docs: private int distToInt(double distance) {
          if (distance < 0)
              throw new IllegalArgumentException("Distance cannot be negative: " + distance);
          if (distance > MAX_DIST) {
              distance = MAX_DIST;
          }
          int integ = (int) Math.round(distance * INT_DIST_FACTOR);
          assert integ >= 0 : "distance out of range";
          return integ;
      }