as a mentoring organization in 2011.

About OpenClonk

Clonk Rage in comparison to OpenClonk

In short, OpenClonk is a successor to the Clonk gaming series. Clonk is a game based on quick and hectic hand to hand combat, large-scale base vs. base battles, underground mining and/or friendly settlement conquests. There is no linear gameplay like a big campaign to advance the story nor is there a secluded game content which reliably reappears in every level you start to play. Every scenario (i.e. level or map) in Clonk is a story of itself, it lasts from a few minutes up to a couple of hours to finish. One scenario may bring you to a watery cave and the next one up in the sky to solitary floating islands where falling down marks the end. The great advantage of Clonk is the easy way to modify it and create your very own scenario or a new set of ingame objects. Past Clonk titles have seen medieval castles, Wild West scenarios, a fantasy setting with powerful magic and scary dragons or futuristic laser battles. To sum it up, Clonk is everything you make out of it. This is because Clonk features an own powerful scripting language called C4Script (documentation on this site) in which the game content is written.

You want to know more? See the About page and the homepage ( of the commercial predecessors of OpenClonk.

Why do we want to participate in GSoC?

OpenClonk possesses a team of motivated developers yet not enough to take on every task required. There is a release of OpenClonk (see Download) which mostly features arena-based combat and races ("parkours"). However for the finished game we want to re-introduce the other gaming types that were available in Clonk Rage, most prominently cooperative settlement gameplay. We hope to gain new members in our developing community and get some long needed tasks done. And of course we want the existence of (Open)Clonk to become widespread known because we all think that it was, it is and will remain a good and fun-to-play game.

Another reason for taking part in GSoC is that, traditionally, the Clonk community is mostly a German one. In OpenClonk we encourage international players and developers to join the community, and these efforts have payed off already: for example we have regular contributions from Poland, the Netherlands or Canada. However GSoC is a great opportunity to further internationalize our community.

OpenClonk is not as big a project as other organizations nor are our tasks for applying students as numerous. Yet most of the team looks back on years of experience in developing and designing a game and wants to share this experience with upcoming developers. We would gladly provide our assistance to some students willing to support our project.

Preceeding participations in GSoC

OpenClonk did not participate in GSoC before. The project started in the middle of 2009 and now looks back on one and a half year of development. In 2010 there was not enough progress done to support applying students.

What about licensing?

OpenClonk uses the ISC license for code and Creative Commons (CC-by) for any other content (graphics, sound, ...). See License

Motivating students to stay with the project

Clonk is game. So it is devoted to everyone who likes playing games! OpenClonk is free to play, the predecessors are freeware except for the newest, Clonk Rage which is free to test. We do not require students to know the shareware titles though - actually an unbiased view on our current game is likely to be much more valuable. Applying students should try out the game before applying to see whether or not they like it. Then they are introduced to a friendly community of developers; most of them knowing each other for years and in person, becoming friends. We are looking forward to students who like Clonk as we do and to many fun online rounds with them.

Contact and communication

The development is organized in the Forum as well as in the #openclonk-dev IRC channel (located in the euIRC). There is no mailing list for developers; instead we use the Developer's Corner board in the forum for technical discussions.

Tasks for applying students

The game (engine) is written in C++, the separate easily-to-modify content is written in Clonk's own C-like scripting language C4Script. As OpenClonk is a game, there are many different areas of work from different disciplines in programming in the engine and generally in the project. Amongst these are: Graphics rendering with OpenGL/DirectX, GUI design, serialization of game objects (for save games/network), network synchronization, (IRC) chat client, script parser and language design, dynamic map generator (including map definition parser), sound and music programming, packaging game content and distributing standalone updates, game logic and mechanics, (customizable) mouse, keyboard and gamepad controls, reading and writing configuration files/windows registry entries, internationalization and, of course, concepting, designing and creating the game content with C4Script.

See our GSoC2011Ideas page for a list of proposed tasks. Custom ideas from student are of course both encouraged and considered as well.


If you are a student planning to apply for OpenClonk in GSoC 2011 please get in touch with us before applying. This allows you to be introduced to the community and it allows the community and especially the mentors to get to know you before they have to rank the student applications. Also this way we can discuss ideas and timelines for the project and tailor them to your individual needs and skills.

Once accepted we will also ask you to give a brief status report every week. This way we make sure to always be up to date on your progress and we notice quickly when things are not running as smooth as expected and we can offer additional help.

Application Template

Please use the following template when applying as a student for OpenClonk in GSoC 2011, or make sure to precisely answer the questions therein.

Name: Your name.

Email Address: Your primary email address.

Other means to get in contact with you (optional): Jabber, Skype, ...

Project Title: The title of your project.

Abstract: A few sentences to briefly describe your project.

Details: A more detailed description of your project.

Timeline: Please divide your project into several smaller tasks and assign a date to each of them when you plan to get them finished. Also let us know if you plan not to be available for some time, such as for vacation. Please feel free to discuss this before applying with our community and mentors in the forums or in IRC.

Qualifications: What skills do you have that allow you to successfully finish the project? What do you maybe need to learn? What makes you the best candidate for this project?

Bio: Tell us a bit about yourself. Where are you living, what are studying? What are you doing besides coding?

Administrators to watch GSoC


Clonkonaut (backup)

Our mentors

Clonk-Karl: I started playing Clonk in 1998, then began creating objects and scenarios in 2000 (my first contact with programming) and joined Redwolf Design in 2003 working on Clonk Endeavour and Clonk Rage. In the meantime I also learned C++ and became an Open Source enthusiast and was (and still am) involved in other projects such as GNOME and Gobby. But I still had a whole lot of fun with Clonk and so I was very pleased when the decision was made to make Clonk Open Source in 2009.

My primary interests these days are more technical things in the Clonk engine. This includes the graphics code (most notably 3D mesh rendering for which I introduced support) and the Linux specific areas. However I have a good grasp of the other areas in the engine as well and when confronted with a problem I know where to look for it. I also know our scripting language, C4Script, so if there are any problems with it I am likely to be able to help.

In the community I am also known simply as ck. I live in Karlsruhe, Germany where I am studying physics in my final year now.

Clonkonaut: Hello everyone! Known as Clonkonaut, I, Felix Wagner, played Clonk for years now as well as working on the previous Clonk titles under Redwolf Design. Since the launch of OpenClonk I ceased active development. This saddened me but due to my upcoming law study my free time shortened radically.

Anyhow, I followed and helped with the conceptual work and progress. So I will assist with concept issues and pass criticism on your work (mainly positive and helpful of course!). I never learned C++ so I cannot help with this but I can aid learning C4Script and I will be there when other problems occur.

PeterW: My involvement with Clonk has been from the development side from the start. Already my first published project was a script editor with heavy script rewriting in order to allow script programmers to use operators in their program. When matthes published Clonk Planet's source code around 2001, it was therefore a straightforward step to "port" my changes directly into the engine.

I quickly joined forces with Sven2 and the rest of the GWE team and started hacking away. Over the years we managed to substantially improve the game. Redwolf Design ended up officially throwing its weight behind it numerous times as well, leading to the Clonk Endeavour and Clonk Rage titles. In that time, I have worked on just about every part of the engine, but script and networking are my specialities.

Generally, working on the Clonk engine has been really fun for me. The engine uses an interesting mix of technologies, like full synchronization, powerful yet easy scripting and dynamic landscapes. My goal would be to enable fellow programmers to have an equally enjoyable experience working on the project, so please don't hesitate to ask.

Maikel: Welcome to what I think is a great project. I have played Clonk during my youth and rediscovered it as a student, which I still am. I immediately got interested in designing levels and creating objects, which I did mainly for my own benefit. As the OpenClonk project started, I was really stimulated to join the development team so I could participate in what I think is the best 2D gaming concept. The project was and still is very open to newcomers, I can say from my own judgement. So I hope that we can attract more developers through this summer of code.

As I am too lazy to take a picture, I can only refer to the blog where my appearance is indicated somewhere. Currently I am still studying, theoretical physics, which is unrelated to the project. Thus my interest in and knowledge of the engine/C++ are limited. In this project I am mainly responsible for scripting objects, which is done in C4Script (Clonk's own scripting language as you might know by now). This is where I'd like to take up my mentoring duties, I'll probably be in IRC most of the evenings, which is a good place to ask questions and have discussions. Really looking forward to see some new faces!

Newton: Hi there, I also volunteer to be your mentor for the GSOC 2011! Clonk has been a hobby for me for many years, I was involved in the previous few Clonk shareware titles under Redwolf Design and I am one of the founders of the OpenClonk project. I got a big deal of experience from past Clonk related projects and actually was the project manager for our first and current OpenClonk milestone "Back to the Rocks".

Recently, I have withdrawn a bit from active development since I am currently in my final weeks of writing my bachelor thesis at the University of Hamburg (Germany) in computer science. After I finished the thesis, I will be gone travelling until May '11, so before that I'll not be available as a mentor.

Also, I should note that I am not one of the die-hard engine developers with a great insight into the Clonk game engine. But this shouldn't be a problem as those who are also idling in our development channel #openclonk-dev on and even those who are not mentors are always happy to help :-)