How to create plane wave not aligned with axis?

Dear all,

The code in Sullivan's book is for total/scattered field formulation for a plane wave aligned with the grid.

My question is: how do I create a plane wave which is not aligned with the grid?
Can the incident array still be used? How? Any sample code (for 2D case)?
Or at least a pseudocode..

Please help.

Thanks.

Yes, it would be really useful. I also have the same problem, am a newbie and transition from the wave parallel to one of the axes to the arbitrary angle is not so easy.

Would appreciate any help,
thanks!