Isn’t Texas one of the states where a candidate who gets a majority (over 50%) gets all of the delegates, but if there is only a plurality, the leading candidate and all others get proportional representation? Neither Cruz nor Trump will get over 50% in Texas, so if they’re close, they’ll probably wind up with similar numbers of delegates from the state.
Your description is close enough. 50% of the state gets 47 delegates, 50% of each congressional district (there are 36 congressional districts) gets 3 delegates per district. Less than that (50%) margin to the winner and the CD delegates are distributed proportionally to the top two. It's possible for three candidates to get CD delegates, but that's down in the weeds in this race.
Texas Republican Delegation 2016