Blender Git Loki

Performance: Never draw channels region during playback

Channels aren't visually changed by playing back an animation so there
is no need to do this. As rendering channels is using a lot of logic
(filtering animation data, converting fcurves to samples etc) it has an
noticeable overhead.

This change has no functional limitation. Users are still able to do
everything during animation playback. There are other mechanisms in
place that take care of that.

Spring 02_020_A.anim.blend went from 11.8 to 12.0 on a Ryzen 1700. I
didn't test with scenes but it should be more noticeable with more
complex scenes.

Reviewed By: Brecht van Lommel

Differential Revision: https://developer.blender.org/D8073