Tex. Code of Criminal Procedure § 1.13

(a) The defendant in a criminal prosecution for any offense other than a capital felony case in which the state notifies the court and the defendant that it will seek the death penalty shall have the right, upon entering a plea, to waive the right of trial by jury, conditioned, however, that, except as provided by Article 27.19, the waiver must be made in person by the defendant in writing in open court with the consent and approval of the court, and the attorney representing the state. The consent and approval by the court shall be entered of record on the minutes of the court, and the consent and approval of the attorney representing the state shall be in writing, signed by that attorney, and filed in the papers of the cause before the defendant enters the defendant's plea.

(b) In a capital felony case in which the attorney representing the State notifies the court and the defendant that it will not seek the death penalty, the defendant may waive the right to trial by jury but only if the attorney representing the State, in writing and in open court, consents to the waiver.

(c) A defendant may agree to waive a jury trial regardless of whether the defendant is represented by an attorney at the time of making the waiver, but before a defendant charged with a felony who has no attorney can agree to waive the jury, the court must appoint an attorney to represent him.