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  3. UMeshTopologySelectionMechanic

UMeshTopologySelectionMechanic

Base class mechanic for selecting a subset of mesh elements (edge loops, groups, corners, etc.) Internally it relies on an [FMeshTopologySelector](API\Plugins\ModelingComponents\Selection\FMeshTopologySelector) to define which type of mesh topology is selectable.

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

Inheritance Hierarchy

References

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

Syntax

UCLASS (Abstract)  
class UMeshTopologySelectionMechanic :  
    public UInteractionMechanic ,  
    public IClickBehaviorTarget ,  
    public IHoverBehaviorTarget

Remarks

Base class mechanic for selecting a subset of mesh elements (edge loops, groups, corners, etc.) Internally it relies on an FMeshTopologySelector to define which type of mesh topology is selectable.

NOTE: Users should not use this class directly, but rather subclass it and specify a particular FMeshTopologySelector to use.

Variables

  Type Name Description
Protected variable TUniquePtr< FMeshTopologySelectionMechanicSelectionChange > ActiveChange  
Public variable bool bAddSelectionFilterPropertiesToParentTool Configuration variables that must be set before bSetup is called
Protected variable FInputCapturePriority BasePriority  
Protected variable bool bCtrlToggle  
Protected variable bool bCurrentlyMarqueeDragging  
Protected variable bool bIsEnabled  
Protected variable bool bShiftToggle  
Protected variable bool bShowEdges  
Protected variable bool bShowSelectableCorners  
Protected variable FViewCameraState CameraState  
Protected variable UProperty TObjectPtr< USingleClickOrDragInputBehavior > ClickOrDragBehavior  
Protected variable TSet< int > CurrentlyHighlightedGroups  
Protected variable UProperty TObjectPtr< UTriangleSetComponent > DrawnTriangleSetComponent  
Protected variable TFunction< FDynamicMeshAABBTree3 *()> GetSpatialFunc  
Protected variable UProperty TObjectPtr< UMaterialInterface > HighlightedFaceMaterial  
Public variable FToolDataVisualizer HilightRenderer  
Protected variable FGroupTopologySelection HilightSelection  
Protected variable UProperty TObjectPtr< UMouseHoverBehavior > HoverBehavior  
Protected variable FVector3d LastClickedHitNormal  
Protected variable FVector3d LastClickedHitPosition  
Protected variable FGroupTopologySelection LastUpdateRectangleSelection  
Protected variable UProperty TObjectPtr< URectangleMarqueeMechanic > MarqueeMechanic  
Protected variable UProperty EMarqueeSelectionUpdateType MarqueeSelectionUpdateType Selection update type (default is OnDrag) as it may not need to be triggered for every rectangle change This can drastically improve the responsiveness of the UI for meshes high density meshes.
Protected variable const FDynamicMesh3 * Mesh  
Public variable FSimpleMulticastDelegate OnFaceSelectionPreviewChanged This is broadcast during marquee rectangle dragging if selected faces change, to allow user to dynamically update face highlighting if desired (needed because OnSelectionChanged is only fired once the rectangle is completed, not while it is being updated).
Public variable FSimpleMulticastDelegate OnSelectionChanged OnSelectionChanged is broadcast whenever the selection is modified (including by FChanges, which means that called functions should not issue undo transactions.
Protected variable TFunction< void()> PendingSelectionFunction Pending selection function to be called if the selection is deferred to tick/release
Protected variable FGroupTopologySelection PersistentSelection  
Public variable FToolDataVisualizer PolyEdgesRenderer  
Protected variable FGroupTopologySelection PreDragPersistentSelection Used for box selection.
Protected variable FGroupTopologySelector::FSelectionSettings PreDragTopoSelectorSettings  
Protected variable UProperty TObjectPtr< APreviewGeometryActor > PreviewGeometryActor The actor we create internally to own the DrawnTriangleSetComponent
Public variable UProperty TObjectPtr< UMeshTopologySelectionMechanicProperties > Properties TODO: Is it worth issuing separate callbacks in normal selection changes and in FChange ones, to allow the user to bundle in some FChanges into the normal callback?
Public variable FToolDataVisualizer SelectionRenderer  
Protected variable int32 SelectionTimestamp  
Protected variable TFunction< bool(void)> ShouldAddToSelectionFunc  
Protected variable TFunction< bool(void)> ShouldRemoveFromSelectionFunc  
Protected variable TFunction< bool(void)> ShouldSelectEdgeLoopsFunc When bSelectEdgeLoops is true, this function is tested to see if we should select edge loops, to allow edge loop selection to be toggled with some key (setting bSelectEdgeLoops to false overrides this function).
Protected variable TFunction< bool(void)> ShouldSelectEdgeRingsFunc When bSelectEdgeRings is true, this function is tested to see if we should select edge rings, to allow edge ring selection to be toggled with some key (setting bSelectEdgeRings to false overrides this function).
Protected variable FTransform3d TargetTransform  
Protected variable TSharedPtr< FMeshTopologySelector, ESPMode::ThreadSafe > TopoSelector Subclass should initialize this with a concrete subclass of FMeshTopologySelector
Protected variable TMap< int32, bool > TriIsOccludedCache  

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Public function void Change Tracking Begin a change record.
Public function void Clear current hover-highlight
Public function void Clear the current selection.
Public function void  
Public function void Removes the mechanic's own click/hover handlers, which means that the parent tool will need to call UpdateSelection(), UpdateHighlight(), ClearHighlight(), and ClearSelection() from its own hover/click handlers.
Public function Virtual void

DrawHUD ( FCanvas* Canvas,
IToolsContextRenderAPI* RenderAPI
)

  
Public function TUniquePtr< FToolCommandChange > End the active change and return it. Returns empty change if the selection was not modified!
Public function bool Ends the active change and emits it via the parent tool, if the selection has been modified.
Public function void  
Public function Const const FGroupTopologySelection &  
Public function Const void

GetClickedHitPosition ( FVector3d& PositionOut,
FVector3d& NormalOut
)

 Can be used by in an OnSelectionChanged event to inspect the clicked location (i.e., the values returned by the UpdateSelection() function when the click happened).
Public function Const TPair< FInputCapturePriority, FInputCapturePriority > Gets the current priority range used by behaviors in the mechanic.
Public function Const FAxisAlignedBox3d

GetSelectionBounds ( bool bWorld
)

  
Public function Const FFrame3d

GetSelectionFrame ( bool bWorld,
FFrame3d* InitialLocalFrame
)

  
Public function TSharedPtr< FMeshTopologySelector, ESPMode::ThreadSafe >  
Protected function FGroupTopologySelector::FSelectionSettings

GetTopoSelectorSettings ( bool bUseOrthoSettings
)

 Get the topology selector settings to use given the current selection settings.
Public function void  
Protected function void

HandleRectangleChanged ( const FCameraRectangle& InRectangle
)

 Calls actual selection using the input marquee rectangle.
Public function Const bool  
Public function void

Initialize ( const FDynamicMesh3* MeshIn,
FTransform3d TargetTransformIn,
UWorld* WorldIn,
TFunction< FDynamicMeshAABBTree3*()> GetSpatialSourceFuncIn
)

  
Public function void  
Public function bool When true, the selection mechanic is currently tracking a marquee rectangle drag, and acting on the selection may be unwise until it is over (and an OnSelectionChanged event is fired).
Public function void

NotifyMeshChanged ( bool bTopologyModified
)

 Notify internal data structures that the associated MeshComponent has been modified.
Protected function Virtual void

OnDragRectangleChanged ( const FCameraRectangle& CurrentRectangle
)

  
Protected function Virtual void

OnDragRectangleFinished ( const FCameraRectangle& Rectangle,
bool bCancelled
)

  
Protected function Virtual void These get bound to marquee mechanic delegates.
Public function void Render only the MarqueeMechanic, without rendering the current selection
Public function void  
Public function void Sets the base priority so that tools can make sure that their own behaviors are higher priority.
Public function void

SetIsEnabled ( bool bBehaviorsEnabled,
bool bRenderTopology
)

 Enable/disable the selection behaviors in the mechanic without permanently removing them or shutting the mechanic down.
Public function void Sets how/when the selection updates are handled.
Public function void

SetSelection ( const FGroupTopologySelection& Selection,
bool bBroadcast
)

 Replace the current selection with an external selection.
Public function void

SetShouldAddToSelectionFunc ( TFunction< bool(void)> Func
)

 By default, the shift key will cause new clicks to add to the selection.
Public function void By default, the Ctrl key will cause new clicks to remove from the existing selection.
Public function void

SetShouldSelectEdgeLoopsFunc ( TFunction< bool(void)> Func
)

  
Public function void

SetShouldSelectEdgeRingsFunc ( TFunction< bool(void)> Func
)

  
Public function void

SetShowEdges ( const bool bRenderEdges
)

 Toggle rendering of edges
Public function void

SetShowSelectableCorners ( bool bShowCorners
)

  
Public function void

SetTransform ( const FTransform3d& InTargetTransform
)

 Update the location of the mesh after Initialize()
Public function void  
Public function bool

TopologyHitTest ( const FRay& WorldRay,
FHitResult& OutHit,
bool bUseOrthoSettings
)

  
Public function bool

TopologyHitTest ( const FRay& WorldRay,
FHitResult& OutHit,
FGroupTopologySelection& OutSelection,
bool bUseOrthoSettings
)

 Perform a hit test on the topology using the current selection settings.
Public function Virtual bool

UpdateHighlight ( const FRay& WorldRay
)

 Hover API Update the hover highlight based on the hit elements at the given World Ray
Protected function Virtual void  
Public function Virtual bool

UpdateSelection ( const FRay& WorldRay,
FVector3d& LocalHitPositionOut,
FVector3d& LocalHitNormalOut
)

 Selection API Intersect the ray with the mesh and update the selection based on the hit element, modifier states, etc

Overridden from UInteractionMechanic

  Type Name Description
Public function Virtual void Allow the Mechanic to do any custom drawing (ie via PDI/RHI)
Public function Virtual void

Setup ( UInteractiveTool* ParentTool
)

 Called to initialize the InteractionMechanic
Public function Virtual void Called to clean up the InteractionMechanic
Public function Virtual void

Tick ( float DeltaTime
)

 ALlow the Mechanic to Tick

Overridden from IClickBehaviorTarget

  Type Name Description
Public function Virtual FInputRayHit

IsHitByClick ( const FInputDeviceRay& ClickPos
)

 IClickBehaviorTarget implementation.
Public function Virtual void

OnClicked ( const FInputDeviceRay& ClickPos
)

 Notify Target that click ocurred

Overridden from IModifierToggleBehaviorTarget

  Type Name Description
Public function Virtual void

OnUpdateModifierState ( int ModifierID,
bool bIsOn
)

 Notify target of current modifier state

Overridden from IHoverBehaviorTarget

  Type Name Description
Public function Virtual FInputRayHit IHoverBehaviorTarget implementation.
Public function Virtual void

OnBeginHover ( const FInputDeviceRay& DevicePos
)

 Initialize hover sequence at given position
Public function Virtual void Terminate active hover sequence
Public function Virtual bool

OnUpdateHover ( const FInputDeviceRay& DevicePos
)

 Update active hover sequence with new input position

Typedefs

Name Description
FAxisAlignedBox3d  
FFrame3d  

Constants

Name Description
CtrlModifierID  
ShiftModifierID  

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