Open Source Game Development

Boudewijn Rempt writes "Amazon's recommendation system recommended me "Open Source Game Development: Qt Games for KDE, PDA's and Windows" when I was looking for an introduction to OpenGL. While it does contain two chapters on OpenGL, there's much, much more. It's not just an introduction to writing open source games, it's a complete introduction to participating in open source projects like KDE." Read the rest of Boudewijn's review. Open Source Game Development: Qt Games for KDE, PDAs and Windows author Martin Heni, Andreas Beckermann pages 554 publisher Charles River Media rating 8 reviewer Boudewijn Rempt ISBN 1-58450-406-4 summary Complete guide on writing small to medium games for Linux, Windows and PDA's using Qt.

As maintainer of Krita, the KOffice paint application, I need to know about graphics. Unfortunately, the four months of retraining from sinologist to Oracle Forms developer that launched me into a life of coding didn't include anything on graphics, and certainly not on OpenGL. Which is very much where Krita 2.0 is going.

So... I was looking for an easy introduction to OpenGL to kind of ease my way into the Red and Orange books. And Amazon's weird recommendations system recommended Open Source Game Development: Qt Games for KDE, PDAs, and Windows by Martin Heni and Andreas Beckermann to me. Intrigued, I ordered the volume forthwith. Turns out that that was a good move: this is an excellent book.

In the first place, the text is very clear and concise, but never dry. Forget about the ho-ho-I'm-funny chatty style that's prevalent in many technical books. This book comes to the point immediately. Then, the information is carefully ordered and the presentation very neat and clear. Those would be good points for any book.

But what makes Open Source Game Development: Qt Games for KDE, PDAs, and Windows even more interesting is that it's much more than its title indicates. It is squarely intended at the hobby coder who wants to work on what the book calls "desktop games" -- not the multi-million dollar multimedia productions that demand a new graphics card every half year, but the games that you play while thinking out a knotty problem or that have some educational value for your kids. The kind of project a single coder, or a small team can complete and maintain while still staying sane. And, of course, that kind of game, defender or zaxxon-type games, maze games or tetris-style games work are perfectly suited for pda's and mobile phones, too,

Actually, this book is the perfect introduction to joining a big Open Source project I've seen. Of course, the focus is on Qt and KDE, which means that if you always had this itch to join KDE development but didn't have the necessary skills, this book will help you get there in a very pleasant way.

One way this is done, is by always first giving a general introduction to a topic, and then more detailed discussion in the next chapter. So, first we've got a very good "Qt Primer", and three chapters "KDE Game Development", "Qt Game Development Using Microsoft Windows" and "Game Development and PDA's". And there's a chapter on "OpenGL" in general, and then a chapter on "OpenGL with Qt".

The first part of the book deals with this type of introductory material. The second part discusses "Artificial Intelligence", "Pathfinding" (this chapter was a revelation to me -- I never understood how that worked. If only I had this information while trying to write games for my ZX Spectrum!), "Particle Effects" and "Math and Physics in Desktop Games". The material in these chapters is foreshadowed by the very first chapter "Introduction to Desktop Gaming", which deals with game balancing, architecture and the ins and outs of developing free software. Armed with these chapters, you can add enough game play to your games to make them satisfying to play.

The next three chapters discussion the Qt network classes and how to use them in your games, the KGame library (free software, of course), that contains a lot of boring groundwork that's the same for most games -- players, input devices, network stuff. For me personally, the "XML" chapter wasn't that useful, but then, I'm a corporate cubby-hole programmer by day, and XML is my bread and butter. It's amazing how many billable hours XML can add to a business application project.

A very important chapter, "Open Source and Intellectual Property Rights" makes it very clear what's allowed and what not. The summary chapter, "A Practical Summary" is a novel idea -- at least, I hadn't come across something like this before -- and it works quite well, tying all strands together. There are plenty of references to earlier chapters, so if works like a kind of hands-on index. Not that the actual index isn't top-notch, too.

I should make clear that this book is not just about coding for KDE. That's what most interesting to me, but if you want to code a game for Windows, for a Qtopia or Qt/Embedded environment, then this is the right book. After all, with the release of Qt4 under GPL for Windows (Qt was already released under GPL for X11 and OS X, as was Qtopia), Qt is a good choice for Windows hobby programmers. You get a high quality toolkit that really helps with the boring ground work, and excellent documentation. Coupled with the clear text in this book, there's nothing to hold you back.

Andreas Beckermann is the author of Boson, an OpenGL real-time strategy game based on Qt and KDE. His experience in working on Boson really is apparent in this book. Martin Heni has written a couple of games that that are in KDE's games pack, and has won a prize for his QTopia game Zauralign.

Oh, and the chapters on OpenGL and OpenGL with Qt were enough to make me understand the OpenGL Krita already has and did prepare me quite adequately for the big Red and Orange books. And I've got the itch to write a little game now..."

You can purchase Open Source Game Development: Qt Games for KDE, PDAs and Windows from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Comments

You sold me :-)

[Coeurderoy]

I was looking for a book easyng me into Qtopia, and it seems to fit the bill.
Thanks for an useful review.

Does it answer a really important question?

[Grey Ninja]

How exactly do you make money on open source games? They are a different beast entirely from regular apps. If someone is paying for support for a game, then there's something very wrong going on. I mean, I'm all for open source software, but I've never been able to figure out how to code them, and still put food on the table. As a result, most of my games have been proprietary.

Re:Does it answer a really important question?

[CrazyJim1]

You can make your game opensoure X years later where X years is when you stop making a profit. The reason some of the big dogs don't do this is that they want to resell the game X years in the future in a classics pack. Or rerelease atari 2600 for example. Making a game open source brings more fame to it as more people enjoy mods on your game and your good heart for allowing it to happen, which brings fame to your company. Company fame results in more units sold in the future when you make new games.

Re:Does it answer a really important question?

[Anonymous Coward]

The answer is: You don't. You just do it.

Re:Does it answer a really important question?

[ImTheDarkcyde]

not overly true, Quake 4 special edition came with Quake 2. Quake 2 has been open source for some while now.

Making the game opensource does not supply people with the game content, only the engine code :)

Re:Does it answer a really important question?

[Zombie Ryushu]

You open Source the Engine, but close the content. Like the Doom/Quake model. Open Source Engine, Closed content packs (WADs, PAKs.)

Re:Does it answer a really important question?

[linvir]

In conjunction with the closed content/open code trick already mentioned, online games should be very easy to open source. You can easily charge for access to the server for the player's account, instead of for the initial disc purchase.

This flies in the face of the Guild Wars model, but for the WoW model, where you pay for both the disc and the account, it can be amended so that for example, you are forced to buy a certain minimum of months of play.

In my uninformed opinion there really is no reason for paid-account MMORPGs to be closed source. They might say that it's to prevent cheating, but I say that open sourcing would kill cheating dead.

Re:Does it answer a really important question?

[xtracto]

It is quite simple really, and it is the way even some closed games have made money: SAS.

Yeah, the buzzword makes sense for games too, a company could make a game and give away the code while maintaining a good online game community/forums etc. Setup some servers and go!

What I would do is making open source the client, keeping the server, then, let the community improve the client and I would improve the network infraestructure, of course with the client code it would be deadly easy to replicate the server, but there is where the company would have to provide some *special* value on its servers (something like Xbox Live community).

Re:Does it answer a really important question?

[Threni]

> How exactly do you make money on open source games? They are a different beast
> entirely from regular apps. If someone is paying for support for a game, then
> there's something very wrong going on. I mean, I'm all for open source software,
> but I've never been able to figure out how to code them, and still put food on
> the table. As a result, most of my games have been proprietary.

You don't do it for money. You do it for a laugh, or to learn something. It's a hobby, right? I'm learning Java so I'm doing a port of a fun, simple game. Once it's done I'm going to release the code and everything, and then I'll mention it in interviews that I have some experience in the language with a URL to Sourceforge if they want proof. I'm sure other people have gone for jobs in the games industry having done something similar. If there's a little bit of feedback from the community then that'll look good too but at the end of the day it's just a bit of fun.

It's not all about money.

Re:Does it answer a really important question?

[vdboor]

From the review, I get the idea that the focus of the book is actually contributing to Open Source, scratching an itch as hobby.

The money comes later when you apply for a job in the industry, and can point out some first-hand examples of what you can already do. Plus you'll have some experience already.

With my own application for a job, I've actually used my own Open Source project and website as examples for the conversation, with great success. :-) Your milage may vary off course, and I must admit I've got lucky it's a small company with a technical-oriented atmosphere.

Re:Does it answer a really important question?

[xtracto]

In my uninformed opinion there really is no reason for paid-account MMORPGs to be closed source. They might say that it's to prevent cheating, but I say that open sourcing would kill cheating dead.
--

The problem here is what happened to blizzard and bnetd, but, with an Open Source client it would be trivial to create servers and you wont be doing andy "reverse engineering" thus not breaking the law.

What is needed in these cases is the company to create a "community" with some value in order to persuade people to join. (Certified servers, fast servers, some kind of updates, etc)

Re:Does it answer a really important question?

[thrift24]

Engine is open and free.
Artwork is open and free.
Anti-cheat is closed and pay for/reliant on central server.

Re:Does it answer a really important question?

[westlake]

The reason some of the big dogs don't do this is that they want to resell the game X years in the future in a classics pack.

The other reason is that a few years in retirement can be good for a title, a character or a genre. Lara Croft and Tomb Raider is the perfect example. Fallout may be another.

Re:Does it answer a really important question?

[Anonymous Coward]

You can sell software while still being Open Source.

Re:Does it answer a really important question?

[The Tyrant]

Thats a matter for the companies to decide. iD software for example, decided to release the Doom source code, but explicitly not the Doom graphics and data files, they could have done, if they wanted to, but since Doom is still being ported to and sold on every small and embedded platform under the sun, it wasn't in their interests to do so.

Re:Does it answer a really important question?

[ltmon]

In fairness to the book and the reviewer the word "hobbyist" is mentioned several times.

It's not a book about how to make a commercially viable game, it's a book for the hobbyist programmer wishing to have some fun.

L.

Re:Does it answer a really important question?

[Deusy]

The same way any website-with-traffic does in the Google age - Google ads.

Re:Does it answer a really important question?

[AnyoneEB]

It seems like a different situation to me. BNET does not host games. BNET simply provides chat and an interface through which players can find and advertise games. On the other hand, making a MMOG server would be a rather large task. In theory, a MMOG server is the part actually running the game and the client is just a thin-client rendering what the server tells it to. Sure an open source WoW client would aid the development of a similar online game, but it is only a small piece of the whole game.

Re:Does it answer a really important question?

[Tough Love]

How exactly do you make money on open source games?

This is not always the reason for participating on open source development. However, assuming it is, note that if you want to enter the game industry as something better than a peon there is no better way than by already having the experience on your resume by joining an open source game project and having the results to show for it. That means results in the form of running code or even better, running code in distribution.

Re:Does it answer a really important question?

[ThosLives]

It's quite simple: you open-source the game, then simply tell everyone who plays it (perhaps on the title screen or whatever) that if they want more games like this from you, send a donation; otherwise you'll have to use up your time doing something that does pay you so you can eat, have a house, etc. which might mean that society will not see more games from you.

If society values your efforts and talents enough, they will compensate you; if they don't, then you will need to choose if you will continue to spend your free time making games and giving them away without compensation or change what you do in your free time.

Economics really isn't that difficult when you realize that there is really no obligation for society to compensate you for your creative efforts unless you were contracted to exert that effort.

Re:Does it answer a really important question?

[Rycross]

Different as it may be, there are "private" WoW servers out there. Of course, I'd imagine you could compete on quality easily. All of those servers have less than 100 players online, and I'd imagine they wouldn't scale very well.

Re:Does it answer a really important question?

[Anonymous Coward]

SAS?

Re:Does it answer a really important question?

[slashdotnickname]

Making a game open source brings more fame to it as more people enjoy mods on your game and your good heart for allowing it to happen, which brings fame to your company.

Name at least one example of something like that ever happening...

Re:Does it answer a really important question?

[slapout]

You could make the game engine itself open source and then sale levels for it.

Re:Does it answer a really important question?

[murdocj]

Economics really isn't that difficult when you realize that there is really no obligation for society to compensate you for your creative efforts unless you were contracted to exert that effort.

Hmmm... the problem with open source is that society doesn't have any "contract" with you to compensate you. With closed source, you produce a product, and if society finds it valuable, it compensates you. Simple economics.

Re:Does it answer a really important question?

[swillden]

you wont be doing andy "reverse engineering" thus not breaking the law.

Just a clarification: Reverse engineering is not illegal. If you've agreed to some contract that prevents you from performing reverse engineering, that's contract violation, and if the reverse engineering you do is to work around copy protection designed to prevent copying of copyrighted works, then distributing a tool that bypasses the copy protection system is illegal. Finally, if you reverse engineer something so precisely that your reversed implementation appears to be a duplicate of the original, then you may be accused of copying, which could land you in court. The notion of "clean room" reverse engineering was invented to ensure that the copyright owner had no prayer of claiming that the code was copied -- not because clean room reverse engineering is actually necessary, but because it's safer than the alternative.

Re:Does it answer a really important question?

[smash]

One option is subscription fees to network services.

Sure, if it's open-source, someone could probably reverse engineer it and build their own server - but still, someone is going to have to pay for the hardware/software to run a big enough game world.

If the choice was between playing a free version on a game world with 20 players, vs a properly maintained cluster that could support thousands, i'm sure a lot of people would be willing to pay for the larger game world...

Just because the game client is open-sourced, it doesn't necessarily mean the network server has to be... :)

Re:Does it answer a really important question?

[Sicnarf]

Well my first reaction would be that they should open source the old game content as well. :)

Re:Does it answer a really important question?

[Sigma 7]

Making a game open source brings more fame to it as more people enjoy mods on your game and your good heart for allowing it to happen, which brings fame to your company.

Name at least one example of something like that ever happening...

That's the wrong way to counter that argument - the release of the source code for Wolf3D shows that the company is willing to show how they did the work. It is also a pattern followed through for the classic Doom series and the Quake series. In a way, it's permanently kept Quake alive in other forms.

A better way of countering the argument is stating that making a game open source has limited impact. As an example, open sourcing a mediocre game would effectivly do nothing as any experienced team of programmers can make a basic C&C clone.

Re:Does it answer a really important question?

[modecx]

SAS?

Yes. Isn't it clear enough?

1) The SAS (Special Air Service), Great Britian's answer to the Navy Seals, will send troops to HALO jump straight into the houses of everyone that plays your Open Source game.

2) They will then proceed to ransack the houses of said players, looting any valuables they happen to find, then they will make love to the wives of these game players for no less than a half hour after a romantic dinner at an expensive resturant, and finally they will kill anything that moves before executing a stealthy exit via the Fulton Recovery System.

3) Profit!!!

Re:Does it answer a really important question?

[Anonymous Coward]

Special value? Easy!

Look at GuildWars as an example. You pay your money (one-off fee) for GuildWars Prophecies. You play that, and 6 months later, they release GuildWars Factions. So you pay the same amount of money again. But you've already bought the game, executables etc, and there's no new features to the software itself.

Essentially, what you're paying for is the game content. The models, textures, plot and voice talent. You're paying for access to a game server where there are thousands of other people. You can download the client for free. You just can't do anything with it.

Now take the free client one step further. Make it open source. What changes? Well, people could set up competing servers, but they'd still have to pay to make all the content. Free servers would spring up, but they'd either have to make their own content (no hobbiest group would manage to build a world as big as Tyria/Cantha), or copy the stuff used for the regular servers. They wouldn't get away with it for long, because they'd need to advertise heavily to get the same number of users.

As long as the server software is well enough designed to prevent cheating, there's no reason that the game couldn't be open source, right?

Wrong. The biggest reason why the client could never be open sourced is botting. Right now, bots work by sending key events to the game, and hoping that the game environment is consistant enough that you can get away with it. If you've got access to the source, you can make fully interactive bots, smarter bots, more profitable bots. The in-game economy would crash in under 24 hours.

Yes, I'd love to be able to use an open source client to games like GuildWars, I'd play on ArenaNet's servers as well as any free ones. But I know it's not going to happen, as long as the farmbots are still around.

Re:Does it answer a really important question?

[Bent Mind]

I'd guess it would depend on the type of game. However, one model I always wondered about was opening the software while selling the content. For a role-playing or FPS, the content would be storyline, graphics, models, music, sound effects, etc. For a puzzle game, content might be levels or some such.

Re:Does it answer a really important question?

[tchernobog]

Actually, you don't have to wait. Arguably, most of what builds up a game nowadays isn't code, but artworks, storyline, 3d models and such.

You can thus release the "engine" under the GPL, for example, and your commercial opponents will anyway have to produce their own artworks/material for their own game, even if they use your code. This can take a year or more for a well-done job; in the mean time the engine "as it is" would probably be obsolete for a _new_ game to hit the shelves, so it isn't a big lose on the long run for your company.

Moreover, using something like the GPL, if another company improves upon your code you'll immediately have access to it when it's released.

On the other hand, releasing the source means improved software support, free bugfixing, greatly extends the product life-cycle span, and ensures great portability for new platforms, potentially making it played for decades.

If I had Starcraft code under hand, for example, I would be even now porting it to GNU/Linux, and adding features! And it's a 1998 game, if I recall correctly.

So here's my recipe: free the code under the GPL, and instead retain copyright under a restrictive license for all the rest of the game, what really defines it. People will have to buy a copy of the game to get the "contents" anyway, while they can hack away on the code.

Just my 2 -cents.

Re:Does it answer a really important question?

[Anonymous Coward]

One word on how to make money - Quantity!

Re:Does it answer a really important question?

[I'm Don Giovanni]

The problem is that you'd still be investing millions of dollars/man-hours to create this engine, and giving it away for free to your competitors. Sure, everyone can then create their own art/story/content, but why give should my competitors get to use an engine that I spent much dollars/man-hours creating, free of charge?

I really think Epic has a better understanding of this industry than random slashdotters or RMS. Epic spend years creating their Unreal 3.0 engine, and guess what, the *license* it to others for a *fee* (and the license may even include the source, but not for redistribution to others). I'm sorry, but open source is not amenable to creating things like Halo, Half-Life, World of Warcraft, etc. Stick with Tux Racer trivialities.

A sidenote:
I've worked on software for years, and the "art" (icons, pictures, sounds, etc) is considered part of the "source". So why do you separate the "art" from the "source code"? You say that devs can GPL the engine but keep the "art" 'closed'. Why not "GPL" the art as well? Seems that the true OSS advocate would advocate "open sourcing" the art/story/content, letting the "community" improve it, and reaping the benefits of the community's effort. That you concede that the art should remain 'closed', tacitly admits a flaw in the GPL model (as far as money-making is concerned).

Re:Does it answer a really important question?

[drinkypoo]

Which has happened in the past. AFAIK the content for Microsoft's "Allegiance" is open and included with the code, although the code itelf is only as open as the typical microsoft "open" - a debate for another time. And of course, "The Ur-Quan Masters" is a port of Star Control 2 to SDL, using the source code and the content from the 3DO version of all things.

Re:Does it answer a really important question?

[6]

This is a sad sad thread. The article clearly stated the book was aimed at the, "hobbyist coder". Despite almost religious believes to the contrary, not all human endeavors must be for profit.

A whole generation of programmers grew up with magazines such as, "Creative Computing", and books such as, "Basic computer Games". Why an entire kernel was created, to quote the author, "just for fun".

Re:Does it answer a really important question?

[Slithe]

What gamer even has a girlfriend, let alone a wife?

Re:Does it answer a really important question?

[modecx]

What gamer even has a girlfriend, let alone a wife?

Oh, the ones with lots of money, or possibly gamers that take a shower semi-regularly...

I like CrystalSpace

[CrazyJim1]

CrystalSpace requires good C++ and 3d skills, but its a very nice open source 3d coding system.

Re:I like CrystalSpace

[xtracto]

I am currently making a 3D game in SDL and OpenGL. I was making the game from the ground up, when I thought of using a 3D/Game Engine.

I tried some of the free engines including CrystalSpace, unfortunately (at least, last time I checked) there ARE NOT precompiled libraries or binaries of that library. I tried compiling it but I really got pissed off after two hours of trying so I threw it up.

The problem with the Open Source engines (at least in my experience) is that they are not readily available, as a game programmer, I do not need/care to compile the library nor to modify it, I am completely happy with a .lib or .so and a bunch of .h files which I can compile and link in order to start to implement my idea right away.

Re:I like CrystalSpace

[vdboor]

CrystalSpace requires good C++ and 3d skills, but its a very nice open source 3d coding system.

Wasn't the review about small desktop-games, instead of going for the big projects with bigger risks they won't get anywhere?

It is squarely intended at the hobby coder who wants to work on what the book calls "desktop games" -- not the multi-million dollar multimedia productions that demand a new graphics card every half year, but the games that you play while thinking out a knotty problem or that have some educational value for your kids. The kind of project a single coder, or a small team can complete and maintain while still staying sane.

Does CrystalSpace support multiplayer networking already BTW?

Re:I like CrystalSpace

[Malawar]

Ogre3D is a very nice LGPL 3D Graphics library. It does have precompiled libraries for Windows available for download, but compiling from SVN is a snap as well. While it doesn't have the other parts of a game engine (sound, networking, physics, etc), there's always other libraries that work well with it, such as: The Open Dynamics Engine for physics, OpenAL for sound and SDL for crossplatform network and input. Ogre's visual quality can easily compete with a lot of top game engines today, as well.

Re:I like CrystalSpace

[Anonymous Coward]

hehe, compiling a "snap"? Ogre has way too many dependencies for that to be the case (last time I looked at it anyway)

Re:I like CrystalSpace

[JFitzsimmons]

There are several precompiled libraries (depending on compiler) for Ogre, at least for windows (since it is MUCH harder to build Ogre proper on windows than it is on linux). To be honest, I also did the source compile on windows, but mainly because I'm crazy.

Re:I like CrystalSpace

[Clay_Culver]

They offer precompiled binaries for windows compilers (including gcc, but you could also use the free Visual Studio compiler). For linux, most of the deps are things that are offered by your distribution. I think there was only one component I had to build from source (aside from ogre itself) under linux last time I put it on a SuSE machine. It's not *that* bad.

Re:I like CrystalSpace

[IceFox]

So rather then spending more then two hours getting the game engine to work you will spend a year or so making an engine?

Re:I like CrystalSpace

[Anonymous Coward]

Irrlicht is pretty nice too. It comes with binaries, and there are lots of support forums for it too ;) Its released under a zlib-ish license too which makes it even better

Re:I like CrystalSpace

[Reverend528]

there ARE NOT precompiled libraries or binaries of that library

Maybe you need a more Universal OS.

Linux Games (SDL, OpenGL)

[Zombie Ryushu]

A large amount of Linux Game programmers make incompotent descions.

Take Boson for example.

There is no reason why Boson should be tied to KDE the way it is.

Some game programs don't utilize automake or autoconf at all.

Another problem is that some Linux game Programmers program are Windows programs who put in a minimum effort nessessary to build a Linux version.

The fact is that we need people to work on better Linux games and Engine Source ports.

Re:Linux Games (SDL, OpenGL)

[alfs boner]

I think the problem is that an open source project has to be self starting to the point where it'll gain a critical mass of developers.

For an original game, that means you'll need a good idea (pretty rare in itself), a rudimentary (or better) engine -- that you'll have to code yourself, plus sufficiently well designed graphics and sound to get people interested.

That basically requires four separate skill sets, whereas writing a web server etc, needs at most two of those, and probably only one. And if you can't get your critical mass of developers, you're just another semi-abandoned sourceforge page.

Re:Linux Games (SDL, OpenGL)

[s16le]

open-source is completely viable for the game industry - in fact if the industry is to survive in the future beyond one or two massive 'mega-publishers' (like EA owning criterion & renderware etc), the rest of the industry is going to HAVE to shift to open-source to defend themselves against these massive companies.

much like how linux gained it's foot hold in the webserver & OS market. the game industry is just a bit further behind the curve.

how much longer will 'indies' (ie small non-publisher-affiliated dev houses like id) be able to compete against the mega dev studios like rockstar or EA? it's coming to the point where the return on investment is becoming too high, most companies simply can't even enter the market because of the cost of entry.

if you can suddenly shave off $250,000 + off of your startup costs (by using an open-source engine as opposed to licensing the tech), or more (as opposed to developing the tech from the ground up, which could cost millions), why wouldn't developers want to go the open-source route?

the main issue at this point is publisher resistance. publishers are the 'old school' business-mindset like the RIAA and the MPAA - they refuse to acknowledge that open-source exists and that it might be useful to their businesses.

in the game industry, it's all about the IP - if you own the IP then you can make money, whereas publishers look at open-source and are just scared away because of the simple words 'open source'. it implies to them that they don't control things...

It all comes down to the licenses and misconceptions about the requirements of those licenses.

GPL is the death of any game-related project for example. It is the kiss of death to a game library or toolset.

publishers have to know that they can close the source of the product, even for a short period around the release date (that crucial 3-5 months after release) so that they can make their money back...then once the game is out and 'old news' then they are more open to releasing code into the open-source field again.

Open source is slowly creeping into the industry, more from the toolset and libraries side of things, slowly sneaking in from the sidelines. Recent games like chrome used open-source physics engines (ODE), Id releases their old tech as open-source, but this doesn't really count because no one has ever used a gpl'd license and actually released a product with it afterwards.

Re:Linux Games (SDL, OpenGL)

[Anonymous Coward]

Another problem is that some Linux game Programmers program are Windows programs who put in a minimum effort nessessary to build a Linux version.

Hrm, could that be do to a lack of standards in linux graphics? Also there's no money involved as everyone in the linux space wants stuff for free or will be the first out to pirate it in the name of some sort of "freedom."

Re:Linux Games (SDL, OpenGL)

[alfs boner]

But I think the point of this is that it's not the tools that are the problem: there are great open-source engines out there that will improve slowly over time as with any lively project... it's the creation of a game itself (on a case-by-case basis) that isn't viable in a traditional open source environment. Rather than slowly chipping away at a project over a few months or years, you need to slog away intensely - and very likely in secret - so that your end result is worth playing.

I don't know that it's necessarily true, though. I'm starting to think that a "walled garden" approach might be best... keep particpation limited somewhat, and keep the product hidden from the public until it's done, and then release the source. Is there anything inherent in open source methodology that would make this impossible, or is it just that the current perception of open source doesn't involve walled gardens?

Re:Linux Games (SDL, OpenGL)

[xtracto]

I will tell you the main problem in a word: CONTENT.

For some strange reason, software developers enjoy giving away their work/time without expect anything in return, but please tell any decent designer, sound fx creator or graphics drawer to give away their time just "for fun" and you wont get really a lot.

In that way, open source will NEVER compete against the big studios. The only "hope" is to make people look at less "graphic intensive" but more "fun" and innovative games. With a bit of luck, Nintendo will aim that way, but I do not have much hope

Re:Linux Games (SDL, OpenGL)

[monopole]

Problem is, the megapublishers and their infrastructure are imploding, much the same way as hollywood. With the blockbuster/IP is everything mentality, the industry is rapidly pricing itself out of the business. After they implode, open source will look very nice.

Re:Linux Games (SDL, OpenGL)

[LocoMan]

I think it has some to do with the subjectivity in the artists side. Or at least that's how it seems to me (3D animator with basically no coding skills other than the ocassional script in maya).

Coding is a very creative process, however, most of the times the results can be masured objectively. If you're making a 3D engine, you can measure how many polygons per second it moves. If someone makes a change, you can measure if it's faster and/or slower, and exactly by how much.

The same doesn't happen that often in the art side. Let's just say I create the animation of a character swinging a sword. Then someone else comes and changes the animation and makes it completely different. Suposedly both are within the parameters of the game (how long it is, the starting and ending poses), how do you define which is better?. Maybe for the other guy his animation is a lot better than mine, but for me maybe mine was better and his hurts my work (to put it in a way). Most of the times there's just not a real measurement of quality when it comes to the art side.

This is one reason (IMHO) that the artists tend to be less of a group workers than coders. Usually in 3D animated series and movies, for example, you can have hundreds of animators working at the same time, but in most of the cases each scene is animated by a single animator, and if there are several, they don't overlap (one animator does one single character on the scene, or in the case where two animators work on the same character one will do the main animation and the other the secondary movement).

In the coding side it just seems to be "ok, here's what I did, let's fix it, or try to fix it"... in the art side it seems to be more of a "ok, here's what I did, tell me what's wrong but DON'T fix it, I'll fix it myself".

Or at least that's how it look from this side of the monitor.

Re:Linux Games (SDL, OpenGL)

[Anonymous Coward]

Problem is, the megapublishers and their infrastructure are imploding, much the same way as hollywood.

Hollywood is imploding? I would like to have that problem, they seem to be doing alright.

Re:Linux Games (SDL, OpenGL)

[miyako]

I have done both programming and 3D modeling/animation professionally. I still do 3D work and graphics design on the side, as well as contributing code to F/OSS applications. While I'm a decent programmer, I don't really have experience writing 3D engines or related code that would be useful to many open source games. Many times, if I come across a game that seems interesting and I would like to contribute, I offer to contribute artwork.
What I have found, and it is really a strange thing to me, but many projects simply do not want to accept contributions from artists. There have been a few projects that I've stepped into the mailing lists or IRC channels for and asked "hey, great game. I'm interested in contributing some artwork to the game, anyone have any ideas of things that might be particularly useful?" or simply looked at what was needed and gotten back "we don't need any more artwork/artists". A lot of times the art in these games is either bad, or a mixed bag of decent stuff and terrible stuff (not that no open source games have good artwork, but more that if a game has enough good artwork then I'm more inclined to offer to contribute to a project that seems like they could really use the contributions).
Another thing I've noticed is that one of the big goals of a lot of open source games is to be able to run on older hardware. This isn't necessarily a bad thing, but it does mean that it limits the quality of the artwork. Many commercial games are released when even a top-of-the-line gaming rig can barely get top performance, while many open source games tend to be written to run on any machine built in the last 5 or 6 years. I'm sure part of this is that not ever open source developer can afford a top of the line machine with two bleeding edge video cards (because buying one video card every 6 months for $500 wasn't draing PC gamers wallets enough apparently, they had to invent SLI) and a couple of gigs of ram.
What would be nice is some sort of site like sourceforge but for creative commons licensed artwork that open source games could make use of.

Re:Linux Games (SDL, OpenGL)

[omeomi]

but please tell any decent designer, sound fx creator or graphics drawer to give away their time just "for fun" and you wont get really a lot.

Actually, it's not at all uncommon for these folks to work on indie games for free, especially when they're just starting out...the game industry is generally pretty difficult to get into without having at least a few games under your belt, and one of the most popular ways to do that is to do work for free. Many of the people doing this are, in fact, quite talented, but have yet to really prove themselves.

Re:Linux Games (SDL, OpenGL)

[Excors]

one of the big goals of a lot of open source games is to be able to run on older hardware. This isn't necessarily a bad thing, but it does mean that it limits the quality of the artwork. Many commercial games are released when even a top-of-the-line gaming rig can barely get top performance, while many open source games tend to be written to run on any machine built in the last 5 or 6 years.

Five years ago saw the GeForce 3 (although admittedly as the high end, not "any machine"), which is perfectly capable of making good-looking games as long as you rely on decent art rather than just adding HDR and bloom and bump-mapping and specular highlights and hoping it'll look good - we've had some reasonable success using none of those features. Currently the only pixel shader in the game is for high-end water, and we have an equivalent effect for GF3/4s; pretty much everything else is just a plain texture map. You can even run modern games like Oblivion on a GeForce 3 and it looks good (though it doesn't run quite so smoothly).

It is a bit harder if you want to support the common integrated graphics chips with limited memory and processing power - but I'd tend to blame ugly games on bad art instead of a bad graphics engine. Anyone can download OGRE and set up a rendering system with modern features, but artists are much harder to find - contributions from people like you can make a big difference (at least when the programmers are happy to accept it)!

Re:Linux Games (SDL, OpenGL)

[grumbel]

### What I have found, and it is really a strange thing to me, but many projects simply do not want to accept contributions from artists.

I think the biggest problem isn't that they don't accept contributions from artists, but much more basic, most projects simply lack almost any kind of organisations. So nobody knows what needs to be done or when it should be done or even how. With engine coding that isn't to much of a problem, since everybody can just code a bit here and there and have his fun, maybe even producing something half usable in the end. But with games its pretty much catastrophic when nobody knows, not even the maintainer, what should be finished next and often not even what should be produced in the end, let alone things like style guides, specs about intended triangle count for and object, etc. So the thing isn't so much that they don't want to accept contributions, but simply that they can't, because they have no idea what to do with the contributions or which contributions are needed.

At least thats experince with doing graphics for OpenSource games.

### What would be nice is some sort of site like sourceforge but for creative commons licensed artwork that open source games could make use of.

Yes, such a thing could definitvly be usefull, while not necessary for direct in-game use, it can be quite helpfull to have some 3d models or drawings for inspiration or reference. I once started such a thing, but it never went very far:

http://clanlib.org/~grumbel/mediarepo/show.cgi?new s

Re:Linux Games (SDL, OpenGL)

[grumbel]

### how do you define which is better?

You look at them and if they both are good enough, you use them both in the game, more varity is a good thing after all. There are of course issues when an animation/model/texture doesn't fit the style of the game, but for such one simply needs a style-guide and or a lead artists doing most of the art for a project. This is really not so much different then with coding, especially with game coding, since there isn't any easy way to tell which thing is better either, especially when it comes to stuff that is gameplay relevant and not just polygon plotting. I might be able to messure the performance of a piece of code, but for most code speed is not really an issue, API elegance, easy to maintain it and such are often far more important and not really easy to messure either. Last not least most artwork and code will be something new, not an improvment to existing code, so you don't have anything to compare with to begin with.

### "ok, here's what I did, tell me what's wrong but DON'T fix it, I'll fix it myself".

This has not only something todo with artwork itself, but also with the fileformats in use, with code I can diff/patch, see the differences, compare and merge them. With an image/model I get two chunks of raw data, I can view them, but I can't merge them without lots of additional work, which makes collaboration a lot more difficult, since conflicts are much harder to resolve then with code.

Re:Linux Games (SDL, OpenGL)

[JFitzsimmons]

I'm working on a couple of doom3 mods right now which more or less agrees with GP and disagrees with Parent. They're both single-player "total conversions", which require a significant amount of work from volunteers, since none of the assets from the original game will be used in the final product. They both use the "Walled Garden" as GP puts it: developers and content creators are welcome to join the project after demonstrating sufficent skill and motive. However, the source, and the content isn't open outside of the occasional media release we make to let people following the mod know that we are in fact still alive. I know for sure that when the games reach their "when it is done" state, we will make a source release along with the normal release of the games. I can't say what will become of the media for the game, since I'm not an artist. A condition of both projects is that artists have to basically "surrender" their rights to their work to the project, although some of us have made contracts that the game cannot go commercial without renegotiating the agreement.

However, the point I'm trying to make is that it seems some artists are in fact willing to donate their time, especially if they're trying to beef up a portfolio. Interestingly enough, both of the projects have a surplus of willing artists and a distinct lack of coders. [For interested coders (or artists I guess), see the end of this post for shameless plug]. Walled Garden doesn't work perfectly though, obviously. A huge downside to it is the sheer amount of time it takes to get anything done. Since everyone is working on a volunteer basis contributions trickle in slowly. A second problem is member turnover. Often times members will leave the team or simply go without communication for months on end, citing lack of progress, personal reasons, education, etc. It is very hard to keep volunteers motivated, especially on a project which progresses so slowly. OTOH, a leader may decide to keep a very small team of highly-dedicated volunteers and avoid the turnover problem, but then introduces that things get done that much slower since there are less people and the process is even more closed. Interestingly enough, both the projects I'm working on exibit each of these characteristics: one has the Cathedral-Garden and the other the Bazaar-Garden.

In this way I agree with the GP in that the so-called Walled Garden does work as a possible open source game development method. However, it does not work well. I'm not sure if there's a better organization method, but if anyone thinks of something I'd certainly like to know about it.

I agree and disagree with the parent. He claims that "In that way, open source will NEVER compete against the big studios. The only "hope" is to make people look at less "graphic intensive" but more "fun" and innovative games." I agree that open source games will not compete with game studios - in terms of timeline. I strongly believe that a group of skilled and motivated volunteers create a game which is just as more "innovative" and fun as any studio, but it will likely take them a significantly longer amount of time. In this respect I disagree with the parent. High quaility models, animations, textures, sounds, music, code, and others are not out of reach of a volunteer project, they just take longer to create, for the simple and obvious fact that people aren't being paid to do it.

If you're wondering why a single coder is working on two projects at the same time, the reason is simple: I noticed that both projects had a reasonable amount of overlap and decided to join both teams and develop the requirements of both games that were the same.

The two projects are:

• Sapphire Scar - Futuristic shooter loosely based on game concepts from FPS/RPGs like Deus Ex or System Shock
• Ground Zero - Post Apoc Timepunk third-person loosely turn based game based on some concep

Re:Linux Games (SDL, OpenGL)

[donscarletti]

Hrm, could that be do to a lack of standards in linux graphics?

What, like OpenGL?

Also there's no money involved as everyone in the linux space wants stuff for free or will be the first out to pirate it in the name of some sort of "freedom."

I've got a legit copy of UT2004 installed on my linux partition as well as most of the quake series, in fact I've never pirated a linux game, though I make windows game piracy an almost daily habit.

Re:Linux Games (SDL, OpenGL)

[lon3st4r]

You've hit the nail right in the head dude! Totally agree with you. CONTENT is the factor that is missing. When I wanted to build a game, all i cared about was building up a good 3D graphics engine. That was the challenge for me, and is for most programmers. Once a good engine is made, I lost interest. I doesn't feel like a challenge to throw content in it!

Even today, there are so many good 3d game engines- but very few games. Probably because people don't find it appealing enough to make the content.

* lon3st4r *

Re:Linux Games (SDL, OpenGL)

[Mant]

Just look at all the free mods for popular games and you will see plenty of people are prepared to give free content, including modeling, skinning and animation.

The problem is, I think, people who do content want to see it in the game. You can get them to do it for a mod for an existing and popular game, but its going to be hard to get anyone to add content to you half complete, always being changed open source engine.

An engine without content though isn't going to interest anyone, so it's something of a catch-22.

Re:Linux Games (SDL, OpenGL)

[neersign]

Just look at all the free mods for popular games and you will see plenty of people are prepared to give free content, including modeling, skinning and animation.

exactly. I think it's safe to say that Counter-Strike is one of the most, if not the most, popular mods ever made. It used to be 100% free, tho I'm not sure if it was open source. At any rate, CS never had a problem with people creating new player models, new textures, and new maps...all for free. I think it's just a matter of creating a game (or application) that grabs a large audience and then random people will want to start helping out.

Re:Linux Games (SDL, OpenGL)

[duffolonious]

"What would be nice is some sort of site like sourceforge but for creative commons licensed artwork that open source games could make use of."

This does exist: Worldforge - although the site appears to be down at the moment (but this on is up: http://purple.worldforge.org/ - svn repository has a number of models in different formats).

As for you main issue of offering to contribute and then getting rejected - for no good reason, well - please contact us: http://fearann.com/ (on irc -freenode- #fearann), we'll be glad to hear from you.

And your art looks good.

Re:Linux Games (SDL, OpenGL)

[NetRAVEN5000]

In general, you're right - open-source games usually don't look very pretty. They're mainly a "programmer's playground" and they don't care about looking pretty.

However, there are quite a few that are at least decent, and even some that are pretty high-quality (look at Glest and Tremulous, they've got pretty good graphics).

Some artists DO, in fact, take part in these projects. Maybe just for fun, but other times to build up their resume and show people what they can do and how good they are.

Reason?

[xtracto]

Well, I understand this book must be an "introduction" but, I am sure there are several better books on OpenGL, personally I have read the "Beggining OpenGL game programming [Premmier Press]" which I think is quite a nice book if you are new to OpenGL.

I mean, besides of the OpenGL-QT bindings you will have to do (mostly just to create a GL window to render if it is similar to SDL) there is nothing magical in the GL-QT combination. I would recommend to get a nice KDE book AND a nice OpenGL book also, as the author said, besides the blue and red books (which I personally use just for reference . Another great book for OpenGl is the OpenGL Super Bible [Sams], and you can find a bunch of KDE books including the KDE Bible.

Of course if you want to go the "student" way, there is, as I have found, PLENTY of information on all of these topics. Just get into Gamedev.net, the Nehes tutorials are one of the best in my opinion.

Now, if looking for game development I would personally incline to SDL, which will provide you with almost everything you need like input support (joystick, mouse, etc), audio and also OpenGL.

As a last comment, could I ask the SlashDot editors do to their job and check (at least) the book reviews grammar/spelling. My native tongue is not English but it kind of hurted my eyes to read the review (which was quite nice anyway).

Re:Reason?

[Chrondeath]

Of course if you want to go the "student" way, there is, as I have found, PLENTY of information on all of these topics. Just get into Gamedev.net, the Nehes tutorials are one of the best in my opinion.

Seconded; I found these more useful than the textbooks or lectures during my computer graphics courses, at least for the OpenGL stuff.

Re:Reason?

[ScottyH]

You're commenting on grammar and spelling yet you use the word "hurted" (not a word) in the same sentence as the critique.

Re:Reason?

[xtracto]

Touché, but then again, in that same sentence I said:
My native tongue is not English but it kind of hurted my eyes to read the review (which was quite nice anyway).

And my commen was not [supposed to be] proof read before publishing in the front page of a very important news site.

Me comprendes?

Re:Reason?

[Anonymous Coward]

... the grammar in the review looks excellent to me. What's the problem?

Re:Reason?

[DanTheLewis]

I realize that you, a lowly commenter on Slashdot, feel less responsibility to grammar than a front page book reviewer on Slashdot. However, setting yourself up as an arbiter of good and bad grammar while not possessing said grammar yourself is asinine. Here in English, we have a few aphorisms you should study:

Don't throw stones in glass houses.
Pot. Kettle. Black.
Those who can, do; those who can't, teach.

And here's the classic treatment from Jesus:
Do not judge, or you too will be judged. For in the same way you judge others, you will be judged, and with the measure you use, it will be measured to you.

Why do you look at the speck of sawdust in your brother's eye and pay no attention to the plank in your own eye? How can you say to your brother, 'Let me take the speck out of your eye,' when all the time there is a plank in your own eye? You hypocrite, first take the plank out of your own eye, and then you will see clearly to remove the speck from your brother's eye.

Re:Reason?

[Anonymous Coward]

Actually, the correct phrase is:
Those who can, do. Those who can't, get MBAs.

Small is good

[Excors]

It is squarely intended at the hobby coder who wants to work on what the book calls "desktop games" -- not the multi-million dollar multimedia productions that demand a new graphics card every half year, but the games that you play while thinking out a knotty problem or that have some educational value for your kids. The kind of project a single coder, or a small team can complete and maintain while still staying sane.

That seems like pretty sensible advice - the phrase "game development" immediately brings to mind the big successful commercial games, but that's not the area in which open source seems capable of competing, and it is much more productive to realise that simple games can be more worthwhile to make.

As for why open source game development has problems when trying to emulate commercial game development, there was some discussion a while back; shamelessly reposting my comment from there:

there are hundreds or thousands of GPL game projects on SourceForge, and most of them are dead

Perhaps the open source idea of havings thousands of eyes, and encouraging anybody to jump in and out of the code making changes, is incompatible with the process of creating a game?

I don't know of any open source applications that are "finished", or even try to be - their early releases are at least slightly useful, and they are always releasing new versions and adding new features. And there always are new features that can be added, each of which will improve the application, so people can work on their favourite features and the project will continue on its path of continual improvement.

Traditional games don't work like that. They're barely recognisable as a game for a large part of their development time - during that time, there has to be a vision for the finished product, and everybody on the project has to work towards that distant vision. It'll be years before anybody can really see the results of their work. That's not very enticing for somebody who can only be certain of spare time for the next couple of months - they would rather work on something much smaller, like a mod or a tech demo, just to get visible results.

And unlike most open source projects, people can't just add features they think are cool and useful - everything has to fit into the overall design of the game. You cannot simply add features without considering the consequences on the whole of the rest of the game - and you can't consider all the consequences unless you've already spent months working on the game and getting a feel for how everything interacts.

For professional game development companies, they get people working towards the vision by simply paying them to do so. That won't work for community-based open source projects, so they need some other way of doing it.

But I don't know what way that would be. I've been working on a "freeware, hobbyist" game instead (0 A.D.), which is a full 3D RTS with its own game engine, comparable in scope to commercial games (or at least to those of a few years ago) - it's making use of various open source libraries (SpiderMonkey, Vorbis, Xerces, etc), but is not itself open source. And I think that's a factor in how it has kept going for so long: 'membership' is still open to anyone who has the right abilities and dedication, but that means there is a strong concept of membership - we're part of a team and feel some responsibility towards making progress, following the design, and seeing the game through until it's finished. I don't think that feeling would be as strong if we were primarily a loose community of people who are just poking around the code with no commitment, which is how I perceive most open source projects.

And programmers are only a small part of game

Re:Small is good

[xtracto]

there are hundreds or thousands of GPL game projects on SourceForge, and most of them are dead
There are 22141 games listed in SourceForge.
Of those, 575 (2.59%) are INACTIVE,
7637(34.5%) are in PLANNING.
6022(27.1%) are in PRE-ALPHA.
4302(19.43%) are in ALPHA
4453(20.1%) are in BETA
3592(16.2%) are in PRODUCTION-STABLE
460 (2.0%) are in MATURE.

Which does not add to 100% because some games have more than two states, however it seems there is a really high trend towards "Unfinished" games. Or as I read from some game developing book, EVERYBODY can have a good game idea, but it takes some hard effort to actually implement it, and it takes really hard nuts to finish it.

And as you said, a game is in fact FINISHED, not like said, OpenOffice, which will never be "finished", with games you can only make bugfixes, but a new game version is something completely different.

Re:Small is good

[cptrootbeer]

Very informative. Please mode parent up. The two styles of development are quite different exactly as you said. I won't go into more details since I think you hit just about everything.

Re:Small is good

[Jerf]

Of the 153,183 projects on Sourceforge as of this writing, 40,823 (26.6%) are "beta", 34,131 (22.3%) are "production", and 2,936 (1.9%) are "mature".

Forgive me for not walking through the rest, but games aren't *that* far away from the average; other ways of slicing the data set would show above-average completion.

My point is that in your phrase:

EVERYBODY can have a good game idea, but it takes some hard effort to actually implement it, and it takes really hard nuts to finish it.

the word "game" is extraneous.

Re:Small is good

[andphi]

The numbers are quite disheartening. In many ways, in fact. What frustrates me is how many one-man, burst-of-effort projects one sees. One wonders how many good ideas died for lack of re-inforcing enthusiasms.

There, are, however, complications to a stastical analysis based on one development site - even a high-profile site like sourceforge. Some projects exist in many places at once - sourceforge, freshmeat, happypenguin, savannah.nongnu.org, linuxgames, berlios, web presence, etc. According to Sourceforge, my project (Adonthell) hasn't updated a file since 2000 - very inactive, and hasn't posted news since 2002-09-30. It has no mailing lists. It's Inactive in Alpha.

According to happypenguin, we're only at 0.3.3. We've released 0.3.4 and are moving on to 0.4, but without specific feature updates, there's nothing to post. Berlios has even less, since we use it primarly as a hosting space for our Wiki and the API documentation.

But my project doesn't actually -use- sourceforge primarily, or the others I mentioned. We use savannah and berlios. All our lists are hosted on savannah, as well as the CVS. The CVS gets commits on an average of twice a week, though that's not a steady rate. So, all told, it's active, if slow, and exists somewhere between Alpha and Beta - we haven't actually declared a Beta-state effort yet. Berlios' main function, aside from API, is to host the Wiki, which we use for a lot of content development and storage.

Getting back to the original point - that of re-inforcing enthusiams - my project started with three people, not one, and had a previous project to work from. I just wish more projects started that way.

Re:Small is good

[civilizedINTENSITY]

If, as you quote,

And as you said, a game is in fact FINISHED, not like said, OpenOffice, which will never be "finished", with games you can only make bugfixes, but a new game version is something completely different.

then why is that the distribution is essentially the same for games as it is for everything else? Perhaps games do evolve? What would be interesting is to see how this distribution has changed over time...

Re:Small is good

[Anonymous Coward]

Well, mmorpgs do evolve...

Re:Small is good

[Anonymous Coward]

You are forgetting that majority of closed source games that are sold in the shops are usually in the alpha of beta stage if you measure them with the same style you would measure open source projects (or as the os developers are measuring their projects). The difference between open source beta and closed source beta is quite huge.

Re:Small is good

[Lodragandraoidh]

Most MMO games (including large scale FPSs - such as WWIIonline/Battlefield Europe) evolve, and I would argue that is the future for multiplayer games of all types.

As new content is developed or old content is revamped, it is added to the mix on a continuous basis.

In fact, for open source games a pay-to-play model would probably work better than attempting to make a living on shrink-wrapped one-offs.

Actually, it could be argued that the idea of 'shrink-wrapped' software in general is on the way out as the new business models shake out. However, the profit margins will be much less than they are today because people aren't going to pay $50 to download a game, but they will pay $5 on a recurring basis for an MMO game (that in 10 months will make your original projection of $50 - and then some in the months and years that follow).

3d engine resources

[Paralizer]

On the topic of game development and OpenGL, can anyone recommend any books/websites/resources good for building OpenGL rendering engines from scratch?

I've recently took an intro course to GL and for a project written an MD3 (quake3 mesh animated model) renderer in Qt (bindings are easy and well documented with "Qt Assistant"). I've wanted to increase my knowledge of GL over the summer by building a relatively primitive rendering engine in C++, and perhaps evolving it over the course of the next few years. I'm considering starting with an importer for Quake3 maps (BSP trees). Ultimately I'd like to build something similar to (of course I'm sure much less advanced) that of the Irrlicht engine.

I've read through the Red Book and have already bought the Superbible. Has anyone any other resources which might help me design and build such a system?

Re:3d engine resources

[nexusone]

some good general sites:
http://www.xmission.com/~nate/tutors.html basic's
http://www.gamedev.net/ Game programming
http://nehe.gamedev.net/ OpenGL programming/game site

Re:3d engine resources

[Faraday's Sloth]

Well, this comment is kinda lateral (as in 'not related to opengl and games'), but I think you'd appreciate flipping through a few basic computer graphics books and related maths --- after all, opengl is just an implementation of the few of the most basic concepts and the red&blue books are mostly 'just' technical reference manuals. getting a handle of the basic concepts also probably clarifies what you actually want to do with the code.

Graphics:

watt&watt: Advanced Animation and Rendering Techniques - not a very recent book but the material is still relevant and the presentation of different concepts is relly good
Hearn & Baker: Computer graphics (c or opengl version depending on your preferences). Basic computer graphics. Pretty good. The opengl version eschews some of the more basic code samples from the c version, which is a bit shame really.
Moller & Haines: Real-Time Rendering - relevant for real time applications and contains great references to computer graphics resources in general

Geometry & linear algebra:
Philip Schneider & David Eberly: geometric tools for computer graphics (contains recipes for eg. checking collisions, raytracing, clipping...). Might be not best book of this type(?) but it's ok.

Freely available online material:
comp.graphics.algorithm faq:
http://www.faqs.org/faqs/graphics/algorithms-faq/

The physical modeling course of David Baraff available online is quite nice:
http://www.cs.cmu.edu/~baraff/sigcourse/index.html

Graphics gem's codes:

http://www.acm.org/pubs/tog/GraphicsGems/

The book's themselves are also excllent recipe repositories, but really useful only after you know the basic concepts from basic textbooks etc. ...and, if you have the access then the http://portal.acm.org/ stuff is really good. (search for 'siggraph "course notes" for starters') You can find details to most of the stuff Pixar, Alias etc. do from there...

If you have the time and resouces, then the Moller & Haines book is a decent roadmap to the field ("Oh, what's this...let's see the referred book/article has to say.. oh, that's interesting!") from the grass roots of z-buffers up to modern fps engine concepts.

Re:3d engine resources

[duckpoopy]

Please not that it takes more than graphics to make a game. After you learn graphics and OpenGL, you will need to learn some datastructures to organize all of your data, AI, Physics simulation, collision detection, audio, UI. Then you will also need art work. So even if you have a great idea and know open gl you are only 5% of the way (at most) toward making a game.

SDL rocks for cross platform game developement

[Anonymous Coward]

We managed to effectively rewrite xpilot in SDL/OpenGL and porting across platforms then became trivial.

XPilotNG (5 stars on Tux games)

http://sourceforge.net/project/showfiles.php?group _id=13411&package_id=15770

Works on just about everything , but there are packages for Linux / Windows and Mac OSX.

ISBN is incorrect

[Anonymous Coward]

The ISBN mentioned in the article (1-58450-406-4) is incorrect. It identifies the book "GNU/Linux Application Programming" by M. Tim Jones. The correct ISBN is 1584504064.

Re:ISBN is incorrect

[Anonymous Coward]

The two ISBNs you mention are identical.

Re:ISBN is incorrect

[Aladrin]

Eh, those are the same number, and the same as the number in the article. And they all identify the correct book.

1584503718 is "GNU/Linux Application Programming" by M. Tim Jones.

If you're considering writing an OSS game

[Trogre]

...then please please PLEASE first take a look at the hundreds of other OSS games out there and consider building on (read: contributing to) one of those.

It's sad looking at the large number of games that have shown promise but for one reason or another have been abandoned or development has slowed or forked. We really don't need another nethack clone, MMORPG or 3D engine. We have all of those in abundance. What we need now is to build on these, both with shader code and good content. It's often easy to tell the OSS games from the commercial ones from a single screenshot because the commercial studios have good artists and the OSS devs don't (I am being overly broad here and there are exceptions such as Frozen Bubble, but these are rare).

One not-quite example: I am a fan of the excellent OSS flight simulator FlightGear. The latest version 0.9.10 has some nice ground textures and real-world data that makes for a truly beautiful view when flying at 30,000 feet. But the planes themselves look like crap. The model detail and decals are average but what really lets it down is the way the plane interacts with light. The engine is badly need of work to take advantage of OpenGL shaders. And the sky looks completely wrong. As you ascend beyond 50,000 feet you should see the sky darken to a very deep blue with some stars becoming visible but the engine doesn't allow for this (you're basically inside a big solid-blue sphere). Not vital properties for learning to fly a 747 I know, but still important polish for a realistic flying experience.

If you have a truly original idea then by all means start from scratch if nothing existing fits the bill, but don't just fire up a text editor and start another MMORPG from scratch. The OSS gaming community don't need it.

Re:If you're considering writing an OSS game

[Aladrin]

"Making a game" isn't about just writing some code and making a game work. It's about bringing your idea to life. Most people don't have enough drive/need to succeed at either (I'm in that category so far, sadly), but they are more likely to have enough drive to put behind their own vision.

Re:If you're considering writing an OSS game

[KingPrad]

I didn't know about this site at all. It has a lot of neat things - I'm sure I can finally find an OSS project that interests me. Thanks for the link and writeup.

Anyone have a preferrred isometric game engine?

[Wabbit Wabbit]

Anyone here have experience with a good isometric game engine in C, C++ or Java on Linux?

I'm not into sidescrollers or FPS, but I love isometric RPG and adventure games (even wrote one back in the day, and always itching to do so again).

Re:Anyone have a preferrred isometric game engine?

[ikekrull]

I have written a mostly complete isometric adventure game framework, I have yet to release any actual games, due to the lack of anything but a vague idea of the story i want, and amount of work needed to create the graphics, but i have a decent renderer, lua scripting, sound and a pretty functional editor for the levels.

http://marchingcubes.com/games.html

A lot of unpolished graphics on there, but the chess shot is kind of more where i want to go graphics-wise (i'm also doing a battle-chess type remake).

I'm undecided on licensing (e.g. whether/which parts to GPL etc.), and i'm not sure what my plans really are - it has been a totally solo project up till this point, and has been fun and very educational. However, if it looks like something you would be interested in collaborating on, or using to run a parallel project, get in touch via email (address on site.)

Re:Anyone have a preferrred isometric game engine?

[Xavier]

Pretty !

While we're making suggestions

[linvir]

If your game depends on a load of exotic libraries, then you should jolly well provide them in their correct versions below the game itself on the downloads page.

Re:While we're making suggestions

[Trogre]

hear hear

ugh. another story promoting dual license software

[Anonymous Coward]

Please don't support the dual license nightmare :

http://www.galatea.com/economics.html

A better one is Programming Linux Games, John Hall

[NRAdude]

The Book is published by No Starch Press, and is available from them for USD ~39 or one can be purchased at the bargain bin for USD ~5 or from eBay for USD 0.99. Covers all topics from modern Video and Sound and Network libraries in application development, and applied to entertainment purposes (which we all know is just a bend from business programming).

The author died recently (9th Month of 2005), and his page is still heldhttp://overcode.yak.net/. To summarize his death, a new and unusual Mole formed on his shoulder and within a Year it spread cancer throughout his body and lymphnodes. He was dead in a Year! He was a great man that I participated with in the forums at LINUXGAMES.COM. His book is a good reference, but is since depricated by the slowling changing APIs. John is an ex-employee of when LOKI was in business.

Those doctors made his last Year of life a living hell with all the medication they gave him. Remember folks: Vitamin-C suffocates cancer; therefore, avoid the consumption foods and drinks known to deplete Vitam-C such as Alcohol-tainted water and animal-flesh and most medication (like Aspirin).

I'm really torn on this

[Weaselmancer]

It's clearly a Slashvertisement. But it teaches people how to contribute to open source projects.

Slashdot, help! How do I feel about this?

Re:I'm really torn on this

[Eideewt]

I'm afraid you will have to submit an "Ask Slashdot" before I can answer this.

Re:I'm really torn on this

[ZachPruckowski]

It's a book review. Obviously it's talking about a specific book. And an interesting one at that. And encouraging OSS games. So don't fret about it. If you think book reviews are slashvertisements, then don't look at any of them.

Re:I'm really torn on this

[msouth]

I think the GP was joking, but supposing we take the first part about it being obvious that this is a Slashvertisement seriously (and that is, I agree, ambiguous), we can go to the link that the guy provided to find that there is, indeed, a person by that name listed on koffice.org as maintainer of Krita, and he is not one of the authors of the book. So if GP wants to come back with some conspiracy theory about how the authors are in it with the Krita guy and he's willing to risk his OSS cred on the cut he would get off a deal with the book's authors, we're all ears.

Otherwise, the fact that it sounds like a Slashvertisement would more appropriately be viewed as evidence that either (a) the book is so good, merely describing it accurately sounds like an advertisement, (b) the Krita maintainer was so in need of this exact book that merely describing his experience accurately makes it sound like a Slashvertisement or (c) everything that has happened so far on this is a highly improbable result of gamma radiation-induced errors in various routers and computers throughout the world.

Pretty sure it's (c).

Re:I'm really torn on this

[Weaselmancer]

I think the GP was joking

Yeah, I was just kidding. I just thought it was kind of funny that the main page had a pretty clear advertisement on it, which a lot of slashdotters dislike. But the product was open-source friendly. Seemed like a goofy kind of a quandary to me. Sort of like watching a lawyer go off a cliff - but in your car.

Stop Making Engines, Start Making Content

[QuantumG]

I know what you're going to say, you're a programmer, you can't make content. Lies! No, I'm not seriously suggesting you break out Blender or even 3d Studio. What I'm suggesting is that you, as a programmer, develop new and exciting tools for content creations. For example, how many open source tree generators are there available that are suitable for use with open source graphics engines? Zilch. Another example, can you write an algorithm that can turn a description of an animal's skeleton and how much weight there is on various points of that skeleton into a walking animation? How about a running animation? How about fighting animations? Can you write an algorithm that turns that same input into a fleshed out 3d model? You can? Great, we're half way to making all the content we could ever want.

"Programmer art" should not be a derogatory term for content whipped up by non-professionals.

Re:Stop Making Engines, Start Making Content

[Futaris]

Agreed... More Opensource Game Tools are needed.

Re:Stop Making Engines, Start Making Content

[Rycross]

So you're suggesting that, when a programmer is faced with the problem of getting content created for his game, he should stop making games and make tools? Most people who create games do so because they want to make a game, not because they want to make tools.

Re:Stop Making Engines, Start Making Content

[grumbel]

ACK, or even if people do work on engines, don't just concentrate on the engine itself, but also on the tools surrounding the engine, nothing sucks more to have a shiny open source engine, but then no exporter available to export some Blender model into the engine.

Re:Stop Making Engines, Start Making Content

[grumbel]

Creating tools is half the work that goes into creating a game. You can't expect people to create levels, if there isn't a level editor available and neither can you expect good 3d models, if the most common modelers aren't supported due to the lack of export/converter scripts. Last not least many things simply are done better in code then in content, a physics engine will make realistic behaviour of the environment much easier then trying to fake it via hand animated stuff, caustics or water in general are easy to generate by algorithm, but hard if you try to hand draw them, etc.

Just because one is able to slam together a bit of content to test an engine, doesn't mean that the engine is good enough to produce a full game if there aren't any good tools around to work with.

Re:Stop Making Engines, Start Making Content

[QuantumG]

You make good points. It's the "done better in code" aspect that I was pushing. So many things are done by the artists today simply because that's how they were done 10 years ago. Hopefully that will change in the future and we'll see procedurally generated characters, animations and whole environments a lot more often.

Re:Stop Making Engines, Start Making Content

[Anonymous Coward]

"You can?" -- let me finish: "You can, and at the same time, can You resist to SELL it for MONEY to the BIG guys?" If so, you're the man.

Some Open Source Games

[peterfa]

I know this isn't quiet on topic... but I thought it would be interesting anyways:

Some Open Source Games

1. Lincity-NG
2. Globulations 2
3. Abuse-SDL
4. The Battle for Wesnoth
5. Solar Wolf
6. Boson
7. FreeCiv

Re:Some Open Source Games

[Eideewt]

A few more for FPS lovers: Warsow Cube and its successor: Sauerbraten Of the three, Warsow is my favorite.

Re:Some Open Source Games

[Anonymous Coward]

For those who love RTS and TA

TA Spring

http://taspring.clan-sy.com/

It even runs on Linux (under wine - they are working on a port though...)

What's the difference?

[Corngood]

If you are talking about programming, it's all tools. A game engine is just as much a tool as photoshop, it just fits in a different spot in the pipeline.

I like to keep the actual software the player uses (the engine) absolutely as compact as possible, which means I spend a lot of time writing software that gets used in production only. For example: our tool chain supports all kinds of image formats for asset creation, but the data actually used by the engine is always in platform specific formats, and the engine never needs to support anything else.

It's pretty much common sense to do as much as possible offline, so I think you should avoid drawing an arbitrary line between 'tools' and 'game', and just enjoy doing any work that contributes to the end product.

Step 1

[Anonymous Coward]

Pick sensible project names that give at least a slight clue as to what the application does.

Re:Step 1

[Makarakalax]

What like Zuma? Or Half-Life? Or Powerpoint?

You naming-elitists are all fucking idiots.

Clean room programs vs. music

[tepples]

Finally, if you reverse engineer something so precisely that your reversed implementation appears to be a duplicate of the original, then you may be accused of copying, which could land you in court. The notion of "clean room" reverse engineering was invented to ensure that the copyright owner had no prayer of claiming that the code was copied -- not because clean room reverse engineering is actually necessary, but because it's safer than the alternative.

That's fine and dandy for computer programs. But an open source computer game consists of more than a computer program; it also contains graphics and music. If I am composing the soundtrack for an open source computer game, how can I make sure that I do not inadvertently copy from an existing copyrighted musical work? What is the equivalent to "clean room reverse engineering" for open source computer game soundtracks and other music?

Re:Clean room programs vs. music

[swillden]

What is the equivalent to "clean room reverse engineering" for open source computer game soundtracks and other music?

Good question. That seems like a common problem for music composition of any sort.

Finally!....

[Tablizer]

....we can have it reward us with porn if we blow up a 3-eyed-monster.

How? I have one word for you.

[Blaede]

Volume.

Hahahahaha!

[Dis*abstraction]

...the megapublishers and their infrastructure are imploding, much the same way as hollywood.

Only on Slashdot.

Or in Pravda. Or from the mouth of our president when he insists the "insurgency" is collapsing from within.

Please get a clue.

Re:Hahahahaha!

[NetRAVEN5000]

Yeah, not like movie sales are down, or all the movies this year sucked, or anything like that. No rip-offs or copy-offs or anything like that. King Kong was a great movie, and GTA San Andreas was TOTALLY different from Vice City.

If you're considering writing an OSS game ...

[Thomas Mertes]

... you should consider to improve/finish an existing game.

IMHO, the cooperation between game developers is less effective than the cooperation between other developers. Additionally there is a non-OSS scene which trys to develop games. I have seen a lot of (non commercial) game projects which try to stay proprietory (and stall with good intermediate results without releasing the source).

Writing games is not my main focus, but as a side effect (writing test programs) I have created some games: Panic, Shisen, Memory, Tetris, Sudoku, Startrek, Hamurabi, Wumpus and more.

Greetings Thomas Mertes

Homepage: http://seed7.sourceforge.net/
Project page: http://sourceforge.net/projects/seed7

So What?

[xtracto]

To be honest, I also did the source compile on windows, but mainly because I'm crazy.

So what?, my dick is bigger than yours.

(note: the previous comment meant to be a joke...)

Re:So What?

[WilliamSChips]

Not only is my dick bigger, I also compile all my software!

Try looking at "Battle for Wesnoth"

[Mathinker]

You might start with www.wesnoth.org : "The Battle for Wesnoth"...

Who knows, maybe you won't have to write any code!

Why should games be "finished"?

[babbling]

Why should games ever become "finished"? If there is a first-person or platform game, can't additional levels always be added to it? Can't new, exciting enemies and weapons also be added in newer versions? Can't the graphics get better and better, as newer hardware comes out?

The only reason why games are ever "finished" is because proprietary software companies want to put them into a box and release them, but even in the proprietary games industry, you still see companies releasing mission packs, which are essentially just version updates (new levels, new monsters, maybe some new gameplay, etc) for the original game.

The time for free culture is coming, because a lot of the software necessary for digital freedom has been created. It's now time to start thinking about free culture, which includes games, movies, music, comics, novels, artwork, and probably other things that don't come to my mind at the moment.

Re:Why should games be "finished"?

[WizMaster]

I don't know about you, but I like "finished" games. Granted, MMORPGs go on and on and on but not every game genre should be like that. Your statement is flawed in that it only works for "expansion packs" and "updates". For example, WarCraft 3 (and expansion). What about the next iteration? Should WoW use the WC3 engine? Should Doom 3 use the original Doom engine? There is a difference between adding levels and such and using new technology. Where do we draw the line? Changing the engine all of a sudden can prevent some players from playing the "update" (drastic change in tech). Storyline-wise, it's done. Sure, more can be added but it's not necessary (example, Zelda). If the game is an ever changing thing, your method works. Otherwise, "blocks" work better. Not saying that the blocks couldn't be improved upon, but the game devs need to move on.

Small to medium games

[VincenzoRomano]

That means little or no interest from gamers. That could also be translated as "little o no money" as well.

Re:A better one is Programming Linux Games, John H

[Anonymous Coward]

> Remember folks: Vitamin-C suffocates cancer

Capitalizing on a man's death to spread your crank message. How nice.

Tools and Freedom to Express Content

[Bombula]

I'm sure I'll get busted up for posting this as I have in the past, but as a non-programming person I hope that one day there will be software tools available, either for purchase or for free, that facilitate the straightforward creation of games so that the medium becomes more accessible to idiots/illiterates like myself.

Before you start calling me a lazy a-hole, take the analogy of the GUI. GUIs are what made computers of ANY kind a tool usable by anyone. Prior to GUI, idiots like me struggled with command-line interfaces, and creating something like King's Quest was completely beyond imagining. Obviously you can argue that it takes some artistry out of the equation, and that's valid, but the tradeoff of accessibility has a huge upside to it. It's like painting. A few centuries ago if you wanted to paint at all you had to make your own paints, canvas, brushes, frames, thinners - everything. I happen to know how to do all those things, but far more often I buy ready-made tools for the task so I can devote as much of my (little) free time to the creative expression of painting as possible. Obviously painting is a lot more accessible to people now than it was 500 years ago.

Fast-forward to today, and I like to think we're seeing the beginning of a similar development stage for gaming. Today, many of the most popular games have cutting-edge technology - that is usually a big part of their appeal: better graphics. But we may one day hit the wall of photorealism with graphics, just as we've hit a wall with 7-channel surround sound: when new games come out now, they do not ALL have unique proprietary audio engines - a musician records the music and sounds, and they simply get dropped into wherever they need to go.

Maybe one day it will be the same for graphics, networking, and other code. Maybe one day there will be engines and editors freely available that will let anyone sit down and just get creative, without having to be a programmer in order to use the tools needed to express that creativity.

For me, I see this as a philosophy underlying ALL tools: ultimately, a tool should be an effortless extension of human will, no different than your arms or legs or fingers and toes. Tools that unleash the human imagination with the least possible resistance are, in my opinion, an ideal towards which we should strive. Indeed we are striving towards that, even if it is not always consciously. Again, the personal computer - thanks to GUIs - is the best example I can think of.

To get back to a more relevant example, I used the mission editor of Operation Flashpoint several years ago, which is a GUI. To get things to actually work sometimes required editing the scripts by hand, but for the most part it worked really well. Since then I've often wondered how long it would be before we got to the point of having not just a mission editor for one game, but a game editor. Obviously the progression of technology is the wrench in the works, as I mentioned, which is why "Shoot-Em-Up Construction Kit" for the C64 was short-lived. But the idea was there. Maybe when we get to photo-realistic graphics just as we've long since gotten to totally 'realistic' sound, these sorts of toolkits will finally emerge - and maybe even open source and free for everyone.

Sam's OpenGL Super Bible

[Combatjuan]

I just wanted to throw in a quick voucher for 'Sam's OpenGL SuperBible' as I picked it up this last weekend (3 days at the inlaws (-8). It's excellent. Being a 4-5 kilo book, it has both breadth and depth on the subject of OpenGL. As a math person, I wish that it touched a bit more on the linear algebra side of things but the fact that it keeps things within the mathematical grasp of about any reader while still being useful is probably a better decistion.

And while I'm posting (this doesn't happen often), I'd like to throw my two cents into the fountain of this Indie games debate. Good for you if you want to write a game, however... Do something new, do something creative, do something that you and your friends and family members and immediate contributors can realistically accomplish. And for the love of sanity, DO IT FOR FUN! If you're in it for money and it's not your full-time job, then don't bother.

Also, if you're a good programmer and find your game lacking content, consider procedural content. It really depends on the kind of game you're writing. The downside is that it can remove the beautiful, personal touch of human-generated content, and it is also very hard to do. The upshot is that if you really enjoy programming and are making your game for you own personal enjoyment, the challenge can be very exciting and entertaining. The second upshot is that procedural content when done well and applied to the right kind of game, can greatly add to replayability. This is the path that I've chosen for the game I'm writing right now (In-depth pausable real-time tactical starship combat). I'm having a blast!

Two ways:

[SanityInAnarchy]

1.) Don't start out open source. Id has only two games out lately -- Doom 3 and Quake 4 -- to which they haven't released the source, but they always wait till they really have no further use for the game.

2.) Open source it from the start, but sell the content under a different license. Id has also (technically) done this with all of their open source games -- I'm still legally required to buy the Quake 3 game if I want the Quake 3 maps and models, though technically I could redo all that and still use the engine.

Computer generated content

[Anonymous Coward]

I think the problem of the content would be solved with some kind of Will Wright's Spore content editor put on a "WikiContent" website. An easy-to-learn 3d editor with prefabs and other stuff made by the people and share them (lik GoogleSketch for example) would probably make the content flourish.

I guess it will require some imagination

[PurpleWizard]

And in fact one of the best ingredients the imaginative can offer their challenged friends (from my experience as a role player) is imagination.

Now specific examples that may or may not work. Well any MMUG could conceivably be run on an open source project much like JBOSS is an application server. So you get a market leading Game server and look after it for the creative talent who want you to hack some neat feature just for them. - It might work, and it is just one example

I suspect there are other business models that might offer a living to the best solution. Who'd have thought someone could get rich selling you phone numbers (OK generic contact) to the people you didn't really like or know from school. It happened.

open source is the game

[shungi]

One way that an open source game might work is if people who play can add bits to it. Having implemented the core of a massive multiplayer game, users who had programming skills might add new weapons, or new buildings or whatever. Unskilled users could still play the game online.