At page (slide in reality) 12/20 of this tutorial it is shown a function used to project lights into SH coefficients, however the value of those coefficients is not given, what are their values and what they are for?Do I have to clamp colors to max value of 1 (float) / 255(uint) when adding lights to SH coefficients?
What are the fConstX in Spherical Harmonics?
shader
I'm not an expert on Spherical Harmonic (SH), but I'll try to answer.SH functions are basis functions. That means that they encode a function $f$ this way by a given basis function $B_i$:$$\int_{}^{} f(x) B_i(x) dx=fConst_i$$So what we can do is to use the $fConst_i$ to reconstruct an approximation of the function $f$ this way:$$\sum_{n=1}^{i} fConst_iB(i)$$In your case they could look like this:$$fConst1 = 0.429043;$$$$fConst2 = 0.511664;$$$$fConst3 = 0.743125;$$$$fConst4 = 0.886227;$$$$fConst5 = 0.247708;$$These coefficients approximate diffuse lighting.