Rendering of Vector Tiles is not that hard as all the geometry is already processed, polygons assembled and data sorted. If you have good source of vector tiles renderer itself can be relatively dumb.

I was able to implement relatively straightforward renderer in Nim language[0].

I have encountered only three hard parts:

- rendering map labels on paths (this is really hard!) - how to render labels not to be clipped by tile boundary (I had some ideas but did not implemented it yet) - collisions between labels and symbols

[0] - https://github.com/severak/lunarender3/