VTK – Rotate Vector To Special Direction

I take notes about how to rotate vector to a special direction.

#include "./tool.h"

#define vtkSPtr vtkSmartPointer
#define vtkSPtrNew(Var, Type) vtkSPtr<Type> Var = vtkSPtr<Type>::New();

int main(int, char *[])
{
    PointStruct vec0( 1, 1, 0 );
    PointStruct vec1( -1, 1, 0 );
    PointStruct vecZ( 0, 0, 1 );
    double radian = vtkMath::AngleBetweenVectors( vec0.point, vec1.point );
    double degree = vtkMath::DegreesFromRadians( radian );
    vtkSPtrNew( trans, vtkTransform );
    if (fabs(degree) > 0.0001)
    {
        PointStruct crossVec;
        if (fabs(degree - 180) < 0.0001)
            crossVec = vecZ;
        else
            crossVec = vec0^vec1;
        crossVec.Unit();
        trans->RotateWXYZ(degree, crossVec[0], crossVec[1], crossVec[2]);
        trans->Update();
    }


    PointStruct tester = vec0;
    trans->TransformVector( tester.point, tester.point );
    cout << tester << endl;
    return EXIT_SUCCESS;
}