4分木分割の場合のムートン座標を求めるプログラム

morton.cc

int main() {
  int width = 640;
  int height = 640;

  int morton_unit_x = width / 8;
  int morton_unit_y = height / 8;

  double x = 533.2;
  double y = 315.8;

  uint16_t morton_x = std::floor(x / morton_unit_x);
  uint16_t morton_y = std::floor(y / morton_unit_y);

  auto separatebit = [](uint16_t n) -> uint32_t {
    n = (n | (n << 8)) & 0x00ff00ff;
    n = (n | (n << 4)) & 0x0f0f0f0f;
    n = (n | (n << 2)) & 0x33333333;
    return (n | (n << 1)) & 0x55555555;
  };

  // morton_x, yの処理
  //  std::cout << morton_x << std::endl;
  //  int morton_x2 = (morton_x | (morton_x << 2)) & 0x33;
  ////  printf("%d\n", morton_x2);
  //  int morton_y2 = (morton_y | (morton_y << 2)) & 0x33;
  ////  printf("%d\n", morton_y2);
  uint32_t region_number = separatebit(morton_x) | (separatebit(morton_y) << 1);

  printf("%d\n", region_number);
}