How do i do client side prediction knockback for npc on non host peer?

[xand00]

I extended StateSyncronizer so it can apply state from current peer instead of _last_received_state from host

So i tried to do it this way, every step is on non host peer:

1. click attack
2. in the middle of animation i check for collisions, if collides with an npc, apply knockback
3. On npc set StateSynchronizer to apply states from same peer instead of host until tick when knockback finishes

For some reason it's jumpy, any other approaches i can use? or maybe i'm doing something wrong in this one

[albertok]

StateSyncronizer might not be the best fit if client side prediction is needed. The local processing will be out of sync with the server one and result in the jumpiness you're seeing.

RollbackSynchronizer and its prediction features will likely work better. You'll just need to make the AI drive inputs.

[xand00]

thank you, i will try it and give feedback here

[xand00]

So i gave it a shot but it's still jumpy and i have no idea how to fix this

In my prototype i have status effects like fire, ice, knockback, every tick i serialize these status effects and store in serialized_status_effects property, this property is also on RollbackSynchronizer, so it gets synchronized across network

StatusEffectManager have this pseudocode:

func save_serialized_status_effects():
  serialized_status_effects = get_serialized_status_effects()
  NetworkRollback.mutate(self)


func apply_status(status):
  save_serialized_status_effects()


func _rollback_tick(tick: int):
  restore_state(serialized_status_effects) # clears status_effects variable and fills from serialized_status_effects
  
  for status_effect in status_effects:
    status_effect.process(tick)
  
  delete_completed_status_effects() # deletes completed status effects from status_effects variable

  save_serialized_status_effects()

and in my knock back status effect i call NetworkRollback.mutate(...) on process

Without latency it works alright, but with latency it gets jumpy, any tips how to make client side prediction (mutate position, velocity of enemies, etc) in status effects?