/**
* Rotate a vector by the inverse of this quaternion.
*
* @param V the vector to be rotated
* @return vector after rotation by the inverse of this quaternion.
*/
public FVector UnrotateVector(FVector V)
{
FVector Q = new FVector(-X, -Y, -Z); // Inverse
FVector T = FVector.CrossProduct(Q, V) * 2.0f;
FVector Result = V + (T * W) + FVector.CrossProduct(Q, T);
return(Result);
}
/**
* Rotate a vector by this quaternion.
*
* @param V the vector to be rotated
* @return vector after rotation
*/
public FVector RotateVector(FVector V)
{
// http://people.csail.mit.edu/bkph/articles/Quaternions.pdf
// V' = V + 2w(Q x V) + (2Q x (Q x V))
// refactor:
// V' = V + w(2(Q x V)) + (Q x (2(Q x V)))
// T = 2(Q x V);
// V' = V + w*(T) + (Q x T)
FVector Q = new FVector(X, Y, Z);
FVector T = FVector.CrossProduct(Q, V) * 2.0f;
FVector Result = V + (T * W) + FVector.CrossProduct(Q, T);
return(Result);
}
