dcss 0.23 stealth mechanics

a sleeping or wandering monster has a (perception + 1/stealth) chance to spot you every time you act
if you are berserk or sacrificed stealth, the roll automatically passes

an orc priest has 21 perception

21/30 to spot you with 10 dex, 0 stealth, robe
21/0 (guaranteed) with 10 dex, 0 stealth, ring mail
21/60 to spot you with 10 dex, 2 stealth, robe
21/28 to spot you with 10 dex, 2 stealth, ring mail
21/58 to spot you with 10 dex, 4 stealth, ring mail
5/58 to spot you with 10 dex, 4 stealth, ring mail, invisibility
4/0 (guaranteed) to spot you with 10 dex, 10 stealth, plate mail, invisibility



HOW STEALTH IS CALCULATED:
each pip of stealth in the % menu is 50 stealth, but the game tracks more granularly

3 * dex
15 * stealth

-66% if confused

-(aevp * aevp * 2 / 3) based on body armor type
-10 for leather
-32 for ring
-66 for scale
-150 for chain
-216 for plate
-352 for crystal plate

+50 per ring of stealth, +stealth artifact
+50 per rank of nightstalker
+25 per rank of thin skeletal structure
+50 per rank of camouflage
+15 per rank of translucent skin
-50 if casting silence
+100 if undead vampire
+50 if octopode or merfolk in water

-50% of current value if non-swimmer in water

+50 if wearing boots of stealth, not flying, and not in water
-10, -15, or -20 if you have hooves and are not flying
+20 if felid and not flying and are either untransformed or using beastly appendage

-60% if corona, glowing, or in halo

apply umbra bonus:
if with dith, multiply stealth by (piety + 200)/200
if wearing ring of shadows, and at less than 100 dith piety, multiply stealth by 1.5

if shadow form, double stealth

if generating qazlal clouds, multiply stealth by (200 - piety / 170) (cap piety at 160)

-66% if carrying the orb

if stealth is below 0, set it to 0



MONSTER PERCEPTION:
+10 for base value
+4 if animal intelligence
+8 if human intelligence
+HD
+15 if monster is wandering and has you as its foe
-75 if monster can't see you (because invis)
-10 if monster is natural and in ensorcelled hibernation
+10 if monster is unnatural and asleep

set to 4 if less than 4