At the point he hit the glass, that was an attempt to enter your vehicle, so you would have been justified to use force to stop him. And, IMO you had every right to do this at that point:
TPC Sec. 9.04. THREATS AS JUSTIFIABLE FORCE.
The threat of force is justified when the use of force is justified by this chapter. For purposes of this section, a threat to cause death or serious bodily injury by the production of a weapon or otherwise, as long as the actor's purpose is limited to creating an apprehension that he will use deadly force if necessary, does not constitute the use of deadly force.
So, it basically goes back to the fact you were on with 911, were telling them what was happening, and they had a recording of it, so they were aware. The tow truck driver quickly realized he was in the wrong and was not going to call in on you, even though you showed your gun. So as gigag04 says, no victim, no offense.
