How does magic resistance affect spells like charm or mind bLast?

[Taqwus]

I don't know if it's changed since Dom I, but section 20.6.4 of the manual for the first game states that it's basically

(4 or 11) + floor(magic/2) + penetration bonuses + dice

versus

magic resistance incl. bonuses + drain scale + dice.

11 = most spells
4 = "easily resisted" spells, e.g. Master Enslave


I don't know where you'd find the penetration bonuses (e.g. for a Rune Smasher), haven't tried to build one in the demo yet.