I do not currently own a pickup

but have had many in the past. (I drive way too far to work to afford the gas lately) Anyway, I was wondering what the laws in Texas are regarding having a loaded rifle behind the seat of a truck? My last truck was a 1998 Ford F150, regular cab.
My understanding for cars is it's OK to have one in the trunk, but this is obviously not an option for trucks (Honda Ridgeline being the exception

).
I know the law states you can have a handgun in your car, so maybe this is a stupid question? I have a TX CHL BTW.
Thanks!