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  3. IGeometrySelector

IGeometrySelector

[IGeometrySelector](API\Plugins\ModelingComponents\Selection\IGeometrySelector) is a base API definition for, roughly, "an object that knows how to

API > API/Plugins > API/Plugins/ModelingComponents > API/Plugins/ModelingComponents/Selection

Inheritance Hierarchy

References

   
Module ModelingComponents
Header /Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/GeometrySelector.h
Include #include "Selection/GeometrySelector.h"

Syntax

class IGeometrySelector

Remarks

IGeometrySelector is a base API definition for, roughly, "an object that knows how to select elements and/or work with element selections on some other object", where "element" is some "part" of the object, like a mesh edge/vertex/triangle, or intermediate structure (eg a polygroup).

Essentially the purpose of IGeometrySelector is to provide the bridge between "object that can have a selection" and "the active selection on that object". The Selection is stored as a FGeometrySelection which has no reference to a type or target object, and standard target objects (eg a StaticMesh, Volume, etc) have no inherent knowledge of, or support for, low-level geometry selections. So the Selector provides these capabilities, as well as related functionality like being able to transform an active selection and emit necessary transactions/etc.

Generally clients will not create a IGeometrySelector instance directly. For a given implmentation, a IGeometrySelectorFactory is registered with the UGeometrySelectionManager, and it creates instances based on the active selection.

Where possible, the UGeometrySelectionManager will also "sleep" a IGeometrySelector for a given target object instead of destroying it when the object is deselected, and then "restore" it if the object is re-selected. This avoids frequent churn in Selectors as the user clicks between objects.

Selector implementations should ideally have a strategy to lazy-construct any large data structures (eg mesh AABBTrees, etc). Again this is to avoid excessive overhead when the user (for example) selects a large object but has no intention of doing element-level selection.

Variables

  Type Name Description
Protected variable FOnGeometryModified OnGeometryModifed  

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Public function void

AccumulateElementsFromPredicate ( FGeometrySelectionElements& ElementsInOut,
bool bTransformToWorld,
bool bIsForPreview,
bool bUseGroupTopology,
TFunctionRef< bool(UE::Geometry::EGeometryElementType, UE::Geometry::FGeoSelectionID)> Predicate
)

 Accumulate all geometric elements (currently 3D triangles, line segments, and points) in the provided ElementsInOut by initializing vertex, edge, and face selections using the provided predicate and then accumulating elements for those selections.
Public function void

AccumulateSelectionBounds ( const FGeometrySelection& Selection,
FGeometrySelectionBounds& BoundsInOut,
bool bTransformToWorld
)

 Accumulate the bounds of the provided Selection in the provided BoundsInOut.
Public function void

AccumulateSelectionElements ( const FGeometrySelection& Selection,
FGeometrySelectionElements& ElementsInOut,
bool bTransformToWorld,
bool bIsForPreview
)

 Accumulate geometric elements (currently 3D triangles, line segments, and points) for the provided Selection in the provided ElementsInOut.
Public function Const FGeometryIdentifier  
Public function Const FTransform  
Public function FOnGeometryModified & The OnGeometryModified delegate will fire if the geometry of the Selector's Target Object is modified.
Public function void

GetSelectionFrame ( const FGeometrySelection& Selection,
UE::Geometry::FFrame3d& SelectionFrameOut,
bool bTransformToWorld
)

 Compute a 3D frame for the provided Selection.
Public function void Query the Selector for a potential selection based on world-space Ray.
Public function void

GetTargetFrame ( const FGeometrySelection& Selection,
UE::Geometry::FFrame3d& SelectionFrameOut
)

 Compute a 3D frame for the Selector's target object
Public function void

InitializeSelectionFromPredicate ( FGeometrySelection& SelectionInOut,
TFunctionRef< bool(UE::Geometry::FGeoSelectionID)> SelectionIDPredicate,
EInitializeSelectionMode InitializeMode,
const FGeometrySelection* ReferenceSelection
)

 Populate a Selection using the provided ReferenceMode, with a Predicate and optional ReferenceSelection.
Public function IGeometrySelectionTransformer * Create and initialize a IGeometrySelectionTransformer for the provided Selection.
Public function Virtual Const bool Locking support.
Public function Virtual Const bool  
Protected function void  
Public function bool Check for intersection between a world-space Ray with the Selector's target object and return a FInputRayHit result.
Public function Virtual bool

Restore ()

 Restore a Selector that has had Sleep() called on it.
Public function Virtual void

SetLockedState ( bool bLocked
)

  
Public function void Disconnect the Selector from its target object and prepare for deletion.
Public function void Shutdown an active IGeometrySelectionTransformer.
Public function Virtual bool

Sleep ()

 Temporarily disable the Selector, with the intention of re-enabling it (via Restore()) in the future.
Public function Virtual Const bool The SelectionManager will call SupportsSleep() to determine if an IGeometrySelector needs to be destroyed when the target object is deselected, or if it can be re-used (generally more efficient)
Public function void

UpdateSelectionFromSelection ( const FGeometrySelection& FromSelection,
bool bAllowConversion,
FGeometrySelectionEditor& SelectionEditor,
const FGeometrySelectionUpdateConfig& UpdateConfig,
UE::Geometry::FGeometrySelectionDelta* SelectionDelta
)

 Combine FromSelection with the current Selection owned/referenced by the Selector, using the provided SelectionEditor and UpdateConfig.
Public function void Update the active selection based on a world-space Ray.
Public function void Update the active selection based on a world-space Shape.

Classes

  Type Name Description
Public struct FWorldRayQueryInfo    
Public struct FWorldShapeQueryInfo    

Enums

  Type Name Description
Public enum EInitializeSelectionMode    

Typedefs

Name Description
FGeometrySelection  
FGeometrySelectionBounds  
FGeometrySelectionEditor  
FGeometrySelectionElements  
FGeometrySelectionUpdateConfig  
FGeometrySelectionUpdateResult  
FOnGeometryModified  

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