So, I prepared the another test project - GitHub - aglitchman/defold-fixedupdate-131-test
If you run it, you will see three sprites (“anchors”, again) that infinitely fall from the top to the bottom. Look at the test2/test.script to see how they are animated - the script adds fixed step every fixed_update.
- Left: it is created from a collection factory and runs on the main timeline.
- Center: it runs from a collection proxy.
- Right: the same as the central sprite, but with interpolation of position and rotation.
Plus, I captured a video (it’s slowed down x2 for convenience):
From the start, the left sprite falls smoothly, but the central sprite falls with jittering. And interpolation doesn’t help at all (actually, it works well - it can be tested if set fixed update frequency to 30hz).
Then, on the second run, the proxy’s time accumulator catches up with the main timeline and the animation starts running smoothly. But still jitters from time to time.