Interesting, didn't know this kind of feature support was possible. I
guess it's still better than no GLES3.2 at all. Also, it's a phone from
2017, so probably not all that important to care about anymore anyway.
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.
The shader requires the input data to be laid out in a rather specific
way, and there will be a dedicated MeshTools utility for it in the
following commits. For independence though, the shader tests use a
custom helper.
The initial implementation has certain corner cases which will be
eventually resolved. For now they are pinned down with repro cases in
the test. But apart from that, it's pretty much usable in practice.
Remaining join styles (round and miter-clip) as well as stipple support
will eventually follow as well.
Vladimír Vondruš