FInstanceAttributeTracker Class Reference

#include <InstanceAttributeTracker.h>

Classes
class	FAnyValidIterator
class	FDeltaRange
struct	FToBit

Public Types
enum class	EFlag : ElementType {   Added , TransformChanged , CustomDataChanged , IndexChanged ,   Num }
using	ElementType = uint32
using	FBitManip = UE::InstanceAttributeTracker::Implementation::FBitManip< ElementType >

Public Member Functions
	FInstanceAttributeTracker ()
	FInstanceAttributeTracker (FInstanceAttributeTracker &&Other)
void	operator= (FInstanceAttributeTracker &&Other)
void	Reset ()
TConstSetBitIterator	GetRemovedIterator () const
void	MarkRemoved (FPrimitiveInstanceId Id)
void	RemoveAtSwap (FPrimitiveInstanceId Id, int32 Index, int32 MaxInstanceIndex)
void	RemoveAt (FPrimitiveInstanceId Id, int32 Index, int32 MaxInstanceIndex)
template<EFlag Flag>
void	MarkIndex (int32 Index, int32 MaxInstanceIndex)
ElementType	GetFlags (int32 Index) const
template<EFlag Flag>
bool	TestFlag (int32 Index) const
void	SetNum (int32 InstanceIndexMax)
template<uint32 Mask = AnyFlagMask>
FAnyValidIterator< Mask >	GetChangedIterator () const
void	Validate () const
template<EFlag Flag>
FDeltaRange< Flag >	GetDeltaRange (bool bForceFullUpdate, int32 InNumItems) const
bool	HasAnyChanges () const
SIZE_T	GetAllocatedSize () const

Static Public Member Functions
static void	Move (FInstanceAttributeTracker &Dest, FInstanceAttributeTracker &Source)

Static Public Attributes
static constexpr uint32	BitsPerElement = sizeof(ElementType) * 8u
static constexpr int32	MasksPerElement = BitsPerElement / uint32(EFlag::Num)
static constexpr ElementType	AnyFlagMask = (ElementType(1U) << uint32(EFlag::Num)) - ElementType(1U)

Detailed Description

Tracks changes for instances, but that assumes storing stuff per index except the removed status which must be kept ID-based Removed items are tracked by ID and kept separate as we need to remember if an item was ever removed in order to handle these correctly. Designed to use move semantics to clear the state and transfer to the updating worker task.

Member Typedef Documentation

ElementType

using FInstanceAttributeTracker::ElementType = uint32

FBitManip

using FInstanceAttributeTracker::FBitManip = UE::InstanceAttributeTracker::Implementation::FBitManip<ElementType>

Member Enumeration Documentation

EFlag

enum class FInstanceAttributeTracker::EFlag : ElementType

strong

Flag describing the changed attribute. Note that not all are created equal, see comments.

Enumerator
Added
TransformChanged	Set when
CustomDataChanged
IndexChanged
Num	Implicitly set when calling Remove or RemoveAt as this causes movement to fill holes.

Constructor & Destructor Documentation

FInstanceAttributeTracker() [1/2]

FInstanceAttributeTracker::FInstanceAttributeTracker

(

)

FInstanceAttributeTracker() [2/2]

FInstanceAttributeTracker::FInstanceAttributeTracker

(

FInstanceAttributeTracker &&

Other

)

Member Function Documentation

GetAllocatedSize()

SIZE_T FInstanceAttributeTracker::GetAllocatedSize ( ) const

inline

GetChangedIterator()

template<uint32 Mask = AnyFlagMask>

FAnyValidIterator< Mask > FInstanceAttributeTracker::GetChangedIterator ( ) const

inline

GetDeltaRange()

template<EFlag Flag>

FDeltaRange< Flag > FInstanceAttributeTracker::GetDeltaRange ( bool  bForceFullUpdate, int32  InNumItems  ) const

inline

GetFlags()

ElementType FInstanceAttributeTracker::GetFlags ( int32  Index ) const

inline

Get the masked flags for a given index.

GetRemovedIterator()

TConstSetBitIterator FInstanceAttributeTracker::GetRemovedIterator

(

)

const

Get an iterator that iterates over the IDs (note, not index as they don't exist any more) of removed instances. The remove flag is not cleared when a new instances is added.

HasAnyChanges()

bool FInstanceAttributeTracker::HasAnyChanges ( ) const

inline

MarkIndex()

template<EFlag Flag>

void FInstanceAttributeTracker::MarkIndex ( int32  Index, int32  MaxInstanceIndex  )

inline

MarkRemoved()

void FInstanceAttributeTracker::MarkRemoved ( FPrimitiveInstanceId  Id )

inline

Lazy allocate bits in the bit vector tracking removed instances and set the flag for the instance ID. Also updates the FirstRemovedIdIndex, such that we can start iteration from that bit.

Move()

void FInstanceAttributeTracker::Move ( FInstanceAttributeTracker &  Dest, FInstanceAttributeTracker &  Source  )

static

operator=()

void FInstanceAttributeTracker::operator=

(

FInstanceAttributeTracker &&

Other

)

RemoveAt()

void FInstanceAttributeTracker::RemoveAt ( FPrimitiveInstanceId  Id, int32  Index, int32  MaxInstanceIndex  )

inline

Mark removed & update the tracked bits (remove & move operation) Note: this is not something that should be used really as it forces the tracker to touch all the masks after the removed item...

RemoveAtSwap()

void FInstanceAttributeTracker::RemoveAtSwap ( FPrimitiveInstanceId  Id, int32  Index, int32  MaxInstanceIndex  )

inline

Mark removed & update the tracked bits (remove & swap operation)

Reset()

void FInstanceAttributeTracker::Reset

(

)

SetNum()

void FInstanceAttributeTracker::SetNum ( int32  InstanceIndexMax )

inline

TestFlag()

template<EFlag Flag>

bool FInstanceAttributeTracker::TestFlag ( int32  Index ) const

inline

Test a specific flag at a given index.

Validate()

void FInstanceAttributeTracker::Validate ( ) const

inline

Member Data Documentation

AnyFlagMask

constexpr ElementType FInstanceAttributeTracker::AnyFlagMask = (ElementType(1U) << uint32(EFlag::Num)) - ElementType(1U)

staticconstexpr

BitsPerElement

constexpr uint32 FInstanceAttributeTracker::BitsPerElement = sizeof(ElementType) * 8u

staticconstexpr

MasksPerElement

constexpr int32 FInstanceAttributeTracker::MasksPerElement = BitsPerElement / uint32(EFlag::Num)

staticconstexpr

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The documentation for this class was generated from the following files:

• Engine/Source/Runtime/Engine/Public/InstancedStaticMesh/InstanceAttributeTracker.h
• Engine/Source/Runtime/Engine/Private/InstancedStaticMesh/InstanceAttributeTracker.cpp