Archive for the ‘Määratlemata’ Category


Friday, September 16th, 2011

Slipstream is a free racing vehicle simulator trying to be physically accurate and fun to play at the same time! Contrary to most simulators out there it’s not designed around a single type of vehicle. It should be able to support anything from a bicycle to a car or anything else that can be driven around on a racetrack for that matter.

Current status

Although Slipstream is still in early development it should already be useful for a couple of purposes. A model of a modern motorcycle has been implemented and it handles well enough to be both fun and challenging to race around the available track. Besides that the vehicle model has been completely based on academic research (see the manual for details and references) and every care has been taken to make it as accurate as possible. Combine this with the fact that it is easily configurable, using either the graphic interface or scripting to the very last detail and you get a pretty good research tool.


One point of difference between Slipstream and every other motorcycle racing simulator I’m aware of is that it does not try to control the vehicle for you in any way. You can’t just expect to press the left arrow key and magically balance the motorcycle at a 50 degree lean angle. Slipstream just simulates the actual machine piece for piece and allows you to use your mouse to apply pressure to the steering bars and control levers, the rest is up to you. This makes it a lot harder to learn how to control your vehicle but it also makes it a lot more fun in my opinion by bringing out all the interesting effects most motorcycle riders are familiar with. Open the throttle too much when you’re leaned over and the bike will drift, drop the front wheel without finesse after a wheelie and you’ll get a tank-slapper, hit the brakes too hard and the bike starts weaving as the rear wheel loses traction. I even managed to “perform” a high-side although to be honest I was trying for it.

Another unique point about Slipstream is that the vehicles are modeled piece for piece and are completely configurable. The current motorcycle model has been based on a couple of academic research papers that describe a particular 1000cc motorcycle so the default configuration reflects that. But that doesn’t mean that only one motorcycle is available. The graphical interface allows the separate configuration of every parameter so that it’s a matter of minutes to, for example, raise the steering head angle a few degrees, move the front wheel mount point further to the front and get a chopper-style motorcycle. Raise the rear spring stiffness to the point of rigidity as well and you get a hard-tail. Or you can leave everything as is and just move the rear wheel mount-point more to the back to get a long-swingarm drag-bike. You can probably make modifications that actually make the bike perform better as well. The possibilities are endless.

Apart from that, the fact that you can make modifications and try them out in real-time should make Slipstream ideal for anyone wanting to study the nature of motorcycle dynamics. It is easy for example to change the steering head rake or offset and see how this affects the handling. For the more academically-inclined it is also very easy to study the motorcycle by recording some parameter and then producing plots. For example it’s easy to change to front chain sprocket position and see how this affects motorcycle squatting during acceleration by recording the extension of the rear damper rod during scripted acceleration runs before and after the modification.

I don’t really know how well Slipstream would fare if applied to research as I’m not capable of assessing that. I’ve tried to produce plots of the models where I could and they seemed to match the published data and I have generally no reason to believe that Slipstream is less accurate than the setups used in the research papers. To be honest I have no reason to believe otherwise either but I would be very interested in finding out so if anyone’s considering doing research with Slipstream let me know and I’ll try to help out as much as I can. More information on the physics model can be found in the documentation.


The graphics are still very primitive I’m afraid but they get the job done at least. Making Slipstream pretty is still a high priority but I doubt I’ll be able to create decent track and vehicle models myself. If you’re an artist and want to participate in making a great racing simulator please drop me a line.

In the mean-time here are a couple of videos that show of the handling of the bike from an on-board and an external point of view.


Slipstream runs on Techne so you’ll need a working installation of the latest version of Techne. Depending on the distribution you’re using there might be packages available or you may need to compile the sources yourself. Head over to Techne’s homepage to see the hardware and software requirements.


This is the first release of Slipstream, released on September the 10th 2011. In addition to these packages you’ll also need to install Techne version 0.2.2 which you can find here.

Slipstream Homepage

Heretic and Hexen liberated!

Friday, September 12th, 2008

After several years of trying, members of the Doom community have succeeded in getting the source code to Heretic and its sequel, Hexen to be re-released as free software under the GNU General Public License.

For those of you who’ve never heard of these games, here’s what we have to look forward to in the near future:

In Heretic, three brothers have used their immense magical powers to turn the seven kings of Parthoris into mindless puppets. However, a group of elves are immune to the brothers’ spells and had no allegiance to any of the seven kings and are thus declared as heretics and a campaign of genocide is launched against them.

In the sequel, Hexen, a new feature is the choice of character class. Players may choose to play as a fighter, cleric, or mage. Each character has unique weapons and physical characteristics, lending an additional degree of variety and replayability to the gameplay. It also introduces the concept of “hub” levels to the series, wherein the player travels back and forth between central hub levels and connected side levels.

The source code for the Doom engine was released under the GPL in 1999. Although Doom was originally created for MS-DOS, the original source release was for the subsequent GNU/Linux version.

The original purpose of source ports was cross-platform compatibility, but shortly after the release of the Doom source, programmers were correcting old, unaddressed Doom bugs and deficiencies in their own source ports, and later on added more source code features to add new game features and alter gameplay. Doom source ports have been created to allow Doom to run on many different platforms including handheld consoles, the OLPC and various cellphones.

Doom has already been ported to the Neo FreeRunner.

Thanks to everyone in the community for their on-going efforts to see these games released as free software, and thanks to Raven Software for finally doing the right thing.

Eternal Lands 1.7.0

Thursday, July 17th, 2008

1. Sky/better 3rd person view.
2. Better minimap (alt+m).
3. Improved weather effects.
4. Context menu for many GUI elements (right click on windows, bars, etc.)
5. Many other smaller improvements and bug fixes.
6. New weapon and armor (not available in the game yet).
7. New eye candy effects.
8. Map bug fixes & a few new additions

Server changes:
1. Engineering god.
2. Fixed the knowledge list.

Contributors (in no particular order)

– lots of Eye Candy related stuff
— missile effects
— level up effects
— harvesting effects
— ongoing effects (client side triggered, server triggers are still WIP)
— EC debug window
— enabling poor man now immediately reduces particle count for smoke and fountains, no map change required
— fireflies
— staff effects
— mine effects
— other effect tweaks

– small stuff
— scale floating damage message with the amount of damage taken
— display a floating message “miss” on missed shots
— fix endian issues in missile messages
— OSX related fixes
— AMD64 related fixes related to different types of float implementations

Sky, new camera movement, weather effects, various bug fixes.

The context menu system (right-click menus); cut/copy/paste, general hud, quick spells, quickbar, player banner and window title menus.
#exp is now client side and has all the skills.
New settings button on login screen.
Print storage catergory items to console (from title context menu).
Print astro text to console (from title context menu).
Inventory window size selection (from title context menu).
Debian/Ubuntu Linux package files

Bugs fixes:
Window text wrapping
Fixed rules and language selection window so they always get used on a new install.
Give warning message for books not in book list.
Prevent astro window bars extending beyond window.
Fixed crash when new character name was too long.
A few additions and fixes for kibora’s rotating minimap.

More work on the shadowed text in the HUD
Mapwalk dance fix
Various small bugfix suggestions with other developers

Galienne temple addition, map bug fixes.

And a big thanks to all the Mods! (IMG:style_emoticons/default/tongue.gif)