FAppTime | Unreal Engine 5.8 Documentation

API > API/Runtime > API/Runtime/Core

Provides global game timing information (delta time, current time etc). The current time is set each frame by the game thread. It may then be retrieved by the game thread and other task threads via FAppTime::Get(). The value from the game thread is pipelined through the TaskGraph such that child tasks receive the correct value for the frame the tasks were spawned in.


Name	FAppTime
Type	class
Header File	/Engine/Source/Runtime/Core/Public/Misc/AppTime.h
Include Path	#include "Misc/AppTime.h"

Syntax

class FAppTime

Structs

Name	Remarks
TRelaxedAtomic	Helper type to perform automatic relaxed-order loads/stores of a std::atomic.

Constants

Name	Type	Include Path
bUseFixedTimeStep	bool	Misc/AppTime.h
GameThreadInstance	FAppTime	Misc/AppTime.h
TLSInstance	thread_local TSharedPtr< const FAppTime >	Misc/AppTime.h

Variables

Public

Name	Type	Remarks	Include Path
CurrentFrameTime	TOptional< FQualifiedFrameTime >	Holds the current frame time and framerate.	Misc/AppTime.h
CurrentTime	TRelaxedAtomic< double >	Holds current time.	Misc/AppTime.h
DeltaTime	double	Holds current delta time in seconds.	Misc/AppTime.h
FixedDeltaTime	double	Holds time step if a fixed delta time is wanted.	Misc/AppTime.h
GameTime	double	Holds overall game time.	Misc/AppTime.h
IdleTime	double	Holds time we spent sleeping in UpdateTimeAndHandleMaxTickRate() if our frame time was smaller than one allowed by target FPS.	Misc/AppTime.h
IdleTimeOvershoot	double	Holds the amount of IdleTime that was LONGER than we tried to sleep. The OS can't sleep the exact amount of time, so this measures that overshoot.	Misc/AppTime.h
LastTime	double	Holds previous value of CurrentTime.	Misc/AppTime.h

Functions

Static

Name	Remarks	Include Path
static TSharedPtr< const FAppTime > Fork()		Misc/AppTime.h
static const FAppTime & Get ()	Returns the FAppTime value for the current thread's time context.	Misc/AppTime.h
static const FAppTime & Get_UnsafeNoCheck()		Misc/AppTime.h
static double GetApproximateCurrentTime ()	Equivalent to GetCurrentTime(), but can be called from any thread, rather than only from threads with valid time contexts.	Misc/AppTime.h
static TOptional< FQualifiedFrameTime > GetCurrentFrameTime ()	Gets a frame number generated by the engine's timecode provider.	Misc/AppTime.h
static double GetCurrentTime()	Gets current frame's time in seconds.	Misc/AppTime.h
static double GetDeltaTime()	Gets the current frame's time delta in seconds.	Misc/AppTime.h
static double GetFixedDeltaTime ()	Gets time step in seconds if a fixed delta time is wanted.	Misc/AppTime.h
static double GetGameTime()	Gets overall game time in seconds.	Misc/AppTime.h
static double GetIdleTime()	Gets idle time in seconds.	Misc/AppTime.h
static double GetIdleTimeOvershoot()	Gets idle time overshoot in seconds (the time beyond the wait time we requested for the frame). Only valid when IdleTime is > 0.	Misc/AppTime.h
static double GetLastTime()	Gets the previous frame's value of CurrentTime.	Misc/AppTime.h
static FTimecode GetTimecode ()	Convert the current frame time into a readable timecode.	Misc/AppTime.h
static FFrameRate GetTimecodeFrameRate()	Get the frame rate of the current frame time. If the current frame time is not set, the frame rate value will be defaulted.	Misc/AppTime.h
static void InvalidateCurrentFrameTime()		Misc/AppTime.h
static void Restore ( TSharedPtr< const FAppTime >&& Ptr )		Misc/AppTime.h
static void Set ( const FAppTime& NewValue )	Sets the new FAppTime value. May only be called from the game thread.	Misc/AppTime.h
static void SetCurrentFrameTime ( FQualifiedFrameTime InFrameTime )		Misc/AppTime.h
static void SetCurrentTime ( double Seconds )		Misc/AppTime.h
static void SetDeltaTime ( double Seconds )		Misc/AppTime.h
static void SetFixedDeltaTime ( double Seconds )	Setter functions matching those from FApp	Misc/AppTime.h
static void SetGameTime ( double Seconds )		Misc/AppTime.h
static void SetIdleTime ( double Seconds )		Misc/AppTime.h
static void SetIdleTimeOvershoot ( double Seconds )		Misc/AppTime.h
static void SetUseFixedTimeStep ( bool bVal )		Misc/AppTime.h
static void UpdateLastTime()		Misc/AppTime.h
static bool UseFixedTimeStep()	Gets whether we want to use a fixed time step or not.	Misc/AppTime.h

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