I worked on a short script a while back that parses OSM data and uses it in Unity 3D. It was written in C#.
You can grab it and contribute to the project here: https://sourceforge.net/projects/osm2unity/
It is a very crudely-written script. It was a quick, messy attempt to actually get the data from OSM into Unity. There are lots of issues with it, the main one being how SLOW it is, probably because of the constant referencing back and forth between arrays. I originally wrote this code for myself for s and giggles, so I didn’t comment it, but it’s rather short and straight-forward (hurray for Structs).
Suggestions always welcome