Tests whether vertex i is a reflex (concave) vertex of the polygon — the
interior angle at that vertex exceeds 180°. Assumes the polygon is wound
counter-clockwise and that 0 <= i < n.
Parameters
vertices: number[]
polygon vertices as a flat array [x0, y0, x1, y1, ...]
Tests whether vertex
iis a reflex (concave) vertex of the polygon — the interior angle at that vertex exceeds 180°. Assumes the polygon is wound counter-clockwise and that0 <= i < n.