THREE.JS / FOUNDATIONS 213

When should late input win?

A bounded rollback window is a policy, not magic. This worker compares ignoring, clamping, and reconciling late commands against the same fixed-tick Rapier world and retained snapshot history.

Initializing Preparing worker

Creating the main-thread scene while the worker loads deterministic Rapier...

physics: -
bodies: -
history: -
current tick: -
late tick: -
policy: -
outcome: -
events: -
step ms: -
fps: -

Late-input policy controlsbox #1

policy

lateness

wireframe instances

The selected body will receive a fixed-tick command from the main thread.

Policy contract

reconcilerestore the nearest checkpoint, replay, verify

clampaccept the command at the next current tick

ignoredrop a command whose tick is already past

Reconciliation is only available while a checkpoint exists at or before the requested tick. A late command older than retained history is reported as exhausted instead of being presented as a successful rollback.

Selected body

statepending

groupboxes

index0

body slot0

position-

velocity-

The worker is loading deterministic Rapier. Once ready, the selected index will address one policy decision.

Based on the official Three.js worker guidance, Rapier serialization guide, determinism guide, World API, and InstancedMesh docs. Measurements are local browser evidence, not a universal networking or cross-platform determinism claim.