code: public Quaternionf normalize() {
          float invNorm = (float) (1.0 / Math.sqrt(x * x + y * y + z * z + w * w));
          x *= invNorm;
          y *= invNorm;
          z *= invNorm;
          w *= invNorm;
          return this;
      }
docs: Normalize this quaternion.
  
  @return this