#include <attributeQuery.h>

Public Member Functions
USD_API	UsdAttributeQuery ()
	Construct an invalid query object. More...

USD_API	UsdAttributeQuery (const UsdAttributeQuery &other)
	Copy constructor. More...

USD_API	UsdAttributeQuery (UsdAttributeQuery &&other)=default
	Move constructor. More...

USD_API	UsdAttributeQuery (const UsdAttribute &attr)
	Construct a new query for the attribute `attr`. More...

USD_API	UsdAttributeQuery (const UsdPrim &prim, const TfToken &attrName)

USD_API	UsdAttributeQuery (const UsdAttribute &attr, const UsdResolveTarget &resolveTarget)

Query information
USD_API const UsdAttribute &	GetAttribute () const
	Return the attribute associated with this query. More...

bool	IsValid () const

	operator bool () const
	Returns `true` if the query object is valid, `false` otherwise. More...

USD_API UsdAttributeQuery &	operator= (const UsdAttributeQuery &other)
	Copy assignment. More...

USD_API UsdAttributeQuery &	operator= (UsdAttributeQuery &&other)=default
	Move assignment. More...

Static Public Member Functions
static USD_API std::vector < UsdAttributeQuery >	CreateQueries (const UsdPrim &prim, const TfTokenVector &attrNames)

Value & Time-Sample Accessors
template<typename T >
bool	Get (T *value, UsdTimeCode time=UsdTimeCode::Default()) const

USD_API bool	Get (VtValue *value, UsdTimeCode time=UsdTimeCode::Default()) const

USD_API bool	GetTimeSamples (std::vector< double > *times) const

USD_API bool	GetTimeSamplesInInterval (const GfInterval &interval, std::vector< double > *times) const

USD_API size_t	GetNumTimeSamples () const

USD_API bool	GetBracketingTimeSamples (double desiredTime, double lower, double upper, bool *hasTimeSamples) const

USD_API bool	HasValue () const

USD_API bool	HasAuthoredValueOpinion () const

USD_API bool	HasAuthoredValue () const

USD_API bool	HasFallbackValue () const

USD_API bool	ValueMightBeTimeVarying () const

static USD_API bool	GetUnionedTimeSamples (const std::vector< UsdAttributeQuery > &attrQueries, std::vector< double > *times)

static USD_API bool	GetUnionedTimeSamplesInInterval (const std::vector< UsdAttributeQuery > &attrQueries, const GfInterval &interval, std::vector< double > *times)

Detailed Description

Object for efficiently making repeated queries for attribute values.

Retrieving an attribute's value at a particular time requires determining the source of strongest opinion for that value. Often (i.e. unless the attribute is affected by Value Clips) this source does not vary over time. UsdAttributeQuery uses this fact to speed up repeated value queries by caching the source information for an attribute. It is safe to use a UsdAttributeQuery for any attribute - if the attribute is affected by Value Clips, the performance gain will just be less.

Resolve targets

An attribute query can also be constructed for an attribute along with a UsdResolveTarget. A resolve target allows value resolution to consider only a subrange of the prim stack instead of the entirety of it. All of the methods of an attribute query created with a resolve target will perform value resolution within that resolve target. This can be useful for finding the value of an attribute resolved up to a particular layer or for determining if a value authored on layer would be overridden by a stronger opinion.

Thread safety

This object provides the basic thread-safety guarantee. Multiple threads may call the value accessor functions simultaneously.

Invalidation

This object does not listen for change notification. If a consumer is holding on to a UsdAttributeQuery, it is their responsibility to dispose of it in response to a resync change to the associated attribute. Failing to do so may result in incorrect values or crashes due to dereferencing invalid objects.

Definition at line 76 of file attributeQuery.h.

Constructor & Destructor Documentation

USD_API UsdAttributeQuery::UsdAttributeQuery ( )

Construct an invalid query object.

USD_API UsdAttributeQuery::UsdAttributeQuery ( const UsdAttributeQuery & other )

Copy constructor.

USD_API UsdAttributeQuery::UsdAttributeQuery ( UsdAttributeQuery && other )

default

Move constructor.

USD_API UsdAttributeQuery::UsdAttributeQuery ( const UsdAttribute & attr )

explicit

Construct a new query for the attribute attr.

USD_API UsdAttributeQuery::UsdAttributeQuery	(	const UsdPrim &	prim,
		const TfToken &	attrName
	)

Construct a new query for the attribute named attrName under the prim prim.

USD_API UsdAttributeQuery::UsdAttributeQuery	(	const UsdAttribute &	attr,
		const UsdResolveTarget &	resolveTarget
	)

Construct a new query for the attribute attr with the given resolve target resolveTarget.

Note that a UsdResolveTarget is associated with a particular prim so only resolve targets for the attribute's owning prim are allowed.

Member Function Documentation

static USD_API std::vector<UsdAttributeQuery> UsdAttributeQuery::CreateQueries	(	const UsdPrim &	prim,
		const TfTokenVector &	attrNames
	)

static

Construct new queries for the attributes named in attrNames under the prim prim. The objects in the returned vector will line up 1-to-1 with attrNames.

template<typename T >

bool UsdAttributeQuery::Get	(	T *	value,
		UsdTimeCode	time = `UsdTimeCode::Default()`
	)		const

inline

Perform value resolution to fetch the value of the attribute associated with this query at the requested UsdTimeCode time.

See Also: UsdAttribute::Get

Definition at line 159 of file attributeQuery.h.

USD_API bool UsdAttributeQuery::Get	(	VtValue *	value,
		UsdTimeCode	time = `UsdTimeCode::Default()`
	)		const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Type-erased access, often not as efficient as typed access.

USD_API const UsdAttribute& UsdAttributeQuery::GetAttribute ( ) const

Return the attribute associated with this query.

USD_API bool UsdAttributeQuery::GetBracketingTimeSamples	(	double	desiredTime,
		double *	lower,
		double *	upper,
		bool *	hasTimeSamples
	)		const

Populate lower and upper with the next greater and lesser value relative to the desiredTime.

See Also: UsdAttribute::GetBracketingTimeSamples

USD_API size_t UsdAttributeQuery::GetNumTimeSamples ( ) const

Returns the number of time samples that have been authored.

See Also: UsdAttribute::GetNumTimeSamples

USD_API bool UsdAttributeQuery::GetTimeSamples ( std::vector< double > * times ) const

Populates a vector with authored sample times. Returns false only on error. Behaves identically to UsdAttribute::GetTimeSamples()

See Also: UsdAttributeQuery::GetTimeSamplesInInterval

USD_API bool UsdAttributeQuery::GetTimeSamplesInInterval	(	const GfInterval &	interval,
		std::vector< double > *	times
	)		const

Populates a vector with authored sample times in interval. Returns false only on an error.

Behaves identically to UsdAttribute::GetTimeSamplesInInterval()

static USD_API bool UsdAttributeQuery::GetUnionedTimeSamples	(	const std::vector< UsdAttributeQuery > &	attrQueries,
		std::vector< double > *	times
	)

static

Populates the given vector, times with the union of all the authored sample times on all of the given attribute-query objects, attrQueries.

Behaves identically to UsdAttribute::GetUnionedTimeSamples()

Returns: false if one or more attribute-queries in attrQueries are invalid or if there's an error fetching time-samples for any of the attribute-query objects.

See Also: UsdAttribute::GetUnionedTimeSamples; UsdAttributeQuery::GetUnionedTimeSamplesInInterval

static USD_API bool UsdAttributeQuery::GetUnionedTimeSamplesInInterval	(	const std::vector< UsdAttributeQuery > &	attrQueries,
		const GfInterval &	interval,
		std::vector< double > *	times
	)

static

Populates the given vector, times with the union of all the authored sample times in the GfInterval, interval on all of the given attribute-query objects, attrQueries.

Behaves identically to UsdAttribute::GetUnionedTimeSamplesInInterval()

Returns: false if one or more attribute-queries in attrQueries are invalid or if there's an error fetching time-samples for any of the attribute-query objects.

See Also: UsdAttribute::GetUnionedTimeSamplesInInterval

USD_API bool UsdAttributeQuery::HasAuthoredValue ( ) const

Return true if this attribute has either an authored default value or authored time samples. If the attribute has been blocked, then return false

See Also: UsdAttribute::HasAuthoredValue()

USD_API bool UsdAttributeQuery::HasAuthoredValueOpinion ( ) const

Deprecated:: This method is deprecated because it returns true even when an attribute is blocked. Please use HasAuthoredValue() instead. If you truly need to know whether the attribute has any authored value opinions, including blocks, you can make the following query: query.GetAttribute().GetResolveInfo().HasAuthoredValueOpinion()

Return true if this attribute has either an authored default value or authored time samples.

USD_API bool UsdAttributeQuery::HasFallbackValue ( ) const

Return true if the attribute associated with this query has a fallback value provided by a registered schema.

See Also: UsdAttribute::HasFallbackValue

USD_API bool UsdAttributeQuery::HasValue ( ) const

Return true if the attribute associated with this query has an authored default value, authored time samples or a fallback value provided by a registered schema.

See Also: UsdAttribute::HasValue

bool UsdAttributeQuery::IsValid ( ) const

inline

Return true if this query is valid (i.e. it is associated with a valid attribute), false otherwise.

Definition at line 128 of file attributeQuery.h.

UsdAttributeQuery::operator bool ( ) const

inlineexplicit

Returns true if the query object is valid, false otherwise.

Definition at line 134 of file attributeQuery.h.

USD_API UsdAttributeQuery& UsdAttributeQuery::operator= ( const UsdAttributeQuery & other )

Copy assignment.

USD_API UsdAttributeQuery& UsdAttributeQuery::operator= ( UsdAttributeQuery && other )

default

Move assignment.

USD_API bool UsdAttributeQuery::ValueMightBeTimeVarying ( ) const

Return true if it is possible, but not certain, that this attribute's value changes over time, false otherwise.

See Also: UsdAttribute::ValueMightBeTimeVarying

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

pxr/usd/usd/attributeQuery.h

Public Member Functions

Static Public Member Functions

Value & Time-Sample Accessors

Detailed Description

Resolve targets

Thread safety

Invalidation

Constructor & Destructor Documentation

Member Function Documentation