Just the dumbest possible idea I had, and it compares surprisingly well
in both efficiency (~comparable to stb_rect_pack) and speed
(significantly faster than stb_rect_pack with tons of tiny images,
slower with larger ones -- would probably need to SIMD Math::max() and
such, haha). It's the very first implementation without any additional
improvements I have in mind, so it'll likely improve further.
Includes a benchmark with a bunch of "datasets" extracted from both
fonts and large glTF models. The stb_rect_pack file isn't commited as
it's not useful apart from this single benchmark, put it to
AtlasTestFiles/ and recompile.
Vladimír Vondruš