Jenalya: Hello, I'm trying to find out if it violates the GPL to use GPL licensed graphics together with other licensed graphics, specifically CC-BY-SA, in the same game. I found this article in the creative commons wiki, http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems to base on the idea that it has to be seen as linking to combine graphics in a game, so GPL graphics can only be used with other GPL licensed graphics in a game. But I wasn't able to find anything specific about that in the FAQ of the GPL, and wondered if it rather falls under https://www.gnu.org/licenses/gpl-faq.html#MereAggregation I'd be very grateful if you could clarify that. Regards, Jessica Tölke ######################################################################## Yoni Rabkin: Hello and thank you for writing in. > I'm trying to find out if it violates the GPL to use GPL licensed > graphics together with other licensed graphics, specifically CC-BY-SA, > in the same game. > I found this article in the creative commons wiki, > http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems > to base on the idea that it has to be seen as linking to combine > graphics in a game, so GPL graphics can only be used with other GPL > licensed graphics in a game. > But I wasn't able to find anything specific about that in the FAQ of the > GPL, and wondered if it rather falls under > https://www.gnu.org/licenses/gpl-faq.html#MereAggregation The question of if one work is a derivative of another can be tricky to answer (indeed, as alluded to by the article you pointed out.) But perhaps I can be of some help if you could provide some additional important details: For each of the works in question, please specify its license and who is the copyright holder. For example: "The game FOO, written by Bob, is licensed under the terms of GPLv3. It includes graphics by Alice which are licensed under GPLv2+. Can Eve include her CC-BY-SA graphics in FOO and distribute the result?" If it is terribly important to remain anonymous feel free to use pseudonyms, but often it is easier for us to just go and download a copy of the code in question and study it directly if we are provided with those details. -- I am not a lawyer, the above is not legal advice Regards, Yoni Rabkin ######################################################################## Jenalya: Hello, thanks for the quick reply. I was asking the question in such a general way because I hoped there's an easy answer to it, but I can also give some background information about the circumstances: I'm involved in the development of "The Mana World", which is an open source online game developed and run by volunteers. Currently, everything in the project is licensed as GPL (2 or later) including graphics and sounds. The repository with the graphics can be found here: https://github.com/themanaworld/tmwa-client-data All repositories of the project can be found here: https://github.com/themanaworld At the moment we consider switching our policy about licenses for graphics and sounds from allowing only GPL to also allowing CC-BY-SA. If we can contact and get the agreement of all contributors to dual-license their work, we would like to switch to CC-BY-SA completely, since we think it's better suited for art. There is a sister project of TMW called Evol Online, where they already use CC-BY-SA for new art (https://gitorious.org/evol/clientdata-beta/blobs/master/LICENSE), but they also use graphics from TMW. It'd be beneficial for both projects to have the same or similar licensing situation, so art can be shared between the projects. When searching for information about the licenses, I found that it might be a unclear area whether we could use graphics that are licensed only as GPL (e.g. the playerset https://github.com/themanaworld/tmwa-client-data/blob/master/graphics/sprites/player_male_base.png) together with a graphic from evol, which is licensed only CC-BY-SA (e.g. https://gitorious.org/evol/clientdata-beta/blobs/master/graphics/sprites/equipment/hands/armbands-male.png ...actually I'm not sure if this one is only CC-BY-SA or if it's dual-licensed, but let's say what if it's only CC-BY-SA). The article from the creative commons wiki suggests that using the graphics together can be considered 'linking'. Another point of view would be to say it's 'Mere Aggregation'. Regarding of how the graphics are used together, the client program draws the graphics on top of each other during execution. Regards, Jessica Tölke On 04/18/2013 02:34 AM, Yoni Rabkin via RT wrote: > Hello and thank you for writing in. > >> I'm trying to find out if it violates the GPL to use GPL licensed >> graphics together with other licensed graphics, specifically CC-BY-SA, >> in the same game. >> I found this article in the creative commons wiki, >> http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems >> to base on the idea that it has to be seen as linking to combine >> graphics in a game, so GPL graphics can only be used with other GPL >> licensed graphics in a game. >> But I wasn't able to find anything specific about that in the FAQ of the >> GPL, and wondered if it rather falls under >> https://www.gnu.org/licenses/gpl-faq.html#MereAggregation > The question of if one work is a derivative of another can be tricky to > answer (indeed, as alluded to by the article you pointed out.) But > perhaps I can be of some help if you could provide some additional > important details: For each of the works in question, please specify its > license and who is the copyright holder. > > For example: "The game FOO, written by Bob, is licensed under the terms > of GPLv3. It includes graphics by Alice which are licensed under > GPLv2+. Can Eve include her CC-BY-SA graphics in FOO and distribute the > result?" > > If it is terribly important to remain anonymous feel free to use > pseudonyms, but often it is easier for us to just go and download a copy > of the code in question and study it directly if we are provided with > those details. > > -- > I am not a lawyer, the above is not legal advice > > Regards, Yoni Rabkin > ######################################################################## Yoni Rabkin: > Hello, > thanks for the quick reply. > I was asking the question in such a general way because I hoped there's > an easy answer to it, but I can also give some background information > about the circumstances: > I'm involved in the development of "The Mana World", which is an open > source online game developed and run by volunteers. > Currently, everything in the project is licensed as GPL (2 or later) > including graphics and sounds. The repository with the graphics can be > found here: https://github.com/themanaworld/tmwa-client-data > All repositories of the project can be found here: > https://github.com/themanaworld > At the moment we consider switching our policy about licenses for > graphics and sounds from allowing only GPL to also allowing CC-BY-SA. If > we can contact and get the agreement of all contributors to dual-license > their work, we would like to switch to CC-BY-SA completely, since we > think it's better suited for art. Both the GPL and CC-BY-SA require that you license derivative works under the same license. So both licenses cannot be simultaneously satisfied in a single work. We would need to prove to the satisfaction of the relevant copyright holders not only that the graphics are not a derivative of the game (the GPL's copyleft requirements) but that the game isn't a derivative of the graphics (CC-BY-SA's copyleft requirements.) The game is designed to require specific graphics files, and those graphics files are created for this game, so it wouldn't be unreasonable if someone assumed that they are mutually derivative. Thus even if the copyright holders of the GPL'd game code and graphics add an explicit exception to the GPL, permitting the combination from the GPL's side (see: http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs) we would still need a similar exception permitting the combination from the CC-BY-SA side (because we don't know if we fall under section 1.a or 1.b CC-BY-SA 2.0) The easiest, strictly from the licensing perspective, solution would be to have the work licensed as a whole under the terms of a single license. Artists may be persuaded to provide the project with a copy of their art under the terms of a GPL-compatible license (aka dual-licensing.) Feel free to write back and also to share our correspondence. I only ask that if you do so, that you share it verbatim and in full since context is important. > There is a sister project of TMW called Evol Online, where they already > use CC-BY-SA for new art > (https://gitorious.org/evol/clientdata-beta/blobs/master/LICENSE), but > they also use graphics from TMW. It'd be beneficial for both projects to > have the same or similar licensing situation, so art can be shared > between the projects. > When searching for information about the licenses, I found that it might > be a unclear area whether we could use graphics that are licensed only > as GPL (e.g. the playerset > https://github.com/themanaworld/tmwa-client-data/blob/master/graphics/sprites/player_male_base.png) > together with a graphic from evol, which is licensed only CC-BY-SA (e.g. > https://gitorious.org/evol/clientdata-beta/blobs/master/graphics/sprites/equipment/hands/armbands-male.png > ...actually I'm not sure if this one is only CC-BY-SA or if it's > dual-licensed, but let's say what if it's only CC-BY-SA). > The article from the creative commons wiki suggests that using the > graphics together can be considered 'linking'. Another point of view > would be to say it's 'Mere Aggregation'. > Regarding of how the graphics are used together, the client program > draws the graphics on top of each other during execution. > Regards, Jessica Tölke > On 04/18/2013 02:34 AM, Yoni Rabkin via RT wrote: >> Hello and thank you for writing in. >> >>> I'm trying to find out if it violates the GPL to use GPL licensed >>> graphics together with other licensed graphics, specifically CC-BY-SA, >>> in the same game. >>> I found this article in the creative commons wiki, >>> http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems >>> to base on the idea that it has to be seen as linking to combine >>> graphics in a game, so GPL graphics can only be used with other GPL >>> licensed graphics in a game. >>> But I wasn't able to find anything specific about that in the FAQ of the >>> GPL, and wondered if it rather falls under >>> https://www.gnu.org/licenses/gpl-faq.html#MereAggregation >> The question of if one work is a derivative of another can be tricky to >> answer (indeed, as alluded to by the article you pointed out.) But >> perhaps I can be of some help if you could provide some additional >> important details: For each of the works in question, please specify its >> license and who is the copyright holder. >> >> For example: "The game FOO, written by Bob, is licensed under the terms >> of GPLv3. It includes graphics by Alice which are licensed under >> GPLv2+. Can Eve include her CC-BY-SA graphics in FOO and distribute the >> result?" >> >> If it is terribly important to remain anonymous feel free to use >> pseudonyms, but often it is easier for us to just go and download a copy >> of the code in question and study it directly if we are provided with >> those details. >> >> -- >> I am not a lawyer, the above is not legal advice >> >> Regards, Yoni Rabkin >> >> >> -- I am not a lawyer, the above is not legal advice Regards, Yoni Rabkin ######################################################################## Jenalya: On 04/18/2013 06:15 PM, Yoni Rabkin via RT wrote: >> Hello, >> thanks for the quick reply. >> I was asking the question in such a general way because I hoped there's >> an easy answer to it, but I can also give some background information >> about the circumstances: >> I'm involved in the development of "The Mana World", which is an open >> source online game developed and run by volunteers. >> Currently, everything in the project is licensed as GPL (2 or later) >> including graphics and sounds. The repository with the graphics can be >> found here: https://github.com/themanaworld/tmwa-client-data >> All repositories of the project can be found here: >> https://github.com/themanaworld >> At the moment we consider switching our policy about licenses for >> graphics and sounds from allowing only GPL to also allowing CC-BY-SA. If >> we can contact and get the agreement of all contributors to dual-license >> their work, we would like to switch to CC-BY-SA completely, since we >> think it's better suited for art. > Both the GPL and CC-BY-SA require that you license derivative works > under the same license. So both licenses cannot be simultaneously > satisfied in a single work. > > We would need to prove to the satisfaction of the relevant copyright > holders not only that the graphics are not a derivative of the game (the > GPL's copyleft requirements) but that the game isn't a derivative of the > graphics (CC-BY-SA's copyleft requirements.) The game is designed to > require specific graphics files, and those graphics files are created > for this game, so it wouldn't be unreasonable if someone assumed that > they are mutually derivative. The game itself is run at the server, which reads in specific configuration files to define the actual game and doesn't need any graphic files. The client program uses the graphics as defined in the XML files provided in the client-data, and doesn't require specific graphic files. Though there of course is a connection between what is defined at the server-data side, and what is provided for use on client-data side, I think it's loose enough that I don't think the graphics' licenses are relevant for the code's license. Since it's even easily possible to play the game using custom data instead of the provided client-data. What my concerns are about is whether the graphics provided in the client-data are to be considered 'linked' from the GPL's perspective. Considering the client program reads them in only at runtime to display them together, I tend to say 'no'. But based on what I read in the article from creative commons, I became unsure. > Thus even if the copyright holders of the GPL'd game code and graphics > add an explicit exception to the GPL, permitting the combination from > the GPL's side (see: > http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs) we would > still need a similar exception permitting the combination from the > CC-BY-SA side (because we don't know if we fall under section 1.a or 1.b > CC-BY-SA 2.0) > > The easiest, strictly from the licensing perspective, solution would be > to have the work licensed as a whole under the terms of a single > license. Artists may be persuaded to provide the project with a copy of > their art under the terms of a GPL-compatible license (aka > dual-licensing.) > > Feel free to write back and also to share our correspondence. I only ask > that if you do so, that you share it verbatim and in full since context > is important. > >> There is a sister project of TMW called Evol Online, where they already >> use CC-BY-SA for new art >> (https://gitorious.org/evol/clientdata-beta/blobs/master/LICENSE), but >> they also use graphics from TMW. It'd be beneficial for both projects to >> have the same or similar licensing situation, so art can be shared >> between the projects. >> When searching for information about the licenses, I found that it might >> be a unclear area whether we could use graphics that are licensed only >> as GPL (e.g. the playerset >> https://github.com/themanaworld/tmwa-client-data/blob/master/graphics/sprites/player_male_base.png) >> together with a graphic from evol, which is licensed only CC-BY-SA (e.g. >> https://gitorious.org/evol/clientdata-beta/blobs/master/graphics/sprites/equipment/hands/armbands-male.png >> ...actually I'm not sure if this one is only CC-BY-SA or if it's >> dual-licensed, but let's say what if it's only CC-BY-SA). >> The article from the creative commons wiki suggests that using the >> graphics together can be considered 'linking'. Another point of view >> would be to say it's 'Mere Aggregation'. >> Regarding of how the graphics are used together, the client program >> draws the graphics on top of each other during execution. >> Regards, Jessica Tölke >> On 04/18/2013 02:34 AM, Yoni Rabkin via RT wrote: >>> Hello and thank you for writing in. >>> >>>> I'm trying to find out if it violates the GPL to use GPL licensed >>>> graphics together with other licensed graphics, specifically CC-BY-SA, >>>> in the same game. >>>> I found this article in the creative commons wiki, >>>> http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems >>>> to base on the idea that it has to be seen as linking to combine >>>> graphics in a game, so GPL graphics can only be used with other GPL >>>> licensed graphics in a game. >>>> But I wasn't able to find anything specific about that in the FAQ of the >>>> GPL, and wondered if it rather falls under >>>> https://www.gnu.org/licenses/gpl-faq.html#MereAggregation >>> The question of if one work is a derivative of another can be tricky to >>> answer (indeed, as alluded to by the article you pointed out.) But >>> perhaps I can be of some help if you could provide some additional >>> important details: For each of the works in question, please specify its >>> license and who is the copyright holder. >>> >>> For example: "The game FOO, written by Bob, is licensed under the terms >>> of GPLv3. It includes graphics by Alice which are licensed under >>> GPLv2+. Can Eve include her CC-BY-SA graphics in FOO and distribute the >>> result?" >>> >>> If it is terribly important to remain anonymous feel free to use >>> pseudonyms, but often it is easier for us to just go and download a copy >>> of the code in question and study it directly if we are provided with >>> those details. >>> >>> -- >>> I am not a lawyer, the above is not legal advice >>> >>> Regards, Yoni Rabkin >>> >>> >>> > > -- > I am not a lawyer, the above is not legal advice > > Regards, Yoni Rabkin > ######################################################################## Yoni Rabkin: > What my concerns are about is whether the graphics provided in the > client-data are to be considered 'linked' from the GPL's perspective. What about the CC-BY-SA perspective? It is a copyleft license as well. I realize that we are used to thinking of the GPL being the only copyleft in a given situation, but this isn't the case. > Considering the client program reads them in only at runtime to > display them together, I tend to say 'no'. But based on what I read in > the article from creative commons, I became unsure. I think it makes sense to be unsure in this case. I've outlined concerns from our perspective in my previous answers, as well as potential solutions. >> Thus even if the copyright holders of the GPL'd game code and >> graphics add an explicit exception to the GPL, permitting the >> combination from the GPL's side (see: >> http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs) we >> would still need a similar exception permitting the combination from >> the CC-BY-SA side (because we don't know if we fall under section >> 1.a or 1.b CC-BY-SA 2.0) >> >> The easiest, strictly from the licensing perspective, solution would be >> to have the work licensed as a whole under the terms of a single >> license. Artists may be persuaded to provide the project with a copy of >> their art under the terms of a GPL-compatible license (aka >> dual-licensing.) >> >> Feel free to write back and also to share our correspondence. I only ask >> that if you do so, that you share it verbatim and in full since context >> is important. >> >>> There is a sister project of TMW called Evol Online, where they already >>> use CC-BY-SA for new art >>> (https://gitorious.org/evol/clientdata-beta/blobs/master/LICENSE), but >>> they also use graphics from TMW. It'd be beneficial for both projects to >>> have the same or similar licensing situation, so art can be shared >>> between the projects. >>> When searching for information about the licenses, I found that it might >>> be a unclear area whether we could use graphics that are licensed only >>> as GPL (e.g. the playerset >>> https://github.com/themanaworld/tmwa-client-data/blob/master/graphics/sprites/player_male_base.png) >>> together with a graphic from evol, which is licensed only CC-BY-SA (e.g. >>> https://gitorious.org/evol/clientdata-beta/blobs/master/graphics/sprites/equipment/hands/armbands-male.png >>> ...actually I'm not sure if this one is only CC-BY-SA or if it's >>> dual-licensed, but let's say what if it's only CC-BY-SA). >>> The article from the creative commons wiki suggests that using the >>> graphics together can be considered 'linking'. Another point of view >>> would be to say it's 'Mere Aggregation'. >>> Regarding of how the graphics are used together, the client program >>> draws the graphics on top of each other during execution. >>> Regards, Jessica Tölke >>> On 04/18/2013 02:34 AM, Yoni Rabkin via RT wrote: >>>> Hello and thank you for writing in. >>>> >>>>> I'm trying to find out if it violates the GPL to use GPL licensed >>>>> graphics together with other licensed graphics, specifically CC-BY-SA, >>>>> in the same game. >>>>> I found this article in the creative commons wiki, >>>>> http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems >>>>> to base on the idea that it has to be seen as linking to combine >>>>> graphics in a game, so GPL graphics can only be used with other GPL >>>>> licensed graphics in a game. >>>>> But I wasn't able to find anything specific about that in the FAQ of the >>>>> GPL, and wondered if it rather falls under >>>>> https://www.gnu.org/licenses/gpl-faq.html#MereAggregation >>>> The question of if one work is a derivative of another can be tricky to >>>> answer (indeed, as alluded to by the article you pointed out.) But >>>> perhaps I can be of some help if you could provide some additional >>>> important details: For each of the works in question, please specify its >>>> license and who is the copyright holder. >>>> >>>> For example: "The game FOO, written by Bob, is licensed under the terms >>>> of GPLv3. It includes graphics by Alice which are licensed under >>>> GPLv2+. Can Eve include her CC-BY-SA graphics in FOO and distribute the >>>> result?" >>>> >>>> If it is terribly important to remain anonymous feel free to use >>>> pseudonyms, but often it is easier for us to just go and download a copy >>>> of the code in question and study it directly if we are provided with >>>> those details. >>>> >>>> -- >>>> I am not a lawyer, the above is not legal advice >>>> >>>> Regards, Yoni Rabkin >>>> >>>> >>>> >> >> -- >> I am not a lawyer, the above is not legal advice >> >> Regards, Yoni Rabkin >> >> >> -- I am not a lawyer, the above is not legal advice Regards, Yoni Rabkin ######################################################################## Jenalya: On 04/18/2013 08:05 PM, Yoni Rabkin via RT wrote: >> What my concerns are about is whether the graphics provided in the >> client-data are to be considered 'linked' from the GPL's perspective. > What about the CC-BY-SA perspective? It is a copyleft license as well. I've been discussing with someone from creative commons about the same topic, and he didn't see a problem from creative commons' side, as far as I understood because the creative commons doesn't have the same concept of linking as in GPL written for software. But it seems this is another unclear point. Thanks for your input on this! > I realize that we are used to thinking of the GPL being the only > copyleft in a given situation, but this isn't the case. > >> Considering the client program reads them in only at runtime to >> display them together, I tend to say 'no'. But based on what I read in >> the article from creative commons, I became unsure. > I think it makes sense to be unsure in this case. I've outlined concerns > from our perspective in my previous answers, as well as potential > solutions. > >>> Thus even if the copyright holders of the GPL'd game code and >>> graphics add an explicit exception to the GPL, permitting the >>> combination from the GPL's side (see: >>> http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs) we >>> would still need a similar exception permitting the combination from >>> the CC-BY-SA side (because we don't know if we fall under section >>> 1.a or 1.b CC-BY-SA 2.0) >>> >>> The easiest, strictly from the licensing perspective, solution would be >>> to have the work licensed as a whole under the terms of a single >>> license. Artists may be persuaded to provide the project with a copy of >>> their art under the terms of a GPL-compatible license (aka >>> dual-licensing.) >>> >>> Feel free to write back and also to share our correspondence. I only ask >>> that if you do so, that you share it verbatim and in full since context >>> is important. >>> >>>> There is a sister project of TMW called Evol Online, where they already >>>> use CC-BY-SA for new art >>>> (https://gitorious.org/evol/clientdata-beta/blobs/master/LICENSE), but >>>> they also use graphics from TMW. It'd be beneficial for both projects to >>>> have the same or similar licensing situation, so art can be shared >>>> between the projects. >>>> When searching for information about the licenses, I found that it might >>>> be a unclear area whether we could use graphics that are licensed only >>>> as GPL (e.g. the playerset >>>> https://github.com/themanaworld/tmwa-client-data/blob/master/graphics/sprites/player_male_base.png) >>>> together with a graphic from evol, which is licensed only CC-BY-SA (e.g. >>>> https://gitorious.org/evol/clientdata-beta/blobs/master/graphics/sprites/equipment/hands/armbands-male.png >>>> ...actually I'm not sure if this one is only CC-BY-SA or if it's >>>> dual-licensed, but let's say what if it's only CC-BY-SA). >>>> The article from the creative commons wiki suggests that using the >>>> graphics together can be considered 'linking'. Another point of view >>>> would be to say it's 'Mere Aggregation'. >>>> Regarding of how the graphics are used together, the client program >>>> draws the graphics on top of each other during execution. >>>> Regards, Jessica Tölke >>>> On 04/18/2013 02:34 AM, Yoni Rabkin via RT wrote: >>>>> Hello and thank you for writing in. >>>>> >>>>>> I'm trying to find out if it violates the GPL to use GPL licensed >>>>>> graphics together with other licensed graphics, specifically CC-BY-SA, >>>>>> in the same game. >>>>>> I found this article in the creative commons wiki, >>>>>> http://wiki.creativecommons.org/GPL_compatibility_use_cases which seems >>>>>> to base on the idea that it has to be seen as linking to combine >>>>>> graphics in a game, so GPL graphics can only be used with other GPL >>>>>> licensed graphics in a game. >>>>>> But I wasn't able to find anything specific about that in the FAQ of the >>>>>> GPL, and wondered if it rather falls under >>>>>> https://www.gnu.org/licenses/gpl-faq.html#MereAggregation >>>>> The question of if one work is a derivative of another can be tricky to >>>>> answer (indeed, as alluded to by the article you pointed out.) But >>>>> perhaps I can be of some help if you could provide some additional >>>>> important details: For each of the works in question, please specify its >>>>> license and who is the copyright holder. >>>>> >>>>> For example: "The game FOO, written by Bob, is licensed under the terms >>>>> of GPLv3. It includes graphics by Alice which are licensed under >>>>> GPLv2+. Can Eve include her CC-BY-SA graphics in FOO and distribute the >>>>> result?" >>>>> >>>>> If it is terribly important to remain anonymous feel free to use >>>>> pseudonyms, but often it is easier for us to just go and download a copy >>>>> of the code in question and study it directly if we are provided with >>>>> those details. >>>>> >>>>> -- >>>>> I am not a lawyer, the above is not legal advice >>>>> >>>>> Regards, Yoni Rabkin >>>>> >>>>> >>>>> >>> -- >>> I am not a lawyer, the above is not legal advice >>> >>> Regards, Yoni Rabkin >>> >>> >>> > > -- > I am not a lawyer, the above is not legal advice > > Regards, Yoni Rabkin > > ######################################################################## Yoni Rabkin: "Jessica Tölke via RT" writes: > I've been discussing with someone from creative commons about the same > topic, and he didn't see a problem from creative commons' side, as far > as I understood because the creative commons doesn't have the same > concept of linking as in GPL written for software. That's interesting to know. Thanks.