UE SC -kismetmathlibrary

project function:

KISMET_MATH_INLINE
FVector UKismetMathLibrary::ProjectVectorOnToVector(FVector V, FVector Target)
{
	if (Target.SizeSquared() > SMALL_NUMBER)
	{
		return V.ProjectOnTo(Target);
	}
	else
	{
		ReportError_ProjectVectorOnToVector();
		return FVector::ZeroVector;
	}
}

　

其中 ProjectOnTo:

FORCEINLINE FVector FVector::ProjectOnTo(const FVector& A) const 
{ 
	return (A * ((*this | A) / (A | A))); 
}

　| 运算符号 override: (Vector.h里面)

FORCEINLINE float operator|(const FVector& V) const;

	/**
	 * Calculate the dot product of two vectors.
	 *
	 * @param A The first vector.
	 * @param B The second vector.
	 * @return The dot product.
	 */

FORCEINLINE float FVector::operator|(const FVector& V) const
{
	return X*V.X + Y*V.Y + Z*V.Z;
}