I’m not sure I quite get it, but if I’m following correctly, you’re using the numbers to indicate a sequence of vertices for a triangle fan here (with indicating the central vertex), right? If so, the vertices are used in more than one triangle; (0, 1, 2) and (0, 2, 3) are triangles that reuse vertex 0 () and vertex 2.
If that’s what’s going on then it should be fairly straightforward to turn shapes defined like this into extrusions; for the simplest case you duplicate and offset the triangle fan for the other end and then generate quads/pairs of triangles for the extruded faces of the prism – and for more complicated cases you can repeat that (with planar alignment if needed) following a curve in small increments.
I might not be following though since I don’t know what you mean by color index face hints.
OK. I think I see what you’re getting at. If you can figure out how to get it to the point of an outline, there are triangulation libraries that can fill in the mesh for you (I think I’ve mentioned one to you before a long time ago) if you want flat end caps on the extrusion. I’m not sure off the top of my head how you’d get to an outline from that star example though – a few ideas come to mind, but they’re very much half-baked ideas… :p
Best of luck!
Edit: the triangulation library I was thinking of: https://github.com/mapbox/earcut