UnrealMathUnlity.h：

``````/** Performs a linear interpolation between two values, Alpha ranges from 0-1 */
template< class T, class U >
static FORCEINLINE_DEBUGGABLE T Lerp( const T& A, const T& B, const U& Alpha )
{
return (T)(A + Alpha * (B-A));
}

/** Performs a linear interpolation between two values, Alpha ranges from 0-1. Handles full numeric range of T */
template< class T >
static FORCEINLINE_DEBUGGABLE T LerpStable( const T& A, const T& B, double Alpha )
{
return (T)((A * (1.0 - Alpha)) + (B * Alpha));
}

/** Performs a linear interpolation between two values, Alpha ranges from 0-1. Handles full numeric range of T */
template< class T >
static FORCEINLINE_DEBUGGABLE T LerpStable(const T& A, const T& B, float Alpha)
{
return (T)((A * (1.0f - Alpha)) + (B * Alpha));
}

/** Performs a 2D linear interpolation between four values values, FracX, FracY ranges from 0-1 */
template< class T, class U >
static FORCEINLINE_DEBUGGABLE T BiLerp(const T& P00,const T& P10,const T& P01,const T& P11, const U& FracX, const U& FracY)
{
return Lerp(
Lerp(P00,P10,FracX),
Lerp(P01,P11,FracX),
FracY
);
}

/** Interpolate vector from Current to Target. Scaled by distance to Target, so it has a strong start speed and ease out. */
static CORE_API FVector VInterpTo( const FVector& Current, const FVector& Target, float DeltaTime, float InterpSpeed );

/** Interpolate rotator from Current to Target. Scaled by distance to Target, so it has a strong start speed and ease out. */
static CORE_API FRotator RInterpTo( const FRotator& Current, const FRotator& Target, float DeltaTime, float InterpSpeed);

/** Interpolate float from Current to Target. Scaled by distance to Target, so it has a strong start speed and ease out. */
static CORE_API float FInterpTo( float Current, float Target, float DeltaTime, float InterpSpeed );
``````
##### Usage example: Uniform velocity mode

Define two member variables:

``````float LerpTime = 0.f;
const float LerpDuration = 2.5f;
``````

Then calculate in Tick：

``````void Tick(float DeltaSecond)
{
if(LerpTime < LerpDuration)
{
LerpTime += DeltaSecond;

FVector NewLoc = FMath::Lerp<FVector>(SrcLoc, DistLoc, LerpTime / LerpDuration);

MyCharacter->SetActorLocation(NewLoc);
}
}
``````
##### Usage example: Damping mode (Cushion mode: strong at first, then soft)

`Lerp` Example：

``````NewLoc = FMath::Lerp<FVector>(NewLoc, DistLoc, LerpTime / LerpDuration);
``````

`VInterpTo` Example：

``````NewLoc = FMath::VInterpTo(NewLoc, DistLoc, DeltaTime, InterpSpeed);
``````

Difference between `Lerp` and `VInterpTo`: `VInterpTo` using `InterpSpeed` instead of `LerpTime / LerpDuration`.

Other types similar `VInterpTo`: `RInterpTo` for Rotator, `FInterpTo` for float.