Thanks Hummel!!!

Btw, I have just a rough idea what spherical harmonics are and why and for what they are used for -- but can YOU recommend a paper/article/whatelse, that describes how to sample e.g. from an illuminated sphere a SH and how to calculate the lighting terms in a shader?

I want to try out two applications:

1.) placing small dummy-spheres as lightprobes in a level, so that they bake the (radiosity) lighting at that world position into a texture - which I in return convert into a leightweight SH, to be used ingame

2.) editing a SH for the whole ambient lighting in realtime by adjusting 6 directional lights on a virtual sphere by their intensity and color... question is then how to translate that into a SH. Realtime baking would be possible, too, so that I could simply apply the technique for case 1.)

Regards,
-Christian