Function PrevIndex

editor/rad_hemicube.cpp:695–700

Returns number preceding val modulo modulus. prevmod(3,4) = 2 prevmod(0,4) = 3

//	prevmod(3,4) = 2
//	prevmod(0,4) = 3
int PrevIndex(int val, int modulus) {
  if (val > 0)
    return val - 1;
  else
    return modulus - 1;
}

//	Returns number succeeding val modulo modulus.
//	succmod(3,4) = 0