Dev Task: make AnimationPlayer's use AnimationTree or Tween

[NancokPS2]

To use simultaneous animations, we either need an AnimationTree or have Tweens replace the functionality of the AnimationPlayer.

For the former, it would keep things mostly the same, but AnimationTree requires quite a bit of manual work + code work.

For the later, the Tweens can simply translate the animations from the AnimationPlayer to their own Tween, that way we can still use AnimationPlayer to create animations instead of relying on code to make them.
If everything works fine, this approach will use a component that is attached to the AnimationPlayer and merely gives it the ability to run several animations simultaneously.

[jonathaneeckhout]

@NancokPS2 do you know an example of this tween approach?

[NancokPS2]

• I had started a PR to implement that translatetion from AnimationPlayer's keys to tweens, but it proved to be pretty convoluted and complex. Very much doable, but it would need a very robust system.

• Another method is to create pre-defined animations (with an AnimationPlayer, since animations are their own Resource) paired with a script that adapts the animations so they can be used as a component (slap it on whatever, set the @export variables and watch it go). But it would provide little benefit (if at all) over creating the AnimationPlayer's manually for each scene and ensuring the node names remain the same.

• One i had considered was splitting this into several classes under a singleton dedicated to visual effects.

  • First having a class in charge of complex visuals like particles and sprites with shaders, not too different from Godot's built-in RenderingServer class. It would show the effect on screen with a specified Transform2D to set it's position, rotation, etc.
  • Then a separate projectile related class that would be more than just for animations, but it would control motion and collision of temporary objects (homing, bouncing, rotating around a point, just straight travel, etc). Terraria uses projectiles for nearly all interactable, temporary objects and it works great. Anything that needs actual procedural motion can be under this class, even if it does not need to collide with anything. Most projectiles would use some tweening.
  • In the future, any other graphical effect could go under this singleton, like screen wide shaders

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All in all, animations can be done with any mix of Tweens and AnimationPlayers