[thomasikzelf]

You can do anti aliasing in the fragment shader using 4 vertices per segment. See: Shader-Based Antialiased Dashed Stroked Polylines- Nicolas Rougier

And:

https://blog.mapbox.com/drawing-antialiased-lines-with-openg...

I am also rendering round caps in the fragment shader. You can then render multiple lines with 1 draw call. The only problem is drawing transparent lines, because of the overlap between segments.