Using Wesnoth Art in a free web-based game?

[Glorfindal]

I have been developing a browser based role-playing game for a while now and the programming is going well, however I am struggling with getting good graphics. (as I am not an artist) I was wondering if I could use some of the wesnoth art (particulary the portraits for the elves, humans, and dwarves) in the alpha & beta versions until I can create my own artwork. I would provide a link to the Wesnoth site, the only thing I can't do is make it open source, although I will probably release a completed engine for the game as open source eventually.

[Cumulus]

I think it's allowed if you clearly indicate that the graphics are obtained under GPL license from Wesnoth.org. At least I hope so or I would have a big problem with the browsergame I'm developing myself...

[Lorbi]

I am not a lawyer but I can tell you this:
This has no clear answer and has as of yet not really been tested in court. Most likely you have to license your entire game under GPL if you include those images, ... but: if it is web based, or even a browser game, everything that happens on the server side is not (re)distributed. GPL says you have to provide the source if you (re)distribute the "program" but with web based games one can make the case that there is no distribution, so you don't have to provide the source to anyone even though the license is GPL.

edit: GPL does not legally require you to attribute the work to the original author but personnly I think it's kind of rude not to give credit where credit is due

[iceiceice]

I also am not a lawyer, but I think the argument that web-based content is not distributed and therefore evades GPL is highly suspect. Whatever client side code there is, java byte code, php, whatever, you need to provide the source code of whatever generated that. At least I don't see how you can evade that responsibility under GPL.

Point 3 of GPL v2:

"3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:"

I think the term object code should be thought of here as an umbrella term for programs that might not strictly be an executable file.

Wikipedia: "Object code, or sometimes object module, is what a computer compiler produces. In a general sense object code is a sequence of statements or instructions in a computer language,[2] usually a machine code language (i.e., 1's and 0's) or an intermediate language such as RTL."

Edit:

Taken to an extreme, the argument would make the whole GPL vacuous. What if instead of distributing programs, I distribute "web-based installers". Does this mean I never need to release the source of anything?

Edit:

I guess that I'm to some extent wrong here. Depending on what kind of web app set up you have, you may not required to release much / any source code. And also in an extreme case that e.g. you let users ssh with x-window forwarding to your machine to use your program, you do not have to release any source. http://www.gnu.org/licenses/old-license ... leasedMods

[Andrettin]

Using the Wesnoth graphics and an engine together is "mere aggregation", so you can distribute them under different licenses, you just have to provide the source code of the graphics (which in the case of graphics are the PNG files themselves).

I don't think it is very nice to use open source graphics if your engine isn't open source itself, but legally it shouldn't be a problem.

[iceiceice]

Using the Wesnoth graphics and an engine together is "mere aggregation", so you can distribute them under different licenses...

I think that this is inaccurate. Using the Wesnoth graphics and an engine together in a game is a collective work, to which section 2 of GPL v2 is relevant.

But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

It would be mere aggregation if e.g. you made a CD-ROM "Software that I like" which contained the Wesnoth graphics, a game engine, and some other software which was simply bundled together for convenience.

https://www.gnu.org/licenses/gpl-faq.ht ... ggregation

Edit: Simply, you cannot use content which is released only under GNU GPL in an integral way in your program unless the distribution of the whole program is under the terms of GNU GPL. That's the whole point of copyleft.

[Lorbi]

[...]
Edit:

Taken to an extreme, the argument would make the whole GPL vacuous. What if instead of distributing programs, I distribute "web-based installers". Does this mean I never need to release the source of anything?

Edit:

I guess that I'm to some extent wrong here. Depending on what kind of web app set up you have, you may not required to release much / any source code. And also in an extreme case that e.g. you let users ssh with x-window forwarding to your machine to use your program, you do not have to release any source. http://www.gnu.org/licenses/old-license ... leasedMods

There is a blurry line between distributing and not-distributing. You don't need to provide the source to every visitor of your website that runs from your own modification of a GPL'd server. (Think google web server, linux based but no source available to public)
Obviously there is a limit to how far that argument carries, but as far as I know (still not lawyer though) a browser bases web-game using GPL'd materials does not need to release any sources of any strictly server-side code.
The html code the server programs generate is obviously open-source anyway.

[iceiceice]

There is a blurry line between distributing and not-distributing. You don't need to provide the source to every visitor of your website that runs from your own modification of a GPL'd server. (Think google web server, linux based but no source available to public)
Obviously there is a limit to how far that argument carries, but as far as I know (still not lawyer though) a browser bases web-game using GPL'd materials does not need to release any sources of any strictly server-side code.
The html code the server programs generate is obviously open-source anyway.

The way I now understand it is, you are always entitled to run modified the program, and "distribution" only includes what you are transmitting from your machine to the client machine. If almost all the work is made server-side, then you may not have to release any of the code that controls what is happening.

But even in that case you are distributing much more than HTML, you are also distributing images and possibly sounds.

If you use any GNU GPL content at all in your project, the GNU GPL license applies to the collective work (regardless of whether you distribute the collective work, it is just that it only enforces conditions on distribution.) (There are edge cases I suppose like this but in the case of a game as you described it seems pretty clear.)

So it is worth some serious thought whether that means you need to release the sources of the images and sounds you are using. I'm not an expert, so take my view with a grain of salt, but if it were me I would release at the very least all the raw image files I use, plus whatever code I use to arrange them into a scene for the client (even if this code is server-side). (I guess I'm assuming that this arrangement isn't happening in HTML.) After all, one could easily imagine how it would look to a jury if they are shown screenshots from your game with elves standing on a landscape, then a picture of the elf sprite stored server-side, and your lawyer has to take the position "nope, definitely no elf sprites being distributed here."

I think most laypeople would say that the spirit of copyright law is to protect content, rather than files, (for example).

[AI]

More layperson lawyering:

The Affero GPL (AGPL) was created for server-side programs, to entitle people that *communicate* with an AGPL-licensed program to its sources. Communicating with a GPL-licensed program does not entitle you to source code and the output of a GPL-licensed program is also not GPL-encumbered just because it was created by that program. If the program uses GPL-licensed *input* however, the output may be a derivative work, as is the case when you compile source code into a binary. Creating an image based on a bunch of sprites definitely sounds like it falls under that category.

[Lorbi]

Yeah, I agree on the images: If you make an image from GPL sprites the image is a derivative work and using it in a web-game is distributing the images to the users, and thus they are entitled to the sprites as the "source".
It does not however make the (server side) program that combinded the images GPL, and I should think that is what's important to the author of a browser-game: using Wesnoth sprites does not require to distribute the (server side) source of the game. (A browser game most likely has pretty much all of it's functionallity happening server-side.)
The same way using a GPL'd compiler does not make every program compiled with it GPL.

Additionally, there may always be tricky edge cases, but it is definitely unfortunate circumstances that Wesnoths graphic art and music are licensed as GPL and many of those murky edge cases could be avoided by having a license better fitted for images and music. It's really the wrong license for non-code.

[iceiceice]

Yeah, I agree on the images: If you make an image from GPL sprites the image is a derivative work and using it in a web-game is distributing the images to the users, and thus they are entitled to the sprites as the "source".
It does not however make the (server side) program that combinded the images GPL, and I should think that is what's important to the author of a browser-game: using Wesnoth sprites does not require to distribute the (server side) source of the game. (A browser game most likely has pretty much all of it's functionallity happening server-side.)
The same way using a GPL'd compiler does not make every program compiled with it GPL.

Yes that is one possible interpretation. However a different one matches the text of the license more closely in my mind. The term source is not the keyword in GPL, rather it is "preferred modifiable format". The images you would see in a game like wesnoth are a game map together with a GUI display. What is the preferred modifiable format for a GUI display? I think it is the source code and underlying image files of the GUI. Notice that an *image* of a GUI display is not *compiled*, and probably shouldn't be thought of as object code.

Think about it this way. Suppose you follow me so far, that you agree that the images underlying the GUI widgets are being "distributed" as part of the GUI display images. If you are thinking of them as the source of the GUI display image as well, ... in terms of GPL that really means you think that the collection of image files is the "preferred modifiable format" for the GUI display image. That seems ridiculous -- the code that lays out the GUI using those ingredients is the preferred way to modify the GUI display. It would be incredibly tedious and difficult to assemble an image of the wesnoth GUI from the underlying image files by hand. (And, tying in with the previous music thread argument, unlike the ogg files, it really is the case that it is quite easy to adjust the GUI by adjusting the underlying code. It is clearly much preferred over just the underlying image files alone.)

So that's why I say you might be required to release the GUI source files as well. Not because you are distributing them, but because they are a necessary piece of the "preferred modifiable format" for the GUI display images that you are transmitting.

Additionally, there may always be tricky edge cases, but it is definitely unfortunate circumstances that Wesnoths graphic art and music are licensed as GPL and many of those murky edge cases could be avoided by having a license better fitted for images and music. It's really the wrong license for non-code.

I guess everyone is very uncomfortable with what preferred modifiable format means for art. But I actually think that copyleft is a good thing, and it is good to force anyone who wants to use our great art to live up to strong copyleft standards. We wouldn't get this if the art was under creative commons for example.

If the licenses are ever changed in the future, I hope that we perhaps change by using a version of AGPL that explicitly states what preferred modifiable source means for music and image files, or carves out exceptions for these (and otherwise updates with AGPL), rather than abandoning copyleft. Maybe there is room for a WGPL (Wesnoth GPL) intended especially for games / entertainment projects.

[Lorbi]

Yeah, I agree on the images: If you make an image from GPL sprites the image is a derivative work and using it in a web-game is distributing the images to the users, and thus they are entitled to the sprites as the "source".
It does not however make the (server side) program that combinded the images GPL, and I should think that is what's important to the author of a browser-game: using Wesnoth sprites does not require to distribute the (server side) source of the game. (A browser game most likely has pretty much all of it's functionallity happening server-side.)
The same way using a GPL'd compiler does not make every program compiled with it GPL.

Yes that is one possible interpretation. However a different one matches the text of the license more closely in my mind. The term source is not the keyword in GPL, rather it is "preferred modifiable format". The images you would see in a game like wesnoth are a game map together with a GUI display. What is the preferred modifiable format for a GUI display? I think it is the source code and underlying image files of the GUI. Notice that an *image* of a GUI display is not *compiled*, and probably shouldn't be thought of as object code.

Think about it this way. Suppose you follow me so far, that you agree that the images underlying the GUI widgets are being "distributed" as part of the GUI display images. If you are thinking of them as the source of the GUI display image as well, ... in terms of GPL that really means you think that the collection of image files is the "preferred modifiable format" for the GUI display image. That seems ridiculous -- the code that lays out the GUI using those ingredients is the preferred way to modify the GUI display. It would be incredibly tedious and difficult to assemble an image of the wesnoth GUI from the underlying image files by hand. (And, tying in with the previous music thread argument, unlike the ogg files, it really is the case that it is quite easy to adjust the GUI by adjusting the underlying code. It is clearly much preferred over just the underlying image files alone.)

So that's why I say you might be required to release the GUI source files as well. Not because you are distributing them, but because they are a necessary piece of the "preferred modifiable format" for the GUI display images that you are transmitting.

I can't really say for sure, but I highly suspect that your interpretation would not hold on court for the following reasons:
The images are most likely legally not even part of the program that creates the GUI but a separate "program". As mentioned before the GPL wasn't really designed for art but the FSF states that it is possible to have a non-free program load and use GPL'd plugins. They only become one larger program if they functionally work together (or share data-structures that both work on)
Source: http://www.gnu.org/licenses/old-license ... GPLPlugins
The FSF also thinks it's ok to include non-functional data (that is data that only serves aesthetic purposes) in a system and still call it free.
Source: http://www.gnu.org/philosophy/free-syst ... lines.html
For those reasons I believe you would have to supply the "source" for the image files but not the source for the GUI creation. Because the image files are a seperate "program" that you distribute while the program that creates the GUI is not distributed.
But even if you consider the images an integral part of the program (although you can in 99% of all cases just switch them out with any other image of a similar size and the program will still work fine) the preferred form to make changes to might be the html of the website that contains the images. You can change the gui by changing the html, and the user always has access to that source. But I do think that this second argument is pretty weak. The argument that image and server-side code are not the same "program" is a strong though. (imho and ianal)

Additionally, there may always be tricky edge cases, but it is definitely unfortunate circumstances that Wesnoths graphic art and music are licensed as GPL and many of those murky edge cases could be avoided by having a license better fitted for images and music. It's really the wrong license for non-code.

I guess everyone is very uncomfortable with what preferred modifiable format means for art. But I actually think that copyleft is a good thing, and it is good to force anyone who wants to use our great art to live up to strong copyleft standards. We wouldn't get this if the art was under creative commons for example.

If the licenses are ever changed in the future, I hope that we perhaps change by using a version of AGPL that explicitly states what preferred modifiable source means for music and image files, or carves out exceptions for these (and otherwise updates with AGPL), rather than abandoning copyleft. Maybe there is room for a WGPL (Wesnoth GPL) intended especially for games / entertainment projects.

I do agree that copyleft is a very good thing! But GPL isn't the only copyleft license out there, and it was never intended to be used for music and images. What disadvantage to the GPL do you see in licensing the art as CC-BY-SA? (or just CC-SA)

[iceiceice]

We recently rehashed the status of how GPL applies to the music in wesnoth in another thread: http://forums.wesnoth.org/viewtopic.php?f=14&t=40087

Sorry, I could have posted a link to that earlier in this thread, it is definitely informing my ideas here to some extent.

I can't really say for sure, but I highly suspect that your interpretation would not hold on court for the following reasons:
The images are most likely legally not even part of the program that creates the GUI but a separate "program".

Sure, there are many different things / groups of things that could be considered programs in any given program, and in this case since the images in question are derived works of a GPL program they are subject to GPL, and since you distribute them you are obligated to release a preferred modifiable format. The question is only what is that format.

As mentioned before the GPL wasn't really designed for art but the FSF states that it is possible to have a non-free program load and use GPL'd plugins.

You can say that, but GPL still applies to art. Wikipedia GPLs all their images, and clearly Wesnoth has succeeded for a decade with everything under GPL. There is no question that GPL can apply to images, the only debates are about what exactly preferred modifiable format means here.

They only become one larger program if they functionally work together (or share data-structures that both work on)
Source: http://www.gnu.org/licenses/old-license ... GPLPlugins

You can paraphrase the FAQ out of context if you like, but it isn't as convincing as reading the actual license. Let's review the text of the actual license. First, what does "The Program" mean?

0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language.

So even though they use the word program, when the term appears in the license it means any work (in the sense of copyright law) which has been GPL'd, or is derived from a work which is subject to GPL.

2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
...

So any "work" which is based on the "work" of the GPL'd image in the sense of copyright law, meaning that it derives in whole or in part from it, is subject to the
conditions.

...
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

So its pretty clear that when you work on a game that incorporates the GPL'd image, that game is then a "Collective Work" deriving in part from the image. There is an exception for mere aggregation, but the text (and FAQ) also makes it clear that that aggregation refers to merely placing unrelated, disjoint projects together on a medium for distribution or convenience, which don't otherwise form a "Collective Work". That is the only exception the license makes to the traditional notion from copyright law, and it is clear that it does not apply in our relevant case.

The FSF also thinks it's ok to include non-functional data (that is data that only serves aesthetic purposes) in a system and still call it free.
Source: http://www.gnu.org/philosophy/free-syst ... lines.html

Again, you are quoting something (not even the FAQ actually) and not the license, and again out of context. Lets see the context.

The page you quote is called "Guidelines for Free Systems Distribution." Right away in the introduction:

The purpose of these guidelines is to explain what it means for an installable system distribution (such as a GNU/Linux distribution) to qualify as free, and help distribution developers make their distributions qualify.

These guidelines are not complete. We have mentioned the issues we are aware of now, but we're sure there are more. We will add them when we come across them.

So this isn't about a "distribution" in the sense of the GPLv2 licensing term, it is rather about a linux distribution. Big difference here, -- this page isn't even about GPLv2 specifically, it is rather Guidelines for managing a collection of software under any of a myriad of Gnu licenses!

The information, and the source, must be provided under an appropriate free license. We list the ones we have evaluated on our license list, with separate sections for licenses that are suitable for software, documentation, fonts, and other useful works. If such a work is released under multiple licenses, at least one of which is free, it can be included in the system; the system developers just need to follow the terms of the available free license(s) when they distribute and/or modify it.

If you are looking to this page for escape clauses from the strict terms of GPLv2, well you are in luck!

There's a lot of code in most free system distributions today; the amount of effort it would take to audit it all directly is impractical for most teams. In the past, some nonfree code has accidentally been included in free system distributions. We don't de-list distributions because of this; instead, we only ask that a distribution put forth a good faith effort to avoid including nonfree software, and commit itself to removing such programs if they are discovered later.

Turns out, you don't have to actually follow the license -- if, oopsie, you include some nonfree software in your distribution, no big deal! I guess this excuses all violations of GPLv2 as long as you say that you tried. What a find, better file that one away in a manila envolope at legal.

Shortly after this we come to the terms about "Non-functional Data":

Non-functional Data

Data that isn't functional, that doesn't do a practical job, is more of an adornment to the system's software than a part of it. Thus, we don't insist on the free license criteria for non-functional data. It can be included in a free system distribution as long as its license gives you permission to copy and redistribute, both for commercial and non-commercial purposes. For example, some game engines released under the GNU GPL have accompanying game information—a fictional world map, game graphics, and so on—released under such a verbatim-distribution license. This kind of data can be part of a free system distribution, even though its license does not qualify as free, because it is non-functional.

That's fine, but (1) Non-functional data is not a term in GPLv2, so it isn't clear how this relates to the licensing of GPL material rather than the FSF guidelines for a free linux distribution. You can tell that something funny is going on because they say "we don't insist". Note: The Gnu GPL is NOT a contract between yourself and FSF, it is rather a contract between you and your users. It doesn't strictly matter so far as the license in concerned what the "FSF guidelines" are -- this page is only about guidelines if you manage a linux distro which you want to be considered "free". (2) The example doesn't have an immediate bearing -- they are speaking about a game engine rather than a game. It is quite natural to distribute example maps associated with a otherwise non-functional game engine, which is not set up to be part of a game. In terms of the license, one might argue that there is no collective work connecting them yet, as you can't even use the game engine without more pieces. But if you think this means that the maps and content in a GPL game don't need to be on the same license as the game, I think you are misreading the GPL.

(3) This doesn't even matter in our case. In the case we are discussing, a game which uses Wesnoth's graphics, the graphics are already under GPL and so there is no question about whether it applies to them, should be they be distributed.

It's worth noting that the same citation from your position appears on the opengamerart.com faq: http://opengameart.org/content/faq#aren ... atible-gpl

But as far as I can tell, this isn't real legal advice and may or may not represent wishful thinking. You can live by this if you like, but for the same reasons I described above I don't find it too convincing.

For those reasons I believe you would have to supply the "source" for the image files but not the source for the GUI creation. Because the image files are a seperate "program" that you distribute while the program that creates the GUI is not distributed.

Right but the images that are *actually displayed* on the clients screen are clearly distributed. It doesn't matter if they aren't stored by the client's webbrowser by default, it doesn't matter if the client promises to delete them -- you are distributing them, and they are subject to GPL if your project derives in part from GPL'd work. The question is what constitutes a preferred modifiable format for those images.

... the preferred form to make changes to might be the html of the website that contains the images. You can change the gui by changing the html, and the user always has access to that source.

I agree in the described scenario. If the server doesn't do any server-side image processing, and the html really does determine they layout then you are probably right here. This is what I was trying to say above when I wrote:

(I guess I'm assuming that this arrangement isn't happening in HTML.)

My understanding is that for most of these games, layouts in HTML just don't cut it, and the server ends up stitching together the images and making a temporary bitmap available for the client. That's the part I'm trying to say should be released (in that scenario).

But I do think that this second argument is pretty weak. The argument that image and server-side code are not the same "program" is a strong though. (imho and ianal)

Sure it's debatable whether they are the same "program" in coloquial terms. But the term "Program" as used in GPL has special meaning, as we saw in section 0 -- it means the GPL'd work in the sense of copyright law. And so its clear that any work at all derived in whole or in part may be subject to GPL terms if distributed.

Again, this is all layman lawyering, IANAL IMHO. I'm simply advising how I would do things if I were in such a position -- also, I suppose this is a tactic that you might use to try to force someone using GPL'd code behind a web service to release at least some of their content under copyleft terms, if you wanted to use their modified images in your game or something.

I do agree that copyleft is a very good thing! But GPL isn't the only copyleft license out there, and it was never intended to be used for music and images. What disadvantage to the GPL do you see in licensing the art as CC-BY-SA? (or just CC-SA)

Licensing the art as CC-BY-SA has the disadvantage that it doesn't have anything to do with open source. I have the right to share and to remix, but a traditional (not web-based) game which uses CC-BY-SA content isn't required, so far as I can see, to open source their *code*, their engine, etc., the way they would be if the art were GPL.

There's no denying that GPL is a pain in the butt for developers. We do it because the benefits of copyleft outweigh these costs -- GPL'ing your content leads to more content being GPL'd which is better for everyone. As RMS loves to point out, we wouldn't have the gcc C++ compiler if GNU GPL wasn't written the way it was. If we really want people to share everything that they can, the best way to get them to do it is to use GNU GPL.

Can we in Wesnoth help with this at all? By being a prominent example of free software we help to some extent. But in terms of forcing others to GPL their code (edit: and their art!) by GPL'ing our key assets? Let's be realistic -- no one who is making a video game or other software is going to want to copy our C++ code. Our infrastructure has changed and changed again many times and the codebase is heavily balkanized and inconsistent. Developers of other games are just going to make their own. The only thing that anyone is realistically going to want to reuse is our art, and specifically our images and our music. Those are the only chips we have to bargain with, so let's not sell ourselves short. We should do everything we can to make sure that if another game wants to incorporate our great content, they have to open source everything under the terms of GPL. If we can convince any game developers to fully GPL their code and art when they otherwise wouldn't (and this may cascade as someone else who wants their content may GPL decide to GPL their own project), we are giving immeasurably back to the community and to the Free Software movement.

That's why I think the creative commons licenses don't quite cut it.

[Lorbi]

We recently rehashed the status of how GPL applies to the music in wesnoth in another thread: http://forums.wesnoth.org/viewtopic.php?f=14&t=40087

Sorry, I could have posted a link to that earlier in this thread, it is definitely informing my ideas here to some extent.

I can't really say for sure, but I highly suspect that your interpretation would not hold on court for the following reasons:
The images are most likely legally not even part of the program that creates the GUI but a separate "program".

Sure, there are many different things / groups of things that could be considered programs in any given program, and in this case since the images in question are derived works of a GPL program they are subject to GPL, and since you distribute them you are obligated to release a preferred modifiable format. The question is only what is that format.

If we agree on that, we agree that _only_ the "source" of the images is subject to the GPL. Everything that is not the same "program" as the images can be legally licensed in any way.

As mentioned before the GPL wasn't really designed for art but the FSF states that it is possible to have a non-free program load and use GPL'd plugins.

You can say that, but GPL still applies to art. Wikipedia GPLs all their images, and clearly Wesnoth has succeeded for a decade with everything under GPL. There is no question that GPL can apply to images, the only debates are about what exactly preferred modifiable format means here.

Yes, you are right! It does apply to art, and it's very possible to license music and images under the GPL, but that's not the point I'm making. The point I'm making is: If you can have a non-free program load and use GPL'd plugins, surely you also can have a non-free program use GPL'd images (without being affected by the GPL) if they are technically treated similiar to a plugin.

They only become one larger program if they functionally work together (or share data-structures that both work on)
Source: http://www.gnu.org/licenses/old-license ... GPLPlugins

You can paraphrase the FAQ out of context if you like, but it isn't as convincing as reading the actual license. Let's review the text of the actual license. First, what does "The Program" mean?

Sorry, should have used the word "work" here. My point is the same as described above: It is possible to combine non-free and GPL'd works in a way that they work together but stay two (legally) seperated works that can have incompatible license. I am here not yet stating that this is the case with images in a web-game. Just stating it is possible to combine works that are non-free and works that are GPL'd (if it is done in a special way as described in the FAQ)

0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language.

So even though they use the word program, when the term appears in the license it means any work (in the sense of copyright law) which has been GPL'd, or is derived from a work which is subject to GPL.

2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
...

So any "work" which is based on the "work" of the GPL'd image in the sense of copyright law, meaning that it derives in whole or in part from it, is subject to the
conditions.

As above.

...
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.

So its pretty clear that when you work on a game that incorporates the GPL'd image, that game is then a "Collective Work" deriving in part from the image. There is an exception for mere aggregation, but the text (and FAQ) also makes it clear that that aggregation refers to merely placing unrelated, disjoint projects together on a medium for distribution or convenience, which don't otherwise form a "Collective Work". That is the only exception the license makes to the traditional notion from copyright law, and it is clear that it does not apply in our relevant case.

I bolded the part I think applies. In a web-based game, the whole is never distributed. Here is also another link with actual legal advice from the Software Freedom Law Center. It is about templates for word press and has even been linked here earlier. In that legal analysis they say "the CSS files and material contained in the images directory of the “default” theme are works separate from the WordPress code". What they are pointing out is: If they are separate works they can have different licenses. This works also in the case where the images are GPL and the rest of the code is non-free.

The FSF also thinks it's ok to include non-functional data (that is data that only serves aesthetic purposes) in a system and still call it free.
Source: http://www.gnu.org/philosophy/free-syst ... lines.html

Again, you are quoting something (not even the FAQ actually) and not the license, and again out of context. Lets see the context.

The page you quote is called "Guidelines for Free Systems Distribution." Right away in the introduction:

The purpose of these guidelines is to explain what it means for an installable system distribution (such as a GNU/Linux distribution) to qualify as free, and help distribution developers make their distributions qualify.

These guidelines are not complete. We have mentioned the issues we are aware of now, but we're sure there are more. We will add them when we come across them.

So this isn't about a "distribution" in the sense of the GPLv2 licensing term, it is rather about a linux distribution. Big difference here, -- this page isn't even about GPLv2 specifically, it is rather Guidelines for managing a collection of software under any of a myriad of Gnu licenses!

The information, and the source, must be provided under an appropriate free license. We list the ones we have evaluated on our license list, with separate sections for licenses that are suitable for software, documentation, fonts, and other useful works. If such a work is released under multiple licenses, at least one of which is free, it can be included in the system; the system developers just need to follow the terms of the available free license(s) when they distribute and/or modify it.

If you are looking to this page for escape clauses from the strict terms of GPLv2, well you are in luck!

There's a lot of code in most free system distributions today; the amount of effort it would take to audit it all directly is impractical for most teams. In the past, some nonfree code has accidentally been included in free system distributions. We don't de-list distributions because of this; instead, we only ask that a distribution put forth a good faith effort to avoid including nonfree software, and commit itself to removing such programs if they are discovered later.

Turns out, you don't have to actually follow the license -- if, oopsie, you include some nonfree software in your distribution, no big deal! I guess this excuses all violations of GPLv2 as long as you say that you tried. What a find, better file that one away in a manila envolope at legal.

Shortly after this we come to the terms about "Non-functional Data":

Non-functional Data

Data that isn't functional, that doesn't do a practical job, is more of an adornment to the system's software than a part of it. Thus, we don't insist on the free license criteria for non-functional data. It can be included in a free system distribution as long as its license gives you permission to copy and redistribute, both for commercial and non-commercial purposes. For example, some game engines released under the GNU GPL have accompanying game information—a fictional world map, game graphics, and so on—released under such a verbatim-distribution license. This kind of data can be part of a free system distribution, even though its license does not qualify as free, because it is non-functional.

That's fine, but (1) Non-functional data is not a term in GPLv2, so it isn't clear how this relates to the licensing of GPL material rather than the FSF guidelines for a free linux distribution. You can tell that something funny is going on because they say "we don't insist". Note: The Gnu GPL is NOT a contract between yourself and FSF, it is rather a contract between you and your users. It doesn't strictly matter so far as the license in concerned what the "FSF guidelines" are -- this page is only about guidelines if you manage a linux distro which you want to be considered "free". (2) The example doesn't have an immediate bearing -- they are speaking about a game engine rather than a game. It is quite natural to distribute example maps associated with a otherwise non-functional game engine, which is not set up to be part of a game. In terms of the license, one might argue that there is no collective work connecting them yet, as you can't even use the game engine without more pieces. But if you think this means that the maps and content in a GPL game don't need to be on the same license as the game, I think you are misreading the GPL.

(3) This doesn't even matter in our case. In the case we are discussing, a game which uses Wesnoth's graphics, the graphics are already under GPL and so there is no question about whether it applies to them, should be they be distributed.

It's worth noting that the same citation from your position appears on the opengamerart.com faq: http://opengameart.org/content/faq#aren ... atible-gpl

But as far as I can tell, this isn't real legal advice and may or may not represent wishful thinking. You can live by this if you like, but for the same reasons I described above I don't find it too convincing.

I quoted those passages not as legal documents but to illustrate how the FSF interprets the GPL. After all the FSF holds the copyright to the GPL, and they are the authors of it.

For those reasons I believe you would have to supply the "source" for the image files but not the source for the GUI creation. Because the image files are a seperate "program" that you distribute while the program that creates the GUI is not distributed.

Right but the images that are *actually displayed* on the clients screen are clearly distributed. It doesn't matter if they aren't stored by the client's webbrowser by default, it doesn't matter if the client promises to delete them -- you are distributing them, and they are subject to GPL if your project derives in part from GPL'd work. The question is what constitutes a preferred modifiable format for those images.

... the preferred form to make changes to might be the html of the website that contains the images. You can change the gui by changing the html, and the user always has access to that source.

I agree in the described scenario. If the server doesn't do any server-side image processing, and the html really does determine they layout then you are probably right here. This is what I was trying to say above when I wrote:

(I guess I'm assuming that this arrangement isn't happening in HTML.)

My understanding is that for most of these games, layouts in HTML just don't cut it, and the server ends up stitching together the images and making a temporary bitmap available for the client. That's the part I'm trying to say should be released (in that scenario).

I was arguing under the assumption of talking about a browser-game (topic of thread), which are usually HTML based. Next thing that comes to my mind is a flash game using art from wesnoth. They probably would have to release the source I think, but I do think there is chance they wouldn't have to, based on the same arguments that so clearly apply for HTML bases browser games.

But I do think that this second argument is pretty weak. The argument that image and server-side code are not the same "program" is a strong though. (imho and ianal)

Sure it's debatable whether they are the same "program" in coloquial terms. But the term "Program" as used in GPL has special meaning, as we saw in section 0 -- it means the GPL'd work in the sense of copyright law. And so its clear that any work at all derived in whole or in part may be subject to GPL terms if distributed.

Again, this is all layman lawyering, IANAL IMHO. I'm simply advising how I would do things if I were in such a position -- also, I suppose this is a tactic that you might use to try to force someone using GPL'd code behind a web service to release at least some of their content under copyleft terms, if you wanted to use their modified images in your game or something.

If they are not the same "program" there is a chance they are also not the same work according to the definition in the GPL. Two programs can interact and still be considered a mere aggregation. https://www.gnu.org/licenses/gpl-faq.ht ... ggregation
And the Wordpress template letter says images that are unaltered used in a website are considered a different work.

I do agree that copyleft is a very good thing! But GPL isn't the only copyleft license out there, and it was never intended to be used for music and images. What disadvantage to the GPL do you see in licensing the art as CC-BY-SA? (or just CC-SA)

Licensing the art as CC-BY-SA has the disadvantage that it doesn't have anything to do with open source. I have the right to share and to remix, but a traditional (not web-based) game which uses CC-BY-SA content isn't required, so far as I can see, to open source their *code*, their engine, etc., the way they would be if the art were GPL.

There's no denying that GPL is a pain in the butt for developers. We do it because the benefits of copyleft outweigh these costs -- GPL'ing your content leads to more content being GPL'd which is better for everyone. As RMS loves to point out, we wouldn't have the gcc C++ compiler if GNU GPL wasn't written the way it was. If we really want people to share everything that they can, the best way to get them to do it is to use GNU GPL.

Can we in Wesnoth help with this at all? By being a prominent example of free software we help to some extent. But in terms of forcing others to GPL their code (edit: and their art!) by GPL'ing our key assets? Let's be realistic -- no one who is making a video game or other software is going to want to copy our C++ code. Our infrastructure has changed and changed again many times and the codebase is heavily balkanized and inconsistent. Developers of other games are just going to make their own. The only thing that anyone is realistically going to want to reuse is our art, and specifically our images and our music. Those are the only chips we have to bargain with, so let's not sell ourselves short. We should do everything we can to make sure that if another game wants to incorporate our great content, they have to open source everything under the terms of GPL. If we can convince any game developers to fully GPL their code and art when they otherwise wouldn't (and this may cascade as someone else who wants their content may GPL decide to GPL their own project), we are giving immeasurably back to the community and to the Free Software movement.

That's why I think the creative commons licenses don't quite cut it.

Doesn't all the trouble with applying the GPL to images and music stem from the source requirement?
A quote from the README that appeared in the music thread:

The game's source code and artwork, sound, and music assets are provided under
the terms of the GNU General Public License version 2, or (at your option) any
later version. Note that for artwork, sound, and music, we interpret
"preferred form of the work for making modifications" as the modifiable form
that the author chooses to ship us for the source tree. For convenience, a
reference copy of the GNU GPL version 2 is provided in the COPYING file in
this distribution.

Isn't that exactly what licensing the images and music with a CC-SA license would achieve? Note: the code would still be GPL'd but the art would be free from the requirement to provide source, which everyone seems to agree in the music thread is not really possible anyway.

Endnote: With neither of us being a lawyer, and while I believe my interpretation to be legally valid, I don't see myself in a position to reject your interpretation. For now I'm just gonna assume they both (I don't think they are that much different actually) are possibly correct and potentially legally sound until an actual legal expert can give me better insight.

[iceiceice]

Hi, last post here.

There are only two substantive points I want to make.

1.

If we agree on that, we agree that _only_ the "source" of the images is subject to the GPL.

I think that it would be helpful to draw attention to the term "work based on the Program":

0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it , either verbatim or with modifications and/or translated into another language.

...

2. You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, ... provided that you also meet all of these conditions:

...

b) You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.

...

5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works.

So, ANY derivative work of any work which contains portions of GPL content, which is then distributed, must be licensed under GPL. This is a significantly stronger than what you wrote. Additionally, don't forget section 3a:

3. You may copy and distribute the Program (or a work based on it, under Section 2) ... provided that you also do one of the following:

a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above ...

The source code for a work means the preferred form of the work for making modifications to it.

So besides GPL's terms applying to the derivative works, it also applies to their preferred modifiable formats, regardless of whether that is actually distributed with the program. (And typically it isn't, i.e. we don't distribute the source code of wesnoth with the wesnoth packages. That doesnt mean that we wouldn't be forced to GPL the source code.)

Since there is potentially something much more than the raw image files being distributed, you will have to decide / ask a lawyer what other derivative works are subject to the terms besides those.

2.

Everything that is not the same "program" as the images can be legally licensed in any way.

Sure if nothing besides the images which we base our work on is GPL or GPL derivative.

I bolded the part I think applies.
If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works.

Here is also another link with actual legal advice from the Software Freedom Law Center. It is about templates for word press and has even been linked here earlier. In that legal analysis they say "the CSS files and material contained in the images directory of the “default” theme are works separate from the WordPress code". What they are pointing out is: If they are separate works they can have different licenses. This works also in the case where the images are GPL and the rest of the code is non-free.

I think a key point here though is that CSS permits web content to totally separated from web design, and indeed even distributed separately to the end user. So its somewhat more extreme than the separation in other kinds of programs.

As you point out the FAQ describes how it might work for command line programs and libraries, here:
http://www.gnu.org/licenses/old-license ... GPLPlugins

Can I release a non-free program that's designed to load a GPL-covered plug-in?
It depends on how the program invokes its plug-ins. If the program uses fork and exec to invoke plug-ins, then the plug-ins are separate programs, so the license of the plug-in makes no requirements about the main program.
If the program dynamically links plug-ins, and they make function calls to each other and share data structures, we believe they form a single program, which must be treated as an extension of both the main program and the plug-ins. In order to use the GPL-covered plug-ins, the main program must be released under the GPL ...

but also here:
http://www.gnu.org/licenses/old-license ... ggregation

What is the difference between “mere aggregation” and “combining two modules into one program”?
Mere aggregation of two programs means putting them side by side on the same CD-ROM or hard disk. We use this term in the case where they are separate programs, not parts of a single program. In this case, if one of the programs is covered by the GPL, it has no effect on the other program.
Combining two modules means connecting them together so that they form a single larger program. If either part is covered by the GPL, the whole combination must also be released under the GPL—if you can't, or won't, do that, you may not combine them.

What constitutes combining two parts into one program? This is a legal question, which ultimately judges will decide. We believe that a proper criterion depends both on the mechanism of communication (exec, pipes, rpc, function calls within a shared address space, etc.) and the semantics of the communication (what kinds of information are interchanged).

If the modules are included in the same executable file, they are definitely combined in one program. If modules are designed to run linked together in a shared address space, that almost surely means combining them into one program.

By contrast, pipes, sockets and command-line arguments are communication mechanisms normally used between two separate programs. So when they are used for communication, the modules normally are separate programs. But if the semantics of the communication are intimate enough, exchanging complex internal data structures, that too could be a basis to consider the two parts as combined into a larger program.

http://www.gnu.org/licenses/old-license ... braryIsGPL

If a library is released under the GPL (not the LGPL), does that mean that any program which uses it has to be under the GPL?

Yes, because the program as it is actually run includes the library.

In the case of a computer game like wesnoth, the image data is clearly not a library or plugin, being communicated with via a simple interface like pipes. Rather, the client loads the entire image file at runtime into its memory, then makes it dance across the screen. Depending on what exactly you do in your web game it might be less complicated. I don't know, maybe you implement everything with CSS style sheets I suppose. But I certainly don't think that there is a wholesale exception carved out to think of images used by a game as "plugins" -- resources like images can be used in a completely different way from these, so you should be careful here, its going to depend alot on your implementation.

_Guidelines for Free Systems Distribution_

I quoted those passages not as legal documents but to illustrate how the FSF interprets the GPL. After all the FSF holds the copyright to the GPL, and they are the authors of it.

Yes, and I feel this was something of a misrepresentation. That page is not meant to describe "how the FSF interprets the GPL", (or any particular version of the GPL), and nothing on it gives that impression. It is describing rather guidelines for Linux distro maintainers who wish to have a relationship with FSF.

If they are not the same "program" there is a chance they are also not the same work according to the definition in the GPL.

Again, see the terms as they mean in GPL. They are the same "program" or work if there is a common derivative work which includes both or portions of both. And regardless, GPL terms may also apply to "works based on the program". In the FAQ, FSF suggests as a guideline to look at the communication between the modules as a guideline to judge when this is the case, but the guideline has no legal status. In cases where the guideline does not make sense, you aren't off the hook from the license.


-----

Doesn't all the trouble with applying the GPL to images and music stem from the source requirement?
A quote from the README that appeared in the music thread:

The game's source code and artwork, sound, and music assets are provided under
the terms of the GNU General Public License version 2, or (at your option) any
later version. Note that for artwork, sound, and music, we interpret
"preferred form of the work for making modifications" as the modifiable form
that the author chooses to ship us for the source tree. For convenience, a
reference copy of the GNU GPL version 2 is provided in the COPYING file in
this distribution.

Isn't that exactly what licensing the images and music with a CC-SA license would achieve? Note: the code would still be GPL'd but the art would be free from the requirement to provide source, which everyone seems to agree in the music thread is not really possible anyway.

Not exactly. The art would be free of the requriement to provide source, but if the art is used by a different game, they would not be required to provide any source from any of their game. What I want is that even if they only take our art, but not our code, they still essentially have to GPL their code (and similarly their art).

So instead of getting rid of the source requirement altogether, I just want to use a form of GPL that explicitly states either that image and sound files are excluded from the requirement, or that no particular format is considered to be the preferred modifiable source, etc. This way the source requirement still exists and has meaning for code, and it can still be "on" art files without causing any fractious debates, but they cause any code they touch to become open source.

Regarding the README:

Right. So actually IMO the situation we have is quite good, except that the terms of the README would ideally be a part of, or an addendum to, our licensing document, rather than a statement about our interpretation of the licensing document. Ideally it would state "for the purposes of this license, the preferred modifiable format of a sprite, portrait, or other image produced by an artist is considered to be the final result." and similarly for music and sound files. And also we should move to Affero GPL, IMO.

Edit: Hmm perhaps I shouldn't have brought this up, I guess it might not really be possible to retroactively add the Affero restrictions. But anyways if it could be done it would be nice.

~iceiceice~