FAlphaBlend Struct Reference

#include <AlphaBlend.h>

Public Member Functions
ENGINE_API	FAlphaBlend (float NewBlendTime=0.2f)
ENGINE_API	FAlphaBlend (const FAlphaBlend &Other, float NewBlendTime)
bool	Serialize (FArchive &Ar)
bool	Serialize (FStructuredArchive::FSlot Slot)
ENGINE_API	FAlphaBlend (const FAlphaBlendArgs &InArgs)
ENGINE_API void	SetBlendOption (EAlphaBlendOption InBlendOption)
ENGINE_API void	SetCustomCurve (UCurveFloat *InCustomCurve)
ENGINE_API void	SetBlendTime (float InBlendTime)
ENGINE_API void	SetValueRange (float Begin, float Desired)
ENGINE_API void	SetDesiredValue (float InDesired)
ENGINE_API void	SetAlpha (float InAlpha)
ENGINE_API float	Update (float InDeltaTime)
ENGINE_API bool	IsComplete () const
float	GetAlpha () const
float	GetBlendedValue () const
float	GetBlendTime () const
float	GetBlendTimeRemaining () const
EAlphaBlendOption	GetBlendOption () const
UCurveFloat *	GetCustomCurve () const
float	GetBeginValue () const
float	GetDesiredValue () const
ENGINE_API void	Reset ()
ENGINE_API void	ResetAlpha ()

Static Public Member Functions
static ENGINE_API float	AlphaToBlendOption (float InAlpha, EAlphaBlendOption InBlendOption, UCurveFloat *InCustomCurve=nullptr)

Detailed Description

Alpha Blend class that supports different blend options as well as custom curves

Constructor & Destructor Documentation

FAlphaBlend() [1/3]

FAlphaBlend::FAlphaBlend

(

float

NewBlendTime = 0.2f

)

FAlphaBlend() [2/3]

FAlphaBlend::FAlphaBlend	(	const FAlphaBlend &	Other,
		float	NewBlendTime
	)

FAlphaBlend() [3/3]

FAlphaBlend::FAlphaBlend ( const FAlphaBlendArgs &  InArgs )

explicit

Member Function Documentation

AlphaToBlendOption()

float FAlphaBlend::AlphaToBlendOption ( float  InAlpha, EAlphaBlendOption  InBlendOption, UCurveFloat *  InCustomCurve = nullptr  )

static

Converts InAlpha from a linear 0...1 value into the output alpha described by InBlendOption

Parameters

InAlpha	In linear 0...1 alpha
InBlendOption	The type of blend to use
InCustomCurve	The curve to use when blend option is set to custom

GetAlpha()

float FAlphaBlend::GetAlpha ( ) const

inline

Gets the current 0..1 alpha value. Changed to AlphaLerp to match with SetAlpha function

GetBeginValue()

float FAlphaBlend::GetBeginValue ( ) const

inline

Get the current begin value

GetBlendedValue()

float FAlphaBlend::GetBlendedValue ( ) const

inline

Gets the current blended value

GetBlendOption()

EAlphaBlendOption FAlphaBlend::GetBlendOption ( ) const

inline

GetBlendTime()

float FAlphaBlend::GetBlendTime ( ) const

inline

Getters

GetBlendTimeRemaining()

float FAlphaBlend::GetBlendTimeRemaining ( ) const

inline

GetCustomCurve()

UCurveFloat * FAlphaBlend::GetCustomCurve ( ) const

inline

GetDesiredValue()

float FAlphaBlend::GetDesiredValue ( ) const

inline

Get the current desired value

IsComplete()

bool FAlphaBlend::IsComplete

(

)

const

Gets whether or not the blend is complete

Reset()

void FAlphaBlend::Reset

(

)

Reset functions -

The distinction is important.

We have 3 different reset functions depending on usability

Reset function : will change Blended Value to BeginValue, so that it can start blending That is only supposed to be used when you want to clear it up and restart

ResetAlpha will change AlphaLerp/AlphaBlend to match with current Blend Value, that way we keep the current blended value and move to target using the current value That will make sure this doesn't pop when you change direction of Desired

ResetBlendTime will change BlendTimeRemaining as well as possibly weight because if BlendTimeRemaining <= 0.f, We'll arrive to the destination

The reason we need ResetAlpha and ResetBlendTime is that we don't want to modify blend time if direction changes or we don't want to reset alpha if blend time changes Those two have to work independently Reset to zero / restart the blend. This resets whole thing.

ResetAlpha()

void FAlphaBlend::ResetAlpha

(

)

Reset alpha, this keeps current BlendedValue but modify Alpha to keep the blending state.

Serialize() [1/2]

bool FAlphaBlend::Serialize

(

FArchive &

Ar

)

Serialize() [2/2]

bool FAlphaBlend::Serialize

(

FStructuredArchive::FSlot

Slot

)

SetAlpha()

void FAlphaBlend::SetAlpha

(

float

InAlpha

)

Sets the Lerp alpha value directly. PLEASE NOTE that this modifies the Blended Value right away.

note this function can modify BlendedValue right away

SetBlendOption()

void FAlphaBlend::SetBlendOption

(

EAlphaBlendOption

InBlendOption

)

Setters - need to refresh cached value

SetBlendTime()

void FAlphaBlend::SetBlendTime

(

float

InBlendTime

)

Update transition blend time. This new value will be applied in the next Update.

SetCustomCurve()

void FAlphaBlend::SetCustomCurve

(

UCurveFloat *

InCustomCurve

)

SetDesiredValue()

void FAlphaBlend::SetDesiredValue

(

float

InDesired

)

Sets the final desired value for the blended value

SetValueRange()

void FAlphaBlend::SetValueRange	(	float	Begin,
		float	Desired
	)

Sets the range of values to map to the interpolation

Parameters

Begin	: this is start value
Desired	: this is target value

This can be (0, 1) if you'd like to increase, or it can be (1, 0) if you'd like to get to 0

Update()

float FAlphaBlend::Update

(

float

InDeltaTime

)

Update interpolation, has to be called once every frame.

Returns

How much time remains after the blend completed if applicable e.g. if we have 0.01s left on the blend and update at 30Hz (~0.033s) we would return ~0.023s

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The documentation for this struct was generated from the following files:

• Engine/Source/Runtime/Engine/Public/AlphaBlend.h
• Engine/Source/Runtime/Engine/Private/AlphaBlend.cpp