"If you’re a student who spends several weeks or months a year in different locations but wants to vote in Texas, you’ll need to decide which place in Texas is the place you call “home,” i.e., where you intend to return after you’ve been away. If you consider your parents’ address to be your permanent residence, you may use that address as your registration address. If you would like to register to vote at your college address, you may do so, but you can’t be registered in both places.
If you consider yourself a permanent resident of another state, you’ll need to consult with officials there for registration and ballot-by-mail procedures." http://votetexas.gov/voting/who#students