fix: do not run behavior simulation while paused

[keturn]

Fixes some of the messages about entities not having finite position or rotation.

Contains

Skips all BehaviorSystem.update when the time delta is zero.

The issue was coming up specifically as a result of movement actions running during this update, since they were coming up with absurd results trying to calculate changes in position over zero time.

But I figured that skipping the entire system is probably a sensible thing to do. Unless you can think of anything Behavior-related that should still be ticking during the pause menu?

Or perhaps we should have a separate variant of UpdateSubscriberSystem that only updates when engine-time is advancing.

How to test

• play single player (no network) with WildAnimals
• find some deer (or some other animal with a functioning movement behavior)
• hit Escape for pause menu
• note whether log is being spammed with messages about entities with a non-finite position or location

[jdrueckert]

Unless you can think of anything Behavior-related that should still be ticking during the pause menu?

Depends on whether time is halted when the player is in the main menu. In multiplayer scenarios it shouldn't be, so behaviors also shouldn't pause. In singleplayer I'm not entirely sure right now, whether or not we pause everything - I thought not, but I could be mistaken. If we indeed don't pause everything, then behaviors should also not be paused such that animals can continue walking around, minions can continue working and for instance the NPCs in cities can continue to go about their business, for instance to satisfy their individual needs.

Or perhaps we should have a separate variant of UpdateSubscriberSystem that only updates when engine-time is advancing.

That would better fit what I described above I guess 👍

[keturn]

The check I added here is for whether the time delta on update is zero. I think it should handle those cases appropriately, but I guess we should take a quick look at it in multiplayer to be sure.

[jdrueckert]

For the record: tested out fine both in singleplayer (behavior halted) and multiplayer (behavior not halted, neither when host in pause, nor when client in pause nor when both in pause).