Rotating an animatableRigidBody2D into liquid will cause phantom collision

[index3rr]

Describe the bug

When you rotate an animatablerigidbody2d, with script or the remote debug feature in godot, into a place such that it pushes water out of the way, that water will never enter that spot ever again, acting as if there is a collision there even if you rotate the rigidbody back

To Reproduce

Steps to reproduce the behavior:
make AnimatableBody2D
add collision shapes so it forms a box or something to keep the liquid inside
add water inside the container
push play
use the remote section in the scene tree to manipulate the containers rotation
observe how the water will not go back into areas it has been pushed out of

Expected behavior

The water should go back into the area after the AnimatableBody2D is rotated away from the liquid

Environment:

• OS: Fedora Linux 40 (KDE Plasma)
• Version: latest
• Godot Version: 4.3.stable (steam)
• Type: liquid

Example project(zip)

Archive.tar.gz

Video of issue:
https://github.com/user-attachments/assets/c34f4834-d653-4c18-b4fa-aaecf14c63bf

[Ughuuu]

The coupling manager in salva calls update_boundaries which is impl by rapier. Right now I use dynamic boundaries for all objects.
What is special about AnimatableBody2D is that it moves with position but it doesn't teleport, like a static body would, it moves it and collides with everything in it's way. I wonder if that has anything to do with this.
Another thing is it's possible some old colliders remain in the simulation that aren't unregistered correctly?

[Ughuuu]

Does this only happen for animatable body(eg kinematic in rapier), or also for static body, and for rigidbody.

[index3rr]

it does happen for static body but im having a hard time testing rigidbody because of whatever this glitch is..

water.mp4

[Ughuuu]

Thats not a glitch :D you have a mass of 1 for an object that big. It's physically inaccurate. You need to increase mass. Note in godot objects have mass not density. So the bigger the object and with mass 1, it means its like its made of a very very lightweigth material.