Funny timing on this post, I just finished implementing this a couple days ago for a little effect in a game. I followed the math in this comment that is now only viewable from the archive http://web.archive.org/web/20190614093605/https://forum.libc...
I notice you use 4 triangles per segment but I believe it's always possible to use only 2 if you only have miter and bevel caps.
I notice you use 4 triangles per segment but I believe it's always possible to use only 2 if you only have miter and bevel caps.