Game development Open source software Open source software Use of open source software (OSS) A ‘copy left licence’ – this is has grown exponentially in the restrictive. It generally requires gaming industry, as it can generally any derivative works to also be be used without royalties or explicit licensed under the same terms as consent, gives developers access the original OSS. For example, if a to a huge library of code, enables game engine is licensed under the collaboration and community GNU General Public License (GPL), involvement, and importantly, opens anyone who distributes the engine up resource for developers to focus or derivative works based on it on the novel elements of the game must also distribute their source that will ultimately determine the code under GPL, including games game’s legacy. built using that engine. Most OSS is supplied under a licence. The key risk here is that you There are many different licences, unknowingly incorporate copy left and the types of restrictions under OSS into your game’s proprietary them can vary greatly, but generally code, which in turn requires that OSS licences fall into one of two derivative code to be made available camps: on the same terms as the original A ‘permissive licence’ – this is OSS copy left licence (commonly flexible. It allows for derivative referred to as ‘infecting’ the code). works to be re-licensed under a If your game then becomes a different licence to the original huge success, this may come to OSS. This means developers can the attention of the author of the incorporate permissively licensed original OSS, who could threaten OSS and publish the game (with enforcement action against you for the modified code) under a not having complied with the original closed-source model. copy left licence terms. 49