// from https://stackoverflow.com/questions/664014/what-integer-hash-function-are-good-that-accepts-an-integer-hash-key
// reversed by: unscrambleInt
static int scrambleInt(int x) {
  x = ((x >>> 16) ^ x) * 0x45d9f3b;
  x = ((x >>> 16) ^ x) * 0x45d9f3b;
  x = (x >>> 16) ^ x;
  ret x;
}