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  3. UGeometrySelectionManager

UGeometrySelectionManager

[UGeometrySelectionManager](API\Plugins\ModelingComponents\Selection\UGeometrySelectionManager) provides the infrastructure for "Element Selection", ie geometric sub-elements of some geometry object like a Triangle Mesh.

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

Inheritance Hierarchy

References

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

Syntax

UCLASS&40;&41;  
class UGeometrySelectionManager : public UObject

Remarks

UGeometrySelectionManager provides the infrastructure for "Element Selection", ie geometric sub-elements of some geometry object like a Triangle Mesh. The Manager is designed to work with a relatively vague concept of "element", so it doesn't explicitly reference triangles/etc, and the selectable-elements and how-elements-are-selected concepts are provided by abstract-interfaces that allow various implememtations.

The "Geometry Objects", eg like a DynamicMeshComponent, Gameplay Volume, etc, are referred to as "Active Targets" in the Manager. External code provides and updates the set of Active Targets, eg for example tracking the active Actor Selection in the Editor.

For a given Target, a tuple (Selector, Selection, SelectionEditor) is created and maintained. The FGeometrySelection is ultimately a basic list of integers and does not have any knowledge of what it is a selection of, and is not intended to be directly edited. Instead the SelectionEditor provides that functionality. This separation allows "selection editing" to be customized, eg to enforce invariants or constraints that might apply to certain kinds of selections.

The IGeometrySelector provides the core implementation of what "selection" means for a given Target, eg like a mesh Component, or mesh object like a UDynamicMesh. The Selector is created by a registered Factory, allowing client code to provide custom implementations for different Target Types. Updates to the Selection are done via the Selector, as well as queries about (eg) renderable selection geometry. 3D Transforms are also applied via the Selector, as only it has the knowledge about what can be transformed and how it can be applied.

The GeometrySelectionManager provides high-level interfaces for this system, for example external code (eg such as something that creates a Gizmo for the active selection) only needs to interact with SelectionManager, calling functions like ::BeginTransformation() / ::UpdateTransformation() / ::EndTransformation(). The SelectionManager also handles Transactions/FChanges for the active Targets and Selections.

Variables

  Type Name Description
Protected variable FGeometrySelection ActivePreviewSelection 3D geometry for active hover/preview highlight note: currently only supporting single target here, will need to be refactored to handle multiple targets...
Protected variable TMap< FGeometryIdentifier, TSharedPtr< FGeometrySelectionTarget > > ActiveTargetMap Map from external Identifiers to active Selection Targets
Protected variable TArray< TSharedPtr< FGeometrySelectionTarget > > ActiveTargetReferences Set of active Selection Targets updated by SynchronizeActiveTargets / etc.
Protected variable UE::Geometry::FGeometrySelectionDelta ActiveTrackedDelta  
Protected variable FGeometrySelection ActiveTrackedSelection  
Protected variable FGeometrySelectionUpdateConfig ActiveTrackedUpdateConfig  
Protected variable TArray< IGeometrySelectionTransformer * > ActiveTransformations TransformationsSet of existing transformer objects, collected from active IGeometrySelector::InitializeTransformation().
Protected variable bool bInTrackedSelectionChange Support for complex selection changes that are driven externally
Protected variable bool bSelectionModifiedDuringTrackedChange  
Protected variable bool bSelectionRenderCachesDirty  
Protected variable FGeometrySelectionElements CachedPreviewRenderElements  
Protected variable TArray< FGeometrySelectionElements > CachedSelectionRenderElements 3D geometry for element selections of each ActiveTarget is cached to improve rendering performance
Protected variable TArray< TUniquePtr< IGeometrySelectorFactory > > Factories Set of registered IGeometrySelector factories
Protected variable UE::Geometry::FGeometrySelectionDelta InitialTrackedDelta  
Protected variable EMeshTopologyMode MeshTopologyMode  
Public variable FModelingSelectionInteraction_SelectionModified OnSelectionModified OnSelectionModified is broadcast if the selection is modified via the above functions.
Protected variable UProperty TObjectPtr< UGeometrySelectionEditCommandArguments > SelectionArguments This is set to current selection during CanExecuteSelectionCommand/ExecuteSelectionCommand, to keep the UObject alive Not expected to be used outside that context
Protected variable EGeometryElementType SelectionElementType  
Protected variable TMap< FGeometryIdentifier, TSharedPtr< FGeometrySelectionTarget > > TargetCache Support for cached FGeometrySelectionTarget / IGeometrySelectors.
Protected variable UProperty TObjectPtr< UInteractiveToolsContext > ToolsContext  
Protected variable IToolsContextTransactionsAPI * TransactionsAPI  
Protected variable TArray< FGeometryIdentifier > UnlockedTargets  

Functions

  Type Name Description
Public function Virtual void

AccumulateSelectionUpdate_Raycast ( const FRay3d& WorldRay,
FGeometrySelectionUpdateResult& ResultOut
)

 Update the tracked selection change via a single Raycast, using the active UpdateConfig mode passed to BeginTrackedSelectionChange
Public function bool Add a target to the active target set, if a valid IGeometrySelectorFactory can be found
Public function Virtual void Undo/Redo
Public function Virtual bool

BeginTrackedSelectionChange ( FGeometrySelectionUpdateConfig UpdateConfig,
bool bClearOnBegin
)

 Begin a tracked selection change.
Public function Virtual bool Begin a transformation of element selections in active Targets.
Public function Virtual Const bool Support for more complex selection changes that might (eg) occur over multiple frames, or be computed externally.
Public function bool Command Execution
Protected function void  
Public function void Empty the active selection target set
Public function Virtual void Selection Updates Clear any active element selections.
Public function Virtual void  
Public function Virtual void Debugging stuffPrint information about the active selection using UE_LOG
Public function Virtual void Visualize the active selection using PDI drawing
Public function Virtual void Close an active tracked selection change.
Public function Virtual void End the current active transformation, and emit changes/transactions
Public function void Execute the selection command for all the current selections
Public function Virtual Const void

GetActiveSelectionInfo ( EGeometryTopologyType& TopologyTypeOut,
EGeometryElementType& ElementTypeOut,
int& NumTargetsOut,
bool& bIsEmpty
)

 Get avaialble information about the active selection/state
Public function Const bool  
Public function Const bool  
Protected function TSharedPtr< FGeometrySelectionTarget >  
Protected function Const UE::Geometry::FGeometrySelectionHitQueryConfig  
Protected function Const TArray< FGeometryIdentifier >  
Public function Virtual Const EMeshTopologyMode  
Public function Virtual Const bool  
Public function Virtual Const EGeometryElementType  
Public function Virtual Const bool Get the active element selection for the given Component, if it exists
Public function Virtual Const EGeometryTopologyType  
Public function Virtual Const void  
Public function Const UInteractiveToolsContext *  
Public function Const IToolsContextTransactionsAPI *  
Public function Const bool Target Management / Queries TODO: be able to update active target set w/o losing current selections?
Public function Virtual Const bool  
Public function Virtual Const bool Selection queries
Public function Virtual Const bool  
Public function Virtual void

Initialize ( UInteractiveToolsContext* ToolsContextIn,
IToolsContextTransactionsAPI* TransactionsAPIIn
)

 Setup/Teardown
Public function Virtual Const bool  
Public function Virtual Const bool  
Protected function void  
Protected function void Apply ProcessFunc to active selections via handles, perhaps should be public?
Public function Virtual bool

RayHitTest ( const FRay3d& WorldRay,
FInputRayHit& HitResultOut
)

 Test if a World-space ray "hits" the current active target set, which can be used to (eg) determine if a higher-level user interaction for selection should "Capture" the click
Protected function void  
Public function Virtual void  
Protected function void  
Public function Virtual void  
Public function void

SetCurrentTargetsLockState ( bool bLocked
)

  
Public function Virtual void  
Protected function void  
Public function Virtual void  
Protected function void  
Public function Virtual bool Directly set the current Selection for the specified Component to NewSelection.
Protected function void

SetTargetLockStateOnUndoRedo ( FGeometryIdentifier TargetIdentifier,
bool bLocked
)

  
Protected function void  
Public function Virtual void  
Protected function void

SleepOrShutdownTarget ( TSharedPtr< FGeometrySelectionTarget > Target,
bool bForceShutdown
)

  
Public function void

SynchronizeActiveTargets ( const TArray< FGeometryIdentifier >& DesiredActiveSet,
TFunctionRef< void()> WillChangeActiveTargetsCallback
)

 Update the current active target set based on DesiredActiveSet, assuming that a valid IGeometrySelectorFactory can be found for each identifier.
Public function Virtual bool

UpdateSelectionPreviewViaRaycast ( const FRay3d& WorldRay
)

 Hover/Preview support
Protected function void  
Public function Virtual void Use the given ConvexVolume to update the active element selection based on UpdateConfig.
Public function Virtual void

UpdateSelectionViaRaycast ( const FRay3d& WorldRay,
const FGeometrySelectionUpdateConfig& UpdateConfig,
FGeometrySelectionUpdateResult& ResultOut
)

 Use the given WorldRay to update the active element selection based on UpdateConfig.
Public function Virtual void

UpdateTransformation ( TFunctionRef< FVector3d(int32VertexID, const FVector3d&, const FTransform&)> PositionTransformFunc
)

 Update the active transformations with the given PositionTransformFunc.

Classes

  Type Name Description
Protected struct FGeometrySelectionTarget FGeometrySelectionTarget is the set of information tracked for a given "Active Target", which is (eg) a Mesh Component or other external object that "owns" selectable Geometry.  

Enums

  Type Name Description
Public enum EMeshTopologyMode ConfigurationEMeshTopologyMode determines what level of mesh element will be selected  

Typedefs

Name Description
EGeometryElementType  
EGeometryTopologyType  
FGeometrySelection  
FGeometrySelectionBounds  
FGeometrySelectionEditor  
FGeometrySelectionElements  
FGeometrySelectionUpdateConfig  
FGeometrySelectionUpdateResult  
FModelingSelectionInteraction_SelectionModified  

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