AnimationTree process the extra frame when restarting Animation by some Nodes

[TokageItLab]

Godot version

4.0.dev (b36447f)

System information

MacOS 11.6

Issue description

When selecting a state, NodeTransition and NodeOneShot internally seeks and restarts the animation after it has played once, but processes the last frame at the time of restart.

2022-06-10.1.54.01-1.mov

Steps to reproduce

Play the animation once using NodeTransition or NodeOneshot, then change the state and play it again.

Minimal reproduction project

node_t_state.zip

[Rindbee]

It may be that when re-seeking in AnimationNodeAnimation::process, the internal step is not reset according to the current state.

Ignoring what we're arguing about, it's actually necessary to let AnimationNodeAnimation know its own state.

[TokageItLab]

The problem with pingpong and the problem that calling last frame will be solved by #68992. The only remaining issue is the first frame method will be called twice by OneShot and Transition.