The Drag[en]gine is an free software project with a highly modular structure based on the GLEM System. Its design is similar to an operating system. The entire functionality is provided by Modules comparable to device drivers. The engine itself acts like a system kernel managing modules, resources and abstracting the underlying system. Due to the loose coupling of the modules with the system and other modules it is very easy to exchange or improve them without interfering with the rest of the engine. As a result the modularity extends from the developer to the end user who can now choose the optimal module combination for his personal computer even down to per game setups ( and even while running a game ) if required. Developers do not have to worry anymore about low level concerns keeping them concentrated on their game. In contrary to other engines (including high-end commercial ones) the Drag[en]gine provides true 0-Day portability of games with no extra costs and no troubles neither for the developer nor the end user.

Advantages of the Drag[en]gine

... for the Game Designer:

  • Use your Scripting Language of choice.
  • Hardware is fully abstracted. You only have to know how your chosen Scripting Language works
  • Updating the engine and modules is handled by the respective teams. You only have to worry about updating your game
  • No need to write specific content for specific systems. The users choice of modules takes care of this for you

... for the Module Coder:

  • Play around with individual parts of the engine without disturbing any other part. Test easy and fast new algorithms or features
  • Various debugging features help to debug fast and easy modules even during run-time
  • Loose coupling and high encapsulation yields in a more stable game engine
  • Platform specific code is only handled in modules increasing portability

... for the Customer:

  • Choose the optimal combination of modules for your system. The Drag[en]gine adapts to match your system not the other way 'round!
  • Open standards and free file formats ensure unrestricted and easy modding using free software applications
  • Various Launchers allow you to use the Drag[en]gine for more than just gaming
  • The Crash Recovery System prevents a game from crashing to desktop. While CRS is running change parameters or entire modules and continue your game from where it went out for lunch.

For more information check out the Drag[en]gine Wiki.


Due to the modular nature a fixed list of engine features as other engines provide is not possible since it all depends on the customer's choices. To avoid cluttering the summary find the features list in this article:

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Skin-like translucency Skin-like material with SSS Jade-like material with SSS and translucency
Blog RSS Feed Report abuse Latest News: This update goes under the skin

About Drag[en]gine with 6 comments by Dragonlord on Mar 30th, 2014

This update contains not that much text which is good for you. Most work happended under the engine hood which is not that interesting to the outside world. This time around I had more ZPOC related experiments going on which produced a couple of bug and enhancement tickets to be added (bad for me as this means more work but good for you as these are problems fixed before the first release). Just read the descriptions in the videos ZPOC2 and ZPOC3 . Now on to to what is really important.

Skin system enhancement

   First things first I wrenched around in the shader system adding shader inclusion support. This helps me to make more optimized shaders with more abilities that are more stable and easier to maintain. The power of the skin system bases a lot on this system there. Nothing for the game developer to get in contact with but nevertheless a very important piece of software, without which all this magic (which in some parts could even beat AAA engines) would not exist.

   Besides this I've added also a video texture property. This has been requested since the current system requires artists to rely on the coders to provide a dynamic skin with a video attached to it. In some cases though you just want to play a video or animation on a texture (for example a monitor) without requiring to deal with dynamic skins. This is now possible.

   Furthermore I've modified the behavior of renderables. Up to now you had to choose between static property content (value, color, image, video) and a renderable. This imposed not required limitations. Now the two are separated. Every property can have now an optional renderable name assigned. The static content (value, color, image, video) is used until a dynamic skin is assigned to a component holding a renderable with the matching name. A renderable is now a true extension to a skin property. If dynamic content is present it overrules the static content. If not the static content is used. I've tested this system in the ZPOC using "zoid paints".

   There have been also other smaller changes not worth nothing here. Now on to the big one.

Sub Surface Scattering and Translucency

   SSS is a buzzword but getting it working is a problem. Papers about this topic are mixed and the results are mixed as well. I don't want to talk long about SSS since I'm sure many know what it is and what it helps so see the new absorption and absorption.range texture property for a description. As always I've spent time to figure out how to add simple and easy to use texture properties to handle this case. So I've reduced it to absorption and absorption.range to provide both SSS and translucency.

   I've taken the liberity to use the algorithm from my SSAO implementation since I've noticed an interesting behavior it exposes. This behavior I used for the SSS implementation. This implementation allows me to do SSS and translucency with only one single shader pass with no multi-pass blurring or texture space blurring hacks as typically employed. Furthermore this implementation is physically inspired which means it's not just blur-without-a-reason and not just a pseudo-SSS as some recent AAA engines like to use. This especially means the SSS and translucency implementation used in the Drag[en]gine runs in average 0.25ms . This makes SSS and translucency rather cheap and usable everywhere it's of use. So I'll let you off the hook for now with some images.

Jade-like material with SSS and translucency  Skin-like material with SSS

Skin-like translucency

   And yes, the Stanford test models (dragon, armadillo, buddha) are included in the editor so you can easily and quickly test your materials with them.


   More tickets to work down. Next tickets are about the game editor. All in all working off more tickets.

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Epsylon Epsylon Indie

Updated 4 months ago TBD Single Player Adventure

Epsylon - The Guardians of Xendron takes the player on a journey to a futuristic world investigating a very special Science-Fiction setup. With a team...

Post comment Comments  (40 - 50 of 85)
Bahl Nov 21 2010, 12:43pm says:

I really like the entire approach of this project. I would like to use this technology for an anticipated project, but after reading the homepage and wiki, I understand that it is in a premature development phase. Do you have any sort of project communication like quakenet IRC? The epsilon forum seems to be down.

+1 vote     reply to comment
Dragonlord Nov 22 2010, 5:35pm replied:

Currently this is done using the ModDB page. The forum is indeed down since the forum software fails to run with the new PostgreSQL server version for some unknown reason (only application on my server right now breaking down on this version). Fixing this forum did not have priority so far but I can try changing this if people want a forum already now.

+1 vote     reply to comment
Bahl Nov 26 2010, 12:15pm replied:

Not necessary. I am mostly interested in some technical information concerning how the game logic can be plugged in. there seem to be modules to support dragonscript and two others, but I will probably want to plugg unscripted. that probably means, I'll implement an own 'script' module that implements the game logic, and there I'd be interested in the API.

+1 vote     reply to comment
Dragonlord Nov 26 2010, 5:04pm replied:

For the game logic you choose a Scripting Module. This choice defines which language you use for your game scripts as well as how the engine is abstracted (ranging from mostly wrapping engine classes all the way to point and click). If you can manage you should choose an existing Scripting Module and start from there. If you want to use a new language not supported yet you can create a new Scripting Module. The module itself has to be available online though so every user (using their launcher of choice) can obtain it to play the game. People are always welcome to add more Scripting Modules.

In general the Scripting Module sort of defines the API you access the engine with and the Scripting/Programming language to use it. So unless the language is not supported there is no need to write a new module since you get with the existing modules (all three languages) already full wrapper access (engine API mostly wrapped 1-to-1). Hence by writing a new Scripting Module one does not gain much more customization. I hope this explains it a bit already otherwise just keep asking.

+1 vote     reply to comment
Bahl Nov 27 2010, 12:11pm replied:

well, it confirms my expectations :-). It is good information though, that all engine classes are wrapped as an API by the three existing script modules.

What I would want to do, is implement more high level game logic facilities inside compiled code (unscripted) and then probably add a different script on top that makes use of these facilities. maybe you could call it a game logic tool box. As long as I don't know what is already part of the API, I can just guess, that I would want such a tool box.

Is there some sort of documentation available of the current API wrapped by the scripting modules?

+1 vote     reply to comment
Dragonlord Nov 27 2010, 12:53pm replied:

Such a documentation does not yet exist. In general though one can look at the Wiki which contains a more descriptive description of some basic building blocks provided by the engine (and exposed more or less 1-1 by the Scripting Modules) as well as the Doxygen of the C++ Engine API (, that said, I should update it again). Since the Scripting Modules wrap the Engine API one can get an idea there. In the scripts it's simpler since C++ related problems like memory management or type safety is taken care of there already.

Concerning un-scripted. In general you should be able to do complex game logic using scripts only in a fast way (I'm doing this with the Epsylon project). The way the engine is designed all the number crunching stuff is done by the engine and made available to the scripts through the wrappers. Hence by combining the building blocks properly one should be able to delegate all time critical computations to the engine modules which in turn optimize them.

Otherwise Python has support for byte code generation in general (*.pyc). I did not check out yet how to incorporate this into an embedded Python session but this is similar to JIT like in Java. Hence if you plan to do number crunching not handled by the engine this language should provide you with a pure scripted solution which still runs fast without having to worry about compiling.

+1 vote     reply to comment
Bahl Nov 28 2010, 1:05pm replied:

Thanks for the information, I shall patiently wait for the doxygen update :-).

+1 vote     reply to comment
Dragonlord Nov 28 2010, 3:54pm replied:

Updated the DoxyGen at the URL given above

+1 vote     reply to comment
AniCator Nov 18 2010, 12:39pm says:

Too bad there is no Engine of the Year contest.

+1 vote     reply to comment
Dragonlord Nov 8 2010, 5:09pm replied:

Yes I do. Currently you can use the texture property "refraction.distortion" which simulates Fresnel refraction behind transparent objects. In the video in the previous news post the glass window uses this property to simulate an uneven glass. I'll though also add a Fresnel texture property later on for more accurate refraction. In general all these properties can be also applied to particles. Distorted particles are though more costly since full transparent rendering is required and here I use a speed hack for the more common case of particles.

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