Add damage method and update README.txt

3d_armor/README.txt

@@ -138,6 +138,25 @@ damage groups need to be defined in the tool/weapon used against the player.
 Reciprocal tool damage will be done only by the first armor inventory item
  with `reciprocate_damage = true`
 
+Armor Functions:
+
+armor:set_player_armor(player)
+
+Primarily an internal function but can be called externally to apply any
+changes that might not otherwise get handled.
+
+armor:punch(player, hitter, time_from_last_punch, tool_capabilities)
+
+Used to apply damage to all equipped armor based on the damage groups of
+each individual item.`hitter`, `time_from_last_punch` and `tool_capabilities`
+are optional but should be valid if included.
+
+armor:damage(player, index, stack, use)
+
+Adds wear to a single armor itemstack, triggers `on_damage` callbacks and
+updates the necessary inventories. Also handles item destruction callbacks
+and so should NOT be called from `on_unequip` to avoid an infinite loop.
+
 Item Callbacks:
 
 on_equip = func(player, index, stack)

3d_armor/api.lua

@@ -445,15 +445,7 @@ armor.punch = function(self, player, hitter, time_from_last_punch, tool_capabili
 				damage = minetest.get_item_group(name, "flammable") > 0
 			end
 			if damage == true then
-				local old_stack = ItemStack(stack)
+				self:damage(player, i, stack, use)
-				stack:add_wear(use)
-				self:set_inventory_stack(player, i, stack)
-				self:run_callbacks("on_damage", player, i, stack)
-				if stack:get_count() == 0 then
-					self:run_callbacks("on_unequip", player, i, old_stack)
-					self:run_callbacks("on_destroy", player, i, old_stack)
-					self:set_player_armor(player)
-				end
 			end
 			state = state + stack:get_wear()
 			count = count + 1
@@ -463,6 +455,18 @@ armor.punch = function(self, player, hitter, time_from_last_punch, tool_capabili
 	self.def[name].count = count
 end
 
+armor.damage = function(self, player, index, stack, use)
+	local old_stack = ItemStack(stack)
+	stack:add_wear(use)
+	self:run_callbacks("on_damage", player, i, stack)
+	self:set_inventory_stack(player, index, stack)
+	if stack:get_count() == 0 then
+		self:run_callbacks("on_unequip", player, index, old_stack)
+		self:run_callbacks("on_destroy", player, index, old_stack)
+		self:set_player_armor(player)
+	end
+end
+
 armor.get_player_skin = function(self, name)
 	local skin = nil
 	if self.skin_mod == "skins" or self.skin_mod == "simple_skins" then