dart_earcut
Earclipping (earcutting) triangulation algorithm, ported (with minor API differences) from earcut4j/earcut4j and mapbox/earcut. Also includes the fix from mapbox/earcut#91.
Usage

2D (x/y) coordinates, without holes
triangulateRaw
: expects points in the format[x0, y0, x1, y1, x2, y2, ...]
triangulateFromPoints
: expects 'dart:math'sPoint
objects
final triangles = Earcut.triangulateRaw([10,0, 0,50, 60,60, 70,10]); final triangles = Earcut.triangulateFromPoints([Point(10, 0), Point(0,50), Point(60,60), Point(70,10)]); // Both return [1,0,3, 3,2,1]

Holes
A list of hole indicies, if any. For example,[5, 8]
for a 12vertice input would mean one hole with vertices 57 and another with 811. If you pass a single vertice as a hole, Earcut treats it as a Steiner point.final List<int> triangles = Earcut.triangulateRaw([0, 0, 100, 0, 100, 100, 0, 100, 20, 20, 80, 20, 80, 80, 20, 80], holeIndices: [4]); // Returns [3,0,4, 5,4,0, 3,4,7, 5,0,1, 2,3,7, 6,5,1, 2,7,6, 6,1,2]

More dimensions
Expected to be in the format[x0, y0, z0, x1, y1, z1, x2, y2, z2, ...]
final List<int> triangles = Earcut.triangulateRaw([10, 0, 1, 0, 50, 2, 60, 60, 3, 70, 10, 4], dimensions: 3); // Returns [1,0,3, 3,2,1]
The Algorithm
The library implements a modified ear slicing algorithm, optimized by zorder curve hashing and extended to handle holes, twisted polygons, degeneracies and selfintersections in a way that doesn't guarantee correctness of triangulation, but attempts to always produce acceptable results for practical data.
It's based on ideas from FIST: Fast IndustrialStrength Triangulation of Polygons by Martin Held andTriangulation by Ear Clipping by David Eberly.