62 lines
2.2 KiB
C++
62 lines
2.2 KiB
C++
// Copyright Epic Games, Inc. All Rights Reserved.
|
|
|
|
#pragma once
|
|
|
|
#include "FixedFrameRateCustomTimeStep.h"
|
|
|
|
#include "CatchupFixedRateCustomTimeStep.generated.h"
|
|
|
|
class UEngine;
|
|
class UObject;
|
|
|
|
/**
|
|
* Control the Engine TimeStep via a fixed frame rate that catches up with real time.
|
|
*
|
|
* - Stays in sync with platform time.
|
|
* - Blocks to prevent getting ahead of real time.
|
|
* - Does not block when it needs to catch up
|
|
* - If it falls behind too much, it will increase simulation delta times.
|
|
*
|
|
*/
|
|
UCLASS(Blueprintable, editinlinenew, meta = (DisplayName = "Catchup Fixed Rate"), MinimalAPI)
|
|
class UCatchupFixedRateCustomTimeStep : public UFixedFrameRateCustomTimeStep
|
|
{
|
|
GENERATED_UCLASS_BODY()
|
|
|
|
public:
|
|
//~ Begin UFixedFrameRateCustomTimeStep interface
|
|
TIMEMANAGEMENT_API virtual bool Initialize(UEngine* InEngine) override;
|
|
TIMEMANAGEMENT_API virtual void Shutdown(UEngine* InEngine) override;
|
|
TIMEMANAGEMENT_API virtual bool UpdateTimeStep(UEngine* InEngine) override;
|
|
TIMEMANAGEMENT_API virtual ECustomTimeStepSynchronizationState GetSynchronizationState() const override;
|
|
TIMEMANAGEMENT_API virtual FFrameRate GetFixedFrameRate() const override;
|
|
//~ End UFixedFrameRateCustomTimeStep interface
|
|
|
|
private:
|
|
|
|
/** Blocks until platform time reaches the given time */
|
|
void BlockUntilPlatformSeconds(const double TargetPlatformSeconds) const;
|
|
|
|
/**
|
|
* Calculates the delta time to apply for the current frame based on the difference between simulation time and platform time.
|
|
* Adjusts the simulation delta time to account for systemic fall-behind, allowing the simulation to catch up smoothly.
|
|
*/
|
|
double CalculateDeltaSeconds(const double CurrentSimulationSeconds, const double CurrentPlatformSeconds) const;
|
|
|
|
public:
|
|
|
|
/** Desired simulation frame rate */
|
|
UPROPERTY(EditAnywhere, Category = "Timing")
|
|
FFrameRate FrameRate;
|
|
|
|
/** Maximum catchup time in seconds. Simulation will catch up instantly if it falls behind beyond this time with respect to platform time */
|
|
UPROPERTY(EditAnywhere, Category = "Timing", meta = (ClampMin = "2"))
|
|
double MaxCatchupSeconds = 16;
|
|
|
|
private:
|
|
|
|
/* Keeps track of our simulation time, which is intentionally kept close to platform time */
|
|
double SimulationSeconds = 0;
|
|
|
|
};
|