Networked Physics with PhysX

[Blue_man]

@twinflyer;706142

Based on the information in this thread and LOTS of reading of UE4 code (mainly CharacterMovementComponent) I have the first part as a proof of concept working. Once the Server sends correction data to the client, I can rewind and replay the PhysX scene. While the replay itself is a big dirty hack and other Clients jitter like crazy the correction itself seems to work. The problem (as TheJamsh already pointed out) is smoothing the correction. As soon as I add a decent amount of PktLag (~120ms) and some lag variation the corrections get extremely noticeable.

Could you explain a bit how you smooth out the corrections to achieve this super smooth behavior from your video? My attempts are all either too aggressive or too permissive which results in jitter or big errors.

I set the update rate to 30 Hz, 10 hz is enough to perform the smoothing. Basically I never snap the actor at the predicted location, if desync is inside a margin of error 0.5% of correction is applied and if desync is more than 50% I apply from 40% to 70% of correction. Correction percentage is lerped based on the desync amount.

Will do a test with a friend to see how it behaves in a real network environment.