Modpack refactor (#4)

Split this mod into a set of sub-mods in a modpack, and in the process did a whole bunch of renovations.

* updated Subterrane's API to allow for more patterned placement of things
* added "warrens"
* clean separation of flooded and non-flooded caverns
* rearranged biomes to make cavern layers more distinct
* added oil layer
* added underworld layer

df_mapitems/ground_cover.lua

@@ -0,0 +1,119 @@
+-- internationalization boilerplate
+local MP = minetest.get_modpath(minetest.get_current_modname())
+local S, NS = dofile(MP.."/intllib.lua")
+
+--------------------------------------------------
+-- Cave moss
+
+-- cyan/dark cyan
+
+minetest.register_node("df_mapitems:dirt_with_cave_moss", {
+	description = S("Dirt With Cave Moss"),
+	_doc_items_longdesc = df_mapitems.doc.cave_moss_desc,
+	_doc_items_usagehelp = df_mapitems.doc.cave_moss_usage,
+	tiles = {"default_dirt.png^dfcaverns_cave_moss.png", "default_dirt.png", 
+		{name = "default_dirt.png^dfcaverns_cave_moss_side.png",
+			tileable_vertical = false}},
+	drop = "default:dirt",
+	is_ground_content = true,
+	light_source = 2,
+	paramtype = "light",
+	groups = {crumbly = 3, soil = 1, light_sensitive_fungus = 8},
+	sounds = default.node_sound_dirt_defaults({
+		footstep = {name = "default_grass_footstep", gain = 0.25},
+	}),
+	soil = {
+		base = "df_mapitems:dirt_with_cave_moss",
+		dry = "farming:soil",
+		wet = "farming:soil_wet"
+	},
+	_dfcaverns_dead_node = "default:dirt",
+})
+
+minetest.register_abm{
+	label = "df_mapitems:cave_moss_spread",
+	nodenames = {"default:dirt"},
+	neighbors = {"df_mapitems:dirt_with_cave_moss"},
+	interval = 60,
+	chance = 15,
+	catch_up = true,
+	action = function(pos)
+		local above_def = minetest.registered_nodes[minetest.get_node({x=pos.x, y=pos.y+1, z=pos.z}).name]
+		if above_def and (above_def.buildable_to == true or above_def.walkable == false) then
+			minetest.swap_node(pos, {name="df_mapitems:dirt_with_cave_moss"})
+		end
+	end,
+}
+
+--------------------------------------------------
+-- floor fungus
+
+-- white/yellow
+
+minetest.register_node("df_mapitems:cobble_with_floor_fungus", {
+	description = S("Cobblestone With Floor Fungus"),
+	_doc_items_longdesc = df_mapitems.doc.floor_fungus_desc,
+	_doc_items_usagehelp = df_mapitems.doc.floor_fungus_usage,
+	tiles = {"default_cobble.png^dfcaverns_floor_fungus.png"},
+	drops = "default:cobble",
+	is_ground_content = true,
+	paramtype = "light",
+	groups = {cracky = 3, stone = 2, slippery = 1, light_sensitive_fungus = 8},
+	_dfcaverns_dead_node = "default:cobble",
+	sounds = default.node_sound_stone_defaults({
+		footstep = {name = "dfcaverns_squish", gain = 0.25},
+	}),
+})
+
+minetest.register_node("df_mapitems:cobble_with_floor_fungus_fine", {
+	description = S("Cobblestone With Floor Fungus"),
+	_doc_items_longdesc = df_mapitems.doc.floor_fungus_desc,
+	_doc_items_usagehelp = df_mapitems.doc.floor_fungus_usage,
+	tiles = {"default_cobble.png^dfcaverns_floor_fungus_fine.png"},
+	drops = "default:cobble",
+	is_ground_content = true,
+	paramtype = "light",
+	groups = {cracky = 3, stone = 2, slippery = 1, light_sensitive_fungus = 8},
+	_dfcaverns_dead_node = "default:cobble",
+	sounds = default.node_sound_stone_defaults({
+		footstep = {name = "dfcaverns_squish", gain = 0.25},
+	}),
+})
+
+minetest.register_abm{
+	label = "df_mapitems:floor_fungus_spread",
+	nodenames = {"default:cobble"},
+	neighbors = {"df_mapitems:cobble_with_floor_fungus"},
+	interval = 60,
+	chance = 10,
+	catch_up = true,
+	action = function(pos)
+		minetest.swap_node(pos, {name="df_mapitems:cobble_with_floor_fungus_fine"})
+	end,
+}
+minetest.register_abm{
+	label = "df_mapitems:floor_fungus_thickening",
+	nodenames = {"default:cobble_with_floor_fungus_fine"},
+	interval = 59,
+	chance = 10,
+	catch_up = true,
+	action = function(pos)
+		minetest.swap_node(pos, {name="df_mapitems:cobble_with_floor_fungus"})
+	end,
+}
+
+------------------------------------------------------
+-- Hoar moss
+
+minetest.register_node("df_mapitems:ice_with_hoar_moss", {
+	description = S("Ice With Hoar Moss"),
+	_doc_items_longdesc = df_mapitems.doc.hoar_moss_desc,
+	_doc_items_usagehelp = df_mapitems.doc.hoar_moss_usage,
+	tiles = {"default_ice.png^dfcaverns_hoar_moss.png"},
+	drops = "default:ice",
+	paramtype = "light",
+	light_source = 2,
+	groups = {cracky = 3, puts_out_fire = 1, cools_lava = 1, slippery = 2, light_sensitive_fungus = 8},
+	sounds = default.node_sound_glass_defaults(),
+	_dfcaverns_dead_node = "default:ice",
+})