PredictionSystem.hpp File Reference

Client-side prediction: run movement+collision locally each tick. More...

#include "ecs/physics/SweptCollision.hpp"
#include "ecs/registry/Registry.hpp"
#include "ecs/systems/CollisionSystem.hpp"
#include "ecs/systems/MovementSystem.hpp"

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Namespaces
namespace	systems
	Client-only input sampling system — split into two halves so mouse look can run every iterate() (smooth camera at any FPS) while movement keys run once per physics tick group (server-consistent).

Functions
void	systems::runPrediction (Registry &registry, float dt, const physics::WorldGeometry &world)
	Run one tick of client-side prediction for the local player.

Detailed Description

Client-side prediction: run movement+collision locally each tick.

Phase 5b: instead of waiting ~1 RTT for the server to apply our input and ship the resulting position back, the client runs the same MovementSystem + CollisionSystem code locally on every physics tick using its own input. Our local position updates immediately — the renderer sees ~0 ms of input → camera latency instead of the ~31 ms + RTT/2 round-trip that pure server-authoritative replication imposes.

How "only the local player" filtering happens automatically. runMovement requires <Position, Velocity, PlayerVisState, PlayerSimState, CollisionShape, InputSnapshot> (with RespawnTimer excluded). On the client, PlayerSimState is not replicated — it's a server-only component. We emplace it on the local player when the connection completes; remote players have only PlayerVisState. So the view's filter naturally narrows to just the local player. No entity-filter parameter on runMovement needed.

Reconciliation. When the server's snapshot arrives ack'ing client tick T, the position in that snapshot represents state-after-applying-our-input-T. The renderer is currently showing our prediction at tick currentPredictTick > T. We snap to the server's state and replay inputs T+1..currentPredictTick from the InputRingBuffer, landing back at the correct predicted state. See runReconciliation in ReconciliationSystem.hpp.