Lighting from Normal Node

Hi everyone.

I am working with a material using nodes, which you can see in the coloured sphere image. As you can see in the other image, the lighting of the material comes from a normal node. If you click and drag on the Preview Sphere of the Normal Node, you change the origin of that light. So, when I am working on the scene, I can place the camera wherever I want, but the material wont be affected by any light nor the camera location. You’ll always see it as it is in the attached image.

What I would like is to control the origin of that lighting from the 3d view scene. Maybe linking it to an empty’s location, or something similar. Does anyone know if that is possible?

I hope I explained myself correctly, and I hope someone can help.