This fast inverse square root function is also getting old. If it was a software patent, which are not recognized in many places, it would have expired a few years ago.

We're discussing copyright though, not patents, which for better or worse, have terms of almost a century.

In the US, the copyright lapses 95 years from publication, or 120 years from creation, or 70 years from author death, whichever is shortest.

So the inverse square root function will stay copyrighted until 2100 (the source was published in 2005 I believe).

This is minor, but it's at least a bit older than that. Via Wikipedia I found a link to the code on a Chinese forum in 2000: https://web.archive.org/web/20150702180504/http://bbs.csdn.n...