This is unfortunately a breaking change to compileLines(), which now
takes the output of generateLines() instead of a line mesh. There's a
new assertion that'll blow up if the code is used the previous way,
sorry for the breakage.
What's however very useful about this change is that now it's possible
to take those generated line meshes and concatenate() them together,
achieving what's otherwise not implemented yet, such as drawing several
disconnected line strips or loops together.
It's all still partially private (the custom mesh attribute names are)
and I'm marking both APIs as experimental now to hint that it's not in
the final form/functionality yet. In particular, the data layout
optimizations described in the shader docs aren't used by these tools
yet, and if/once the line-specific vertex attributes become builtin,
compileLines() will not need to exist anymore as compile() will handle
that directly.
Currently just the bare minimum, more features such as handling
multiple contiguous strips and loops inside a single mesh or an
overlapping layout will come later.
Vladimír Vondruš