(a) The court may, on its own motion, call a court appointed expert,
call a witness regarding the competency of any party, or call a child witness or, at the suggestion of a party, call such witnesses, and all parties shall be entitled to cross-examine such witnesses. In all other situations, the court may only call witnesses when there is an agreement of all of the parties for the court to call such witnesses and all parties shall be entitled to cross-examine such witnesses.
(b) The court may interrogate witnesses whether called by itself pursuant to subsection (a) of this Code section or by a party.
(c) Objections to the calling of witnesses by the court or to interrogation by the court may be made at the time or at the next available opportunity when the jury is not present.