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UsdImagingNiPrototypePropagatingSceneIndex Class Referencefinal

A scene index implementing USD native instancing. More...

#include <niPrototypePropagatingSceneIndex.h>

+ Inheritance diagram for UsdImagingNiPrototypePropagatingSceneIndex:

Public Types

using SceneIndexAppendCallback = std::function< HdSceneIndexBaseRefPtr(const HdSceneIndexBaseRefPtr &inputScene)>
 
- Public Types inherited from TfRefBase
typedef void(* UniqueChangedFuncPtr) (TfRefBase const *, bool)
 

Public Member Functions

USDIMAGING_API HdSceneIndexPrim GetPrim (const SdfPath &primPath) const override
 Returns a pair of (prim type, datasource) for the object at primPath.
 
USDIMAGING_API SdfPathVector GetChildPrimPaths (const SdfPath &primPath) const override
 Returns the paths of all scene index prims located immediately below primPath.
 
USDIMAGING_API std::vector< HdSceneIndexBaseRefPtr > GetInputScenes () const override
 
virtual std::vector< HdSceneIndexBaseRefPtr > GetInputScenes () const =0
 
- Public Member Functions inherited from HdSceneIndexBase
HD_API void AddObserver (const HdSceneIndexObserverPtr &observer)
 Adds an observer to this scene index.
 
HD_API void RemoveObserver (const HdSceneIndexObserverPtr &observer)
 Removes an observer from this scene index; the given observer will no longer be forwarded notices.
 
virtual HdSceneIndexPrim GetPrim (const SdfPath &primPath) const =0
 Returns a pair of (prim type, datasource) for the object at primPath.
 
virtual SdfPathVector GetChildPrimPaths (const SdfPath &primPath) const =0
 Returns the paths of all scene index prims located immediately below primPath.
 
HdDataSourceBaseHandle GetDataSource (const SdfPath &primPath, const HdDataSourceLocator &locator) const
 A convenience function: look up the object at primPath, and if successful return the datasource at locator within that prim.
 
HD_API void SystemMessage (const TfToken &messageType, const HdDataSourceBaseHandle &args)
 Sends a message with optional arguments to this and any upstream input scene indices.
 
HD_API std::string GetDisplayName () const
 Returns a value previously set by SetDisplayName.
 
HD_API void SetDisplayName (const std::string &n)
 Allows for scene index instances to be identified in a more contextually relevant way.
 
HD_API void AddTag (const TfToken &tag)
 Adds a specified tag token to a scene index instance.
 
HD_API void RemoveTag (const TfToken &tag)
 Removes a specified tag token to a scene index instance.
 
HD_API bool HasTag (const TfToken &tag) const
 Returns true if a specified tag token has been added to a scene index instance.
 
HD_API TfTokenVector GetTags () const
 Returns all tag tokens currently added to a scene index instance.
 
- Public Member Functions inherited from TfRefBase
 TfRefBase (TfRefBase const &)
 
TfRefBaseoperator= (TfRefBase const &)
 
size_t GetCurrentCount () const
 Return the current reference count of this object.
 
bool IsUnique () const
 Return true if only one TfRefPtr points to this object.
 
void SetShouldInvokeUniqueChangedListener (bool shouldCall)
 
- Public Member Functions inherited from TfWeakBase
 TfWeakBase (const TfWeakBase &)
 
const TfWeakBase__GetTfWeakBase__ () const
 
const TfWeakBaseoperator= (const TfWeakBase &)
 
void EnableNotification2 () const
 
TF_API void const * GetUniqueIdentifier () const
 

Static Public Member Functions

static USDIMAGING_API UsdImagingNiPrototypePropagatingSceneIndexRefPtr New (HdSceneIndexBaseRefPtr const &inputSceneIndex, const TfTokenVector &instanceDataSourceNames, const SceneIndexAppendCallback &sceneIndexAppendCallback)
 
- Static Public Member Functions inherited from TfRefBase
static TF_API void SetUniqueChangedListener (UniqueChangedListener listener)
 

Friends

class _InstanceAggregationSceneIndexObserver
 
class _MergingSceneIndexObserver
 

Additional Inherited Members

- Protected Member Functions inherited from HdSceneIndexBase
HD_API void _SendPrimsAdded (const HdSceneIndexObserver::AddedPrimEntries &entries)
 Notify attached observers of prims added to the scene.
 
HD_API void _SendPrimsRemoved (const HdSceneIndexObserver::RemovedPrimEntries &entries)
 Notify attached observers of prims removed from the scene.
 
HD_API void _SendPrimsDirtied (const HdSceneIndexObserver::DirtiedPrimEntries &entries)
 Notify attached observers of datasource invalidations from the scene.
 
HD_API void _SendPrimsRenamed (const HdSceneIndexObserver::RenamedPrimEntries &entries)
 Notify attached observers of prims (and their descendents) which have been renamed or reparented.
 
HD_API bool _IsObserved () const
 Returns whether the scene index has any registered observers; this information can be used to skip work preparing notices when there are no observers.
 
virtual HD_API void _SystemMessage (const TfToken &messageType, const HdDataSourceBaseHandle &args)
 Implement in order to react directly to system messages sent from downstream.
 
- Protected Member Functions inherited from TfWeakBase
TfRefPtr< Tf_Remnant > _Register () const
 
template<class T >
TfRefPtr< Tf_Remnant > _Register (T *tempRmnt) const
 
bool _HasRemnant () const
 

Detailed Description

A scene index implementing USD native instancing.

If combined with the UsdImagingPiPrototypePropagatingSceneIndex, the native instancing scene index has to be run after the point instancing scene index.

This scene index uses the UsdImagingNiInstanceAggregationSceneIndex to find all instances, aggregate them and insert instancers for each set of aggregated instances. This scene index then inserts flattened and possibly further transformed (e.g. applying draw mode) copies of the corresponding USD prototype underneath each of these instancers. Each of these copies is actually a UsdImagingNiPrototypePropagatingSceneIndex itself. This way, we can handle nested native instancing. In other words, we can call the UsdImagingNiPrototypePropagatingSceneIndex for a USD prototype and it will find the instances within that prototype.

The instancing scene index uses the instancedBy:prototypeRoot of the input scene index during aggregation. Typically, the input scene index will be a UsdImagingPiPrototypePropagatingSceneIndex which populates instancedBy:prototypeRoot based on which point instancer is instancing a prim.

This scene index is implemented by a merging scene index with the following inputs:

  • a scene index ultimately tracing back to UsdImaging_NiPrototypeSceneIndex which prepares the prototype for which this scene index was created. The scene indices applied after UsdImaging_NiPrototypeSceneIndex include a flattening scene index as well as scene indices that can be specified through a callback by a user (typically, the draw mode scene index).
  • the UsdImaging_NiInstanceAggregationSceneIndex instantiated from the above scene index. The instance aggregation scene index will insert the instancers for the instances within this prototype.
  • More UsdImagingNiPrototypePropagatingSceneIndex's: The _InstanceAggregationSceneIndexObserver will observe the latter scene index to add respective UsdImagingNiPrototypePropagatingSceneIndex's under each instancer.

Example 1 (also see Example 1 in niInstanceAggregationSceneIndex.h)

USD:

def Xform "MyPrototype" { def Cube "MyCube" { } }

def "Cube_1" ( instanceable = true references = </MyPrototype> { }

Inputs of the UsdImagingNiPrototypePropagatingSceneIndex(inputSceneIndex):

* HdMergingSceneIndex
    * UsdImagingDrawModeSceneIndex (through SceneIndexAppendCallback)
         * HdFlatteningSceneIndex 
           inputArgs = UsdImagingFlattenedDataSourceProviders()
           [So model:drawMode is also flattened]
             * UsdImaging_NiPrototypeSceneIndex
                 forPrototype = false
                 prototypeRootOverlayDs = null
                 * UsdImaging_NiPrototypePruningSceneIndex
                   forPrototype = false
                     * inputSceneIndex (typically a UsdImagingPiPrototypePropagatingSceneIndex)
    * UsdImaging_NiInstanceAggregationSceneIndex 
      forPrototype = false
      instanceDataSourceNames = ['materialBindings', 'purpose', 'model']
         * UsdImagingDrawModeSceneIndex
           [... as above]
    * UsdImagingRerootingSceneIndex
      (inserted by _InstanceAggregationSceneIndexObserver::PrimsAdded
       through _MergingSceneIndexEntry)
      srcPrefix = /UsdNiInstancer
      dstPrefix = /UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer
        * UsdImagingNiPrototypePropagatingSceneIndex
          prototypeName = __Prototype_1
            * HdMergingSceneIndex
                * UsdImagingDrawModeSceneIndex (through SceneIndexAppendCallback)
                    * HdFlatteningSceneIndex 
                      inputArgs = UsdImagingFlattenedDataSourceProviders()
                      [So model:drawMode is also flattened]
                        * UsdImaging_NiPrototypeSceneIndex
                          forPrototype = true
                            * UsdImagingRerootingSceneIndex
                              srcPrefix = /__PrototypeRoot1
                              dstPrefix = /UsdNiInstancer/UsdNiPrototype
                                * inputSceneIndex
                * UsdImaging_NiInstanceAggregationSceneIndex
                  forPrototype = true
                    * UsdImagingDrawModeSceneIndex
                      [... as just above]

UsdImagingNiPrototypePropagatingSceneIndex

/Cube_1 primType: "" dataSource: instance: # Useful for translating Usd proxy paths for selection.

See corresponding example in niInstanceAggregationIndex

for more details.

instancer: /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer prototypeId: 0 instanceId: 0 purpose: # From flattening scene index purpose: geometry xform: # From flattening scene index matrix: [ identity matrix] primOrigin: scenePath: HdPrimOriginSchema::OriginPath(/Cube_1) ... /MyPrototype # Not referenced from a different file, so appears here

as non-prototype as well

primType: "" /MyPrototype/MyCube primType: cube /UsdNiPropagatedPrototypes primType: "" /UsdNiPropagatedPrototypes/Bindings_423...234 primType: "" dataSource: purpose: # Added by instance aggregation scene index, copied from /Cube_1 purpose: geometry

No xform, visibility (never copied by instance aggregation, written to

instancer instead) /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1 primType: "" /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer primType: instancer dataSource: instancerTopology: instanceIndices: i0: [ 0 ] prototypes: [ /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer/UsdNiPrototype instanceLocations: [ /Cube_1 ] # for picking primvars: hydra:instanceTransforms: primvarValue: [ identity matrix ] interpolation: instance /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer/UsdNiPrototype primType: "" dataSource: instancedBy: paths: [ /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer ] prototypeRoot: /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1 /UsdNiInstancer/UsdNiPrototype purpose: # Added by prototype scene index, copied from /UsdNiPropagatedPrototypes/Bindings_423...234

Flattened scene index did not touch it.

purpose: geometry xform: # From flattening scene index matrix: [ identity matrix ] resetXformStack: true primOrigin: scenePath: HdPrimOriginSchema::OriginPath(.) /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer/UsdNiPrototype/MyCube primType: cube dataSource: instancedBy: paths: [ /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1/UsdNiInstancer ] prototypeRoot: /UsdNiPropagatedPrototypes/Bindings_423...234/__Prototype_1 /UsdNiInstancer/UsdNiPrototype purpose: # From flattening scene index purpose: geometry xform: # From flattening scene index matrix: [ identity matrix ] resetXformStack: true primOrigin: scenePath: HdPrimOriginSchema::OriginPath(MyCube)

Example 2:

def Xform "MyNestedPrototype" # Will become USD prototype /__Prototype_1 { def Cube "MyCube" { } }

def Xform "MyPrototype" # Will become USD prototype /__Prototype_2 { def "MyNestedInstance" ( instanceable = true references = </MyNestedPrototype> ) { } }

def Xform "MyInstance" ( instanceable = true references = </MyPrototype>) {

}

UsdImagingNiPrototypePropagatingSceneIndex

... /MyInstance primType: "" dataSource: instance: instancer: /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer prototypeId: 0 instanceId: 0 ... /UsdNiPropagatedPrototypes primType: "" /UsdNiPropagatedPrototypes/NoBindings primType: "" dataSource: ... /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2 primType: "" /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer primType: instancer dataSource: instanerTopology: prototypes: [ /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype ] ... /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/_Prototype_2 primType: "" /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/_Prototype_2/MyNestedInstance primType: "" dataSource: instancer: /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer prototypeId: 0 instanceId: 0 ... /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings primType: "" dataSource: ... /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1 primType: "" /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer primType: instancer dataSource: instanerTopology: prototypes: [ /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer/UsdPiPrototype ] ... instancedBy: paths: [ /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer ] prototypeRoot: /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer/UsdPiPrototype primType: "" dataSource: instancedBy: paths: [ /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer ] prototypeRoot: /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer/UsdPiPrototype ... /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer/UsdPiPrototype/MyCube primType: "cube" dataSource: instancedBy: paths: [ /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/UsdPiPrototype/UsdNiInstancer ] prototypeRoot: /UsdNiPropagatedPrototypes/NoBindings/__Prototype_2/UsdNiInstancer/UsdPiPrototype/UsdNiPropagatedPrototypes/NoBindings/__Prototype_1/UsdNiInstancer/UsdPiPrototype ...

Definition at line 303 of file niPrototypePropagatingSceneIndex.h.

Member Typedef Documentation

◆ SceneIndexAppendCallback

using SceneIndexAppendCallback = std::function< HdSceneIndexBaseRefPtr(const HdSceneIndexBaseRefPtr &inputScene)>

Definition at line 307 of file niPrototypePropagatingSceneIndex.h.

Member Function Documentation

◆ GetChildPrimPaths()

USDIMAGING_API SdfPathVector GetChildPrimPaths ( const SdfPath primPath) const
overridevirtual

Returns the paths of all scene index prims located immediately below primPath.

This function can be used to traverse the scene by recursing from SdfPath::AbsoluteRootPath(); such a traversal is expected to give the same set of prims as the flattening of the scene index's PrimsAdded and PrimsRemoved messages. This function is expected to be threadsafe.

Implements HdSceneIndexBase.

◆ GetInputScenes()

USDIMAGING_API std::vector< HdSceneIndexBaseRefPtr > GetInputScenes ( ) const
overridevirtual

◆ GetPrim()

USDIMAGING_API HdSceneIndexPrim GetPrim ( const SdfPath primPath) const
overridevirtual

Returns a pair of (prim type, datasource) for the object at primPath.

If no such object exists, the type will be the empty token and the datasource will be null. This function is expected to be threadsafe.

Implements HdSceneIndexBase.

Friends And Related Function Documentation

◆ _InstanceAggregationSceneIndexObserver

friend class _InstanceAggregationSceneIndexObserver
friend

Definition at line 349 of file niPrototypePropagatingSceneIndex.h.

◆ _MergingSceneIndexObserver

friend class _MergingSceneIndexObserver
friend

Definition at line 373 of file niPrototypePropagatingSceneIndex.h.


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