• world is simulated using rapier
• players are moved using a character controller
• only player deltas are sent over the network
• the system runs in ticks

What happens in a tick?

Client

• Receive incoming server state events

  • Check if predicted states match server states
  • Rollback if necessary, and re-simulate to the present using the stored commands
  • Mark the received server state as confirmed, and drop all previous state and command data

• Handle Inputs

  • Accumulate inputs to command
  • Send command to server
  • Add command to history

• Calculate a new predicted state

  • Predict commands from other players
  • Apply commands
  • Push new state to history

Server

• Receive Player Commands

  • Ignore out-of-date commands
  • Store commands for future ticks
  • Advise Sync Corrections if commands come to slow, or too quickly
  • Push to command buffer

• Calculate a new state

  • For critical commands (e.g. fire), rollback to adjust for the clients ping
  • Perform hit registration
  • Predict commands from other players
  • Apply current commands

• Calculate deltas for each player

  • Occlusion Culling
  • (Frustum Culling)
  • Send deltas to their respective clients