(a) Except as provided by Subsection (b), the punishment prescribed for an offense under this chapter is increased to the punishment prescribed for the next highest category of offense if it is shown beyond a reasonable doubt on the trial of the offense that the actor committed the offense in a place that the actor knew was:
(1) within 300 feet of the premises of a school; or
(2) on premises where:
(A) an official school function is taking place; or
(B) an event sponsored or sanctioned by the University Interscholastic League is taking place.
(b) This section does not apply to an offense under § 46.03(a)(1).
(c) In this section:
(1) “Premises” has the meaning assigned by § 481.134, Health and Safety Code.
(2) “School” means a private or public elementary or secondary school.