1. Epic GamesDeveloper
  3. UMaterialExpression

UMaterialExpression

API > API/Runtime > API/Runtime/Engine

   
Name UMaterialExpression
Type class
Header File /Engine/Source/Runtime/Engine/Public/Materials/MaterialExpression.h
Include Path #include "Materials/MaterialExpression.h"

Syntax

UCLASS (Abstract, Optional, BlueprintType, Config=MaterialExpressions, HideCategories=Object,  
       MinimalAPI)  
class UMaterialExpression : public UObject

Inheritance Hierarchy

Derived Classes

UMaterialExpression derived class hierarchy

Constructors

Name Remarks Include Path Unreal Specifiers

UMaterialExpression ( const FObjectInitializer& ObjectInitializer
)

   Materials/MaterialExpression.h  

Structs

Name Remarks
FContainsInputLoopInternalExpressionStack  

Typedefs

Name Type Remarks Include Path
ReferencedTextureArray TArray< UObject *, TInlineAllocator< 4 > >   Materials/MaterialExpression.h

Constants

Name Type Remarks Include Path
CompileExecutionOutputIndex int32   Materials/MaterialExpression.h

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
bCollapsed uint32 If true, show a collapsed version of the node Materials/MaterialExpression.h  
bCommentBubbleVisible uint32 If true, the comment bubble will be visible in the graph editor Materials/MaterialExpression.h  
bHidePreviewWindow uint32 If true, do not render the preview window for the expression Materials/MaterialExpression.h  
bIsParameterExpression uint8 Indicates that this is a 'parameter' type of expression and should always be loaded (ie not cooked away) because we might want the default parameter. Materials/MaterialExpression.h  
bNeedToUpdatePreview uint32 If true, we should update the preview next render. This is set when changing bRealtimePreview. Materials/MaterialExpression.h
  • Transient
bRealtimePreview uint32 Set to true by RecursiveUpdateRealtimePreview() if the expression's preview needs to be updated in realtime in the material editor. Materials/MaterialExpression.h  
bShaderInputData uint32 Whether the node represents an input to the shader or not. Used to color the node's background. Materials/MaterialExpression.h
  • Config
bShowInputs uint32 Whether to draw the expression's inputs. Materials/MaterialExpression.h  
bShowMaskColorsOnPin uint32 If true, changes the pin color to match the output mask Materials/MaterialExpression.h  
bShowOutputNameOnPin uint32 If true, use the output name as the label for the pin Materials/MaterialExpression.h  
bShowOutputs uint32 Whether to draw the expression's outputs. Materials/MaterialExpression.h  
Desc FString A description that level designers can add (shows in the material editor UI). Materials/MaterialExpression.h
  • EditAnywhere
  • Category=MaterialExpression
  • Meta=(MultiLine=true, DisplayAfter="SortPriority")
Function TObjectPtr< class UMaterialFunction > The material function that this expression is being used with, if any. Materials/MaterialExpression.h  
GraphNode TObjectPtr< UEdGraphNode > Expression's Graph representation Materials/MaterialExpression.h
  • Transient
LastErrorText FString Text of last error for this expression Materials/MaterialExpression.h  
Material TObjectPtr< class UMaterial > The material that this expression is currently being compiled in. Materials/MaterialExpression.h  
MaterialExpressionEditorX int32   Materials/MaterialExpression.h
  • BlueprintReadWrite
  • Category=MaterialEditing
MaterialExpressionEditorY int32   Materials/MaterialExpression.h
  • BlueprintReadWrite
  • Category=MaterialEditing
MaterialExpressionGuid FGuid GUID to uniquely identify this node, to help the tutorials out Materials/MaterialExpression.h  
MenuCategories TArray< FText > Localized categories to sort this expression into... Materials/MaterialExpression.h
  • Config
NumExecutionInputs int32 Number of expressions connected to this expression's execution input Materials/MaterialExpression.h  
Outputs TArray< FExpressionOutput > The expression's outputs, which are set in default properties by derived classes. Materials/MaterialExpression.h  
SubgraphExpression TObjectPtr< UMaterialExpression > If exists, expresssion containing this expression within its subgraph. Materials/MaterialExpression.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

virtual void Build ( MIR::FEmitter& Emitter
)

 Builds this expression's material IR. Materials/MaterialExpression.h  

virtual bool CanDeletePin ( EEdGraphPinDirection PinDirection,
int32 PinIndex
) const

 Checks if a pin of specified PinDirection and PinIndex can be deleted Materials/MaterialExpression.h  

virtual bool CanIgnoreOutputIndex()

 If true, discards the output index when caching this expression which allows more cases to re-use the output instead of adding a separate instruction Materials/MaterialExpression.h  

virtual bool CanReferenceTexture()

 Returns true if GetReferencedTexture() / GetReferencedTextures() can ever return a valid pointer(s). Materials/MaterialExpression.h  

virtual bool CanRenameNode()

 Can this node be renamed? Materials/MaterialExpression.h  

virtual bool CanUserDeleteExpression()

   Materials/MaterialExpression.h  

virtual int32 Compile ( FMaterialCompiler* Compiler,
int32 OutputIndex
)

 Create the new shader code chunk needed for the Abs expression Materials/MaterialExpression.h  

virtual int32 CompilePreview ( FMaterialCompiler* Compiler,
int32 OutputIndex
)

   Materials/MaterialExpression.h  

virtual int32 CompilerError ( FMaterialCompiler* Compiler,
const TCHAR* pcMessage
)

   Materials/MaterialExpression.h  

virtual void ConnectExpression ( FExpressionInput* Input,
int32 OutputIndex
)

 Connects the specified input expression to the specified output of this expression. Materials/MaterialExpression.h  

void ConnectToPreviewMaterial ( UMaterial* InMaterial,
int32 OutputIndex
)

 Connects the specified output to the passed material for previewing. Materials/MaterialExpression.h  

bool ContainsInputLoop ( const bool bStopOnFunctionCall
)

 Checks whether any inputs to this expression create a loop Materials/MaterialExpression.h  

bool ContainsInputLoop ( TSet< UMaterialExpression* >& VisitedExpressions,
const bool bStopOnFunctionCall
)

 This overload accepts the set of visited expressions to avoid visiting them again when checking at once whether multiple expressions contain a loop. Materials/MaterialExpression.h  

virtual int32 CountInputs()

 Counts the number of inputs this expression has. Default implementation has O(n) complexity. Materials/MaterialExpression.h  

virtual TSharedPtr< class SGraphNodeMaterialBase > CreateCustomGraphNodeWidget()

   Materials/MaterialExpression.h  

virtual void DeletePin ( EEdGraphPinDirection PinDirection,
int32 PinIndex
)

 Deletes the pin of specified PinDirection and PinIndex. Materials/MaterialExpression.h  

virtual void ForcePropertyValueChanged ( FProperty* Property,
bool bUpdatePreview
)

   Materials/MaterialExpression.h  

virtual void GatherSubstrateMaterialInfo ( FSubstrateMaterialInfo& SubstrateMaterialInfo,
int32 OutputIndex
)

 Recursively parse nodes outputing Substrate material in order to gather all the possible shading models used in a material graph output a Substrate material. Materials/MaterialExpression.h  

bool GetAllInputExpressions ( TArray< UMaterialExpression* >& InputExpressions
)

 Recursively gets a list of all expressions that are connected to this Checks for repeats so that it can't end up in an infinite loop Materials/MaterialExpression.h  

UObject * GetAssetOwner()

   Materials/MaterialExpression.h  

FString GetAssetPathName()

   Materials/MaterialExpression.h  

virtual void GetCaption ( TArray< FString >& OutCaptions
) const

 Returns the text to display on the material expression (in the material editor). Materials/MaterialExpression.h  

virtual void GetConnectorToolTip ( int32 InputIndex,
int32 OutputIndex,
TArray< FString >& OutToolTip
)

 Get a tooltip for the specified connector. Materials/MaterialExpression.h  

virtual FText GetCreationDescription()

   Materials/MaterialExpression.h  

virtual FText GetCreationName()

   Materials/MaterialExpression.h  

virtual FString GetDescription()

 Get a single line description of the material expression (used for lists) Materials/MaterialExpression.h  

virtual FString GetEditableName ()

 Returns the current 'name' of the node (typically a parameter name). Materials/MaterialExpression.h  

virtual void GetExpressionToolTip ( TArray< FString >& OutToolTip
)

 Get a tooltip for the expression itself. Materials/MaterialExpression.h  

virtual int32 GetHeight()

   Materials/MaterialExpression.h  

virtual void GetIncludeFilePaths ( TSet< FString >& OutIncludeFilePaths
) const

   Materials/MaterialExpression.h  

virtual FExpressionInput * GetInput ( int32 InputIndex
)

 Returns the input at index InputIndex if valid, nullptr otherwise. Materials/MaterialExpression.h  

const FExpressionInput * GetInput ( int32 InputIndex
) const

   Materials/MaterialExpression.h  

virtual FName GetInputName ( int32 InputIndex
) const

   Materials/MaterialExpression.h  

virtual FString GetInputPinDefaultValue ( int32 PinIndex
)

   Materials/MaterialExpression.h  

virtual TArray< FProperty * > GetInputPinProperty ( int32 PinIndex
)

 Find the property that is associated with the input pin. Materials/MaterialExpression.h  

virtual FName GetInputPinSubCategory ( int32 PinIndex
)

   Materials/MaterialExpression.h  

virtual UObject * GetInputPinSubCategoryObject ( int32 PinIndex
)

   Materials/MaterialExpression.h  

virtual TArrayView< FExpressionInput * > GetInputsView()

   Materials/MaterialExpression.h  

virtual uint32 GetInputType ( int32 InputIndex
)

   Materials/MaterialExpression.h  

virtual EMaterialValueType GetInputValueType ( int32 InputIndex
)

   Materials/MaterialExpression.h  

virtual FText GetKeywords()

 Returns the keywords that should be used when searching for this expression Materials/MaterialExpression.h  

virtual int GetLabelPadding()

 Returns the amount of padding to use for the label. Materials/MaterialExpression.h  

virtual void GetLandscapeLayerNames ( TArray< FName >& OutLayers
) const

   Materials/MaterialExpression.h  

virtual FGuid & GetMaterialExpressionId()

 Return the material expression guid. Materials/MaterialExpression.h  

FExpressionOutput * GetOutput ( int32 OutputIndex
)

 Returns the output at specified index is valid Materials/MaterialExpression.h  

virtual TArray< FExpressionOutput > & GetOutputs()

   Materials/MaterialExpression.h  

virtual uint32 GetOutputType ( int32 OutputIndex
)

   Materials/MaterialExpression.h  

virtual EMaterialValueType GetOutputValueType ( int32 OutputIndex
)

   Materials/MaterialExpression.h  

virtual FGuid & GetParameterExpressionId()

 Callback to access derived classes' parameter expression id. Materials/MaterialExpression.h  

virtual FName GetParameterName()

   Materials/MaterialExpression.h  

EMaterialParameterType GetParameterType()

   Materials/MaterialExpression.h  

virtual bool GetParameterValue ( FMaterialParameterMetadata& OutMeta
) const

   Materials/MaterialExpression.h  

virtual FText GetPreviewOverlayText()

   Materials/MaterialExpression.h  

virtual TArray< FProperty * > GetPropertyInputs()

   Materials/MaterialExpression.h  
To get any texture references this expression emits. Materials/MaterialExpression.h  

virtual UTextureCollection * GetReferencedTextureCollection()

   Materials/MaterialExpression.h  

virtual ReferencedTextureArray GetReferencedTextures()

   Materials/MaterialExpression.h  

virtual void GetShaderTags ( TArray< FName >& ShaderTagsOut
)

 Material expressions can add shader tags that to a material. Materials/MaterialExpression.h  

virtual void GetTexturesForceMaterialRecompile ( TArray< UTexture* >& Textures
) const

 Fill the array with all textures dependence that should trig a recompile of the material. Materials/MaterialExpression.h  

virtual int32 GetWidth()

 Get the width required by this expression (in the material editor). Materials/MaterialExpression.h  

virtual bool HasAParameterName()

 Parameter Name functions, this is requires as multiple class have ParameterName but are not UMaterialExpressionParameter due to class hierarchy. Materials/MaterialExpression.h  

virtual bool HasClassAndNameCollision ( UMaterialExpression* OtherExpression
) const

   Materials/MaterialExpression.h  

virtual bool HasConnectedOutputs()

   Materials/MaterialExpression.h  

virtual bool IsAllowedIn ( const UObject* MaterialOrFunction
) const

 Returns whether the creation of this expression is allowed in a given material or material function Materials/MaterialExpression.h  

virtual bool IsExpressionConnected ( FExpressionInput* Input,
int32 OutputIndex
)

 Check if input exppresion is directly connected to the material. Materials/MaterialExpression.h  

virtual bool IsInputConnectionRequired ( int32 InputIndex
) const

   Materials/MaterialExpression.h  

virtual bool IsResultMaterialAttributes ( int32 OutputIndex
)

 Marks certain expression types as outputting material attributes. Materials/MaterialExpression.h  

virtual bool IsResultSubstrateMaterial ( int32 OutputIndex
)

 Marks certain expression types as outputting Substrate material. Materials/MaterialExpression.h  

bool IsUsingNewHLSLGenerator()

   Materials/MaterialExpression.h  

virtual bool MatchesSearchQuery ( const TCHAR* SearchQuery
)

 MatchesSearchQuery: Check this expression to see if it matches the search query Materials/MaterialExpression.h  

virtual bool NeedsRealtimePreview()

   Materials/MaterialExpression.h  

virtual void PinDefaultValueChanged ( int32 PinIndex,
const FString& DefaultValue
)

   Materials/MaterialExpression.h  

virtual void PostCopyNode ( const TArray< UMaterialExpression* >& CopiedExpressions
)

 Called after a node copy, once the Material and Function properties are set correctly and that all new expressions are added to Material->Expressions Materials/MaterialExpression.h  

virtual void RefreshNode ( bool bUpdatePreview
)

   Materials/MaterialExpression.h  

virtual void RegisterAdditionalMenuActions ( FGraphActionMenuBuilder& ActionMenuBuilder,
const FText& CategoryName
)

 Allows Material Expressions to register additional actions in the context menu Materials/MaterialExpression.h  

virtual void SetEditableName ( const FString& NewName
)

 Sets the current 'name' of the node (typically a parameter name) Only valid to call on a node that previously returned CanRenameNode() = true. Materials/MaterialExpression.h  

virtual void SetParameterName ( const FName& Name
)

   Materials/MaterialExpression.h  

virtual bool SetParameterValue ( const FName& Name,
const FMaterialParameterMetadata& Meta,
EMaterialExpressionSetParameterValueFlags Flags
)

   Materials/MaterialExpression.h  
A starta material is a tree with FrontMateiral being its root and BSDF being leaves, with operators in the middle. Materials/MaterialExpression.h  

void UpdateMaterialExpressionGuid ( bool bForceGeneration,
bool bAllowMarkingPackageDirty
)

 Generates a GUID for this expression if one doesn't already exist. Materials/MaterialExpression.h  

void UpdateParameterGuid ( bool bForceGeneration,
bool bAllowMarkingPackageDirty
)

 Generates a GUID for the parameter expression if one doesn't already exist and we are one. Materials/MaterialExpression.h  

virtual bool UsesLeftGutter()

   Materials/MaterialExpression.h  

virtual bool UsesRightGutter()

   Materials/MaterialExpression.h  

virtual void ValidateParameterName ( const bool bAllowDuplicateName
)

   Materials/MaterialExpression.h  

void ValidateState()

 Asserts if the expression is not contained by its Material or Function's expressions array. Materials/MaterialExpression.h  

Overridden from UObject

Name Remarks Include Path Unreal Specifiers

virtual bool CanEditChange ( const FProperty* InProperty
) const

   Materials/MaterialExpression.h  

virtual bool Modify ( bool bAlwaysMarkDirty
)

   Materials/MaterialExpression.h  

virtual void PostDuplicate ( bool bDuplicateForPIE
)

   Materials/MaterialExpression.h  

virtual void PostEditChangeProperty ( FPropertyChangedEvent& PropertyChangedEvent
)

   Materials/MaterialExpression.h  

virtual void PostEditImport()

   Materials/MaterialExpression.h  

virtual void PostInitProperties()

   Materials/MaterialExpression.h  

virtual void PostLoad()

   Materials/MaterialExpression.h  

virtual void Serialize ( FStructuredArchive::FRecord Record
)

   Materials/MaterialExpression.h  

Static

Name Remarks Include Path Unreal Specifiers

static void CopyMaterialExpressions ( const TArray< class UMaterialExpression* >& SrcExpressions,
const TArray< class UMaterialExpressionComment* >& SrcExpressionComments,
UMaterial* Material,
UMaterialFunction* Function,
TArray< class UMaterialExpression* >& OutNewExpressions,
TArray< class UMaterialExpression* >& OutNewComments
)

 Copy the SrcExpressions into the specified material, preserving internal references. Materials/MaterialExpression.h  

Ask questions and help your peers Developer Forums

Write your own tutorials or read those from others Learning Library

On this page