earcut (Rust)

A Rust port of the mapbox/earcut polygon triangulation library.

• Based on the latest earcut 3.0.2 release.
• Designed to avoid unnecessary memory allocations. Internal buffers and the output index vector can be reused across multiple triangulations.
• Also provides earcut::int::EarcutI32 for integer coordinates with exact integer predicates, but it can be slower than the float-based Earcut on modern CPUs.
• An additional module, utils3d, can project 3D coplanar polygons onto a 2D plane before triangulation.

Benchmarks

Time per iteration (smaller is better). Measured on a MacBook Pro (M1 Pro).

Polygon	earcut.hpp (C++)	earcut (Rust)
bad_hole	3.53 µs/i	2.712 µs/i
building	351 ns/i	157 ns/i
degenerate	153 ns/i	41 ns/i
dude	5.21 µs/i	4.204 µs/i
empty_square	201 ns/i	67 ns/i
water	420 µs/i	345.8 µs/i
water2	338 µs/i	249.7 µs/i
water3	13.5 µs/i	11.91 µs/i
water3b	1.27 µs/i	1.087 µs/i
water4	88.9 µs/i	67.40 µs/i
water_huge	6.674 ms/i	7.059 ms/i
water_huge2	15.23 ms/i	14.82 ms/i

Note: earcut.hpp has not fully caught up with the latest mapbox/earcut.

Demo

A simple egui-based visualizer for inspecting how earcut works.

cargo run --example visualizer

License

Licensed under either the MIT License (LICENSE-MIT) or the Apache License 2.0 (LICENSE-APACHE) at your option.

This project contains portions derived from mapbox/earcut, originally distributed under the ISC License (LICENSE-ISC).