Player skills do not change damage blocked by armor. Why would they? Why skill in defending by shield should increase armor?
That formula is for shield/weapon/fist defense, not for armor.
If player wears shield + weapon, it uses skill Shielding and defense of shield + 'extra def' of weapon.
If player wears shield, it uses skill Shielding and defense of shield.
If player wears weapon, it uses skill of given weapon (sword/axe/club) and defense+extra def of weapon.
If player wears nothing (no shield and no armor), it uses skill Fist fighting and
7
as defense value.
(
forgottenserver/player.cpp at 4bd81f335133b42caae11c26f42cfaa3bc57e1c5 · otland/forgottenserver (https://github.com/otland/forgottenserver/blob/4bd81f335133b42caae11c26f42cfaa3bc57e1c5/src/player.cpp#L367-L397) )
Armor formula is here:
A free and open-source MMORPG server emulator written in C++ - otland/forgottenserver
github.com
It's very simple. It just reduce damage by armor value (random 50-100% of armor):
C++:
damage -= uniform_random(armor / 2, armor - (armor % 2 + 1));