Function pseudoAngle

docs/app/js/sanddance-app.js:140146–140149

(dx, dy)

exports.default = Delaunator;
// monotonically increases with real angle, but doesn't need expensive trigonometry
function pseudoAngle(dx, dy) {
    const p = dx / (Math.abs(dx) + Math.abs(dy));
    return (dy > 0 ? 3 - p : 1 + p) / 4; // [0..1]
}
function dist(ax, ay, bx, by) {
    const dx = ax - bx;
    const dy = ay - by;