I posed a question on Twitter recently where I asked developers to jump in with thoughts on essential things to know about when bringing a game to Linux. Let’s look over some answers!
In this article I will go over a few useful answers, giving full credit to the person who sent it in with a link to the tweet they sent to us. I will then give my own thoughts on each point, with any relevant links to help. There's likely hundreds of things we could point up, but these are what I consider to be some of the more common and important issues to keep in mind.
Some of the answers made me laugh, let’s start off with a good old joke about Arch Linux (source):
I enjoy a good poke about distributions here and there, but it’s actually very true. Of all the distributions there are, Arch does end up being the most problematic. That's not saying Arch is bad, but being on the edge (it gets newer software faster than most other distributions) obviously increases the amount of issues that are likely to come up, since it's had less time in the oven to work out issues.
Test on Ubuntu and if you can, SteamOS too. If it doesn't work on other distributions, they likely have workarounds as they are likely doing something different. Do not feel the need to test every distribution around, it will be impossible and it's just not needed, don't overthink it. Don't be afraid to limit support to the main bigger distributions either. Some people may not like the idea, but it's too much work for little gain most of the time. Support the big distributions, forget the rest (at least until you're much more familiar with Linux).
One from David Gow (source):
It doesn't necessarily need to be SDL2, there's also SFML and likely others. The point is, projects like that can make your life a lot easier. You might be wanting to keep everything small, but these projects are bigger for a reason, as they cover tons of edge cases and nuisances you likely haven't even thought of.
There's a reason why Valve, Feral Interactive, Humble Indie Bundle and many others use SDL2 for the Linux ports. Heck, even the Unity game engine moved over to use SDL2 in Unity 5.6.
This next one comes from none other than Timothee Bessett, formerly of id Software (source):
I think this is an important point for any developer to remember. Linux users want your game to do well, we will often help you test for free, because we want to help. Any time I’ve seen a developer call for Linux testers, they end up getting overwhelmed with the amount of people willing to offer their free time to help out. Opening up a private beta to a few select people is always an option too, there's many ways to get users involved early.
However, this is not a replacement for your own testing! Linux is free to download and use forever, it can be installed by itself or along side Windows & Mac. You can install it inside a virtual machine too if you want to just give it a look over.
This little tidbit comes from Holarse Linux-Gaming, our German friends (source):
This in particular is something I’m keen for developers to know about. Please, for the love of my sanity, don’t put a plain folder of “Game Name” inside my home directory. If you want to know where to store config files and saved games, you can find more info here.
As an example, Unity games tend to be in /home/user/.config/unity3d. Notice the dot before “config”, it’s a hidden directory so it doesn’t pollute a user's home directory and fill it to the brim with random folders.
Another one from Holarse Linux-Gaming (source):
You likely know what this means, but in case you don't: "This" is not the same as "THIS" when it comes to filenames on Linux. A crash in a game that's absolutely bugging you? Check you're looking for the right filename. This single issue has tripped up a lot of developers I've personally spoken to.
Let’s break things up with another amusing one, this time from a Feral Interactive developer (source):
I would be lying if I said this didn’t make me laugh quite a lot. You think some bug reports you got from Windows were weird enough? Prepare yourself.
The same Feral Interactive developer also put forward probably one of the most important points possible (source):
The amount of times we’ve seen developers announce a Linux port, be it on Steam’s old Greenlight platform, Kickstarter or wherever else, only to announce much later they can’t do it due to something they use being Windows-only is quite staggering. Check early and often that the tools, middleware and whatever else will be able to work somehow on Linux. Don't get stuck in the professionally embarrassing position where you have to u-turn on platform support.
Asking for help is not embarrassing and should not be seen as any kind of weakness, if you put out a call for help finding replacements or getting something to work on Linux, you might be surprised to find people able to help out quite often. I've seen hundreds of developers chatting away on Twitter, Reddit and other sites giving out help and advice about Linux issues.
Another one from a Feral developer (source):
The amount of times I've seen developers put up builds where they talk about knowing nothing about Linux: how do you expect to fix bugs in it, if you don't know the first thing about the platform? A little early research and testing will go a long way. The terminal might seem a little scary at first, but from someone who doesn't consider himself even remotely smart: just do it! Learn it and you might find a new friend. Still scared? This site might help you with the basics of the Linux command line.
If you plan to release your game outside of Steam and you want to use a handy installer, take a look at MojoSetup. GOG, the well known game store actually use this for their Linux releases.
An important point I would like to also raise: don't expect Linux sales to make you rich. It's a smaller platform. Bringing a game to Linux isn't just about getting sales from the additional platform, you should also keep in mind all of us likely know people on Windows & Mac we will end up recommending the game to, especially if it has any form of multiplayer. The extra advertising through various Linux websites and the extra word of mouth can be useful.
If you're wondering whether you need to make a 32bit build of your game, in my honest opinion you don't need to bother. 64bit only is fine especially since our own statistics tell us out of 1921 people who answered about their distribution, only 1 person is on a 32bit distribution.
Also, please don't take loud and idiotic users to heart. All communities will have trolls and haters, please do ignore any you find.
If you're trying to port to Linux and you're stuck, don't fret! Take a breath, come have a chat. We have a Forum, our Email inbox is always open, we have an IRC channel, Discord and more.
Finally, if you are considering bringing your game to Linux — thank you, can't wait to try it!
Please do share any other general tips you have in the comments. Article taken from GamingOnLinux.com.
In this article I will go over a few useful answers, giving full credit to the person who sent it in with a link to the tweet they sent to us. I will then give my own thoughts on each point, with any relevant links to help. There's likely hundreds of things we could point up, but these are what I consider to be some of the more common and important issues to keep in mind.
Some of the answers made me laugh, let’s start off with a good old joke about Arch Linux (source):
QuoteIf you are getting completely impossible and weird bugs that is almost impossible to reproduce, check if they are running Arch Linux…
I enjoy a good poke about distributions here and there, but it’s actually very true. Of all the distributions there are, Arch does end up being the most problematic. That's not saying Arch is bad, but being on the edge (it gets newer software faster than most other distributions) obviously increases the amount of issues that are likely to come up, since it's had less time in the oven to work out issues.
Test on Ubuntu and if you can, SteamOS too. If it doesn't work on other distributions, they likely have workarounds as they are likely doing something different. Do not feel the need to test every distribution around, it will be impossible and it's just not needed, don't overthink it. Don't be afraid to limit support to the main bigger distributions either. Some people may not like the idea, but it's too much work for little gain most of the time. Support the big distributions, forget the rest (at least until you're much more familiar with Linux).
One from David Gow (source):
QuoteUse SDL2. Or use something which itself uses SDL. Under no circumstances write X11 code directly.
It doesn't necessarily need to be SDL2, there's also SFML and likely others. The point is, projects like that can make your life a lot easier. You might be wanting to keep everything small, but these projects are bigger for a reason, as they cover tons of edge cases and nuisances you likely haven't even thought of.
There's a reason why Valve, Feral Interactive, Humble Indie Bundle and many others use SDL2 for the Linux ports. Heck, even the Unity game engine moved over to use SDL2 in Unity 5.6.
This next one comes from none other than Timothee Bessett, formerly of id Software (source):
QuotePlayers want you to succeed with your Linux release. Get them involved, for instance have them test stuff up for you.
I think this is an important point for any developer to remember. Linux users want your game to do well, we will often help you test for free, because we want to help. Any time I’ve seen a developer call for Linux testers, they end up getting overwhelmed with the amount of people willing to offer their free time to help out. Opening up a private beta to a few select people is always an option too, there's many ways to get users involved early.
However, this is not a replacement for your own testing! Linux is free to download and use forever, it can be installed by itself or along side Windows & Mac. You can install it inside a virtual machine too if you want to just give it a look over.
This little tidbit comes from Holarse Linux-Gaming, our German friends (source):
QuoteFor your files and savegames there is XDG (like %approot% on windows
This in particular is something I’m keen for developers to know about. Please, for the love of my sanity, don’t put a plain folder of “Game Name” inside my home directory. If you want to know where to store config files and saved games, you can find more info here.
As an example, Unity games tend to be in /home/user/.config/unity3d. Notice the dot before “config”, it’s a hidden directory so it doesn’t pollute a user's home directory and fill it to the brim with random folders.
Another one from Holarse Linux-Gaming (source):
QuoteYes linux filesystems ARE case sensitive
You likely know what this means, but in case you don't: "This" is not the same as "THIS" when it comes to filenames on Linux. A crash in a game that's absolutely bugging you? Check you're looking for the right filename. This single issue has tripped up a lot of developers I've personally spoken to.
Let’s break things up with another amusing one, this time from a Feral Interactive developer (source):
QuoteSomeone WILL play your game on their work render farm, and report the bugs [..] I'd be lying if I said this had only happened once. 128 cores!? 1TB RAM!?
I would be lying if I said this didn’t make me laugh quite a lot. You think some bug reports you got from Windows were weird enough? Prepare yourself.
The same Feral Interactive developer also put forward probably one of the most important points possible (source):
QuoteUse cross compatible tools whenever and where ever, anything can turn into a crutch when you try and port
The amount of times we’ve seen developers announce a Linux port, be it on Steam’s old Greenlight platform, Kickstarter or wherever else, only to announce much later they can’t do it due to something they use being Windows-only is quite staggering. Check early and often that the tools, middleware and whatever else will be able to work somehow on Linux. Don't get stuck in the professionally embarrassing position where you have to u-turn on platform support.
Asking for help is not embarrassing and should not be seen as any kind of weakness, if you put out a call for help finding replacements or getting something to work on Linux, you might be surprised to find people able to help out quite often. I've seen hundreds of developers chatting away on Twitter, Reddit and other sites giving out help and advice about Linux issues.
Another one from a Feral developer (source):
Quoteembrace the shell, the sooner the better. The last thing you want 2 hours before release is to be fumbling around learning bash
The amount of times I've seen developers put up builds where they talk about knowing nothing about Linux: how do you expect to fix bugs in it, if you don't know the first thing about the platform? A little early research and testing will go a long way. The terminal might seem a little scary at first, but from someone who doesn't consider himself even remotely smart: just do it! Learn it and you might find a new friend. Still scared? This site might help you with the basics of the Linux command line.
If you plan to release your game outside of Steam and you want to use a handy installer, take a look at MojoSetup. GOG, the well known game store actually use this for their Linux releases.
An important point I would like to also raise: don't expect Linux sales to make you rich. It's a smaller platform. Bringing a game to Linux isn't just about getting sales from the additional platform, you should also keep in mind all of us likely know people on Windows & Mac we will end up recommending the game to, especially if it has any form of multiplayer. The extra advertising through various Linux websites and the extra word of mouth can be useful.
If you're wondering whether you need to make a 32bit build of your game, in my honest opinion you don't need to bother. 64bit only is fine especially since our own statistics tell us out of 1921 people who answered about their distribution, only 1 person is on a 32bit distribution.
Also, please don't take loud and idiotic users to heart. All communities will have trolls and haters, please do ignore any you find.
If you're trying to port to Linux and you're stuck, don't fret! Take a breath, come have a chat. We have a Forum, our Email inbox is always open, we have an IRC channel, Discord and more.
Finally, if you are considering bringing your game to Linux — thank you, can't wait to try it!
Please do share any other general tips you have in the comments. Article taken from GamingOnLinux.com.
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Quoting: PhiladelphusThere may very well be good reasons for making games 64-bit and I've love to hear them, it's just that I tend to see 64-bit thrown around as a bit of a buzz-word.
Another advantage of 64 bit builds is more registers, which might make some things faster. But if they are far from needing 4 GB, a port of their engine to 64 bits might actually not be worth it. (And depending how well it was implemented, possibly long ago, it might be hard.) There's no magical performance doubling or something along the lines.
Last edited by Eike on 6 July 2017 at 7:56 am UTC
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Awesome! You can't write too many of these articles! Keep them coming and I'll never stop supporting this site! ;)
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Quoting: rkfgQuoting: EhvisI remember one game where the developer had a Unity3D game running within a day, but had dependency problems when starting from the Steam runtime.STASIS is suffering from this right now. The engine needs newer libstdc++.so.6 than provided in SteamOS so it doesn't start there. So another advice: check your dependencies on older distros if possible and either ship the libs with the game or link them statically if you can.
Actually this is a very specially sad case. SteamOS supplies 6.0.20 but the Steam runtime supplies the 6.0.21 version that STASIS requires so the problem with STATIS is that it doesn't use the Steam runtime but the system one and that Valve somehow messed up their own distribution by supplying an older version for the OS than what they themselves support via their runtime.
For STASIS it should work on SteamOS if they changed their start script to look in the Steam runtime path for libraries before looking at the system path.
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Quoting: GuestGreat article Liam,
One of my worries for Linux is how should developers code their programs and place all their folders and files so that 5 years down the line with newer hardware, kernel and distro and any updates associated, it can still be guaranteed that our purchased software will still be forward/backwards compatible and run? I personally find it annoying when your system is running fine for 2 years or so and just works, then have to do an update to the latest distro to get game x to work just to find you have to hunt down and figure out how to install xyz library or package to get an old game or software running again.
I'd like to point out that the community is great generally and with a little googling and patience one generally finds answers to solve your problems, for myself I guess I should save all those sources of help and index them all in a text file of sorts.
I second this. Usually this can be achieved by NOT STATICALLY LINKING the libraries (which is one of the reasons to have them in the first place). The libraries get updated (especially if they are open source), and make the games run in their new environment. This is why LGPL/zlib2 (iirc) is such a great thing :)
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Quoting: MayeulCQuoting: GuestGreat article Liam,
One of my worries for Linux is how should developers code their programs and place all their folders and files so that 5 years down the line with newer hardware, kernel and distro and any updates associated, it can still be guaranteed that our purchased software will still be forward/backwards compatible and run? I personally find it annoying when your system is running fine for 2 years or so and just works, then have to do an update to the latest distro to get game x to work just to find you have to hunt down and figure out how to install xyz library or package to get an old game or software running again.
I'd like to point out that the community is great generally and with a little googling and patience one generally finds answers to solve your problems, for myself I guess I should save all those sources of help and index them all in a text file of sorts.
I second this. Usually this can be achieved by NOT STATICALLY LINKING the libraries (which is one of the reasons to have them in the first place). The libraries get updated (especially if they are open source), and make the games run in their new environment. This is why LGPL/zlib2 (iirc) is such a great thing :)
Most libraries will break with major updates, so you should bundle almost all your dependencies. But there are some libraries that should not be bundled, you should just use what the system provide instead. This page was not updated for a long time but it's still relevant: https://freegamedev.net/wiki/Portable_binaries#System_libraries_that_cannot_be_bundled
I worked on a company that developed OpenGL applications and using this approach we were able to build on CentOS 5 and run on Ubuntu 16.10, for example. That's 9 years of backward compatibility.
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Quoting: gqmeloI worked on a company that developed OpenGL applications and using this approach we were able to build on CentOS 5 and run on Ubuntu 16.10, for example. That's 9 years of backward compatibility.
How much work was it to follow all security problems, update the statically linked binaries and ship them for nine years...?
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Quoting: EikeOnly an issue if the software "faces out" as it were. You're assuming this isn't something that just simply runs on the computer; not everything has to be networked.Quoting: gqmeloI worked on a company that developed OpenGL applications and using this approach we were able to build on CentOS 5 and run on Ubuntu 16.10, for example. That's 9 years of backward compatibility.
How much work was it to follow all security problems, update the statically linked binaries and ship them for nine years...?
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Quoting: gqmeloMost libraries will break with major updates, so you should bundle almost all your dependencies. But there are some libraries that should not be bundled, you should just use what the system provide instead. This page was not updated for a long time but it's still relevant: https://freegamedev.net/wiki/Portable_binaries#System_libraries_that_cannot_be_bundled"Bundling" can be interpreted differently form statically linking, though. I usually agree with "bundling"/providing the shared libraries along with the executable (and maybe a LD_LIBRARY_PATH "hack" in a launcher script), but not with static linking.
I worked on a company that developed OpenGL applications and using this approach we were able to build on CentOS 5 and run on Ubuntu 16.10, for example. That's 9 years of backward compatibility.
The only "valid" reason I can think of for statically linking executables is to distribute your program as only one binary. But even then, there are better options (sfxs, flatpack-like files with an embedded filesystem image or archive), and it only concerns a very nice portion of all applications (usually, portable ones).
Link time optimization and other optimizations are another reason it could be useful, but that's not true in practice (and ld can perform lto on shared objects as well, IIRC).
But yes, carefully pick the libs you bundle. To me, the general rules are:
- Libs everyone have (double check everyone *is* everyone). Don't bundle them, dynamically link.
- Libraries provided by a third party as part of a special contract with your studio/company: provide them as .so
- Internal libraries developed by your studio/company: statically link them, perform a monolithic compilation with them or provide them as .so depending on your needs or update/modding/debug policy
- Relatively common libraries that are well maintained: provide them with a .so, but prefer the ones on the system (query ld folders, add them to LD_LIBRARY_PATH, then add the folders they are in to LD_LIBRARY_PATH, essentially what Steam is doing)
- "wild" libraries that are not very well maintained, or can break the API (early development version, for instance): avoid them, you will probably run into problems a few years down. If you must use them, provide them, don't statically link them but prefer them to the host libraries. That way, you make it possible to tinker with them if it stops working, but they should work the same way regardless of the system.
- Prefer open source libraries whenever possible (still avoid the previous case): generally well maintained, people can fix them easily if they are broken a few years down the line, or write wrappers for them in the worst case.
- Whenever possible (and that's usually a more general software rule), avoid complex dependencies. Both for the libs you choose (they should depend on a minimum of other libraries) and for your application. Bonus points if you can enable/disable some dependencies via a config file (though you may have to manually load your libraries. It's not *that* complicated, and as a bonus, you can gracefully fallback and disable features)
Do you agree with those, or would you change/add something?
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You had a fair share of valid points (I especially agree with the very last one), but I read your post as being quite aggressive, and it seems that I have been misunderstood multiple times. So there goes the counter-multiquote.
Quoting: devnullI don't think I understood this correctly. What shouldn't be required?Quote"Bundling" can be interpreted differently form statically linking, though. I usually agree with "bundling"/providing the shared libraries along with the executable (and maybe a LD_LIBRARY_PATH "hack" in a launcher script), but not with static linking.
Shouldn't be required if symbol versions are used.
Quoting: devnullI am not sure statically linking actually reduces risks at all (it doesn't prevent code injection at all, but just raises the difficulty a bit). It can also be a security risk, because you then statically linked libs with CVEs in them, and no mean to upgrade them (especially if the developer doesn't care anymore, which is unfortunately often the case).QuoteThe only "valid" reason I can think of for statically linking executables is to distribute your program as only one binary. But even then, there are better options (sfxs, flatpack-like files with an embedded filesystem image or archive), and it only concerns a very nice portion of all applications (usually, portable ones).
Security. How secure depends entirely on the attack surface of course but in general preload is easier then binary editing.
Quoting: devnullI didn't mean it that way. What I meant is that you had to provide them (but preferably as shared objects, so that they can be upgraded later by the consumer, if you care about your consumer, that is ;) )QuoteBut yes, carefully pick the libs you bundle. To me, the general rules are:
- Libs everyone have (double check everyone *is* everyone). Don't bundle them, dynamically link.
- Libraries provided by a third party as part of a special contract with your studio/company: provide them as .so
Redistribution rights may prohibit it.
Quoting: devnullThe difference here is that if that's *your* IP, *you* are the one who is going to update it. Contrast this to the case where ex. Valve releases a steamaudio fix. If they do, the customer can upgrade the .so (that's done transparently trough Steam, usually). If that's your lib, you will probably release an update to the game when you update the lib (if you are a good guy). Of course, this is only useful when the company producing the game goes downhill, and that's not the use case most companies care most about.QuoteInternal libraries developed by your studio/company: statically link them, perform a monolithic compilation with them or provide them as .so depending on your needs or update/modding/debug policy
Don't quite see the difference between this and above. If it's not public IP, there's no reason not to protect it.
Quoting: devnullAvoiding poorly maintained libraries is an invitation to disaster? Come on, tell me you didn't say this just to contradict me. Breaking the ABI/API is ok when the library is well versioned. That way, the system can provide the different versions, or compatibility shims.Quote"wild" libraries that are not very well maintained, or can break the API (early development version, for instance): avoid them, you will probably run into problems a few years down. If you must use them, provide them, don't statically link them but prefer them to the host libraries. That way, you make it possible to tinker with them if it stops working, but they should work the same way regardless of the system.
Invitation to disaster. There are MANY libraries that aren't backward compatible. Pulse for example. Simply including or not including doesn't negate other dependencies elsewhere.
Quoting: devnullI must confess that I didn't really get your sentence.QuotePrefer open source libraries whenever possible (still avoid the previous case): generally well maintained, people can fix them easily if they are broken a few years down the line, or write wrappers for them in the worst case.
Bit irrelevant. There are quite open source libraries that are not backward compatible and outright refuse to run otherwise. Pulse, dbus, etc.
Quoting: devnullAs far as I know, the linker has to link every dependency at runtime, before even starting to execute the program. You have to dlopen() if you want to handle complex feature toggling.QuoteWhenever possible (and that's usually a more general software rule), avoid complex dependencies. Both for the libs you choose (they should depend on a minimum of other libraries) and for your application. Bonus points if you can enable/disable some dependencies via a config file (though you may have to manually load your libraries. It's not *that* complicated, and as a bonus, you can gracefully fallback and disable features)
Also a bit irrelevant. The linker has no problems resolving dependencies. There is a bit of overhead at runtime though.
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