@thi.ng/geom-tessellate/quad-fan.js

2D/3D convex polygon tessellators

import { centroid } from "@thi.ng/geom-poly-utils/centroid";
import { addmN } from "@thi.ng/vectors";
const quadFan = (tess, faces, pids) => {
  const points = tess.pointsForIDs(pids);
  const c = tess.addPoint(centroid(points));
  const n = pids.length - 1;
  let m0 = tess.addPoint(addmN([], points[n], points[0], 0.5));
  let mprev = m0;
  for (let i = 0; i <= n; i++) {
    const m = i < n ? tess.addPoint(addmN([], points[i], points[i + 1], 0.5)) : m0;
    faces.push([c, mprev, pids[i], m]);
    mprev = m;
  }
  return faces;
};
export {
  quadFan
};