code: static float vDistSqr(float[] v1, float[] v2) {
          float dx = v2[0] - v1[0];
          float dy = v2[1] - v1[1];
          float dz = v2[2] - v1[2];
          return dx * dx + dy * dy + dz * dz;
      }
docs: / @return The distance between the two points.