Texas Code of Criminal Procedure - CRIM P Art. 36.15. Requested special charges

Before the court reads his charge to the jury, counsel on both sides shall have a reasonable time to present written instructions and ask that they be given to the jury.  The requirement that the instructions be in writing is complied with if the instructions are dictated to the court reporter in the presence of the court and the state's counsel, before the reading of the court's charge to the jury.  The court shall give or refuse these charges.  The defendant may, by a special requested instruction, call the trial court's attention to error in the charge, as well as omissions therefrom, and no other exception or objection to the court's charge shall be necessary to preserve any error reflected by any special requested instruction which the trial court refuses.

Any special requested charge which is granted shall be incorporated in the main charge and shall be treated as a part thereof, and the jury shall not be advised that it is a special requested charge of either party.  The judge shall read to the jury only such special charges as he gives.

When the defendant has leveled objections to the charge or has requested instructions or both, and the court thereafter modifies his charge and rewrites the same and in so doing does not respond to objections or requested charges, or any of them, then the objections or requested charges shall not be deemed to have been waived by the party making or requesting the same, but shall be deemed to continue to have been urged by the party making or requesting the same unless the contrary is shown by the record;  no exception by the defendant to the action of the court shall be necessary or required in order to preserve for review the error claimed in the charge.