API for configuring Level of Detail (LOD) facilities on a prim. More...

#include <rootAPI.h>

Inheritance diagram for UsdLodRootAPI:

Public Member Functions
	UsdLodRootAPI (const UsdPrim &prim=UsdPrim())
	Construct a UsdLodRootAPI on UsdPrim `prim` .

	UsdLodRootAPI (const UsdSchemaBase &schemaObj)
	Construct a UsdLodRootAPI on the prim held by `schemaObj` .

virtual USDLOD_API	~UsdLodRootAPI ()
	Destructor.

USDLOD_API UsdAttribute	GetLodDefaultIndexAttr () const
	The LOD item child to use if none of the heuristics are understood by the renderer or if none return a usable LOD.

USDLOD_API UsdAttribute	CreateLodDefaultIndexAttr (VtValue const &defaultValue=VtValue(), bool writeSparsely=false) const
	See GetLodDefaultIndexAttr(), and also Create vs Get Property Methods for when to use Get vs Create.

USDLOD_API UsdRelationship	GetLodHeuristicsRel () const
	Relationship targeting all the heuristic prims that could be used for this particular LOD root.

USDLOD_API UsdRelationship	CreateLodHeuristicsRel () const
	See GetLodHeuristicsRel(), and also Create vs Get Property Methods for when to use Get vs Create.

UsdPrimSiblingRange	GetLODItems () const
	Return the prim's LOD item children.

Public Member Functions inherited from UsdAPISchemaBase
	UsdAPISchemaBase (const UsdPrim &prim=UsdPrim())
	Construct a UsdAPISchemaBase on UsdPrim `prim` .

	UsdAPISchemaBase (const UsdSchemaBase &schemaObj)
	Construct a UsdAPISchemaBase on the prim held by `schemaObj` .

virtual USD_API	~UsdAPISchemaBase ()=0
	Destructor.

Public Member Functions inherited from UsdSchemaBase
bool	IsConcrete () const
	Returns whether or not this class corresponds to a concrete instantiable prim type in scene description.

bool	IsTyped () const
	Returns whether or not this class inherits from UsdTyped.

bool	IsAPISchema () const
	Returns whether this is an API schema or not.

bool	IsAppliedAPISchema () const
	Returns whether this is an applied API schema or not.

bool	IsMultipleApplyAPISchema () const
	Returns whether this is an applied API schema or not.

UsdSchemaKind	GetSchemaKind () const
	Returns the kind of schema this class is.

USD_API	UsdSchemaBase (const UsdPrim &prim=UsdPrim())
	Construct and store `prim` as the held prim.

USD_API	UsdSchemaBase (const UsdSchemaBase &otherSchema)
	Construct and store for the same prim held by `otherSchema`.

virtual USD_API	~UsdSchemaBase ()
	Destructor.

UsdPrim	GetPrim () const
	Return this schema object's held prim.

SdfPath	GetPath () const
	Shorthand for GetPrim()->GetPath().

USD_API const UsdPrimDefinition *	GetSchemaClassPrimDefinition () const
	Return the prim definition associated with this schema instance if one exists, otherwise return null.

USD_API	operator bool () const
	Return true if this schema object is compatible with its held prim, false otherwise.

Static Public Member Functions
static USDLOD_API const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)
	Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes.

static USDLOD_API UsdLodRootAPI	Get (const UsdStagePtr &stage, const SdfPath &path)
	Return a UsdLodRootAPI holding the prim adhering to this schema at `path` on `stage`.

static USDLOD_API bool	CanApply (const UsdPrim &prim, std::string *whyNot=nullptr)
	Returns true if this single-apply API schema can be applied to the given `prim`.

static USDLOD_API UsdLodRootAPI	Apply (const UsdPrim &prim)
	Applies this single-apply API schema to the given `prim`.

Static Public Member Functions inherited from UsdAPISchemaBase
static USD_API const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)
	Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes.

Static Public Member Functions inherited from UsdSchemaBase
static const TfTokenVector &	GetSchemaAttributeNames (bool includeInherited=true)

Static Public Attributes
static const UsdSchemaKind	schemaKind = UsdSchemaKind::SingleApplyAPI
	Compile time constant representing what kind of schema this class is.

Static Public Attributes inherited from UsdAPISchemaBase
static const UsdSchemaKind	schemaKind = UsdSchemaKind::AbstractBase
	Compile time constant representing what kind of schema this class is.

Static Public Attributes inherited from UsdSchemaBase
static const UsdSchemaKind	schemaKind = UsdSchemaKind::AbstractBase
	Compile time constant representing what kind of schema this class is.

Protected Member Functions
USDLOD_API UsdSchemaKind	_GetSchemaKind () const override
	Returns the kind of schema this class belongs to.

Protected Member Functions inherited from UsdAPISchemaBase
	UsdAPISchemaBase (const UsdPrim &prim, const TfToken &instanceName)
	Construct a multiple-apply UsdAPISchemaBase on UsdPrim `prim` with the specified `instanceName`.

	UsdAPISchemaBase (const UsdSchemaBase &schemaObj, const TfToken &instanceName)
	Construct a multiple-apply UsdAPISchemaBase on the prim held by `schemaObj` with the given `instanceName`.

const TfToken &	_GetInstanceName () const
	Returns the instance name of the API schema object belonging to a multiple-apply API schema.

USD_API bool	_IsCompatible () const override
	Check whether this APISchema object is valid for the currently held prim.

Protected Member Functions inherited from UsdSchemaBase
virtual UsdSchemaKind	_GetSchemaType () const

const TfType &	_GetType () const

USD_API UsdAttribute	_CreateAttr (TfToken const &attrName, SdfValueTypeName const &typeName, bool custom, SdfVariability variability, VtValue const &defaultValue, bool writeSparsely) const

Friends
class	UsdSchemaRegistry

Additional Inherited Members
Static Protected Member Functions inherited from UsdAPISchemaBase
static USD_API TfTokenVector	_GetMultipleApplyInstanceNames (const UsdPrim &prim, const TfType &schemaType)
	Returns a vector of names of API schema objects belonging to a multiple-apply API schema applied to a given prim.

Detailed Description

API for configuring Level of Detail (LOD) facilities on a prim.

This API schema marks a prim as the root of an LOD selection hierarchy. The immediate namespace children of this prim are the LOD items that can be selected during rendering. The order of LOD item child prims in the USD stage determines the LOD index, from 0 to the number_of_children - 1.

Selection of appropriate LOD items is entirely up to the renderer that is processing the scene. Upon encountering an LOD root, the renderer should check for an LOD override (see UsdLodOverrideAPI), then check the targets of the lod:heuristics relationship for an appropriate heuristic using the heuristic's type and lod:domain value to select one, falling back to the lod:default:index value if all else fails. Each heuristic type will likely have a specific, unique API to query that heuristic for its LOD recommendation. It is then up to the renderer to display the selected LOD item child and not display LOD item children that are not selected.

LOD heuristics are specified by heuristic prims targeted by the lod:heuristics relationship. The targeted heuristics are intended to be queried and used by the renderer.

LOD items are generally mutually exclusive selections, though renderers may blend between multiple children or even display all of them when given an appropriate override.

The schema is singleApply, but multiple systems may independently specify level of detail criteria via heuristics specified by the lod:heuristics relationship. For example, a single prim may have both "imaging" and "physics" domain heuristics; the choice of the domains to consider and the heuristic(s) to use is up to the renderer.

A child or descendent of an LODRootAPI prim may itself have LODRootAPI applied to create nested hierarchical LOD structures.

Definition at line 73 of file rootAPI.h.

Constructor & Destructor Documentation

◆ UsdLodRootAPI() [1/2]

UsdLodRootAPI ( const UsdPrim & prim = UsdPrim() )

inlineexplicit

Construct a UsdLodRootAPI on UsdPrim prim .

Equivalent to UsdLodRootAPI::Get(prim.GetStage(), prim.GetPath()) for a valid prim, but will not immediately throw an error for an invalid prim

Definition at line 85 of file rootAPI.h.

◆ UsdLodRootAPI() [2/2]

UsdLodRootAPI ( const UsdSchemaBase & schemaObj )

inlineexplicit

Construct a UsdLodRootAPI on the prim held by schemaObj .

Should be preferred over UsdLodRootAPI(schemaObj.GetPrim()), as it preserves SchemaBase state.

Definition at line 93 of file rootAPI.h.

◆ ~UsdLodRootAPI()

virtual USDLOD_API ~UsdLodRootAPI ( )

virtual

Destructor.

Member Function Documentation

◆ _GetSchemaKind()

USDLOD_API UsdSchemaKind _GetSchemaKind ( ) const

overrideprotectedvirtual

Returns the kind of schema this class belongs to.

See also: UsdSchemaKind

Reimplemented from UsdAPISchemaBase.

◆ Apply()

static USDLOD_API UsdLodRootAPI Apply ( const UsdPrim & prim )

static

Applies this single-apply API schema to the given prim.

This information is stored by adding "LODRootAPI" to the token-valued, listOp metadata apiSchemas on the prim.

Returns: A valid UsdLodRootAPI object is returned upon success. An invalid (or empty) UsdLodRootAPI object is returned upon failure. See UsdPrim::ApplyAPI() for conditions resulting in failure.

See also: UsdPrim::GetAppliedSchemas(); UsdPrim::HasAPI(); UsdPrim::CanApplyAPI(); UsdPrim::ApplyAPI(); UsdPrim::RemoveAPI()

◆ CanApply()

static USDLOD_API bool CanApply	(	const UsdPrim &	prim,
		std::string *	whyNot = nullptr )

static

Returns true if this single-apply API schema can be applied to the given prim.

If this schema can not be a applied to the prim, this returns false and, if provided, populates whyNot with the reason it can not be applied.

Note that if CanApply returns false, that does not necessarily imply that calling Apply will fail. Callers are expected to call CanApply before calling Apply if they want to ensure that it is valid to apply a schema.

See also: UsdPrim::GetAppliedSchemas(); UsdPrim::HasAPI(); UsdPrim::CanApplyAPI(); UsdPrim::ApplyAPI(); UsdPrim::RemoveAPI()

◆ CreateLodDefaultIndexAttr()

USDLOD_API UsdAttribute CreateLodDefaultIndexAttr	(	VtValue const &	defaultValue = VtValue(),
		bool	writeSparsely = false ) const

See GetLodDefaultIndexAttr(), and also Create vs Get Property Methods for when to use Get vs Create.

If specified, author defaultValue as the attribute's default, sparsely (when it makes sense to do so) if writeSparsely is true - the default for writeSparsely is false.

◆ CreateLodHeuristicsRel()

USDLOD_API UsdRelationship CreateLodHeuristicsRel ( ) const

See GetLodHeuristicsRel(), and also Create vs Get Property Methods for when to use Get vs Create.

◆ Get()

static USDLOD_API UsdLodRootAPI Get	(	const UsdStagePtr &	stage,
		const SdfPath &	path )

static

Return a UsdLodRootAPI holding the prim adhering to this schema at path on stage.

If no prim exists at path on stage, or if the prim at that path does not adhere to this schema, return an invalid schema object. This is shorthand for the following:

UsdLodRootAPI(stage->GetPrimAtPath(path));

UsdLodRootAPI::UsdLodRootAPI

UsdLodRootAPI(const UsdPrim &prim=UsdPrim())

Construct a UsdLodRootAPI on UsdPrim prim .

Definition rootAPI.h:85

◆ GetLodDefaultIndexAttr()

USDLOD_API UsdAttribute GetLodDefaultIndexAttr ( ) const

The LOD item child to use if none of the heuristics are understood by the renderer or if none return a usable LOD.

Consider an "audio" renderer that does not understand "imaging" domain heuristics. When it encounters a prim with LODRootAPI applied and only "imaging" domain heuristics, it should select and process the child indicated by lod:default:index and ignore the other children.


Declaration	`int lod:default:index = 0`
C++ Type	int
Usd Type	SdfValueTypeNames->Int

◆ GetLodHeuristicsRel()

USDLOD_API UsdRelationship GetLodHeuristicsRel ( ) const

Relationship targeting all the heuristic prims that could be used for this particular LOD root.

The choice of which heuristic(s) will be used is up to the renderer.

◆ GetLODItems()

UsdPrimSiblingRange GetLODItems ( ) const

inline

Return the prim's LOD item children.

Equivalent to GetPrim().GetChildren();

Definition at line 242 of file rootAPI.h.

◆ GetSchemaAttributeNames()

static USDLOD_API const TfTokenVector & GetSchemaAttributeNames ( bool includeInherited = true )

static

Return a vector of names of all pre-declared attributes for this schema class and all its ancestor classes.

Does not include attributes that may be authored by custom/extended methods of the schemas involved.

Friends And Related Symbol Documentation

◆ UsdSchemaRegistry

friend class UsdSchemaRegistry

friend

Definition at line 171 of file rootAPI.h.

Member Data Documentation

◆ schemaKind

const UsdSchemaKind schemaKind = UsdSchemaKind::SingleApplyAPI

static

Compile time constant representing what kind of schema this class is.

See also: UsdSchemaKind

Definition at line 79 of file rootAPI.h.

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

pxr/usd/usdLod/rootAPI.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ UsdLodRootAPI() [1/2]

◆ UsdLodRootAPI() [2/2]

◆ ~UsdLodRootAPI()

Member Function Documentation

◆ _GetSchemaKind()

◆ Apply()

◆ CanApply()

◆ CreateLodDefaultIndexAttr()

◆ CreateLodHeuristicsRel()

◆ Get()

◆ GetLodDefaultIndexAttr()

◆ GetLodHeuristicsRel()

◆ GetLODItems()

◆ GetSchemaAttributeNames()

Friends And Related Symbol Documentation

◆ UsdSchemaRegistry

Member Data Documentation

◆ schemaKind