TX has a version of "Castle Doctrine" . . . it basically says that if you're in a place you have a legal right to be, you have no duty to retreat. If the situation justifies the use of deadly force, and you do, you have protection from civil proceedings.
The protections of the Castle Doctrine law do not come into play if you are engaged in criminal activity (selling dope, breaking & entering, etc.) and they do not apply if you employ deadly force in a situation not allowed for under the law.
No doubt the Castle Doctrine laws, even when enacted, differ from state to state . . . but the people who raise objections during the debates all seem to come from the same mold.