gistfile1.d

auto mksphere(int depth) {
  alias V = vec3f;
  (V,V,V)[auto~] res;
  if false return res[]; // return type hint
  if (!depth) {
    auto points = [for tup <- cross([-1, 1] x 3): V tup].eval[];
    for auto tup <- [
      (0, 1, 3), (0, 3, 2),
      (4, 5, 7), (4, 7, 6),
      
      (0, 1, 5), (0, 5, 4),
      (2, 3, 7), (2, 7, 6),
      
      (0, 2, 6), (0, 6, 4),
      (1, 3, 7), (1, 7, 5)
    ] {
      res ~= points[tup];
    }
  } else {
    auto next = mksphere (depth - 1);
    onSuccess next.free;
    V half(V a, b) { return (a*0.5)+(b*0.5); }
    for auto val <- next {
      auto halves = (val[0].half val[1], val[1].half val[2], val[2].half val[0]);
      res ~= (val[0], halves[0], halves[2]);
      res ~= (val[1], halves[0], halves[1]);
      res ~= (val[2], halves[1], halves[2]);
      res ~= (halves[2], halves[1], halves[0]);
    }
  }
  for ref v <- res {
    v[0] /= |v[0]|;
    v[1] /= |v[1]|;
    v[2] /= |v[2]|;
  }
  return res[];
}