try html formspec:

problems:
* image width and height doesn't seem to work
* font is too small

.gitignore

@@ -0,0 +1,4 @@
+## Generic ignorable patterns and files
+*~
+.*.swp
+debug.txt

LICENSE.txt

@@ -0,0 +1,2 @@
+GPLv3 (lkloel's version)
+MIT for the changes

README.md

@@ -0,0 +1,15 @@
+For a description of this Minetest mod, please refer to the forum topic:
+https://forum.minetest.net/viewtopic.php?f=9&t=10265
+
+
+TODO:
+* Find a way to get the perlin noise inside [-1; 1] or use another noise
+* Add some node which containing items to the simple pyramid "buildings"
+* Change the sky background, fog, etc. in the nether
+* Improve the guide formspec.
+  Writing it in Markdown would be nice.
+  These could be useful:
+  * https://forum.minetest.net/viewtopic.php?t=23855
+    Minetest Bedrock Markup Language
+  * https://github.com/mpeterv/markdown
+    Markdown to HTML converter; Minetest formspecs support HTML

README.txt

@@ -1,3 +0,0 @@
-TODO:
-— change the portal
-— add a teleportation ball

modpack.txt

@@ -0,0 +1 @@
+0

nether/.luacheckrc

@@ -0,0 +1,15 @@
+read_globals = {
+	-- Defined by Minetest
+	"minetest", "vector", "PseudoRandom", "VoxelArea", "ItemStack", "dump",
+	"string",
+
+	-- Mods
+	"default", "stairs", "creative"
+}
+globals = {"nether"}
+ignore = {
+	"212",
+		-- Unused argument
+	"411", "421", "422", "423", "431", "432",
+		-- Shadowing
+}

nether/Nicht Leere Datei.lua

@@ -1,199 +0,0 @@
--- Throne of Hades
-HADES_THRONE = {
-	-- Lava Moat
-	{pos={x=-1,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=0}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=1}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=2}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=3}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=4}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=5}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=6}, block="default:lava_source"},
-	{pos={x=-1,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=0,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=1,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=2,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=3,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=4,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=5,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=7}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=6}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=5}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=4}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=3}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=2}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=1}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=0}, block="default:lava_source"},
-	{pos={x=6,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=5,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=4,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=3,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=2,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=1,y=-1,z=-1}, block="default:lava_source"},
-	{pos={x=0,y=-1,z=-1}, block="default:lava_source"},
-	-- Floor 1
-	{pos={x=0,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=2,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=0,z=0}, block="nether:netherrack"},
-	-- Floor 2
-	{pos={x=0,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=2,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=1}, block="nether:netherrack"},
-	-- Floor 3
-	{pos={x=0,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=2,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=2}, block="nether:netherrack"},
-	-- Floor 4
-	{pos={x=0,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=5}, block="nether:netherrack"},
-	-- Floor 5
-	{pos={x=2,y=4,z=4}, block="nether:netherrack"},
-	{pos={x=2,y=4,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=4,z=4}, block="nether:netherrack"},
-	{pos={x=3,y=4,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=4,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=4,z=6}, block="nether:netherrack"},
-	-- Torches on floor 5
-	{pos={x=0,y=4,z=4}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=4}, block="nether:torch_bottom"},
-	{pos={x=0,y=4,z=5}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=5}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=4}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=4}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=5}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=5}, block="nether:torch_bottom"},
-	{pos={x=0,y=4,z=0}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=0}, block="nether:torch_bottom"},
-	{pos={x=0,y=4,z=1}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=1}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=0}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=0}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=1}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=1}, block="nether:torch_bottom"},
-	{pos={x=0,y=4,z=2}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=2}, block="nether:torch_bottom"},
-	{pos={x=0,y=4,z=3}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=3}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=2}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=2}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=3}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=3}, block="nether:torch_bottom"},
-	{pos={x=4,y=4,z=6}, block="nether:torch_bottom"},
-	{pos={x=5,y=4,z=6}, block="nether:torch_bottom"},
-	{pos={x=0,y=4,z=6}, block="nether:torch_bottom"},
-	{pos={x=1,y=4,z=6}, block="nether:torch_bottom"},
-	-- Nether Portal
-	{pos={x=1,y=5,z=6}, portalblock=true},
-}
-

nether/crafting.lua

@@ -0,0 +1,253 @@
+minetest.register_craft({
+	output = "nether:fim",
+	recipe = {
+		{"nether:shroom_head"},
+		{"nether:fruit_no_leaf"},
+		{"nether:shroom_head"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:fruit_leaves",
+	recipe = {
+		{"nether:fruit_leaf", "nether:fruit_leaf", "nether:fruit_leaf"},
+		{"nether:fruit_leaf", "nether:fruit_leaf", "nether:fruit_leaf"},
+		{"nether:fruit_leaf", "nether:fruit_leaf", "nether:fruit_leaf"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:pick_mushroom",
+	recipe = {
+		{"nether:shroom_head", "nether:shroom_head", "nether:shroom_head"},
+		{"", "nether:shroom_stem", ""},
+		{"", "nether:shroom_stem", ""},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:pick_wood",
+	recipe = {
+		{"nether:wood_cooked", "nether:wood_cooked", "nether:wood_cooked"},
+		{"", "group:stick", ""},
+		{"", "group:stick", ""},
+	}
+})
+
+for _,m in pairs({"netherrack", "netherrack_blue", "white"}) do
+	local input = "nether:"..m
+
+	minetest.register_craft({
+		output = "nether:pick_"..m,
+		recipe = {
+			{input, input, input},
+			{"", "group:stick", ""},
+			{"", "group:stick", ""},
+		}
+	})
+
+	minetest.register_craft({
+		output = "nether:axe_"..m,
+		recipe = {
+			{input, input},
+			{input, "group:stick"},
+			{"", "group:stick"},
+		}
+	})
+
+	minetest.register_craft({
+		output = "nether:sword_"..m,
+		recipe = {
+			{input},
+			{input},
+			{"group:stick"},
+		}
+	})
+
+	minetest.register_craft({
+		output = "nether:shovel_"..m,
+		recipe = {
+			{input},
+			{"group:stick"},
+			{"group:stick"},
+		}
+	})
+end
+
+minetest.register_craft({
+	output = "nether:netherrack_brick 4",
+	recipe = {
+		{"nether:netherrack", "nether:netherrack"},
+		{"nether:netherrack", "nether:netherrack"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:netherrack_brick_black 4",
+	recipe = {
+		{"nether:netherrack_black", "nether:netherrack_black"},
+		{"nether:netherrack_black", "nether:netherrack_black"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:netherrack_brick_blue 4",
+	recipe = {
+		{"nether:netherrack_blue", "nether:netherrack_blue"},
+		{"nether:netherrack_blue", "nether:netherrack_blue"},
+	}
+})
+
+minetest.register_craft({
+	output = "default:furnace",
+	recipe = {
+		{"nether:netherrack_brick", "nether:netherrack_brick", "nether:netherrack_brick"},
+		{"nether:netherrack_brick", "", "nether:netherrack_brick"},
+		{"nether:netherrack_brick", "nether:netherrack_brick", "nether:netherrack_brick"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:extractor",
+	recipe = {
+		{"nether:netherrack_brick", "nether:blood_top_cooked", "nether:netherrack_brick"},
+		{"nether:blood_cooked", "nether:shroom_stem", "nether:blood_cooked"},
+		{"nether:netherrack_brick", "nether:blood_stem_cooked", "nether:netherrack_brick"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:wood 4",
+	recipe = {
+		{"nether:blood_stem"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:wood_empty 4",
+	recipe = {
+		{"nether:blood_stem_empty"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:stick 4",
+	recipe = {
+		{"nether:wood_empty"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:torch",
+	recipe = {
+		{"nether:bark"},
+		{"group:stick"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:forest_wood",
+	recipe = {
+		{"nether:forest_planks", "nether:forest_planks", "nether:forest_planks"},
+		{"nether:forest_planks", "", "nether:forest_planks"},
+		{"nether:forest_planks", "nether:forest_planks", "nether:forest_planks"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:forest_planks 8",
+	recipe = {
+		{"nether:forest_wood"},
+	}
+})
+
+minetest.register_craft({
+	output = "nether:forest_planks 7",
+	recipe = {
+		{"nether:tree"},
+	},
+})
+
+local sound_allowed = true
+minetest.register_on_craft(function(itemstack, player, old_craft_grid, craft_inv)
+	if itemstack:get_name() ~= "nether:forest_planks"
+	or itemstack:get_count() ~= 7 then
+		return
+	end
+	local tree
+	for i = 1,9 do
+		if old_craft_grid[i]:get_name() == "nether:tree" then
+			tree = i
+			break
+		end
+	end
+	if not tree then	-- do nth if theres no tree
+		return
+	end
+	local rdif = math.random(-1,1)	-- add a bit randomness
+	local barkstack = ItemStack("nether:bark "..4-rdif)
+	local inv = player:get_inventory()
+	if not inv:room_for_item("main", barkstack) then	-- disallow crafting if there's not enough free space
+		craft_inv:set_list("craft", old_craft_grid)
+		itemstack:set_name("")
+		return
+	end
+	itemstack:set_count(7+rdif)
+	inv:add_item("main", barkstack)
+	if not sound_allowed then	-- avoid playing the sound multiple times, e.g. when middle mouse click
+		return
+	end
+	minetest.sound_play("default_wood_footstep", {pos=player:get_pos(),  gain=0.25})
+	sound_allowed = false
+	minetest.after(0, function()
+		sound_allowed = true
+	end)
+end)
+
+minetest.register_craft({
+	output = "default:paper",
+	recipe = {
+		{"nether:grass_dried", "nether:grass_dried", "nether:grass_dried"},
+	}
+})
+
+
+minetest.register_craft({
+	type = "cooking",
+	output = "default:coal_lump",
+	recipe = "nether:tree",
+})
+
+minetest.register_craft({
+	type = "cooking",
+	output = "nether:grass_dried",
+	recipe = "nether:grass",
+})
+
+minetest.register_craft({
+	type = "cooking",
+	output = "nether:pearl",
+	recipe = "nether:fim",
+})
+
+minetest.register_craft({
+	type = "cooking",
+	output = "nether:hotbed",
+	recipe = "nether:blood_extracted",
+})
+
+for  _,i in ipairs({"nether:blood", "nether:blood_top", "nether:blood_stem", "nether:wood"}) do
+	local cooked = i.."_cooked"
+
+	minetest.register_craft({
+		type = "cooking",
+		output = cooked,
+		recipe = i,
+	})
+
+	minetest.register_craft({
+		type = "fuel",
+		recipe = cooked,
+		burntime = 30,
+	})
+end

nether/depends.txt

@@ -1,3 +0,0 @@
-default
-riesenpilz
-glow

nether/furnace.lua

@@ -0,0 +1,346 @@
+-- minetest time speed
+local time_speed = tonumber(minetest.settings:get("time_speed"))
+if not time_speed then
+	time_speed = 1
+else
+	time_speed = time_speed/72
+end
+
+local function get_date()
+	return os.date("%y %d %H %M %S")
+end
+
+-- returns the time difference in seconds
+local function get_timediff(d1, d2)
+	local d = string.split(d1, " ")
+	for n,i in pairs(string.split(d2, " ")) do
+		d[n] = i-d[n]
+	end
+	local secs = 0
+	local y,d,h,m,s = unpack(d)
+	if s ~= 0 then
+		secs = secs+s
+	end
+	if m ~= 0 then
+		secs = secs+m*60
+	end
+	if h ~= 0 then
+		secs = secs+h*3600	-- 60*60
+	end
+	if d ~= 0 then
+		secs = secs+d*86400	-- 60*60*24
+	end
+	if y ~= 0 then
+		secs = secs+y*31557600	-- 60*60*24*365.25
+	end
+	--secs = math.floor(secs+0.5)
+	if secs < 0 then
+		minetest.log("action", "play warzone2100?")
+	end
+	return secs*time_speed
+end
+
+-- copied from older default furnace code and edited a bit
+
+function nether.get_furnace_active_formspec(pos, percent)
+	local formspec =
+		"size[8,9]"..
+		"image[2,2;1,1;default_furnace_fire_bg.png^[lowpart:"..
+		(100-percent)..":default_furnace_fire_fg.png]"..
+		"list[current_name;fuel;2,3;1,1;]"..
+		"list[current_name;src;2,1;1,1;]"..
+		"list[current_name;dst;5,1;2,2;]"..
+		"list[current_player;main;0,5;8,4;]"
+	return formspec
+end
+
+nether.furnace_inactive_formspec =
+	"size[8,9]"..
+	"image[2,2;1,1;default_furnace_fire_bg.png]"..
+	"list[current_name;fuel;2,3;1,1;]"..
+	"list[current_name;src;2,1;1,1;]"..
+	"list[current_name;dst;5,1;2,2;]"..
+	"list[current_player;main;0,5;8,4;]"
+
+minetest.register_node("nether:furnace", {
+	description = "Furnace",
+	tiles = {"default_furnace_top.png", "default_furnace_bottom.png", "default_furnace_side.png",
+		"default_furnace_side.png", "default_furnace_side.png", "default_furnace_front.png"},
+	paramtype2 = "facedir",
+	groups = {cracky=2},
+	legacy_facedir_simple = true,
+	is_ground_content = false,
+	sounds = default.node_sound_stone_defaults(),
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("formspec", nether.furnace_inactive_formspec)
+		meta:set_string("infotext", "Furnace")
+		local inv = meta:get_inventory()
+		inv:set_size("fuel", 1)
+		inv:set_size("src", 1)
+		inv:set_size("dst", 4)
+	end,
+	can_dig = function(pos,player)
+		local meta = minetest.get_meta(pos);
+		local inv = meta:get_inventory()
+		if not inv:is_empty("fuel") then
+			return false
+		elseif not inv:is_empty("dst") then
+			return false
+		elseif not inv:is_empty("src") then
+			return false
+		end
+		return true
+	end,
+	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("last_active", get_date())
+		local inv = meta:get_inventory()
+		if listname == "fuel" then
+			if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
+				if inv:is_empty("src") then
+					meta:set_string("infotext","Furnace is empty")
+				end
+				return stack:get_count()
+			else
+				return 0
+			end
+		elseif listname == "src" then
+			return stack:get_count()
+		elseif listname == "dst" then
+			return 0
+		end
+	end,
+	allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("last_active", get_date())
+		local inv = meta:get_inventory()
+		local stack = inv:get_stack(from_list, from_index)
+		if to_list == "fuel" then
+			if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
+				if inv:is_empty("src") then
+					meta:set_string("infotext","Furnace is empty")
+				end
+				return count
+			else
+				return 0
+			end
+		elseif to_list == "src" then
+			return count
+		elseif to_list == "dst" then
+			return 0
+		end
+	end,
+})
+
+minetest.register_node("nether:furnace_active", {
+	description = "Furnace",
+	tiles = {
+		"default_furnace_top.png",
+		"default_furnace_bottom.png",
+		"default_furnace_side.png",
+		"default_furnace_side.png",
+		"default_furnace_side.png",
+		{
+			image = "default_furnace_front_active.png",
+			backface_culling = false,
+			animation = {
+				type = "vertical_frames",
+				aspect_w = 16,
+				aspect_h = 16,
+				length = 1.5
+			},
+		}
+	},
+	paramtype2 = "facedir",
+	light_source = 8,
+	drop = "nether:furnace",
+	groups = {cracky=2, not_in_creative_inventory=1,hot=1},
+	legacy_facedir_simple = true,
+	is_ground_content = false,
+	sounds = default.node_sound_stone_defaults(),
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("formspec", nether.furnace_inactive_formspec)
+		meta:set_string("infotext", "Furnace");
+		local inv = meta:get_inventory()
+		inv:set_size("fuel", 1)
+		inv:set_size("src", 1)
+		inv:set_size("dst", 4)
+	end,
+	can_dig = function(pos,player)
+		local meta = minetest.get_meta(pos);
+		local inv = meta:get_inventory()
+		if not inv:is_empty("fuel") then
+			return false
+		elseif not inv:is_empty("dst") then
+			return false
+		elseif not inv:is_empty("src") then
+			return false
+		end
+		return true
+	end,
+	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("last_active", get_date())
+		local inv = meta:get_inventory()
+		if listname == "fuel" then
+			if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
+				if inv:is_empty("src") then
+					meta:set_string("infotext","Furnace is empty")
+				end
+				return stack:get_count()
+			else
+				return 0
+			end
+		elseif listname == "src" then
+			return stack:get_count()
+		elseif listname == "dst" then
+			return 0
+		end
+	end,
+	allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("last_active", get_date())
+		local inv = meta:get_inventory()
+		local stack = inv:get_stack(from_list, from_index)
+		if to_list == "fuel" then
+			if minetest.get_craft_result({method="fuel",width=1,items={stack}}).time ~= 0 then
+				if inv:is_empty("src") then
+					meta:set_string("infotext","Furnace is empty")
+				end
+				return count
+			else
+				return 0
+			end
+		elseif to_list == "src" then
+			return count
+		elseif to_list == "dst" then
+			return 0
+		end
+	end,
+})
+
+local function swap_node(pos,name)
+	local node = minetest.get_node(pos)
+	if node.name == name then
+		return
+	end
+	node.name = name
+	minetest.swap_node(pos,node)
+end
+
+minetest.register_abm({
+	nodenames = {"nether:furnace","nether:furnace_active"},
+	interval = 1.0,
+	chance = 1,
+	action = function(pos)
+		local meta = minetest.get_meta(pos)
+		if meta:get_string("timedif") == "" then
+			meta:set_float("timedif", 0.0)
+		end
+
+		-- lag shouldn't control the furnace speed
+		local current_time = get_date()
+		local last_time = meta:get_string("last_active")
+		if last_time == "" then
+			meta:set_string("last_active", current_time)
+			return
+		end
+		if last_time == current_time then
+			return
+		end
+
+		local timediff = get_timediff(last_time, current_time)+meta:get_string("timedif")
+		local times = math.floor(timediff)
+		meta:set_string("last_active", current_time)
+		meta:set_float("timedif", timediff-times)
+
+
+		for _ = 1,times do
+			for _,name in pairs({
+					"fuel_totaltime",
+					"fuel_time",
+					"src_totaltime",
+					"src_time",
+			}) do
+				if meta:get_string(name) == "" then
+					meta:set_float(name, 0.0)
+				end
+			end
+			local inv = meta:get_inventory()
+			local srclist = inv:get_list("src")
+			local cooked = nil
+			local aftercooked
+
+			if srclist then
+				cooked, aftercooked = minetest.get_craft_result({method = "cooking", width = 1, items = srclist})
+			end
+
+			local was_active = false
+
+			if meta:get_float("fuel_time") < meta:get_float("fuel_totaltime") then
+				was_active = true
+				meta:set_float("fuel_time", meta:get_float("fuel_time") + 1)
+				meta:set_float("src_time", meta:get_float("src_time") + 1)
+				if cooked
+				and cooked.item
+				and meta:get_float("src_time") >= cooked.time then
+					-- check if there's room for output in "dst" list
+					if inv:room_for_item("dst",cooked.item) then
+						-- Put result in "dst" list
+						inv:add_item("dst", cooked.item)
+						-- take stuff from "src" list
+						inv:set_stack("src", 1, aftercooked.items[1])
+					--~ else
+						--print("Could not insert '"..cooked.item:to_string().."'")
+					end
+					meta:set_string("src_time", 0)
+				end
+			end
+
+			if meta:get_float("fuel_time") < meta:get_float("fuel_totaltime") then
+				local percent = math.floor(meta:get_float("fuel_time") /
+						meta:get_float("fuel_totaltime") * 100)
+				meta:set_string("infotext","Furnace active: "..percent.."%")
+				swap_node(pos,"nether:furnace_active")
+				meta:set_string("formspec",nether.get_furnace_active_formspec(pos, percent))
+				return
+			end
+
+			local fuel = nil
+			local afterfuel
+			local cooked = nil
+			local fuellist = inv:get_list("fuel")
+			local srclist = inv:get_list("src")
+
+			if srclist then
+				cooked = minetest.get_craft_result({method = "cooking", width = 1, items = srclist})
+			end
+			if fuellist then
+				fuel, afterfuel = minetest.get_craft_result({method = "fuel", width = 1, items = fuellist})
+			end
+
+			if not fuel or fuel.time <= 0 then
+				meta:set_string("infotext","Furnace out of fuel")
+				swap_node(pos,"nether:furnace")
+				meta:set_string("formspec", nether.furnace_inactive_formspec)
+				return
+			end
+
+			if cooked.item:is_empty() then
+				if was_active then
+					meta:set_string("infotext","Furnace is empty")
+					swap_node(pos,"nether:furnace")
+					meta:set_string("formspec", nether.furnace_inactive_formspec)
+				end
+				return
+			end
+
+			meta:set_string("fuel_totaltime", fuel.time)
+			meta:set_string("fuel_time", 0)
+
+			inv:set_stack("fuel", 1, afterfuel.items[1])
+		end
+	end,
+})

nether/guide.lua

@@ -0,0 +1,464 @@
+local cube = minetest.inventorycube
+
+-- the content of the guide
+local guide_infos = {
+	{
+		description = "Mushrooms",
+		{"text", "Nether mushrooms can be found on the nether's ground and\n"..
+			"on netherrack soil, it can be dug by hand."},
+		{"image", {1, 1, "riesenpilz_nether_shroom_side.png"}},
+		{"y", 0.2},
+		{"text", "If you drop it without holding the fast key, you can split it into its stem and head:"},
+		{"image", {1, 1, "nether_shroom_top.png", 1}},
+		{"image", {1, 1, "nether_shroom_stem.png"}},
+		{"y", 0.1},
+		{"text", "You can get more mushrooms by using a netherrack soil:\n"..
+			"1. search a dark place and, if necessary, place netherrack with air about it\n"..
+			"2. right click with cooked blood onto the netherrack to make it soiled\n"..
+			"3. right click onto the netherrack soil with a nether mushroom head to add some spores\n"..
+			"4. dig the mushroom which grew after some time to make place for another one"},
+		{"image", {1, 1, "riesenpilz_nether_shroom_side.png", 6, 0.12}},
+		{"y", 1},
+		{"image", {1, 1, "nether_netherrack.png^nether_netherrack_soil.png", 1.8}},
+		{"image", {1, 1, "nether_hotbed.png", 1.3, -0.4}},
+		{"image", {1, 1, "nether_netherrack.png^nether_netherrack_soil.png", 3.6}},
+		{"image", {1, 1, "nether_shroom_top.png", 3.1, -0.5}},
+		{"image", {1, 1, "nether_netherrack.png^nether_netherrack_soil.png", 6}},
+		{"image", {1, 1, "nether_netherrack.png"}},
+	},
+	{
+		description = "Tools",
+		{"text", "You can craft 5 kinds of tools in the nether,\n"..
+			"which (except the mushroom pick) require sticks to be crafted:"},
+		{"image", {1, 1, "nether_pick_mushroom.png"}},
+		{"y", 0.1},
+		{"text", "strength : 1\n"..
+			"The mushroom pick needs mushroom stems and heads to be crafted."},
+		{"image", {1, 1, "nether_pick_wood.png"}},
+		{"y", 0.1},
+		{"text", "strength : 2\n"..
+			"The nether wood pick can be crafted with cooked nether blood wood."},
+		{"image", {1, 1, "nether_axe_netherrack.png", 1.5}},
+		{"image", {1, 1, "nether_shovel_netherrack.png", 3}},
+		{"image", {1, 1, "nether_sword_netherrack.png", 4.5}},
+		{"image", {1, 1, "nether_pick_netherrack.png"}},
+		{"y", 0.1},
+		{"text", "strength : 3\n"..
+			"The red netherrack tools can be crafted with usual netherrack."},
+		{"image", {1, 1, "nether_axe_netherrack_blue.png", 1.5}},
+		{"image", {1, 1, "nether_shovel_netherrack_blue.png", 3}},
+		{"image", {1, 1, "nether_sword_netherrack_blue.png", 4.5}},
+		{"image", {1, 1, "nether_pick_netherrack_blue.png"}},
+		{"y", 0.1},
+		{"text", "strength : 3\n"..
+			"The blue netherrack tools can be crafted with blue netherrack."},
+		{"image", {1, 1, "nether_axe_white.png", 1.5}},
+		{"image", {1, 1, "nether_shovel_white.png", 3}},
+		{"image", {1, 1, "nether_sword_white.png", 4.5}},
+		{"image", {1, 1, "nether_pick_white.png"}},
+		{"y", 0.1},
+		{"text", "strength : 3\n"..
+			"The siwtonic tools can be crafted with the siwtonic ore."},
+	},
+	{
+		description = "Blood structures",
+		{"text", "You can find blood structures on the ground and\n"..
+			"dig their nodes even with the bare hand."},
+		{"y", 0.5},
+		{"text", "One contains 4 kinds of blocks :"},
+		{"image", {1, 1, cube("nether_blood.png"), 1}},
+		{"image", {1, 1,
+			cube("nether_blood_top.png",
+				"nether_blood.png^nether_blood_side.png",
+				"nether_blood.png^nether_blood_side.png"),
+			2}},
+		{"image", {1, 1, "nether_fruit.png", 3}},
+		{"image", {1, 1, cube("nether_blood_stem_top.png",
+			"nether_blood_stem.png", "nether_blood_stem.png")}},
+		{"y", 0.1},
+		{"text", "Blood stem, blood, blood head and nether fruit"},
+		{"y", 0.1},
+		{"text", "You can craft 4 blood wood with the stem :"},
+		{"image", {1, 1, cube("nether_wood.png")}},
+		{"y", 0.1},
+		{"text", "The 4 blood nodes can be cooked and, except\n"..
+			"blood wood, their blood can be extracted."},
+	},
+	{
+		description = "Fruits",
+		{"text", "You can find the nether fruits on blood structures\n"..
+			"and dig them even with the bare hand."},
+		{"image", {1, 1, "nether_fruit.png"}},
+		{"text", "Eating it will make you lose life but\n"..
+			"it might feed you and give you blood :"},
+		{"image", {1, 1, "nether_blood_extracted.png"}},
+		{"y", 0.2},
+		{"text", "If you eat it at the right place inside a portal,\n"..
+			"you will teleport instead of getting blood."},
+		{"y", 0.2},
+		{"text", "If you drop it without holding the fast key,\n"..
+			"you can split it into its fruit and leaf:"},
+		{"image", {1, 1, "nether_fruit_leaf.png", 1}},
+		{"image", {1, 1, "nether_fruit_no_leaf.png"}},
+		{"y", 0.2},
+		{"text", "Craft a fruit leave block out of 9 fruit leaves\n"..
+			"The fruit can be used to craft a nether pearl."},
+		{"image", {1, 1, cube("nether_fruit_leaves.png")}},
+		{"y", 0.2},
+		{"text", "A fruit leaves block"},
+	},
+	{
+		description = "Cooking",
+		{"text", "To get a furnace you need to dig at least 8 netherrack bricks.\n"..
+			"They can be found at pyramid like constructions and require at least\n"..
+			"a strength 1 nether pick to be dug.\n"..
+			"To craft the furnace, use the netherrack bricks like cobble:"},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 0.5}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 1}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png")}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 1}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png")}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 0.5}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 1}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png")}},
+		{"y", 0.2},
+		{"text", "To begin cooking stuff, you can use a mushroom or fruit.\n"..
+			"After that it's recommended to use cooked blood nodes."},
+		{"y", 0.1},
+		{"text", "Some nether items can be cooked:"},
+		{"image", {1, 1, cube("nether_blood_stem_top_cooked.png",
+			"nether_blood_stem_cooked.png", "nether_blood_stem_cooked.png"),
+			0.35}},
+		{"image", {1, 1, cube("nether_blood_cooked.png"), 1.6}},
+		{"image", {1, 1,
+			cube("nether_blood_top_cooked.png",
+				"nether_blood_cooked.png^nether_blood_side_cooked.png",
+				"nether_blood_cooked.png^nether_blood_side_cooked.png"),
+			2.9}},
+		{"image", {1, 1, cube("nether_wood_cooked.png"), 4.3}},
+		{"y", 1.2},
+		{"text", "Some cooked blood stem, cooked blood,\n"..
+			"cooked blood head and cooked blood wood,"},
+		{"image", {1, 1, "nether_hotbed.png", 0.3}},
+		{"image", {1, 1, "nether_pearl.png", 2}},
+		{"y", 1.2},
+		{"text", "Some cooked extracted blood and a nether pearl"},
+	},
+	{
+		description = "Extractors",
+		{"text", "Here you can find out information about the nether extractor."},
+		{"y", 0.2},
+		{"text", "Here you can see its craft recipe:"},
+		{"image", {0.5, 0.5, cube("nether_blood_top_cooked.png",
+			"nether_blood_cooked.png^nether_blood_side_cooked.png",
+			"nether_blood_cooked.png^nether_blood_side_cooked.png"), 0.5}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 1}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png")}},
+		{"image", {0.5, 0.5, cube("nether_blood_extractor.png"), 2.5}},
+		{"image", {0.5, 0.5, "nether_shroom_stem.png", 0.5}},
+		{"image", {0.5, 0.5, cube("nether_blood_cooked.png"), 1}},
+		{"image", {0.5, 0.5, cube("nether_blood_cooked.png")}},
+		{"image", {0.5, 0.5, cube("nether_blood_stem_top_cooked.png",
+			"nether_blood_stem_cooked.png", "nether_blood_stem_cooked.png"),
+			0.5}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png"), 1}},
+		{"image", {0.5, 0.5, cube("nether_netherrack_brick.png")}},
+		{"y", 0.2},
+		{"text", "Extract blood from the blood nodes you get from the blood structures.\n"..
+			"You can also get blood with a nether fruit."},
+		{"y", 0.2},
+		{"text", "So you can use it:\n"..
+			"1. place it somewhere\n"..
+			"2. place blood blocks next to it (4 or less)\n"..
+			"3. right click with extracted blood onto it to power it\n"..
+			"4. take the new extracted blood and dig the extracted nodes"},
+		{"y", 0.2},
+		{"text", "Example (view from the top):"},
+		{"y", 0.88},
+		{"image", {1, 1, "nether_blood_stem_top.png", 0.82, -0.88}},
+		{"image", {1, 1, "nether_blood.png", 1.63}},
+		{"image", {1, 1, "nether_blood_extractor.png", 0.82}},
+		{"image", {1, 1, "nether_blood_stem_top_empty.png", 3.82, -0.88}},
+		{"image", {1, 1, "nether_blood_empty.png", 4.63}},
+		{"image", {1, 1, "nether_blood_empty.png", 3.001}},
+		{"image", {1, 1, "nether_blood_extractor.png", 3.82}},
+		{"image", {1, 1, "nether_blood.png"}},
+		{"image", {1, 1, "nether_blood.png", 0.82, -0.12}},
+		{"image", {1, 1, "nether_blood_empty.png", 3.82, -0.12}},
+		{"y", 1.2},
+		{"text", "The empty blood stem can be crafted into empty nether wood,\n"..
+			"which can be crafted into nether sticks."},
+	},
+	{
+		description = "Ores",
+		{"text", "You can find 5 types of ores:"},
+		{"image", {1, 1, cube("nether_netherrack_black.png"), 4}},
+		{"image", {1, 1, cube("nether_netherrack.png")}},
+		{"y", 0.2},
+		{"text", "The red netherrack is generated like stone.\n"..
+			"The black netherrack is generated like gravel.\n"..
+			"Both require at least a strength 2 nether pick to be dug."},
+		{"image", {1, 1, cube("nether_white.png"), 4}},
+		{"image", {1, 1, cube("nether_netherrack_blue.png")}},
+		{"y", 0.2},
+		{"text", "The blue netherrack is generated like diamond ore.\n"..
+			"The siwtonic ore is generated like mese blocks.\n"..
+			"Both require at least a strength 3 nether pick to be dug."},
+		{"image", {1, 1, cube("nether_netherrack_tiled.png"), 4}},
+		{"image", {1, 1, cube("glow_stone.png")}},
+		{"y", 0.2},
+		{"text", "Glow stone can be used for lighting.\n"..
+			"Tiled netherrack is generated like coal ore.\n"..
+			"Glow stone requires at least a strength 1 pick to be dug.\n"..
+			"Dig tiled netherrack with at least a level 2 pickaxe."},
+	},
+	{
+		description = "Vines",
+		{"text", "Feed nether vines with blood.\n"..
+			"Dig them with anything."},
+		{"image", {1, 1, "nether_vine.png"}},
+		{"y", 0.2},
+		{"text", "Grow nether child by placing\n"..
+			"placing it to a dark place onto a\n"..
+			"blood structure head node."},
+		{"image", {1, 1, "nether_sapling.png"}},
+		{"y", -0.10},
+		{"image", {1, 1, "nether_blood.png^nether_blood_side.png"}},
+	},
+	{
+		description = "Pearls",
+		{"text", "The nether pearl can be used to teleport by throwing it.\n"..
+			"Here is how to get one :"},
+		{"y", 0.2},
+		{"text", "First of all craft 2 mushroom heads and 1 nether fruit\n"..
+			"without leaf together :"},
+		{"image", {1, 1, "nether_shroom_top.png"}},
+		{"image", {1, 1, "nether_fim.png", 3}},
+		{"image", {1, 1, "nether_fruit_no_leaf.png"}},
+		{"image", {1, 1, "nether_shroom_top.png"}},
+		{"y", 0.2},
+		{"text", "Put the result into the furnace\n"..
+			"to cook it into a nether pearl :"},
+		{"image", {1, 1, "nether_pearl.png"}},
+	},
+	{
+		description = "Bricks",
+		{"text", "Craft bricks out of red,\n"..
+			"black and blue netherrack."},
+		{"image", {1, 1, cube("nether_netherrack_brick_black.png"), 1}},
+		{"image", {1, 1, cube("nether_netherrack_brick_blue.png"), 2}},
+		{"image", {1, 1, cube("nether_netherrack_brick.png")}},
+		{"y", 0.4},
+		{"text", "Dig them with at least a level 1 pickaxe."},
+		{"y", 0.2},
+	},
+	{
+		description = "Portals",
+		{"text", "Here you can find out how to built the nether portal."},
+		{"y", 0.3},
+		{"text", "A nether portal requires following nodes:"},
+		{"y", 0.05},
+		{"text", "25 empty nether wooden planks\n"..
+			"16 black netherrack\n"..
+			"12 blue netherrack bricks\n"..
+			"8 red netherrack\n"..
+			"8 cooked nether blood\n"..
+			"4 nether fruits\n"..
+			"2 siwtonic blocks"},
+		{"y", 0.2},
+		{"text", "It should look approximately like this one:"},
+		{"image", {5.625, 6, "nether_teleporter.png", 0, -1.5}},
+		{"y", 5.5},
+		{"text", "Activate it by standing in the middle,\n"..
+			"on the siwtonic block and eating a nether fruit.\n"..
+			"Take enough stuff with you to build a portal when you'll come back."},
+	},
+	{
+		description = "Forests",
+		{"text", "The nether forest is generated in caves,\n"..
+			"above the usual nether."},
+		{"y", 0.2},
+		{"text", "There you can find some plants:"},
+		{"image", {1, 1, "nether_grass_middle.png", 1}},
+		{"image", {1, 1, "nether_grass_big.png", 2}},
+		{"image", {1, 1, "nether_grass_small.png"}},
+		{"y", 0.2},
+		{"text", "Use the nether forest grass to get paper.\n"..
+			"Craft paper out of the dried grass."},
+		{"image", {1, 1, cube("nether_tree_top.png", "nether_tree.png", "nether_tree.png")}},
+		{"y", 0.2},
+		{"text", "Nether trunks can be found at nether trees.\n"..
+			"Craft nether wood out of nether trunk."},
+		{"image", {1, 1, "nether_glowflower.png"}},
+		{"y", 0.2},
+		{"text", "Use it for lighting and decoration."},
+	},
+}
+
+-- the size of guide pages
+local guide_size = {x=40, y=10, cx=0.2, cy=0.2}
+
+-- informations about settings and ...
+local formspec_offset = {x=0.25, y=0.50}
+local font_size
+if minetest.is_singleplayer() then
+	font_size = tonumber(minetest.settings:get("font_size")) or 13
+else
+	font_size = 13
+end
+guide_size.fx = math.floor((40*(guide_size.cx+formspec_offset.x))*font_size)
+guide_size.fy = font_size/40
+
+-- the default guide formspecs
+local guide_forms = {
+	contents = "size[3.6,"..(#guide_infos)-2 ..";]label["..guide_size.cx+0.7 ..","..guide_size.cy+0.2 ..";Contents:]",
+}
+
+-- change the infos to formspecs
+for n,data in ipairs(guide_infos) do
+	local html_text = ""
+	local form = ""
+	local y = 0
+	local x = guide_size.cx
+	for _,i in ipairs(data) do
+		local typ, content = unpack(i)
+		if typ == "y" then
+			y = y+content
+		elseif typ == "x" then
+			x = math.max(x, content)
+		elseif typ == "text" then
+			html_text = html_text .. content .. "\n"
+			local tab = minetest.wrap_text(content, guide_size.fx, true)
+			local l = guide_size.cx
+			for _,str in ipairs(tab) do
+				--~ form = form.."label["..guide_size.cx ..","..guide_size.cy+y..";"..str.."]"
+				y = y+guide_size.fy
+				l = math.max(l, #str)
+			end
+			x = math.max(x, l/font_size)
+		elseif typ == "image" then
+			local w, h, texture_name, px, py = unpack(content)
+			if not px then
+				--~ form = form.."image["..guide_size.cx..","..guide_size.cy+y+h*0.3 ..";"..w..","..h..";"..texture_name.."]"
+				html_text = html_text ..
+					("<img name=%s width=%g height=%g>\n"):format(
+					texture_name, w, h)
+				y = y+h
+			else
+				px = guide_size.cx+px
+				py = py or 0
+				html_text = html_text ..
+					("<img name=%s width=%g height=%g>\n"):format(
+					texture_name, w, h)
+				--~ form = form.."image["..px..","..
+					--~ guide_size.cy+y+h*0.3+py ..";"..w..","..h..";"..texture_name.."]"
+				x = math.max(x, px+w)
+			end
+		end
+	end
+	form = ("formspec_version[4]size[%g,%g;]hypertext[0,0;%g,%g;html;%s]button[%g,%g;1,2;quit;Back]"
+		):format(
+		x * 1.8, y + 1,
+		x * 1.8, y,
+		minetest.formspec_escape(html_text),
+		0.5 * x - 0.5, y)
+
+	guide_forms[n] = {data.description, form}
+end
+print(dump(guide_forms))
+--[[
+for n,data in ipairs(guide_infos) do
+	local form = ""
+	local y = 0
+	local x = guide_size.cx
+	for _,i in ipairs(data) do
+		local typ, content = unpack(i)
+		if typ == "y" then
+			y = y+content
+		elseif typ == "x" then
+			x = math.max(x, content)
+		elseif typ == "text" then
+			local tab = minetest.wrap_text(content, guide_size.fx, true)
+			local l = guide_size.cx
+			for _,str in ipairs(tab) do
+				form = form.."label["..guide_size.cx ..","..guide_size.cy+y..";"..str.."]"
+				y = y+guide_size.fy
+				l = math.max(l, #str)
+			end
+			x = math.max(x, l/font_size)
+		elseif typ == "image" then
+			local w, h, texture_name, px, py = unpack(content)
+			if not px then
+				form = form.."image["..guide_size.cx..","..guide_size.cy+y+h*0.3 ..";"..w..","..h..";"..texture_name.."]"
+				y = y+h
+			else
+				px = guide_size.cx+px
+				py = py or 0
+				form = form.."image["..px..","..
+					guide_size.cy+y+h*0.3+py ..";"..w..","..h..";"..texture_name.."]"
+				x = math.max(x, px+w)
+			end
+		end
+	end
+	form = "size["..x*1.8 ..","..y+1 ..";]"..form.."button["..x/2-0.5 ..","..y ..";1,2;quit;Back]"
+	guide_forms[n] = {data.description, form}
+end
+--]]
+
+local desc_tab = {}
+for n,i in ipairs(guide_forms) do
+	desc_tab[i[1]] = n
+end
+
+-- creates contents formspec
+for y,i in ipairs(guide_forms) do
+	local desc = i[1]
+	local s = #desc * 1.3 / font_size + 1.5
+	guide_forms.contents = guide_forms.contents ..
+		"button[" .. guide_size.cx * 12 / s - 0.5 .. "," ..
+		guide_size.cy + y / 1.3 .. ";" .. s .. ",1;name;" .. desc .. "]"
+end
+
+-- shows the contents of the formspec
+local function show_guide(pname)
+	minetest.show_formspec(pname, "nether_guide_contents", guide_forms["contents"])
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname == "nether_guide_contents" then
+		local fname = fields.name
+		local pname = player:get_player_name()
+		if fname
+		and pname then
+			minetest.show_formspec(pname, "nether_guide", guide_forms[desc_tab[fname]][2])
+		end
+	elseif formname == "nether_guide" then
+		local fname = fields.quit
+		local pname = player:get_player_name()
+		if fname
+		and pname then
+			minetest.show_formspec(pname, "nether_guide_contents", guide_forms["contents"])
+		end
+	end
+end)
+
+minetest.register_chatcommand("nether_help", {
+	params = "",
+	description = "Shows a nether guide",
+	func = function(name)
+		local player = minetest.get_player_by_name(name)
+		if not player then
+			minetest.chat_send_player(name, "Something went wrong.")
+			return false
+		end
+		if player:get_pos().y > nether.start then
+			minetest.chat_send_player(name,
+				"Usually you don't neet this guide here. " ..
+				"You can view it in the nether.")
+			return false
+		end
+		minetest.chat_send_player(name, "Showing guide...")
+		show_guide(name)
+		return true
+	end
+})

nether/mod.conf

@@ -0,0 +1,3 @@
+name = nether
+depends = default,glow,riesenpilz,stairs,vector_extras
+optional_depends = creative,fence_registration,function_delayer,watershed

nether/pearl.lua

@@ -0,0 +1,190 @@
+
+local function throw_pearl(item, player)
+	local playerpos = player:get_pos()
+	playerpos.y = playerpos.y+1.625
+	local obj = minetest.add_entity(playerpos, "nether:pearl_entity")
+	local dir = player:get_look_dir()
+	obj:setvelocity(vector.multiply(dir, 30))
+	obj:setacceleration({x=dir.x*-3, y=-dir.y^8*80-10, z=dir.z*-3})
+	local pname = player:get_player_name()
+	obj:get_luaentity().player = pname
+	if not minetest.is_creative_enabled(pname) then
+		item:take_item()
+		return item
+	end
+end
+
+local function get_node(pos)
+	local name = minetest.get_node(pos).name
+	if name ~= "ignore" then
+		return name
+	end
+	minetest.get_voxel_manip():read_from_map(pos, pos)
+	name = minetest.get_node_or_nil(pos)
+	if not name then
+		return
+	end
+	return name.name
+end
+
+local softs = {}
+local function is_soft(pos)
+	local name = get_node(pos)
+	if not name then
+		return false
+	end
+	local is_soft = softs[name]
+	if is_soft ~= nil then
+		return is_soft
+	end
+	if not minetest.registered_nodes[name] then
+		softs[name] = false
+		return false
+	end
+	is_soft = minetest.registered_nodes[name].walkable == false
+	softs[name] = is_soft
+	return is_soft
+end
+
+-- teleports the player there if there's free space
+local function teleport_player(pos, player)
+	if not is_soft(pos) then
+		return false
+	end
+	if not is_soft({x=pos.x, y=pos.y+1, z=pos.z})
+	and not is_soft({x=pos.x, y=pos.y-1, z=pos.z}) then
+		return false
+	end
+	pos.y = pos.y+0.05
+	player:moveto(pos)
+	return true
+end
+
+--[[
+local dg_ps = {}
+local function forceload(pos)
+	dg_ps[#dg_ps+1] = pos
+	minetest.forceload_block(pos)
+	minetest.after(5, function(pos)
+		minetest.forceload_free_block(pos)
+		for i,p in pairs(dg_ps) do
+			if vector.equals(p, pos) then
+				dg_ps[i] = nil
+				return
+			end
+		end
+	end, pos)
+end
+minetest.register_on_shutdown(function()
+	for _,p in pairs(dg_ps) do
+		minetest.forceload_free_block(p)
+	end
+end)--]]
+
+minetest.register_entity("nether:pearl_entity", {
+	collisionbox = {0,0,0,0,0,0}, --not pointable
+	visual_size = {x=0.1, y=0.1},
+	physical = false, -- Collides with things
+	textures = {"nether_pearl.png"},
+	on_activate = function(self, staticdata)
+		if not staticdata
+		or staticdata == "" then
+			return
+		end
+		local tmp = minetest.deserialize(staticdata)
+		if not tmp then
+			minetest.log("error", "[nether] pearl: invalid staticdata ")
+			return
+		end
+		self.player = tmp.player
+	end,
+	get_staticdata = function(self)
+		--forceload(vector.round(self.object:get_pos()))
+		return minetest.serialize({
+			player = self.player,
+		})
+	end,
+	timer = 0,
+	on_step = function(self, dtime)
+		self.timer = self.timer+dtime
+
+	--[[
+		local delay = self.delay
+		if delay < 0.1 then
+			self.delay = delay+dtime
+			return
+		end
+		self.delay = 0--]]
+
+		if self.timer > 20 then
+			self.object:remove()
+			return
+		end
+
+		local pos = self.object:get_pos()
+		local rpos = vector.round(pos)
+		local lastpos = self.lastpos
+		if not lastpos then
+			self.lastpos = vector.new(rpos)
+			return
+		end
+		if lastpos.x
+		and vector.equals(vector.round(lastpos), rpos) then
+			return
+		end
+
+		local player = self.player
+		if not player then
+			minetest.log("error", "[nether] pearl: missing playername")
+			self.object:remove()
+			return
+		end
+		player = minetest.get_player_by_name(player)
+		if not player then
+			minetest.log("error", "[nether] pearl: missing player")
+			self.object:remove()
+			return
+		end
+
+		if not get_node(rpos) then
+			minetest.log("error", "[nether] pearl: missing node")
+			self.object:remove()
+			return
+		end
+
+		self.lastpos = vector.new(pos)
+
+		local free, p = minetest.line_of_sight(lastpos, pos)
+		if free then
+			return
+		end
+		if is_soft(p) then
+			return
+		end
+		self.object:remove()
+		minetest.after(0, function(p) --minetest.after is used that the sound is played after the teleportation
+			minetest.sound_play("nether_pearl", {pos=p, max_hear_distance=10})
+		end, p)
+		p.y = p.y+1
+		if teleport_player(vector.new(p), player) then
+			return
+		end
+		p.y = p.y-2
+		for i = -1,1,2 do
+			for _,j in pairs({{i, 0}, {0, i}}) do
+				if teleport_player({x=p.x+j[1], y=p.y, z=p.z+j[2]}, player) then
+					return
+				end
+			end
+		end
+		for i = -1,1,2 do
+			for j = -1,1,2 do
+				if teleport_player({x=p.x+j, y=p.y, z=p.z+i}, player) then
+					return
+				end
+			end
+		end
+	end
+})
+
+minetest.override_item("nether:pearl", {on_use = throw_pearl})

nether/portal.lua

@@ -0,0 +1,696 @@
+--code copied from Pilzadam's nether mod and edited
+
+-- kills the player if he uses PilzAdam portal
+local portal_target = nether.buildings+1
+local damage_enabled = minetest.settings:get_bool"enable_damage"
+local mclike_portal = false
+
+local abm_allowed
+minetest.after(5, function()
+	abm_allowed = true
+end)
+
+local save_path = minetest.get_worldpath() .. "/nether_players"
+local players_in_nether = {}
+
+-- Load the list of players which are trapped in the nether
+-- (or would be trapped if nether.trap_players was true)
+do
+	local file = io.open(save_path, "r")
+	if file then
+		local contents = file:read"*all"
+		io.close(file)
+		if contents then
+			local playernames = string.split(contents, " ")
+			for i = 1,#playernames do
+				players_in_nether[playernames[i]] = true
+			end
+		end
+	end
+end
+
+local function save_nether_players()
+	local playernames,n = {},1
+	for name in pairs(players_in_nether) do
+		playernames[n] = name
+		n = n+1
+	end
+	local f = io.open(save_path, "w")
+	assert(f, "Could not open nether_players file for writing.")
+	f:write(table.concat(playernames, " "))
+	io.close(f)
+end
+
+local update_background
+if nether.trap_players then
+	function update_background(player, down)
+		if down then
+			player:set_sky({r=15, g=0, b=0}, "plain")
+		else
+			player:set_sky(nil, "regular")
+		end
+	end
+else
+	function update_background()end
+end
+
+-- returns nodename if area is generated, else calls generation function
+local function generated_or_generate(pos)
+	local node = minetest.get_node_or_nil(pos)
+	if node then
+		return node.name
+	end
+	minetest.get_voxel_manip():read_from_map(pos, pos)
+	node = minetest.get_node_or_nil(pos)
+	if not node then
+		minetest.emerge_area(vector.subtract(pos, 80), vector.add(pos, 80))
+		return false
+	end
+	return node.name
+end
+
+-- where the player appears after dying
+local function get_player_died_target(player)
+	local target = vector.add(player:get_pos(),
+		{x=math.random(-100,100), y=0, z=math.random(-100,100)})
+	target.y = portal_target + math.random(4)
+	return target
+end
+
+-- used for obsidian portal
+local function obsidian_teleport(player, pname, target)
+	minetest.chat_send_player(pname, "For any reason you arrived here. Type " ..
+		"/nether_help to find out things like craft recipes.")
+	players_in_nether[pname] = true
+	save_nether_players()
+	update_background(player, true)
+	if target then
+		player:set_pos(target)
+	else
+		player:set_hp(0)
+	end
+end
+
+-- teleports players to nether or helps it
+local function player_to_nether(player, pos)
+	local pname = player:get_player_name()
+	players_in_nether[pname] = true
+	save_nether_players()
+	update_background(player, true)
+	if pos then
+		player:set_pos(pos)
+		return
+	end
+	minetest.chat_send_player(pname, "For any reason you arrived here. " ..
+		"Type /nether_help to find out things like craft recipes.")
+	if nether.trap_players then
+		player:set_hp(0)
+	end
+	if not damage_enabled or not nether.trap_players then
+		player:set_pos(get_player_died_target(player))
+	end
+end
+
+local function player_from_nether(player, pos)
+	local pname = player:get_player_name()
+	if players_in_nether[pname] then
+		players_in_nether[pname] = nil
+		save_nether_players()
+	end
+	update_background(player, false)
+	player:set_pos(pos)
+end
+
+
+local function player_exists(name)
+	local players = minetest.get_connected_players()
+	for i = 1,#players do
+		if players[i]:get_player_name() == name then
+			return true
+		end
+	end
+	return false
+end
+
+-- Chatcommands (edited) written by sss
+minetest.register_chatcommand("to_hell", {
+	params = "[<player_name>]",
+	description = "Send someone to hell",
+	func = function(name, pname)
+		if not minetest.check_player_privs(name, {nether=true}) then
+			return false,
+				"You need the nether privilege to execute this chatcommand."
+		end
+		if not player_exists(pname) then
+			pname = name
+		end
+		local player = minetest.get_player_by_name(pname)
+		if not player then
+			return false, "Something went wrong."
+		end
+		minetest.chat_send_player(pname, "Go to hell !!!")
+		player_to_nether(player)
+		return true, pname.." is now in the nether."
+	end
+})
+
+minetest.register_chatcommand("from_hell", {
+	params = "[<player_name>]",
+	description = "Extract from hell",
+	func = function(name, pname)
+		if not minetest.check_player_privs(name, {nether=true}) then
+			return false,
+				"You need the nether priv to execute this chatcommand."
+		end
+		if not player_exists(pname) then
+			pname = name
+		end
+		local player = minetest.get_player_by_name(pname)
+		if not player then
+			return false, "Something went wrong."
+		end
+		minetest.chat_send_player(pname, "You are free now")
+		local pos = player:get_pos()
+		player_from_nether(player, {x=pos.x, y=100, z=pos.z})
+		return true, pname.." is now out of the nether."
+	end
+})
+
+
+-- Disallow teleportation and change spawn positions if the nether traps players
+if nether.trap_players then
+	-- randomly set player position when he/she dies in nether
+	minetest.register_on_respawnplayer(function(player)
+		local pname = player:get_player_name()
+		if not players_in_nether[pname] then
+			return
+		end
+		local target = get_player_died_target(player)
+		player:set_pos(target)
+		minetest.after(0, function(pname, target)
+			-- fixes respawn bug
+			local player = minetest.get_player_by_name(pname)
+			if player then
+				player:moveto(target)
+			end
+		end, pname, target)
+		return true
+	end)
+
+	-- override set_pos etc. to disallow player teleportion by e.g. travelnet
+	local function can_teleport(player, pos)
+		if not player:is_player() then
+			-- the same metatable is used for entities
+			return true
+		end
+		local pname = player:get_player_name()
+		local in_nether = players_in_nether[pname] == true
+
+		-- test if the target is valid
+		if pos.y < nether.start then
+			if in_nether then
+				return true
+			end
+		elseif not in_nether then
+			return true
+		end
+
+		-- test if the current position is valid
+		local current_pos = player:get_pos()
+		local now_in_nether = current_pos.y < nether.start
+		if now_in_nether ~= in_nether then
+			if in_nether then
+				minetest.log("action", "Player \"" .. pname ..
+					"\" has to be in the nether, teleporting it!")
+				update_background(player, true)
+				current_pos.y = portal_target
+				player:set_pos(current_pos)
+			else
+				minetest.log("action", "Player \"" .. pname ..
+					"\" must not be in the nether, teleporting it!")
+				update_background(player, false)
+				current_pos.y = 20
+				player:set_pos(current_pos)
+			end
+			return false
+		end
+
+		minetest.chat_send_player(pname,
+			"You can not simply teleport to or from the nether!")
+		minetest.log("action", "Player \"" .. pname ..
+			"\" attempted to teleport from or to the nether, ignoring.")
+		return false
+	end
+	local methods = {"set_pos", "move_to", "setpos", "moveto"}
+	local metatable_overridden
+	minetest.register_on_joinplayer(function(player)
+		-- set the background when the player joins
+		if player:get_pos().y < nether.start then
+			update_background(player, true)
+		end
+
+		-- overide set_pos etc. if not yet done
+		if metatable_overridden then
+			return
+		end
+		metatable_overridden = true
+		local mt = getmetatable(player)
+		for i = 1,#methods do
+			local methodname = methods[i]
+			local origfunc = mt[methodname]
+			mt[methodname] = function(...)
+				if can_teleport(...) then
+					origfunc(...)
+				end
+			end
+		end
+	end)
+end
+
+-- removes the violet stuff from the obsidian portal
+local function remove_portal_essence(pos)
+	for z = -1,1 do
+		for y = -2,2 do
+			for x = -1,1 do
+				local p = {x=pos.x+x, y=pos.y+y, z=pos.z+z}
+				if minetest.get_node(p).name == "nether:portal" then
+					minetest.remove_node(p)
+				end
+			end
+		end
+	end
+end
+
+-- change parts of the particledefinition instead of recreating it every time
+local particledef = {
+	amount = 32,
+	time = 4,
+	minvel = {x=0, y=1, z=0},
+	maxvel = {x=0, y=2, z=0},
+	minacc = {x=-0.5,y=-3,z=-0.3},
+	maxacc = {x=0.5,y=-0.4,z=0.3},
+	minexptime = 1,
+	maxexptime = 1,
+	minsize = 0.4,
+	maxsize = 3,
+	collisiondetection = true,
+}
+
+-- teleports player to neter (obsidian portal)
+local function obsi_teleport_player(player, pos, target)
+	local pname = player:get_player_name()
+	if players_in_nether[pname] then
+		return
+	end
+
+	local objpos = player:get_pos()
+	objpos.y = objpos.y+0.1 -- Fix some glitches at -8000
+	if minetest.get_node(vector.round(objpos)).name ~= "nether:portal" then
+		return
+	end
+
+	local has_teleported
+	if damage_enabled then
+		obsidian_teleport(player, pname)
+		has_teleported = true
+	elseif not mclike_portal then
+		local target = vector.round(get_player_died_target(player))
+		if generated_or_generate(target) then
+			obsidian_teleport(player, pname, target)
+			has_teleported = true
+		end
+	end
+
+	if not has_teleported then
+		-- e.g. ungenerated area
+		return
+	end
+
+	remove_portal_essence(pos)
+
+	minetest.sound_play("nether_portal_usual", {to_player=pname, gain=1})
+end
+
+-- abm for particles of the obsidian portal essence and for teleporting
+minetest.register_abm({
+	nodenames = {"nether:portal"},
+	interval = 1,
+	chance = 2,
+	catch_up = false,
+	action = function(pos, node)
+		if not abm_allowed then
+			return
+		end
+		particledef.minpos = {x=pos.x-0.25, y=pos.y-0.5, z=pos.z-0.25}
+		particledef.maxpos = {x=pos.x+0.25, y=pos.y+0.34, z=pos.z+0.25}
+		particledef.texture = "nether_portal_particle.png^[transform" ..
+			math.random(0, 7)
+		minetest.add_particlespawner(particledef)
+		for _,obj in pairs(minetest.get_objects_inside_radius(pos, 1)) do
+			if obj:is_player() then
+				local meta = minetest.get_meta(pos)
+				local target = minetest.string_to_pos(meta:get_string("target"))
+				if target then
+					minetest.after(3, obsi_teleport_player, obj, pos, target)
+				end
+			end
+		end
+	end,
+})
+
+local function move_check(p1, max, dir)
+	local p = {x=p1.x, y=p1.y, z=p1.z}
+	local d = math.abs(max-p1[dir]) / (max-p1[dir])
+	while p[dir] ~= max do
+		p[dir] = p[dir] + d
+		if minetest.get_node(p).name ~= "default:obsidian" then
+			return false
+		end
+	end
+	return true
+end
+
+local function check_portal(p1, p2)
+	if p1.x ~= p2.x then
+		if not move_check(p1, p2.x, "x") then
+			return false
+		end
+		if not move_check(p2, p1.x, "x") then
+			return false
+		end
+	elseif p1.z ~= p2.z then
+		if not move_check(p1, p2.z, "z") then
+			return false
+		end
+		if not move_check(p2, p1.z, "z") then
+			return false
+		end
+	else
+		return false
+	end
+
+	if not move_check(p1, p2.y, "y") then
+		return false
+	end
+	if not move_check(p2, p1.y, "y") then
+		return false
+	end
+
+	return true
+end
+
+-- tests if it's an obsidian portal
+local function is_portal(pos)
+	for d=-3,3 do
+		for y=-4,4 do
+			local px = {x=pos.x+d, y=pos.y+y, z=pos.z}
+			local pz = {x=pos.x, y=pos.y+y, z=pos.z+d}
+			if check_portal(px, {x=px.x+3, y=px.y+4, z=px.z}) then
+				return px, {x=px.x+3, y=px.y+4, z=px.z}
+			end
+			if check_portal(pz, {x=pz.x, y=pz.y+4, z=pz.z+3}) then
+				return pz, {x=pz.x, y=pz.y+4, z=pz.z+3}
+			end
+		end
+	end
+end
+
+-- put here the function for creating a second portal
+local create_second_portal
+if mclike_portal then
+	function create_second_portal(target)
+		-- change target here
+	end
+end
+
+-- adds the violet portal essence
+local function make_portal(pos)
+	local p1, p2 = is_portal(pos)
+	if not p1
+	or not p2 then
+		print("[nether] something failed.")
+		return false
+	end
+
+	local in_nether = p1.y < nether.start
+
+	if in_nether
+	and not mclike_portal then
+		print("[nether] aborted, obsidian portals can't be used to get out")
+		return
+	end
+
+	for d=1,2 do
+	for y=p1.y+1,p2.y-1 do
+		local p
+		if p1.z == p2.z then
+			p = {x=p1.x+d, y=y, z=p1.z}
+		else
+			p = {x=p1.x, y=y, z=p1.z+d}
+		end
+		if minetest.get_node(p).name ~= "air" then
+			return false
+		end
+	end
+	end
+
+	local param2
+	if p1.z == p2.z then
+		param2 = 0
+	else
+		param2 = 1
+	end
+
+	local target = {x=p1.x, y=p1.y, z=p1.z}
+	target.x = target.x + 1
+	if in_nether then
+		target.y = 0
+		create_second_portal(target)
+	else
+		target.y = portal_target + math.random(4)
+	end
+
+	if not generated_or_generate(target)
+	and mclike_portal then
+		return false
+	end
+
+	for d=0,3 do
+	for y=p1.y,p2.y do
+		local p
+		if param2 == 0 then
+			p = {x=p1.x+d, y=y, z=p1.z}
+		else
+			p = {x=p1.x, y=y, z=p1.z+d}
+		end
+		if minetest.get_node(p).name == "air" then
+			minetest.set_node(p, {name="nether:portal", param2=param2})
+		end
+		local meta = minetest.get_meta(p)
+		meta:set_string("p1", minetest.pos_to_string(p1))
+		meta:set_string("p2", minetest.pos_to_string(p2))
+		meta:set_string("target", minetest.pos_to_string(target))
+	end
+	end
+	print("[nether] construction accepted.")
+	return true
+end
+
+-- destroy the portal when destroying obsidian
+minetest.override_item("default:obsidian", {
+	on_destruct = function(pos)
+		local meta = minetest.get_meta(pos)
+		local p1 = minetest.string_to_pos(meta:get_string("p1"))
+		local p2 = minetest.string_to_pos(meta:get_string("p2"))
+		local target = minetest.string_to_pos(meta:get_string("target"))
+		if not p1 or not p2 then
+			return
+		end
+		for x=p1.x,p2.x do
+		for y=p1.y,p2.y do
+		for z=p1.z,p2.z do
+			local nn = minetest.get_node({x=x,y=y,z=z}).name
+			if nn == "default:obsidian" or nn == "nether:portal" then
+				if nn == "nether:portal" then
+					minetest.remove_node({x=x,y=y,z=z})
+				end
+				local m = minetest.get_meta({x=x,y=y,z=z})
+				m:set_string("p1", "")
+				m:set_string("p2", "")
+				m:set_string("target", "")
+			end
+		end
+		end
+		end
+		meta = minetest.get_meta(target)
+		if not meta then
+			return
+		end
+		p1 = minetest.string_to_pos(meta:get_string("p1"))
+		p2 = minetest.string_to_pos(meta:get_string("p2"))
+		if not p1 or not p2 then
+			return
+		end
+		for x=p1.x,p2.x do
+		for y=p1.y,p2.y do
+		for z=p1.z,p2.z do
+			local nn = minetest.get_node({x=x,y=y,z=z}).name
+			if nn == "default:obsidian" or nn == "nether:portal" then
+				if nn == "nether:portal" then
+					minetest.remove_node({x=x,y=y,z=z})
+				end
+				local m = minetest.get_meta({x=x,y=y,z=z})
+				m:set_string("p1", "")
+				m:set_string("p2", "")
+				m:set_string("target", "")
+			end
+		end
+		end
+		end
+	end
+})
+
+-- override mese crystal fragment for making an obsidian portal
+minetest.after(0.1, function()
+	minetest.override_item("default:mese_crystal_fragment", {
+		on_place = function(stack, player, pt)
+			if pt.under
+			and minetest.get_node(pt.under).name == "default:obsidian" then
+				local done = make_portal(pt.under)
+				if done then
+					minetest.chat_send_player(player:get_player_name(),
+						"Warning: If you are in the nether you may not be " ..
+						"able to find the way out!")
+					if not minetest.settings:get_bool("creative_mode") then
+						stack:take_item()
+					end
+				end
+			end
+			return stack
+		end
+	})
+end)
+
+
+-- a not filled square
+local function vector_square(r)
+	local tab, n = {}, 1
+	for i = -r+1, r do
+		for j = -1, 1, 2 do
+			local a, b = r*j, i*j
+			tab[n] = {a, b}
+			tab[n+1] = {b, a}
+			n=n+2
+		end
+	end
+	return tab
+end
+
+local function is_netherportal(pos)
+	local x, y, z = pos.x, pos.y, pos.z
+	for _,i in pairs({-1, 3}) do
+		if minetest.get_node({x=x, y=y+i, z=z}).name ~= "nether:white" then
+			return
+		end
+	end
+	for _,sn in pairs(vector_square(1)) do
+		if minetest.get_node({x=x+sn[1], y=y-1, z=z+sn[2]}).name ~= "nether:netherrack"
+		or minetest.get_node({x=x+sn[1], y=y+3, z=z+sn[2]}).name ~= "nether:blood_cooked" then
+			return
+		end
+	end
+	for _,sn in pairs(vector_square(2)) do
+		if minetest.get_node({x=x+sn[1], y=y-1, z=z+sn[2]}).name ~= "nether:netherrack_black"
+		or minetest.get_node({x=x+sn[1], y=y+3, z=z+sn[2]}).name ~= "nether:wood_empty" then
+			return
+		end
+	end
+	for i = -1,1,2 do
+		for j = -1,1,2 do
+			if minetest.get_node({x=x+i, y=y+2, z=z+j}).name ~= "nether:apple" then
+				return
+			end
+		end
+	end
+	for i = -2,2,4 do
+		for j = 0,2 do
+			for k = -2,2,4 do
+				if minetest.get_node({x=x+i, y=y+j, z=z+k}).name ~= "nether:netherrack_brick_blue" then
+					return
+				end
+			end
+		end
+	end
+	for i = -1,1 do
+		for j = -1,1 do
+			if minetest.get_node({x=x+i, y=y+4, z=z+j}).name ~= "nether:wood_empty" then
+				return
+			end
+		end
+	end
+	return true
+end
+
+-- cache known portals
+local known_portals_d = {}
+local known_portals_u = {}
+local function get_portal(t, z,x)
+	return t[z] and t[z][x]
+end
+local function set_portal(t, z,x, y)
+	t[z] = t[z] or {}
+	t[z][x] = y
+end
+
+local function get_player_nodepos(player)
+	local pos = player:get_pos()
+	pos.y = pos.y + player:get_properties().collisionbox[2] + 0.5
+	return vector.round(pos)
+end
+
+-- used when a player eats that fruit in a portal
+function nether.teleport_player(player)
+	if not player then
+		minetest.log("error", "[nether] Missing player.")
+		return
+	end
+	local pos = get_player_nodepos(player)
+	if not is_netherportal(pos) then
+		return
+	end
+	minetest.sound_play("nether_teleporter", {pos=pos})
+	local meta = minetest.get_meta({x=pos.x, y=pos.y-1, z=pos.z})
+	if pos.y < nether.start then
+		set_portal(known_portals_d, pos.z,pos.x, pos.y)
+
+		local my = tonumber(meta:get_string("y"))
+		local y = get_portal(known_portals_u, pos.z,pos.x)
+		if y then
+			if y ~= my then
+				meta:set_string("y", y)
+			end
+		else
+			y = my or 100
+		end
+		pos.y = y - 0.3
+
+		player_from_nether(player, pos)
+	else
+		set_portal(known_portals_u, pos.z,pos.x, pos.y)
+
+		local my = tonumber(meta:get_string("y"))
+		local y = get_portal(known_portals_d, pos.z,pos.x)
+		if y then
+			if y ~= my then
+				meta:set_string("y", y)
+			end
+		else
+			y = my or portal_target+math.random(4)
+		end
+		pos.y = y - 0.3
+
+		player_to_nether(player, pos)
+	end
+	minetest.sound_play("nether_teleporter", {pos=pos})
+	return true
+end

nether/settings.lua

@@ -0,0 +1,23 @@
+local default_settings = {
+	trap_players = true,
+	log_to_chat = false,
+	log_level = 2,
+}
+
+nether.settings = {}
+
+for name,dv in pairs(default_settings) do
+	local setting
+	local setting_name = "nether." .. name
+	if type(dv) == "boolean" then
+		setting = minetest.settings:get_bool(setting_name)
+	elseif type(dv) == "number" then
+		setting = tonumber(minetest.settings:get(setting_name))
+	else
+		error"[nether] Only boolean and number settings are available"
+	end
+	if setting == nil then
+		setting = dv
+	end
+	nether[name] = setting
+end

nether/settingtypes.txt

@@ -0,0 +1,19 @@
+#    If enabled, regular players which are in the nether can leave it only with
+#    a nether portal and other ways of teleportation, e.g. the /spawn
+#    chatcommand, are blocked. Similarly, the nether can only be entered with a
+#    portal.
+#    This forces the players to investigate the nether and build a portal with
+#    hellish effort to go back to their home in the overworld.
+#    It is recommended to disable this setting in creative mode or if damage is
+#    disabled.
+nether.trap_players (Trap players) bool true
+
+#    If enabled, show log messages in the chat and not only in debug.txt
+nether.log_to_chat (Log messages to chat) bool false
+
+#    Specify how much text is printed for debugging purposes
+#    0: Disabled
+#    1: A bit of information
+#    2: Acceptable amount of information
+#    3: Lots of text
+nether.log_level (Log level) int 2 0 3

nether/temp.txt

@@ -1,166 +0,0 @@
-	-- Floor 1
-	{pos={x=0,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=2,y=0,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=0,z=0}, block="nether:netherrack"},
-	-- Floor 2
-	{pos={x=0,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=2,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=1,z=1}, block="nether:netherrack"},
-	{pos={x=4,y=1,z=1}, block="nether:netherrack"},
-	-- Floor 3
-	{pos={x=0,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=2,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=1}, block="nether:netherrack"},
-	{pos={x=1,y=2,z=2}, block="nether:netherrack"},
-	{pos={x=4,y=2,z=2}, block="nether:netherrack"},
-	-- Floor 4
-	{pos={x=0,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=0,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=6}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=5,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=0}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=1}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=2}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=3}, block="nether:netherrack"},
-	{pos={x=1,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=4,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=2,y=3,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=4}, block="nether:netherrack"},
-	{pos={x=3,y=3,z=5}, block="nether:netherrack"},
-	-- Floor 5
-	{pos={x=2,y=4,z=4}, block="nether:netherrack"},
-	{pos={x=2,y=4,z=5}, block="nether:netherrack"},
-	{pos={x=3,y=4,z=4}, block="nether:netherrack"},
-	{pos={x=3,y=4,z=5}, block="nether:netherrack"},
-	{pos={x=2,y=4,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=4,z=6}, block="nether:netherrack"},
-	-- Torches on floor 5
-	{pos={x=0,y=4,z=4}, block="nether:nether_torch_bottom"},
-	{pos={x=1,y=4,z=4}, block="nether:nether_torch_bottom"},
-	{pos={x=0,y=4,z=5}, block="nether:nether_torch_bottom"},
-	{pos={x=1,y=4,z=5}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=4}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=4}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=5}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=5}, block="nether:nether_torch_bottom"},
-	{pos={x=0,y=4,z=0}, block="nether:nether_torch_bottom"},
-	{pos={x=1,y=4,z=0}, block="nether:nether_torch_bottom"},
-	{pos={x=0,y=4,z=1}, block="nether:nether_torch_bottom"},
-	{pos={x=1,y=4,z=1}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=0}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=0}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=1}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=1}, block="nether:nether_torch_bottom"},
-	{pos={x=0,y=4,z=2}, block="nether:nether_torch_bottom"},
-	{pos={x=1,y=4,z=2}, block="nether:nether_torch_bottom"},
-	{pos={x=0,y=4,z=3}, block="nether:nether_torch_bottom"},
-	{pos={x=1,y=4,z=3}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=2}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=2}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=3}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=3}, block="nether:nether_torch_bottom"},
-	{pos={x=4,y=4,z=6}, block="nether:nether_torch_bottom"},
-	{pos={x=5,y=4,z=6}, block="nether:nether_torch_bottom"},
-	-- Floor 6
-	{pos={x=2,y=5,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=5,z=6}, block="nether:netherrack"},
-	-- Floor 7
-	{pos={x=2,y=6,z=6}, block="nether:netherrack"},
-	{pos={x=3,y=6,z=6}, block="nether:netherrack"},