I remember having to write something similar for Lua, because there was no math.approximately() function and I was dealing with networking floats and comparing values over the wire to predicted movement in 2D space.

https://github.com/Planimeter/grid-sdk/blob/master/engine/sh...

https://en.wikipedia.org/wiki/Machine_epsilon

https://pubs.opengroup.org/onlinepubs/009696899/basedefs/flo...