Improve recompute charts algorithm to avoid creating too many charts

[Ben-Mack]

I've just started to use xatlas and I'm really amazed by its speed and quality.

However, I've found that recompute charts created too many unnecessary charts (to the point that it looks more like an error). The problem is more visible in high poly meshes.
Disable recompute charts will create self-overlapped charts so it's not an option.

The default viewer with XA_RECOMPUTE_CHARTS enabled (522 charts), these small charts gonna create lots of lightmap seams:

XA_RECOMPUTE_CHARTS disabled looks great at first sight (55 charts):

But actually there're many self-overlapped charts:

It would be great if xatlas's recompute charts algorithm could be improved somehow.
Decreasing number of charts gonna benefit in many aspect: avoid lightmap seams, improve UV coverage when packing with padding...

This is the teapot FBX file: teapot-hi.zip (just the default teapot in 3ds Max with 32 segments)

[jpcy]

High-poly models with a lot of curved geometry like that tend to give poor results. Try the same teapot model with fewer segments.

[Ben-Mack]

I've just discovered the post of thekla_atlas author mentioned https://github.com/microsoft/UVAtlas saying that their stretch-minimization parameterization is certainly better than our plain LSCM. Maybe it would give you some idea.