Here's a link to Texas' definitions per Section 30.01
http://law.onecle.com/texas/penal/30.01.00.html
Here's a link to the Texas Castle Doctrine
http://www.rc123.com/texas_castle_doctrine.html
Hope that helps.
Before Texas adopted concealed carry, a person was allowed to carry a handgun in his vehicle if he was "traveling". At that time, the weapon was NOT supposed to be concealed. Where the law was a little 'murky' was in the definition of "traveling". There were several versions to what it meant, anywhere from outside your city of residence to two counties away from your home county. Seems it was kinda up to whatever DA had jurisdiction & what he considered traveling to be. Obviously a bad deal. So, the concealed carry laws have pretty well helped even the folks that do not desire to conceal carry.