As a live performer for the Batchass AV project, the singer made some drawings he asked me to animate.

I chose to create a Cinder desktop app involving a image sequence with a back-light fragment shader.

In order to sync with the music which is played in Ableton Live, I tryed several options to get the tempo, beat, bar, start:
– LiveOSC, which I used in past, but not compatible with Live 10
– Ableton Link, useful with an openFrameworks app I made, but couldn’t the bar of song’s start.
– Transthor, a Max4Live patch sending OSC messages of the info I need, so I chose this!

Then, the difficult part was to find the right formula to synchronise the amount of light in the fragment shader along with the tempo of the song playing.
Some friends from the Cookie Collective helped me:
sin( iTime / 60.0 * iBpm * iTimeFactor * 2 * PI ) + iExposure – 1.0
Where iTime is the time in seconds from the start, iBpm the tempo of the song, iTimeFactor a time multiplier (some animation last longer then a bar…), iExposure to change the amount of light from the UI.

The source code is available on request.