Hi,

It's impractical to use SH for high freq IBL, as you need a crazy amount of terms. Additionally, Brian's split sum approximation splits the radiance integral into two parts - one which can be stored in a cube map and second which can be stored in a small 2D texture (this is why there is no L(i) term in the second equation). Anyway, I'm not sure what are you trying to calculate here, as your equations look quite strange - e.g. f(l,v) term is missing.