Spawn Nether Wart

mods/MAPGEN/mcl_mapgen_core/init.lua

@@ -1224,13 +1224,7 @@ local function generate_underground_mushrooms(minp, maxp, seed)
 	end
 end
 
-local nether_wart_chance
+-- Generate Nether decorations manually: Eternal fire, mushrooms
-if v6 then
-	nether_wart_chance = 85
-else
-	nether_wart_chance = 170
-end
--- Generate Nether decorations manually: Eternal fire, mushrooms, nether wart
 -- Minetest's API does not support decorations in caves yet. :-(
 local function generate_nether_decorations(minp, maxp, seed)
 	if c_nether == nil then
@@ -1292,15 +1286,6 @@ local function generate_nether_decorations(minp, maxp, seed)
 			end
 		end)
 	end
-
-	-- Nether wart on soul sand
-	-- TODO: Spawn in Nether fortresses
-	special_deco(ssand, function(bpos)
-		if pr_nether:next(1, nether_wart_chance) == 1 then
-			minetest.set_node(bpos, {name = "mcl_nether:nether_wart"})
-		end
-	end)
-
 end
 
 -- Generate basic layer-based nodes: void, bedrock, realm barrier, lava seas, etc.
@@ -1589,6 +1574,7 @@ mcl_mapgen.register_mapgen_block_lvm(basic_safe, 1)
 local modpath = minetest.get_modpath(minetest.get_current_modname())
 dofile(modpath .. "/clay.lua")
 dofile(modpath .. "/tree_decoration.lua")
+dofile(modpath .. "/nether_wart.lua")
 
 -- Nether Roof Light:
 mcl_mapgen.register_mapgen_block_lvm(function(vm_context)

mods/MAPGEN/mcl_mapgen_core/nether_wart.lua

@@ -0,0 +1,57 @@
+local nether_wart_chance
+if mcl_mapgen.v6 then
+	nether_wart_chance = 85
+else
+	nether_wart_chance = 170
+end
+
+local y_min = mcl_mapgen.nether.min
+local y_max = mcl_mapgen.nether.max
+local place_on = {"group:soil_nether_wart"}
+
+local block_size = mcl_mapgen.BS
+local decrease_search_area = math.min(2, math.floor(block_size/2))
+local search_area_size = math.max(block_size - 2 * decrease_search_area, math.max(1, math.ceil(nether_wart_chance^(1/3))))
+nether_wart_chance = math.floor(nether_wart_chance * (search_area_size^3) / (block_size^3))
+local nether_wart_chance_threshold = nether_wart_chance
+local minetest_swap_node = minetest.swap_node
+
+local wart_perlin
+local noise_params = {
+	offset = 0.4,
+	scale = 0.4,
+	spread = {x = block_size, y = block_size, z = block_size},
+	seed = 238742,
+	octaves = 1,
+	persist = 0.5,
+}
+
+minetest.log("action", "Nether Wart block_size=" .. block_size .. ", search_area_size=" .. search_area_size .. ", per-area nether_wart_chance=" .. nether_wart_chance)
+
+local minetest_find_nodes_in_area_under_air = minetest.find_nodes_in_area_under_air
+local minetest_get_perlin = minetest.get_perlin
+
+mcl_mapgen.register_mapgen_block(function(minp, maxp, seed)
+	local minp = minp
+	local y1 = minp.y
+	if y1 > y_max then return end
+
+	local maxp = maxp
+	local y2 = maxp.y
+	if y2 < y_min then return end
+
+	local p1 = {x = minp.x + decrease_search_area, y = y1 + decrease_search_area, z = minp.z + decrease_search_area}
+	local p2 = {x = maxp.x - decrease_search_area, y = y2 - decrease_search_area, z = maxp.z - decrease_search_area}
+
+	pos_list = minetest_find_nodes_in_area_under_air(p1, p2, place_on)
+	local pr = PseudoRandom(seed)
+	wart_perlin = wart_perlin or minetest_get_perlin(noise_params)
+
+	for i = 1, #pos_list do
+		local pos = pos_list[i]
+		if pr:next(1, nether_wart_chance) + wart_perlin:get_3d(pos) >= nether_wart_chance_threshold then
+			pos.y = pos.y + 1
+			minetest.swap_node(pos, {name = "mcl_nether:nether_wart"})
+		end
+	end
+end, 999999999)