Animation Player resetting main spine rotation when playing animation

[Cobradabest]

Godot version

v4.0.beta8.official [45cac42]

System information

Ubuntu 20.04

Issue description

I have this weird bug where if I make a character model's skeleton seems to reset when I switch to another animation that doesn't use that bone.

To give context, I'm trying to make a Virtua Cop style game where the enemies show a death animation, but it stops and the enemies flash away. When I try to recreate this, it works fine in the editor, but in the actual game, it resets the main spine bone rotation, resulting in the error below. This didn't happen with me on Godot 3.5.

Steps to reproduce

1. Import a glf or dae of a character with armature animations
2. Make a new animation for it that doesn't use any of the bones
3. Make it switch between an armature animation and the new animation in game

Minimal reproduction project

problem.zip

[TokageItLab]

Duplicate of #63465. Tentatively, you can use reset_bone_poses() to solve this problem.

[TokageItLab]

Oh sorry, I might have misunderstood, are you saying that the problem is that the bones are reset even though you are only using AnimationPlayer? If you are using AnimationTree, it will reset, but it seems strange that only AnimationPlayer is causing the reset. I will take a look at it later.

[TokageItLab]

I investigated. It seems that this problem can be solved by making the scene instance containing the AnimationPlayer local by Make Local. Backport projects on alpha 5 seem to work even if it run on latest master. What the difference is is a puzzle to me, but I suspect that the dependencies have something to do with it...

_problem_backport.zip

I guess there is probably a referencing issue somewhere, but I don't know if this is what was intended. I will continue to investigate.

[TokageItLab]

Ah, the problem is much simpler: the default_blend_time in AnimationPlayer was set to 0.5.

The blending algorithm has changed in 4.0, so blending is now based on the default value (rest in Skeleton). To resolve this, either temporarily set default_blend_time to 0 or use AnimationPlayer::stop(true).