FFixedTickState | Unreal Engine 4.27 Documentation

API > API/Plugins > API/Plugins/NetworkPrediction

References


Module	NetworkPrediction
Header	/Engine/Plugins/Runtime/NetworkPrediction/Source/NetworkPrediction/Public/NetworkPredictionTickState.h
Include	#include "NetworkPredictionTickState.h"

Syntax

struct FFixedTickState

Remarks

(Global) Tick state for fixed tick services

Notes about Fix Ticking in NetworkPrediction: 1, This is the only mode that supports physics rewind/resim.

For now, this requires the engine to run in a fixed step mode on both server and clients a. GEngine->bUseFixedFrameRate / GEngine->FixedFrameRate

If you aren't using Physics, FixedTick mode will accumulate real time and run 0-N Sim frames per engine frame.

If you are using Physics, FixedTick will always run 1 sim frame per engine frame to stay in sync with physics. a. Since NP uses int32 ms and the engine will use float DeltaTimeSeconds, NP will slowly lose time compared to the rest of the engine/physics

The long term goal is supporting fixed physics steps without engine fix ticking. There is no guarantee or timeline this will happen though.

Variables

Type	Name	Description
int32	ConfirmedFrame	Latest confirmed local frame number. Anything at or before this frame is "set in stone".
int32	FixedStepMS	FixedStepMS that simulations should use.
float	FixedStepRealTimeMS	Realtime steps.
FInterpolationState	Interpolation
int32	Offset	Maps ForwardPredicted authority frames to local frame.
int32	PendingFrame	Next frame to be ticked (used as input to generated PendingFrame+1)
int32	PhysicsOffset	Maps PendingFrame to PhysicsRewindData()->CurrentFrame().
Chaos::FRewindData *	PhysicsRewindData
float	UnspentTimeMS	Accumulates raw delta time into our fixed steps, Note this not used when physics recording is enabled since NP must stay in sync with physics tick.