Finer gradations of radioactivity

Make the "radioactive" group value be the safe distance in millimeters
rather than meters, to allow for intermediate values.  Use such
intermediate values for the uranium blocks, using the existing formula
with this finer quantisation.  All other radioactive nodes retain their
existing radioactivity exactly.

technic/items.lua

@@ -197,15 +197,15 @@ for p = 0, 35 do
 	-- linear interpolation of activity along that scale, rooted at
 	-- a natural (0.7%-fissile) uranium block having the activity of
 	-- 9 uranium ore blocks (due to 9 ingots per block).  The group
-	-- value is proportional to the square root of the activity,
-	-- and uranium ore has radioactive=1.  This yields radioactive=2
-	-- for a fully-depleted uranium block and radioactive=5 for a
-	-- 3.5%-fissile uranium block.
+	-- value is proportional to the square root of the activity, and
+	-- uranium ore has radioactive=1000.  This yields radioactive=2065
+	-- for a fully-depleted uranium block and radioactive=5286 for
+	-- a 3.5%-fissile uranium block.
 	(ov or minetest.register_node)(block, {
 		description = string.format(S("%.1f%%-Fissile Uranium Block"), p/10),
 		tiles = {"technic_uranium_block.png"},
 		is_ground_content = true,
-		groups = {uranium_block=1, not_in_creative_inventory=nici, cracky=1, level=2, radioactive=math.floor(math.sqrt((1+5.55*p/35) * 9 / (1+5.55*7/35)) + 0.5)},
+		groups = {uranium_block=1, not_in_creative_inventory=nici, cracky=1, level=2, radioactive=math.floor(1000*math.sqrt((1+5.55*p/35) * 9 / (1+5.55*7/35)) + 0.5)},
 		sounds = default.node_sound_stone_defaults(),
 	});
 	if not ov then

technic/machines/HV/nuclear_reactor.lua

@@ -293,7 +293,7 @@ minetest.register_node("technic:hv_nuclear_reactor_core_active", {
 	tiles = {"technic_hv_nuclear_reactor_core.png", "technic_hv_nuclear_reactor_core.png",
 	         "technic_hv_nuclear_reactor_core.png", "technic_hv_nuclear_reactor_core.png",
 		 "technic_hv_nuclear_reactor_core.png", "technic_hv_nuclear_reactor_core.png"},
-	groups = {cracky=1, technic_machine=1, radioactive=7, not_in_creative_inventory=1},
+	groups = {cracky=1, technic_machine=1, radioactive=7000, not_in_creative_inventory=1},
 	legacy_facedir_simple = true,
 	sounds = default.node_sound_wood_defaults(),
 	drop="technic:hv_nuclear_reactor_core",
@@ -541,10 +541,10 @@ end
 --
 -- A radioactive node is identified by being in the "radioactive" group,
 -- and the group value signifies the strength of the radiation source.
--- The group value is the distance in metres from a node at which an
--- unshielded player will be damaged by 0.25 HP/s.  Or, equivalently, it
--- is half the square root of the damage rate in HP/s that an unshielded
--- player 1 m away will take.
+-- The group value is the distance in millimetres from a node at which
+-- an unshielded player will be damaged by 0.25 HP/s.  Or, equivalently,
+-- it is 500 times the square root of the damage rate in HP/s that an
+-- unshielded player 1 m away will take.
 --
 -- Shielding is assessed by sampling every 0.25 m along the path
 -- from the source to the player, ignoring the source node itself.
@@ -571,7 +571,7 @@ minetest.register_abm({
 	chance = 1,
 	action = function (pos, node)
 		local strength = minetest.registered_nodes[node.name].groups.radioactive
-		for _, o in ipairs(minetest.get_objects_inside_radius(pos, strength + assumed_abdomen_offset_length)) do
+		for _, o in ipairs(minetest.get_objects_inside_radius(pos, strength*0.001 + assumed_abdomen_offset_length)) do
 			if o:is_player() then
 				local rel = vector.subtract(vector.add(o:getpos(), assumed_abdomen_offset), pos)
 				local dist_sq = vector.length_square(rel)
@@ -586,7 +586,7 @@ minetest.register_abm({
 						resistance = resistance + node_radiation_resistance(minetest.get_node(intnodepos).name)
 					end
 				end
-				local dmg_rate = 0.25 * strength*strength * math.exp(-0.0025*resistance) / math.max(0.75, dist_sq)
+				local dmg_rate = 0.25e-6 * strength*strength * math.exp(-0.0025*resistance) / math.max(0.75, dist_sq)
 				if dmg_rate >= 0.25 then
 					local dmg_int = math.floor(dmg_rate)
 					if math.random() < dmg_rate-dmg_int then
@@ -636,7 +636,7 @@ for _, state in ipairs({ "flowing", "source" }) do
 			liquid = 2,
 			hot = 3,
 			igniter = 1,
-			radioactive = (state == "source" and 32 or 16),
+			radioactive = (state == "source" and 32000 or 16000),
 			not_in_creative_inventory = (state == "flowing" and 1 or nil),
 		},
 	})
@@ -656,7 +656,7 @@ minetest.register_node("technic:chernobylite_block", {
         description = S("Chernobylite Block"),
 	tiles = { "technic_chernobylite_block.png" },
 	is_ground_content = true,
-	groups = { cracky=1, radioactive=5, level=2 },
+	groups = { cracky=1, radioactive=5000, level=2 },
 	sounds = default.node_sound_stone_defaults(),
 	light_source = 2,
 

technic_worldgen/nodes.lua

@@ -5,7 +5,7 @@ minetest.register_node( ":technic:mineral_uranium", {
 	description = S("Uranium Ore"),
 	tiles = { "default_stone.png^technic_mineral_uranium.png" },
 	is_ground_content = true,
-	groups = {cracky=3, radioactive=1},
+	groups = {cracky=3, radioactive=1000},
 	sounds = default.node_sound_stone_defaults(),
 	drop = 'craft "technic:uranium_lump" 1',
 }) 
@@ -56,7 +56,7 @@ minetest.register_node(":technic:uranium_block", {
 	description = S("Uranium Block"),
 	tiles = { "technic_uranium_block.png" },
 	is_ground_content = true,
-	groups = {uranium_block=1, cracky=1, level=2, radioactive=3},
+	groups = {uranium_block=1, cracky=1, level=2, radioactive=3000},
 	sounds = default.node_sound_stone_defaults()
 })