allow mods to change damage taken by radiation

allow using technic's radiation resistance function and add resistance to lead (needs rework)

technic/machines/HV/nuclear_reactor.lua

@@ -507,22 +507,31 @@ local default_radiation_resistance_per_group = {
 local cache_radiation_resistance = {}
 local function node_radiation_resistance(nodename)
 	local eff = cache_radiation_resistance[nodename]
-	if eff then return eff end
+	if eff then
+		return eff
+	end
 	local def = minetest.registered_nodes[nodename] or {groups={}}
 	eff = def.radiation_resistance or default_radiation_resistance_per_node[nodename]
 	if not eff then
 		for g, v in pairs(def.groups) do
-			if v > 0 and default_radiation_resistance_per_group[g] then
+			if v > 0
+			and default_radiation_resistance_per_group[g] then
 				eff = default_radiation_resistance_per_group[g]
 				break
 			end
 		end
 	end
-	if not eff then eff = 0 end
+	if not eff then
+		eff = 0
+	end
 	cache_radiation_resistance[nodename] = eff
 	return eff
 end
 
+function technic.get_node_radiation_resistance(...)
+	return node_radiation_resistance(...)
+end
+
 -- Radioactive nodes cause damage to nearby players.  The damage
 -- effect depends on the intrinsic strength of the radiation source,
 -- the distance between the source and the player, and the shielding
@@ -575,6 +584,16 @@ local cache_scaled_shielding = {}
 local damage_enabled = minetest.setting_getbool("enable_damage")
 
 if damage_enabled then
+	local registered_on_radiation_damaging = {}
+	function technic.register_on_radiation_damaging(func)
+		registered_on_radiation_damaging[#registered_on_radiation_damaging+1] = func
+	end
+	--[[technic.register_on_radiation_damaging(function(dmg, player, pos, node, strength)
+		return -- do nothing
+		return dmg*2 -- change damage
+		return false -- do not damage player
+	end)]]
+
 	minetest.register_abm({
 		nodenames = {"group:radioactive"},
 		interval = 1,
@@ -609,11 +628,26 @@ if damage_enabled then
 							dmg_int = dmg_int + 1
 						end
 						if dmg_int > 0 then
+							for _,func in ipairs(registered_on_radiation_damaging) do
+								local newdmg = func(dmg_int, o, pos, node, strength)
+								if newdmg == false then
+									dmg_int = 0
+									break
+								elseif newdmg then
+									if newdmg <= 0 then
+										dmg_int = 0
+										break
+									end
+									dmg_int = newdmg
+								end
+							end
+							if dmg_int ~= 0 then
 								o:set_hp(math.max(o:get_hp() - dmg_int, 0))
 							end
 						end
 					end
 				end
+			end
 		end,
 	})
 end

technic_worldgen/nodes.lua

@@ -99,7 +99,8 @@ minetest.register_node(":technic:lead_block", {
 	tiles = { "technic_lead_block.png" },
 	is_ground_content = true,
 	groups = {cracky=1, level=2},
-	sounds = default.node_sound_stone_defaults()
+	sounds = default.node_sound_stone_defaults(),
+	radiation_resistance = 500
 })
 
 minetest.register_alias("technic:wrought_iron_block", "default:steelblock")