feat: SpineRuntimeObject: Disable updateHitboxes to avoid unnecessary recomputation

[danvervlad]

Summary

This PR disables hitbox updates for SpineRuntimeObject by making updateHitBoxes() a no-op and leaving hitBoxes empty. Continuously invalidating and recomputing hitboxes provided no benefit and added per-frame overhead.

Context & motivation

• Spine animations update every frame, which previously triggered invalidateHitboxes() often.
• Making updateHitBoxes() a no-op removes wasted work and reduces CPU usage in scenes with multiple Spine animations.

What’s changed

• Extensions/Spine/spineruntimeobject.ts: updateHitBoxes() is now intentionally empty; hitBoxes remains empty for Spine objects. Other calls to invalidateHitboxes() remain but will not trigger any heavy recomputation for Spine.

[4ian]

Hi!

Thanks for the PR. This will remove entirely hitboxes for this kind of object, is that right?
That's a bit risky when it's used for actual collision or boundary checks in some games.
Instead, I think we could only have the hitboxes invalidated when the object is moved or animation changed (during an animation, the hitboxes would not change). This could already help a lot reducing unnecessary CPU usage.

[danvervlad]

Hi!

Thanks for the PR. This will remove entirely hitboxes for this kind of object, is that right? That's a bit risky when it's used for actual collision or boundary checks in some games. Instead, I think we could only have the hitboxes invalidated when the object is moved or animation changed (during an animation, the hitboxes would not change). This could already help a lot reducing unnecessary CPU usage.

Hi! During animation, parts of spine can move out of previous boundaries, so I guess, that was the reason of placing invalidateHitboxes() in update(). I think moving invalidateHitboxes() from update() to setAnimation*() methods will not update hit boxes correctly.

What's your opinion regarding these options?

1. Add custom "static" hitbox for runtime object from GDevelop UI. It will be updated on changing transform of RuntimeObject, but not on its content. It can be like "Behavior" which you can add to object. I understand, it's long term complex task.
2. Add global flag for SpineRuntimeObject, to turn off hitbox calculations from the code.

[4ian]

Hello @danvervlad! After thinking a bit more about this, I think it's safer and faster to start with a global flag, or a property in the Spine Runtime object that can be toggled on/off from the object editor/object panel, to deactivate hitboxes update.
I think it's still important to return hitboxes, but they can be never updated when the flag is set.

[danvervlad]

Hi @4ian! What do you think about global static flag for SpineRuntimeObject to disable hitboxes update, as a quick solution, which I've just committed?