Watch the attached image - each time the artwork reaches a 90 degree angle, the rotation seems to "pause" before moving on. It's really distracting...

This is the code that's rotating it;
func _process(delta):
rotate(radians_per_seconds * delta)
radians_per_seconds
is currently 0.5
I think this has something to do with the game running at a low resolution. Is there any way to avoid this? It's not noticeable with faster rotations, but I want a slow rotation.