Fix armor penetration increasing negative object's and mob silicon's armor (ParadiseSS13#30105)

* fix

* no src allowed

Author: kyunkyunkyun

code/game/objects/obj_defense.dm

@@ -25,13 +25,12 @@
 		return 0
 	if(damage_type != BRUTE && damage_type != BURN)
 		return 0
-	var/armor_protection = 0
+	var/armor_protection
 	if(damage_flag)
 		armor_protection = armor.getRating(damage_flag)
-	if(armor_protection)		//Only apply weak-against-armor/hollowpoint effects if there actually IS armor.
-		armor_protection = clamp((armor_protection * ((100 - armor_penetration_percentage) / 100)) - armor_penetration_flat, min(armor_protection, 0), 100)
-	var/damage_multiplier = (100 - armor_protection) / 100
-	return round(damage_amount * damage_multiplier, DAMAGE_PRECISION)
+	if(armor_protection > 0)		//Only apply weak-against-armor/hollowpoint effects if there actually IS armor.
+		armor_protection = clamp(armor_protection * (100 - armor_penetration_percentage) / 100 - armor_penetration_flat, 0, 100)
+	return round(damage_amount * (100 - armor_protection) / 100, DAMAGE_PRECISION)
 
 /// returns the amount of damage required to destroy this object in a single hit.
 /obj/proc/calculate_oneshot_damage(damage_type, damage_flag = 0, attack_dir, armor_penetration_flat = 0, armor_penetration_percentage = 0)
@@ -42,11 +41,11 @@
 	if(damage_type != BRUTE && damage_type != BURN)
 		return INFINITY
 
-	var/armor_protection = 0
+	var/armor_protection
 	if(damage_flag)
 		armor_protection = armor.getRating(damage_flag)
-	if(armor_protection)        // Only apply weak-against-armor/hollowpoint effects if there actually IS armor.
-		armor_protection = clamp((armor_protection * ((100 - armor_penetration_percentage) / 100)) - armor_penetration_flat, min(armor_protection, 0), 100)
+	if(armor_protection > 0)        // Only apply weak-against-armor/hollowpoint effects if there actually IS armor.
+		armor_protection = clamp(armor_protection * (100 - armor_penetration_percentage) / 100 - armor_penetration_flat, 0, 100)
 
 	var/damage_multiplier = (100 - armor_protection) / 100
 	if(damage_multiplier <= 0)

code/modules/mob/living/silicon/silicon_mob.dm

@@ -312,12 +312,12 @@
 /mob/living/silicon/proc/run_armor(damage_amount, damage_type, damage_flag = 0, attack_dir, armor_penetration_flat = 0, armor_penetration_percentage = 0)
 	if(damage_type != BRUTE && damage_type != BURN)
 		return 0
-	var/armor_protection = 0
+	var/armor_protection
 	if(damage_flag)
 		armor_protection = armor.getRating(damage_flag)
-	if(armor_protection)		//Only apply weak-against-armor/hollowpoint effects if there actually IS armor.
-		armor_protection = clamp((armor_protection * ((100 - armor_penetration_percentage) / 100)) - armor_penetration_flat, min(armor_protection, 0), 100)
-	return round(damage_amount * (100 - armor_protection) * 0.01, DAMAGE_PRECISION)
+	if(armor_protection > 0)		//Only apply weak-against-armor/hollowpoint effects if there actually IS armor.
+		armor_protection = clamp(armor_protection * (100 - armor_penetration_percentage) / 100 - armor_penetration_flat, 0, 100)
+	return round(damage_amount * (100 - armor_protection) / 100, DAMAGE_PRECISION)
 
 /mob/living/silicon/apply_effect(effect = 0, effecttype = STUN, blocked = 0)
 	return FALSE //The only effect that can hit them atm is flashes and they still directly edit so this works for now