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  3. UNiagaraSimCache

UNiagaraSimCache

Recording of multiple frames of simulation data from a running Niagara system.

API > API/Plugins > API/Plugins/Niagara

Recording of multiple frames of simulation data from a running Niagara system. Can be used to play back the captured recording or to inspect the captured data for debug purposes. Depending on the capture settings, not all attributes from the simulation are present in the cache.

To capture a cache, either (1) use the baker tool in the system editor, (2) use the Niagara component cache track in sequencer or (3) manually capture a running system with the "CaptureNiagaraSimCache" Blueprint functions

   
Name UNiagaraSimCache
Type class
Header File /Engine/Plugins/FX/Niagara/Source/Niagara/Classes/NiagaraSimCache.h
Include Path #include "NiagaraSimCache.h"

Syntax

UCLASS (BlueprintType, MinimalAPI)  
class UNiagaraSimCache : public UObject

Inheritance Hierarchy

Constructors

Name Remarks Include Path Unreal Specifiers

UNiagaraSimCache ( const FObjectInitializer& ObjectInitializer
)

   NiagaraSimCache.h  

Typedefs

Name Type Remarks Include Path
FOnCacheBeginWrite TMulticastDelegate_OneParam< void, UNiagaraSimCache * >   NiagaraSimCache.h
FOnCacheEndWrite TMulticastDelegate_OneParam< void, UNiagaraSimCache * >   NiagaraSimCache.h

Constants

Name Type Remarks Include Path
CacheAgeResolution float Used to reduce rounding issues with age. NiagaraSimCache.h
OnCacheBeginWrite FOnCacheBeginWrite   NiagaraSimCache.h
OnCacheEndWrite FOnCacheEndWrite   NiagaraSimCache.h

Variables

Protected

Name Type Remarks Include Path Unreal Specifiers
bCanRunAsync bool   NiagaraSimCache.h
  • Transient
bNeedsReadComponentMappingRecache bool   NiagaraSimCache.h
  • Transient
CachedScriptVMIds TArray< FNiagaraVMExecutableDataId >   NiagaraSimCache.h
  • Transient
CacheFrames TArray< FNiagaraSimCacheFrame >   NiagaraSimCache.h  
CacheGuid FGuid   NiagaraSimCache.h
  • VisibleAnywhere
  • Category=SimCache
CacheLayout FNiagaraSimCacheLayout   NiagaraSimCache.h  
CaptureStartTime double   NiagaraSimCache.h  
CaptureTickCount int32   NiagaraSimCache.h  
CreateParameters FNiagaraSimCacheCreateParameters   NiagaraSimCache.h  
DataInterfaceStorage TMap< FNiagaraVariableBase, TObjectPtr< UObject > >   NiagaraSimCache.h  
DebugData TObjectPtr< UNiagaraSimCacheDebugData >   NiagaraSimCache.h  
DurationSeconds float   NiagaraSimCache.h
  • VisibleAnywhere
  • Category=SimCache
PendingCommandsInFlight std::atomic< int32 >   NiagaraSimCache.h  
RWLock FRWLock   NiagaraSimCache.h  
SoftNiagaraSystem TSoftObjectPtr< UNiagaraSystem >   NiagaraSimCache.h
  • VisibleAnywhere
  • Category=SimCache
  • Meta=(DisplayName="Niagara System")
StartSeconds float   NiagaraSimCache.h
  • VisibleAnywhere
  • Category=SimCache

Functions

Public

Name Remarks Include Path Unreal Specifiers

bool BeginAppend ( FNiagaraSimCacheCreateParameters InCreateParameters,
UNiagaraComponent* NiagaraComponent
)

   NiagaraSimCache.h  

bool BeginAppend ( FNiagaraSimCacheCreateParameters InCreateParameters,
UNiagaraComponent* NiagaraComponent,
FNiagaraSimCacheFeedbackContext& FeedbackContext
)

   NiagaraSimCache.h  

bool BeginWrite ( FNiagaraSimCacheCreateParameters InCreateParameters,
UNiagaraComponent* NiagaraComponent
)

   NiagaraSimCache.h  

bool BeginWrite ( FNiagaraSimCacheCreateParameters InCreateParameters,
UNiagaraComponent* NiagaraComponent,
FNiagaraSimCacheFeedbackContext& FeedbackContext
)

   NiagaraSimCache.h  

bool CanRead ( UNiagaraSystem* NiagaraSystem
)

   NiagaraSimCache.h  

bool CanRunAsync()

   NiagaraSimCache.h  

bool EndWrite ( bool bAllowAnalytics
)

   NiagaraSimCache.h  

void ForEachEmitterAttribute ( int32 EmitterIndex,
TFunction< bool(const FNiagaraSimCacheVariable&)> Function
) const

 Runs a function for each attribute for the provided emitter index. NiagaraSimCache.h  

ENiagaraSimCacheAttributeCaptureMode GetAttributeCaptureMode()

 How were the attributes captured for this sim cache. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

const FGuid & GetCacheGuid()

 Get the caches assigned GUID, this can be set from a user or will be auto created on first write of the cache. NiagaraSimCache.h  

const UObject * GetDataInterfaceStorageObject ( const FNiagaraVariableBase& DataInterface
) const

 Returns the actual data we have captured in the SimCache for the given data interface. NiagaraSimCache.h  

const UNiagaraSimCacheDebugData * GetDebugData()

 Returns the debug data stored inside the cache, intended for internal use only. NiagaraSimCache.h  

float GetDurationSeconds()

 Get the duration the cache was recorded over. NiagaraSimCache.h  

int GetEmitterIndex ( FName EmitterName
) const

 Get the emitter index from a name NiagaraSimCache.h  

FName GetEmitterName ( int32 EmitterIndex
) const

 Get the emitter name at the provided index. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

TArray< FName > GetEmitterNames()

 Returns a list of emitters we have captured in the SimCache. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

int GetEmitterNumInstances ( int32 EmitterIndex,
int32 FrameIndex
) const

 Get number of active instances for the emitter at the given frame. NiagaraSimCache.h  

int GetNumEmitters()

 Get number of emitters stored inside the cache. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

int GetNumFrames()

 Get number of frames stored in the cache. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

float GetStartSeconds()

 Get the time the simulation was at when recorded. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

TArray< FNiagaraVariableBase > GetStoredDataInterfaces()

 Returns a list of data interfaces we have captured in the SimCache. NiagaraSimCache.h  

UNiagaraSystem * GetSystem ( bool bLoadSynchronous
)

 Get the system this cache is based on NiagaraSimCache.h  

TSoftObjectPtr< UNiagaraSystem > GetSystemAsset()

 Get the system asset this cache was created from. NiagaraSimCache.h  

bool HasStoredDataInterfaces()

 Returns true if we have stored data interfaces, otherwise false. NiagaraSimCache.h  

bool IsCacheValid()

 A valid cache is one that contains at least 1 frames worth of data. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache
  • Meta=(DisplayName="IsValid")

bool IsEmpty()

 An empty cache contains no frame data and can not be used NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

bool IsRebaseEnabled()

 Returns true if we have any rebasing enabled. NiagaraSimCache.h  

bool Read ( float TimeSeconds,
FNiagaraSystemInstance* SystemInstance
) const

   NiagaraSimCache.h  

void ReadAttribute ( TArray< float >& OutFloats,
TArray< FFloat16 >& OutHalfs,
TArray< int32 >& OutInts,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara attributes by name from the cache frame and appends them into the relevant arrays. NiagaraSimCache.h  

void ReadColorAttribute ( TArray< FLinearColor >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara Color attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

UObject * ReadDataInterfaceAs ( UClass* RequestedType,
FName AttributeName,
int FrameIndex
) const

 Reads data interface data from the cache as the requested type. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

T * ReadDataInterfaceAs ( FName AttributeName,
int FrameIndex
) const

   NiagaraSimCache.h  

void ReadFloatAttribute ( TArray< float >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara float attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

bool ReadFrame ( int32 FrameIndex,
float FrameFraction,
FNiagaraSystemInstance* SystemInstance
) const

   NiagaraSimCache.h  

void ReadIDAttribute ( TArray< FNiagaraID >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara ID attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void ReadIntAttribute ( TArray< int32 >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara int attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void ReadPositionAttribute ( TArray< FVector >& OutValues,
FName AttributeName,
FName EmitterName,
bool bLocalSpaceToWorld,
int FrameIndex
) const

 Reads Niagara Position attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache
  • Meta=(AdvancedDisplay="bLocalSpaceToWorld")

void ReadPositionAttributeWithRebase ( TArray< FVector >& OutValues,
FTransform Transform,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara Position attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void ReadQuatAttribute ( TArray< FQuat >& OutValues,
FName AttributeName,
FName EmitterName,
bool bLocalSpaceToWorld,
int FrameIndex
) const

 Reads Niagara Quaternion attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache
  • Meta=(AdvancedDisplay="bLocalSpaceToWorld")

void ReadQuatAttributeWithRebase ( TArray< FQuat >& OutValues,
FQuat Quat,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara Quaternion attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void ReadVector2Attribute ( TArray< FVector2D >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara Vec2 attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void ReadVector4Attribute ( TArray< FVector4 >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara Vec4 attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void ReadVectorAttribute ( TArray< FVector >& OutValues,
FName AttributeName,
FName EmitterName,
int FrameIndex
) const

 Reads Niagara Vec3 attributes by name from the cache frame and appends them into the OutValues array. NiagaraSimCache.h
  • BlueprintCallable
  • Category=NiagaraSimCache

void RemoveDebugData()

 Remove the debug data from the cache NiagaraSimCache.h  

void SetCacheGuid ( const FGuid& InGuid
)

 Set the caches GUID to use. NiagaraSimCache.h  

bool WriteFrame ( UNiagaraComponent* NiagaraComponent
)

   NiagaraSimCache.h  

bool WriteFrame ( UNiagaraComponent* NiagaraComponent,
FNiagaraSimCacheFeedbackContext& FeedbackContext
)

   NiagaraSimCache.h  

Overridden from UObject

Name Remarks Include Path Unreal Specifiers

virtual bool IsReadyForFinishDestroy()

   NiagaraSimCache.h  

virtual void Serialize ( FArchive& Ar
)

   NiagaraSimCache.h  

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