Time to Breach

1) Continuous State (Ring Buffer)

The component samples the owner’s state at a fixed interval and stores each snapshot in a constant-size ring buffer. This keeps memory usage stable and prevents unbounded growth over long sessions.

Each snapshot contains:

• World transform

• Linear velocity

• Angular velocity

• Movement mode + movement input velocity (used to drive correct animation state during rewind)

When rewind is active:

• Physics simulation is disabled on the actor

• Snapshots are read backwards through the ring buffer

• The actor is positioned using interpolation to avoid visual snapping or jitter

This recreates the player's physical motion in reverse, smoothly.

Code

void URewindComponent::RecordSnapshot(float DeltaTime)

{

    TimeSinceSnapshotsChanged += DeltaTime;

    LocalTimeFromStart += DeltaTime;

    // sample at fixed frequency

    if (TimeSinceSnapshotsChanged < SnapshotFrequencySeconds &&

        TransformAndVelocityRecentHistory.Num() != 0)

        return;

    // ring buffer: drop oldest when full

    if (TransformAndVelocityRecentHistory.Num() == MaxSnapshots)

        TransformAndVelocityRecentHistory.PopFront();

    const FTransform T = GetOwner()->GetActorTransform();

    const FVector Lin = OwnerRootComponent

        ? OwnerRootComponent->GetPhysicsLinearVelocity() : FVector::ZeroVector;

    const FVector Ang = OwnerRootComponent

        ? OwnerRootComponent->GetPhysicsAngularVelocityInRadians() : FVector::ZeroVector;

    LatestSnapshotIndex =

        TransformAndVelocityRecentHistory.Emplace(LocalTimeFromStart,

                                                  TimeSinceSnapshotsChanged,

                                                  T, Lin, Ang);

    // optional animation sampling (if enabled)

    if (bSnapshotAnimationVariables && OwnerMovementComponent)

    {

        if (AnimationRecentHistory.Num() == MaxSnapshots)

            AnimationRecentHistory.PopFront();

        AnimationRecentHistory.Emplace(LocalTimeFromStart,

                                       TimeSinceSnapshotsChanged,

                                       OwnerMovementComponent->Velocity,

                                       OwnerMovementComponent->MovementMode);

    }

    TimeSinceSnapshotsChanged = 0.f;

}