Triangulate

The triangles that fill the ring, each as indices of its corners, counterclockwise.

The triangles that fill the outer ring less its holes, each as indices of its corners in the rings one after another, the outer ring's first, counterclockwise: Mapbox's earcut, without its z-order hash, which cuts off one convex corner with no other corner in its triangle at a time, once each hole is joined to the outer ring by a bridge from its leftmost corner to a corner it sees. A ring's last corner may repeat its first. An outer ring of fewer than three corners gives none, and a hole of fewer than three is left out. A corner that isn't finite panics.