fwiw, Spine is made using libgdx [1], which is open source. The various stretch-goal animation runtimes are also available [2] on Github.<p>AFAIK the team behind both libgdx and Spine are quite good at giving back to the community. After libgdx they quit their day jobs and went full-time as Esoteric Software [3] and did an excellent job following through with Spine&#x27;s two kickstarters.<p>I think this is very relevant to HN not only because of the guys&#x27; open source contributions but also their entrepreneurial history (success?).<p>[1] <a href="https:&#x2F;&#x2F;github.com&#x2F;libgdx&#x2F;libgdx" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;libgdx&#x2F;libgdx</a>
[2] <a href="https:&#x2F;&#x2F;github.com&#x2F;EsotericSoftware&#x2F;spine-runtimes" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;EsotericSoftware&#x2F;spine-runtimes</a>
[3] <a href="http:&#x2F;&#x2F;esotericsoftware.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;esotericsoftware.com&#x2F;</a><p>(I&#x27;m not affiliated with ES but was a backer of Spine and am a user of libgdx)