Fix camera desync

[GliczDev]

Setting player's camera before they had sent ServerboundPlayerLoadedPacket desyncs it.
This should fix it

[Owen1212055]

Where are you getting the player camera to have this happen? This seems xy, I donno.

[GliczDev]

when I teleport player to a different world and set camera directly after that (so player has not yet fully loaded the world, entities do not exist for them, so there's no entity to set camera to - I checked client code for that)

[Owen1212055]

Couldnt you instead run that logic in the PlayerClientLoadedWorldEvent instead of setting the entity in that spot?
Just seems like a niche sort of case, but could be argued as a valid desync.

[GliczDev]

Couldnt you instead run that logic in the PlayerClientLoadedWorldEvent instead of setting the entity in that spot?

no, the event is not called on dimension change (which, imo, is wrong, because the packet is being sent on dimension change too).

either way, it is a desync and should be fixed in Paper, not with a plugin.

[Owen1212055]

Okay, the event not firing on dimension change is a bug due to paper reusing the player entity on dimension switch.

[Owen1212055]

The issue is the spectator logic is VERY client state dependent and is prone to stuff like this.

[Owen1212055]

I believe that the proper fix is to instead use the player ready event, and on Player#reset change clientLoaded. As the event is currently not fired on dimension change, which is a bug. This is due to the player instance being reused.

[GliczDev]

I believe that the proper fix is to instead use the player ready event, and on Player#reset change clientLoaded. As the event is currently not fired on dimension change, which is a bug. This is due to the player instance being reused.

@Owen1212055 are you sure it should be Player#reset? It doesn't seem to be called when teleporting to a different world with the API

[Owen1212055]

Hmmm, thinking about this again, I really am not sure of the best fix. Since even at the current position with using that packet, its not really even guaranteed that the client can see that entity.

If you wait a tick after PlayerTrackEntityEvent and then set the camera only when its received how does that look?