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  3. FExpression

FExpression

Represents an HLSL expression.

Unreal Engine C++ API Reference > Runtime > Engine > HLSLTree

Inheritance Hierarchy

References

   
Module Engine
Header /Engine/Source/Runtime/Engine/Public/HLSLTree/HLSLTree.h
Include #include "HLSLTree/HLSLTree.h"

Syntax

class FExpression : public UE::HLSLTree::FOwnedNode

Remarks

Represents an HLSL expression. This is a piece of code that evaluates to a value, but has no side effects. Unlike statements, expressions are not expected to execute in any particular order. Examples include constant literals, variable accessors, and various types of math operations This is an abstract base class, with derived classes representing various types of expression Derived expression classes should provide a constructor to fully initialize all fields. All types given to this constructor must be hashable via HLSLTree::AppendHash(). A unique hash value will be generated for each expression, by hashing the constructor arguments, which will be used to deduplicate expressions

Functions

  Type Name Description
Public function Const bool

CheckObjectSupportsCustomHLSL ( FEmitContext& Context,
FEmitScope& Scope,
const FName& ObjectTypeName
)

 Some expressions may support passing object types to custom HLSL expressions CheckObjectSupportsCustomHLSL() will return true if this is supported If supported, GetObjectCustomHLSLParameter() will generate code to declare the parameters in the custom HLSL function, and forward the parameters EmitValueShader() will be called to generate the actual HLSL code for the expression
Protected function Virtual Const void Create new expressions representing DDX/DDY of this expression
Protected function Virtual Const const FExpression *

ComputePreviousFrame ( FTree& Tree,
const FRequestedType& RequestedType
)

 Creates a new expression representing this expression on the previous frame.
Protected function Virtual Const bool

EmitCustomHLSLParameter ( FEmitContext& Context,
FEmitScope& Scope,
const FName& ObjectTypeName,
const TCHAR* ParameterName,
FEmitCustomHLSLParameterResult& OutResult
)

 Allows custom objects to be passed to custom HLSL functions.
Protected function Virtual Const bool

EmitValueObject ( FEmitContext& Context,
FEmitScope& Scope,
const FName& ObjectTypeName,
void* OutObjectBase
)

 Emit an object. The given 'ObjectTypeName' determines the C++ type pointed to by OutObjectBase
Protected function Virtual Const void

EmitValuePreshader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
FEmitValuePreshaderResult& OutResult
)

 Emit Preshader code representing this expression
Protected function Virtual Const void

EmitValueShader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
FEmitValueShaderResult& OutResult
)

 Emit HLSL shader code representing this expression
Public function Const void

GetObjectCustomHLSLParameter ( FEmitContext& Context,
FEmitScope& Scope,
const FName& ObjectTypeName,
const TCHAR* ParameterName,
FStringBuilderBase& OutDeclarationCode,
FStringBuilderBase& OutForwardCode
)

  
Public function Const Shader::FValue

GetValueConstant ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const FPreparedType& PreparedType,
const Shader::FType& ResultType
)

  
Public function Const Shader::FValue

GetValueConstant ( FEmitContext& Context,
FEmitScope& Scope,
const FPreparedType& PreparedType,
const Shader::FType& ResultType
)

  
Public function Const Shader::FValue

GetValueConstant ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const Shader::FType& ResultType
)

  
Public function Const Shader::FValue

GetValueConstant ( FEmitContext& Context,
FEmitScope& Scope,
const FPreparedType& PreparedType,
Shader::EValueType ResultType
)

  
Public function Const Shader::FValue

GetValueConstant ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType
)

  
Public function Const Shader::FValue

GetValueConstant ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const FPreparedType& PreparedType
)

  
Public function Const bool

GetValueObject ( FEmitContext& Context,
FEmitScope& Scope,
ObjectType& OutObject
)

  
Public function Const bool

GetValueObject ( FEmitContext& Context,
FEmitScope& Scope,
const FName& ObjectTypeName,
void* OutObjectBase
)

 Gets the value as an 'Object' with a certain type Individual expressions will potentially support different types of objects
Public function Const Shader::FType

GetValuePreshader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
Shader::FPreshaderData& OutPreshader
)

  
Public function Const Shader::FType

GetValuePreshader ( FEmitContext& Context,
FEmitScope& Scope,
const Shader::FType& ResultType,
Shader::FPreshaderData& OutPreshader
)

  
Public function Const Shader::FType

GetValuePreshader ( FEmitContext& Context,
FEmitScope& Scope,
Shader::EValueType ResultType,
Shader::FPreshaderData& OutPreshader
)

  
Public function Const Shader::FType

GetValuePreshader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const Shader::FType& ResultType,
Shader::FPreshaderData& OutPreshader
)

  
Public function Const Shader::FType

GetValuePreshader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const FPreparedType& PreparedType,
const Shader::FType& ResultType,
Shader::FPreshaderData& OutPreshader
)

  
Public function Const FEmitShaderExpression *

GetValueShader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const Shader::FType& ResultType
)

  
Public function Const FEmitShaderExpression *

GetValueShader ( FEmitContext& Context,
FEmitScope& Scope
)

 Get Shader/Preshader/Constant value for the expression
Public function Const FEmitShaderExpression *

GetValueShader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType
)

 Get Shader/Preshader/Constant value for the expression
Public function Const FEmitShaderExpression *

GetValueShader ( FEmitContext& Context,
FEmitScope& Scope,
const Shader::FType& ResultType
)

 Get Shader/Preshader/Constant value for the expression
Public function Const FEmitShaderExpression *

GetValueShader ( FEmitContext& Context,
FEmitScope& Scope,
Shader::EValueType ResultType
)

 Get Shader/Preshader/Constant value for the expression
Public function Const FEmitShaderExpression *

GetValueShader ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
const FPreparedType& PreparedType,
const Shader::FType& ResultType
)

 Get Shader/Preshader/Constant value for the expression
Protected function Const bool

PrepareValue ( FEmitContext& Context,
FEmitScope& Scope,
const FRequestedType& RequestedType,
FPrepareValueResult& OutResult
)

 Computes a FPreparedType for this expression, given a FRequestedType.

Overridden from FOwnedNode

  Type Name Description
Public function Virtual Const TConstArrayView< UObject * >  

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