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  3. UMeshOpPreviewWithBackgroundCompute

UMeshOpPreviewWithBackgroundCompute

[UMeshOpPreviewWithBackgroundCompute](API\Plugins\ModelingComponents\UMeshOpPreviewWithBackgroundComp-) is an infrastructure object that implements a common UI pattern in interactive 3D tools, where we want to run an expensive computation on a mesh that is based on user-specified parameters, and show a preview of the result.

API > API/Plugins > API/Plugins/ModelingComponents

UMeshOpPreviewWithBackgroundCompute is an infrastructure object that implements a common UI pattern in interactive 3D tools, where we want to run an expensive computation on a mesh that is based on user-specified parameters, and show a preview of the result. The expensive computation (a MeshOperator) must run in a background thread so as to not block the UI. If the user changes parameters while the Operator is running, it should be canceled and restarted. When it completes, the Preview will be updated. When the user is happy, the current Mesh is returned to the owner of this object.

The MeshOperators are provided by the owner via a IDynamicMeshOperatorFactory implementation. The owner must also Tick() this object regularly to allow the Preview to update when the background computations complete.

If an InProgress Material is set (via ConfigureMaterials) then when a background computation is active, this material will be used to draw the previous Preview result, to give the user a visual indication that work is happening.

   
Name UMeshOpPreviewWithBackgroundCompute
Type class
Header File /Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/MeshOpPreviewHelpers.h
Include Path #include "MeshOpPreviewHelpers.h"

Syntax

UCLASS (MinimalAPI, Transient)  
class UMeshOpPreviewWithBackgroundCompute : public UObject

Inheritance Hierarchy

Typedefs

Name Type Remarks Include Path
FOnMeshUpdated TMulticastDelegate_OneParam< void, UMeshOpPreviewWithBackgroundCompute * > Change notification MeshOpPreviewHelpers.h
FOnOpCompleted TMulticastDelegate_OneParam< void, const UE::Geometry::FDynamicMeshOperator * >   MeshOpPreviewHelpers.h

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
bAllowDirtyResultUpdates bool When true, the preview mesh is allowed to be temporarily updated using results that we know are dirty (i.e., the preview was invalidated, but a result became available before the operation was restarted, so we can at least show that while we wait for the new result). MeshOpPreviewHelpers.h  
OnMeshUpdated FOnMeshUpdated This delegate is broadcast whenever the embedded preview mesh is updated MeshOpPreviewHelpers.h  
OnOpCompleted FOnOpCompleted   MeshOpPreviewHelpers.h  
OverrideMaterial TObjectPtr< UMaterialInterface > Override material to forward to PreviewMesh if set MeshOpPreviewHelpers.h  
PreviewMesh TObjectPtr< UPreviewMesh > Preview of MeshOperator result MeshOpPreviewHelpers.h  
PreviewWorld TWeakObjectPtr< UWorld >   MeshOpPreviewHelpers.h  
SecondaryMaterial TObjectPtr< UMaterialInterface > Secondary render material to forward to PreviewMesh if set MeshOpPreviewHelpers.h  
StandardMaterials TArray< TObjectPtr< UMaterialInterface > > Input set of materials to assign to PreviewMesh MeshOpPreviewHelpers.h  
WorkingMaterial TObjectPtr< UMaterialInterface > If non-null, this material is swapped in when a background compute is active MeshOpPreviewHelpers.h  

Protected

Name Type Remarks Include Path Unreal Specifiers
bWaitingForBackgroundTasks bool   MeshOpPreviewHelpers.h  
MaxActiveBackgroundTasks int32   MeshOpPreviewHelpers.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

void Cancel()

 Terminate any active computation without returning anything. Destroys the preview mesh. MeshOpPreviewHelpers.h  

void CancelCompute()

 Cancel the active computation without returning anything. Doesn't destroy the mesh. MeshOpPreviewHelpers.h  
Stops any running computes and swaps in a different op generator. MeshOpPreviewHelpers.h  

void ClearOpFactory()

   MeshOpPreviewHelpers.h  

void ConfigureMaterials ( TArray< UMaterialInterface* > StandardMaterials,
UMaterialInterface* InProgressMaterial,
UMaterialInterface* SecondaryMaterial
)

 Configure the Standard and In-Progress materials MeshOpPreviewHelpers.h  

void ConfigureMaterials ( UMaterialInterface* StandardMaterial,
UMaterialInterface* InProgressMaterial
)

 Optional configuration Configure the Standard and In-Progress materials MeshOpPreviewHelpers.h  

void ConfigurePreviewMaterials ( UMaterialInterface* InProgressMaterial,
UMaterialInterface* SecondaryMaterial
)

 Configure the In-Progress and Secondary Materials MeshOpPreviewHelpers.h  

void DisablePreviewMaterials()

 Disable the In Progress and Secondary Materials MeshOpPreviewHelpers.h  

bool GetCurrentResultCopy ( FDynamicMesh3& MeshOut,
bool bOnlyIfValid
)

 Read back a copy of current preview mesh. MeshOpPreviewHelpers.h  

double GetValidResultComputeTime()

   MeshOpPreviewHelpers.h  

virtual UWorld * GetWorld()

   MeshOpPreviewHelpers.h  

bool HaveEmptyResult()

   MeshOpPreviewHelpers.h  

bool HaveValidNonEmptyResult()

   MeshOpPreviewHelpers.h  

bool HaveValidResult()

   MeshOpPreviewHelpers.h  

void InvalidateResult()

 Control flow Request that the current computation be canceled and a new one started MeshOpPreviewHelpers.h  

bool IsUsingWorkingMaterial()

   MeshOpPreviewHelpers.h  

bool ProcessCurrentMesh ( TFunctionRef< void(const UE::Geometry::FDynamicMesh3&)> ProcessFunc,
bool bOnlyIfValid
)

 Allow an external function to safely access the PreviewMesh's mesh MeshOpPreviewHelpers.h  

void SetIsMeshTopologyConstant ( bool bOn,
EMeshRenderAttributeFlags ChangingAttributes
)

 If set to true, then it will be assumed that the mesh topology (i.e. triangle/edge connectivity) remains constant, which will allow updates after the first one to modify existing render proxy buffers rather than creating entirely new ones. MeshOpPreviewHelpers.h  

void SetMaxActiveBackgroundTasks ( int32 NewMaxTasks
)

 Configure the maximum allowed number of background tasks. MeshOpPreviewHelpers.h  

void SetMaxActiveBackgroundTasksFromMeshSizeHeuristic ( int32 InputMeshTriangleCount,
int32 MaxSimultaneousTrianglesToProcess,
int32 MaxShouldNotExceed
)

 Configure maximum allowed number of background tasks heuristically from the input triangle count. MeshOpPreviewHelpers.h  

void Setup ( UWorld* InWorld
)

   MeshOpPreviewHelpers.h  

void Setup ( UWorld* InWorld,
UE::Geometry::IDynamicMeshOperatorFactory* OpGenerator
)

 Required calls to setup/update/shutdown this object MeshOpPreviewHelpers.h  

void SetVisibility ( bool bVisible
)

 Set the visibility of the Preview mesh MeshOpPreviewHelpers.h  

void SetWorkingMaterialDelay ( float TimeInSeconds
)

 Set time that Preview will wait before showing working material MeshOpPreviewHelpers.h  
Terminate any active computation and return the current Preview Mesh/Transform MeshOpPreviewHelpers.h  

void Tick ( float DeltaTime
)

 Tick the background computation and Preview update. MeshOpPreviewHelpers.h  

Protected

Name Remarks Include Path Unreal Specifiers

void UpdateResults()

 Update the PreviewMesh if a new result is available from BackgroundCompute MeshOpPreviewHelpers.h  

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