# ludic.base/ecs_group.ludic - a group is every row an index files under one value: a kind, or a
# chunk of the world, loaded and let go together. A chunk's number packs its two cell coordinates.
export function chunk_of(x: float, z: float, size: float) -> int {
  let cx = int(Math.floor(x / size))
  let cz = int(Math.floor(z / size))
  return ((cx & 32767) << 15) | (cz & 32767)
}

# every row filed under v in ix removed (the observers told of each); how many went. The index's
# own list shrinks as each goes, so it is read from its end until it is empty.
export function tb_remove_all<T>(tb: Table<T>, ix: IntIndex, v: int) -> int {
  var n = 0
  let rows = ix_rows(ix, v)
  while len(rows) > 0 {
    let h = tb.ent[rows[len(rows) - 1]]
    if not tb_remove(tb, h) { return n }
    n += 1
  }
  return n
}