public Builder mergeFrom(org.box2d.proto.Box2D.PbFilter other) {
        if (other == org.box2d.proto.Box2D.PbFilter.getDefaultInstance()) return this;
        if (other.hasCategoryBits()) {
          setCategoryBits(other.getCategoryBits());
        }
        if (other.hasMaskBits()) {
          setMaskBits(other.getMaskBits());
        }
        if (other.hasGroupIndex()) {
          setGroupIndex(other.getGroupIndex());
        }
        this.mergeUnknownFields(other.getUnknownFields());
        return this;
      }