auto delta_wi = CalcArea(x, y, width, height);
for (int l = 0; l <= SHOrder; l++) {
for (int m = -l; m <= l; m++) {
int k = sh::GetIndex(l, m);
double SH = sh::EvalSH(l, m, dir.cast<double>().normalized());
SHCoeffiecents[k] += Le * delta_wi * SH;
}
}