Austin director Keith Maitland has two films at SXSW this year. One, on the Austin City Limits TV show, is called, as one might imagine, “A Song for You: The Austin City Limits Story.”

The other is this hypnotic look at America’s first mass shooting, which took place Aug. 1, 1966, when Charles Whitman killed 12 people and wounded 32 others while shooting from the UT Tower. (As the movie points out, Texas’ campus carry law goes into effect on the 50th anniversary of this event.)

“Tower” has a very clever conceit, combining archival footage and reenactments that have been rotoscope-animated in the manner of “Waking Life.”

For example, the contemporary interview with Claire Wilson, Whitman’s first victim, is acted out by a young actress animated to look like Wilson at 18-years old. The men who ultimately stopped  the shooter, — Allen Crum, Houston McCoy and Ramiro Martinez — are all represented. Former Statesman reporter Brenda Bell, who witnessed the massacre and once researched a book on the day, talks of her own fear while her animated self hides in a buildings.

The film shifts between victims, police, reporters and observers, and the animation solves a common documentary problem — while doc reenactments can often seem corny, the rotoscoping gives the reenactments the distance and haze of memory even as the events unfold almost in real time. (People forget that Whitman was shooting for about 90 minutes; as an officer who was there notes, there was no real police protocol at the time for dealing with a crime of this nature.)

At the film’s end, things jump into the present with real-life interviews with several participants. We see Wilson testifying against open-carry; we see two men, cousins on a paper route when Whitman shot one of them, meeting for the firs time in a while.

This section is less strong that the extraordinary animated portion, but it doesn’t stop “Tower” for being a must-see.

Other screenings: 7:15 p.m. March 14 at the Rollins Theatre at the Long Center and 11:30 a.m. Thursday at the Paramount.