Redesign damage modifier execution

mods/CORE/mcl_damage/init.lua

@@ -15,7 +15,7 @@ mcl_damage = {
 		out_of_world = {bypasses_armor = true, bypasses_invulnerability = true},
 		generic = {bypasses_armor = true},
 		magic = {is_magic = true, bypasses_armor = true},
-		wither = {bypasses_armor = true},		-- unused
+		wither = {bypasses_armor = true}, -- unused
 		anvil = {},
 		falling_node = {}, -- unused
 		dragon_breath = {bypasses_armor = true}, -- unused
@@ -30,24 +30,45 @@ mcl_damage = {
 	}
 }
 
-local old_register_hpchange = minetest.register_on_player_hpchange
-
-function minetest.register_on_player_hpchange(func, modifier)
-	if modifier then
-		mcl_damage.register_modifier(func, 0)
-	else
-		old_register_hpchange(func, modifier)
-	end
-end
-
 function mcl_damage.register_modifier(func, priority)
 	table.insert(mcl_damage.modifiers, {func = func, priority = priority or 0})
 end
 
-function mcl_damage.get_mcl_damage_reason(mt_reason)
-	local mcl_reason = {
-		type = "generic",
-	}
+function mcl_damage.do_modifiers(player, damage, reason)
+	for _, modf in ipairs(mcl_damage.modifiers) do
+		damage = modf.func(player, damage, reason) or damage
+		if damage == 0 then
+			return 0
+		end
+	end
+
+	return damage
+end
+
+function mcl_damage.from_punch(mcl_reason, object)
+	mcl_reason.direct = object
+	local luaentity = mcl_reason.direct:get_luaentity()
+	if luaentity then
+		if luaentity._is_arrow then
+			mcl_reason.type = "arrow"
+		elseif luaentity._is_fireball then
+			mcl_reason.type = "fireball"
+		elseif luaentity._cmi_is_mob then
+			mcl_reason.type = "mob"
+		end
+		mcl_reason.source = mcl_reason.source or luaentity._source_object
+	else
+		mcl_reason.type = "player"
+	end
+end
+
+function mcl_damage.finish_reason(mcl_reason)
+	mcl_reason.source = mcl_reason.source or mcl_reason.direct
+	mcl_reason.flags = mcl_damage.types[mcl_reason.type]
+end
+
+function mcl_damage.from_mt(mt_reason)
+	local mcl_reason = {type = "generic"}
 
 	if mt_reason._mcl_type then
 		mcl_reason.type = mt_reason._mcl_type
@@ -56,22 +77,7 @@ function mcl_damage.get_mcl_damage_reason(mt_reason)
 	elseif mt_reason.type == "drown" then
 		mcl_reason.type = "drown"
 	elseif mt_reason.type == "punch" then
-		mcl_reason.direct = mt_reason.object
-		if mcl_reason.direct then
-			local luaentity = mcl_reason.direct:get_luaentity()
-			if luaentity then
-				if luaentity._is_arrow then
-					mcl_reason.type = "arrow"
-				elseif luaentity._is_fireball then
-					mcl_reason.type = "fireball"
-				elseif luaentity._cmi_is_mob then
-					mcl_reason.type = "mob"
-				end
-				mcl_reason.source = mcl_reason.source or luaentity._source_object
-			else
-				mcl_reason.type = "player"
-			end
-		end
+		mcl_damage.from_punch(mcl_reason, mt_reason.object)
 	elseif mt_reason.type == "node_damage" and mt_reason.node then
 		if minetest.get_item_group(mt_reason.node, "fire") > 0 then
 			mcl_reason.type = "in_fire"
@@ -87,8 +93,7 @@ function mcl_damage.get_mcl_damage_reason(mt_reason)
 		end
 	end
 
-	mcl_reason.source = mcl_reason.source or mcl_reason.direct
-	mcl_reason.flags = mcl_damage.types[mcl_reason.type]
+	mcl_damage.finish_reason(mcl_reason)
 
 	return mcl_reason
 end
@@ -97,16 +102,10 @@ function mcl_damage.register_type(name, def)
 	mcl_damage.types[name] = def
 end
 
-old_register_hpchange(function(player, hp_change, mt_reason)
-	local mcl_reason = mcl_damage.get_mcl_damage_reason(mt_reason)
-
-	for _, modf in ipairs(mcl_damage.modifiers) do
-		hp_change = modf.func(player, hp_change, mt_reason, mcl_reason) or hp_change
-		if hp_change == 0 then
-			return 0
-		end
+minetest.register_on_player_hpchange(function(player, hp_change, mt_reason)
+	if hp_change < 0 then
+		hp_change = -mcl_damage.do_modifiers(player, -hp_change, mcl_damage.from_mt(mt_reason))
 	end
-
 	return hp_change
 end, true)
 

mods/ITEMS/mcl_armor/damage.lua

@@ -1,13 +1,8 @@
-function mcl_armor.damage_modifier(obj, hp_change, reason)
-	if hp_change > 0 then
-		return hp_change
-	end
-
-	local damage = -hp_change
+mcl_damage.register_modifier(function(obj, damage, reason)
 	local flags = reason.flags
 
 	if flags.bypasses_armor and flags.bypasses_magic then
-		return hp_change
+		return damage
 	end
 
 	local uses = math.max(1, math.floor(damage / 4))
@@ -95,5 +90,5 @@ function mcl_armor.damage_modifier(obj, hp_change, reason)
 
 	mcl_armor.update(obj)
 
-	return -math.floor(damage + 0.5)
-end
+	return math.floor(damage + 0.5)
+end, 0)

mods/ITEMS/mcl_armor/player.lua

@@ -155,7 +155,3 @@ end)
 minetest.register_on_leaveplayer(function(player)
 	mcl_armor.player_view_range_factors[player] = nil
 end)
-
-mcl_damage.register_modifier(function(player, hp_change, _, reason)
-	return mcl_armor.damage_modifier(player, hp_change, reason)
-end)

mods/PLAYER/mcl_criticals/init.lua

@@ -1,8 +1,5 @@
-mcl_criticals = {}
-
-function mcl_criticals.modifier(obj, hp_change, reason)
-	local damage = -hp_change
-	if damage > 0 and reason.type == "player" then
+mcl_damage.register_modifier(function(obj, damage, reason)
+	if reason.type == "player" then
 		local hitter = reason.direct
 		if mcl_sprint.is_sprinting(hitter) then
 			obj:add_velocity(hitter:get_velocity())
@@ -27,12 +24,7 @@ function mcl_criticals.modifier(obj, hp_change, reason)
 			})
 			minetest.sound_play("mcl_criticals_hit", {object = obj})
 			-- the minecraft wiki is actually wrong about a crit dealing 150% damage, see minecraft source code
-			damage = damage + math.random(0, math.floor(damage * 1.5 + 2))
+			return damage + math.random(0, math.floor(damage * 1.5 + 2))
 		end
 	end
-	return -damage
-end
-
-mcl_damage.register_modifier(function(player, hp_change, _, mcl_reason)
-	return mcl_criticals.modifier(player, hp_change, mcl_reason)
 end, -100)