The creative commons abbreviations is fairly simple. The first, "cc" is obviously short for "Creative Commons", which tells you what the license is. The groups of letters that follow the "cc" then details the requirements of the creative commons license.

So, armed with that knowledge, "cc by sa" requires two things:

1. "by" is reference to the author. You must give appropriate credit, provide a link to the license, and indicate if changes were made.

Usually the "appropriate credit" is the artists name and the url to find their work. A lot of artists here will just say to link to OGA, however some will require their own website instead. Check with each author first how they want to be attributed.

2. "sa" is "share alike", so if you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.

For example, you take an image where the background of an image is white, and for your game you remove the white background to be transparent, the license requires you with the by clause to note what assets you changed, and with the sa clause to share your modifications. Embedding them inside a game isn't "shared" - however posting the modified art here or on your own website for others to freely download is definitely shared, but you will have to link to it.

One of the things about the work that is available here on OGA is that the "nc" clause (non commercial use only) is not allowed here, so the commercial aspect of your game is irrelevant to the usage of the asset.

Some additional points:

you must specify that you used the works under terms of the cc-by license and include a copy of the cc-by license with your distribution.

cc-by/cc-by-sa both include an 'anti-DRM' clause in them, meaning you can't distribute the works through channels that impose some sort of DRM on the works (eg. IOS AppStore, XBLive, PSN, possibly Steam/Android depending on how you slice things)   As a rule of thumb, end users must be able to directly access the source images, sound files, etc. whenever/wherever they download the work.   For example, on PC, if you distribute the works along side the executable for your game, they should be stored in a well named file and folder structure and in their native file formats (jpg, png, mp3, etc).

If you have created new works based on cc-sa stuff, you don't have to share them with the world, but if you do (including sharing them via your game) you must distribute them under terms of the cc-by-sa license.  That means specifying them as under cc-by-sa and including them in your game distribution as I just described for other cc-by-sa assets.   It nevers hurst to post them to OGA also!  :)

tldr;

don't distribute cc-by/sa assets on DRM'd platforms.

include cc-by/sa assets in their native formats in your game distribution 

include the full text of the cc-by/sa license(s) with your game distribution 

Include a 'readme.txt' or 'licenses.txt' file with your game, listing which assets are used, crediting their authors and specifying which license(s) they are used undsr 

Whoops, let me add to tldr;

distribute derivatives of cc-by-sa works as cc-by-sa

No, the license only applies to the assets in question. You can have a combination of cc-by-sa assets and private assets, but the license is per asset that it applies to.

Your code and other assets you own are not applied. You are confusing the cc license with a GPL license, and they are very different.

Unfortuately the question of whether the licence applies to the entire game is unclear for both CC BY SA and the GPL. In practice most people seem to assume that it doesn't (and it would be a right pain, especially for CC BY SA, if this was the case). I don't think it's been tested in court one way or the other.

Distribution on Google Play is fine, Google offer DRM but it is not required. (And DRM certainly isn't an issue for distrbuting Android applications elsewhere.) As far as I know, DRM is optional for Steam too.

"For example, on PC, if you distribute the works along side the executable for your game, they should be stored in a well named file and folder structure and in their native file formats (jpg, png, mp3, etc)."

This can be nice to do, but note there is no legal requirement to structure it in this way. Indeed, converting to alternative formats as required is certainl allowed under all free licence on OGA.

You must include cc-by/sa assets in a common file format that end user could easily use to open/modify the work themselves if they wanted.   I mention this because it is not wholly uncommon for games to re-package assets into their own file format schemes.   As an example, for textures, it's not uncommon to have some kind of build step that compresses them into some kind of a raw gl/direct format in order to speed load times.  I've also seen plenty of devs that like to bundle all the files for their game into a single file with some kind of zip or otherwise compressed format.   Pretty sure distributing cc-by/sa works like this would be violation of the license.   Though for sure, if you just flip a PNG to a JPG that is ok.

re: android/steam, as with so many things license related, I have seen it argued both ways.  But for sure with Android, you would want to take care to distribute without google's DRM feature.

I can't speak for how the LPC team would like their stuff credited, but I can say for satisfying the license it should be fine.  You may want to add the text 'see CC-BY-SA-3.0.txt for details.' to each of the license call outs.  

That looks fine, though you should also include the URLs of the relevant CC licences (or alternatively include the full licence texts, but URLs are easier).

@capbros What sources argue that Google Play and Steam enforce DRM? I believe the information for enabling DRM for Google Play is at https://developer.android.com/google/play/licensing/index.html . This does not seem to be the kind of thing that one could enable without realising. For Steam, I note there are plenty of articles listing DRM-free games on Steam.

"You must include cc-by/sa assets in a common file format that end user could easily use to open/modify the work themselves if they wanted.   I mention this because it is not wholly uncommon for games to re-package assets into their own file format schemes.   As an example, for textures, it's not uncommon to have some kind of build step that compresses them into some kind of a raw gl/direct format in order to speed load times.  I've also seen plenty of devs that like to bundle all the files for their game into a single file with some kind of zip or otherwise compressed format.   Pretty sure distributing cc-by/sa works like this would be violation of the license."

I can't see where in the licences it says this?

There is no requirement AFAIK that the recipient must be able to reconstruct or directly access the original work, otherwise that would be problematic for derivative works (e.g., distributing a rendered image that uses CC BY models or textures doesn't require inclusion of those models or textures in a common format). As you note, repackaging or converting to more suitable formats is common practice for games, so would be problematic.

I can see that argument applying to the GPL, if such things were deemed to be the "source", but CC licences having nothing like that. (Even for the GPL, there's no requirement to bundle all of the source formats with your binary distribution, instead you just have to offer it as a separate download.)

Bundling the files into a single compressed file is certainly allowed. If it wasn't, an awful lot of pages on OGA where files are bundled into a zip would be violating this.

Note, the bit about technical restrictions is specifically defined as "A technological measure is considered an ETM if circumventing it carries penalties under laws fulfilling obligations under Article 11 of the WIPO Copyright Treaty adopted on December 20, 1996, or similar international agreements." ( https://creativecommons.org/faq/ ). It's intended to address the problem that even if I'm able to get round DRM, in many countries I'd be breaking the law to do so. But I'm not breaking the law to unzip an zip file - nor does putting it in a zip stop me from redistributing. It's about preserving people's right to allow redistribution, but if the work has been transformed, the originals don't have to be supplied.

The FAQ says "Note that merely converting material into a different format that is difficult to access ... does not violate the restriction".

@mdwh:   You are correct.   Not sure where I got that idea but indeed the cc faq directly addresses this very point twice and very clearly states that distributing a work in whatever format you wish is permitted by all cc licenses.

https://creativecommons.org/faq/#when-i-release-my-work-under-a-cc-licen...

And

https://creativecommons.org/faq/#can-i-take-a-cc-licensed-work-and-use-i...

TBH, even in GPL land, you are not required to include source with every distribution of a work, you only agree to make it available upon request. 

As far as android/steam, all I can say is somewhere in these forums.  TBH, i haven't investigated the issue personally myself so my default advice is simply to flag it is a possible concern.   However, as I have been working on the OGA faq rewrite it's probably worth looking into for that.  My main concerns would be how broadly 'technical measures' is defined and what is buried in the fine print of the Google Play and Steam EULA.

So reading through the Steam EULA:

http://store.steampowered.com/subscriber_agreement/

There doesn't seem to be anything explicit about DRM in there (not too surprising since it is a legal not technical document but there are definitely a fair number of 'additional restrictions' placed on what you can do with works distributed via Steam.  Ex.

You are entitled to use the Content and Services for your own personal use, but you are not entitled to: (i) sell, grant a security interest in or transfer reproductions of the Content and Services to other parties in any way, nor to rent, lease or license the Content and Services to others without the prior written consent of Valve, 

I guess the idea would be, these terms apply to your game but not the cc assets it uses, which are distributed along side it but under a different license.  However, I don't see anywhere in the Steam EULA where it allows for that, or implies that anything distributed on Steam could be subject to different terms (more restrictive terms yes, but wholly different terms no).   Since this seems like pretty boilerplate stuff that I'd imagine most storefront EULA's would include, I think I'll try contacting both CC and Valve to see if either can provide any guidance on fhr question.

Googling 'can I use cc-by work in steam game' found this discussion:

http://opensource.stackexchange.com/questions/175/can-i-redistribute-cc-...

If you look at the first answer, he outlines three options for using CC stuff with DRM'd services:

* Referring to the CC media rather than including it (downloaded from the web)

* Publishing a link (inside the app) to the CC media in an approved non-drm mechanism.

* Including the CC media in a form that is unprotected.

My memory is foggy, but if I had to guess, I'd say I have probably read this or similar analysis before, which is most likley where I got the idea you should include CC-BY/SA in their original form in your game distribution.  The idea is you can use DRM to restrict access/use of your game you just can't use it to restrict use/access of the CC-BY/SA works.  By including the works in a common format in your game distribution, you are allowing the end user to exercise their full CC-BY/SA rights to the work even if they must use DRM to access/run your game.  TBH, this seems like the something that meets the license in spirit and practical terms, but may not actually meet the bar legally.  As previously noted, I don't see anyway w/in the Steam EULA to exclude certain items from it's terms, terms which clearly place additional restrictions on a work's use.

Note that for the entire discussion it is simply assumed that Steam constitutes DRM.  So here is one place where the point is maybe not argued but certainly stated.  Not trying to argue that point myself either, just pointing out that I've seen it stated both ways, which is why I have taken to flagging it as a potential issue.  Whereas, going the other way, nobody ever argues that IOS, PSN or XBL /don't/ constitute DRM, so in those cases I think it's fine to state unequivocally that they use DRM.

Further down in that thread is an interesting discussion of what I think is a new feature to CC-BY/SA 4.0.  That is an explicit waiver by the copyright holder of the right to sue/etc someone for cracking/hacking a DRM scheme in order to access the CC-BY/SA work.  In other words, you can break/crack a DRM scheme to access a CC-BY/SA work.  It's an interesting idea, although it doesn't exonerate one for distributing a CC-BY/SA work with DRM and I'm not sure it's sufficient to prevent a Valve or other platform holder for going after someone for cracking their DRM to access a work.  I mean, it seems like it should, but I'm sure Valve, et. al. have the fine print and lawyers to go after people who tinker with their DRM schemes anyways.

Hello 

My team and I are working on a project it's a 2D side scroller under the name Ignis, it is not funded. While looking for sprites we came accross your sprite sheet, it is very well made and we would love to use it for our project. We give you our word of giving credit for your hard work. We will ony be making aesthetic & minor changes to it; for example hair, color, scarring, age etc... We hope to hear from you soon and would really appreciate this oportunity. It is very important that you reply to this message promptly so that we can take action and continue with our project.

Regards, Vivian G.

Hello. Welcone to OGA!

I'm not sure which sprite sheet you are referring to. If you mean one of the main entries, they all have licence informarion in the top left. Read that, and it should tell you what their requirements are. Arts in comment threads is less obvious; you generally need to read the thread, and if it's not clear, ask there. All the licences are open; that means you will be able to use the art so long as you follow the rules and they tend not to be ardous, although this thread is about a licence that is perhaps difficult to interpret.

As an aside, I am sure you didn't mean to sound pushy, but remember: we all give our time for free, including answering questions about licencing, so you can't always expect a prompt response to questions. We all have lives. :)

Having said that, it's lovely to see people who want to build stuff. Good luck with your project, and tell us how you get on! Post something on the thread showing off your work.

Hello

Thank you for your prompt reply. I do appreciate you taking your time to answer my question. We will be moving forward with the project and posting updates.