OpenGL vector map library - running on Android, iOS

I'm trying to develop a cross platform (ios/android) navigation app which requires maps, polylines, markers, (preferably , but not essentially offline routing), so far nothing is quite as flexible as I want it to be and obviously I need to stay away from google services.
I've been playing with @warwound 's OSM/mapsforge library and some navigation backends such as mapquest ,project-OSRM and openrouteservice.org.
I can't style maps with the OSMdroid4_1 library and I can't access the OSM data embedded in OSM's offline mapfiles for the likes of poi's and navigation.

It occurs to me that perhaps three platforms within b4x (java/ios/android) could benefit from the OPENGL vector map library ,styled maps and provide a rather stunning 3d interface which is arguably on par with the current google maps

https://jitpack.io/p/mapsforge/vtm
https://github.com/mapsforge/vtm/blob/master/docs/Integration.md

There is a good example here, cruiser : appstore, https://play.google.com/store/apps/details?id=gr.talent.cruiser&hl=en_US

Interested in thoughts on this, how many might use it , and how many hours /$ it might take to get something like this working on b4A

I managed to compile b4a part but still no working sample , I will see if I can complete it