structs: use mcl_register_generator, cave decos

mods/MAPGEN/mcl_biomes/init.lua

@@ -3356,6 +3356,29 @@ local function register_decorations()
 		rotation = "0",
 	})
 
+	--Mushrooms in caves
+	minetest.register_decoration({
+		deco_type = "simple",
+		place_on = {"group:material_stone"},
+		sidelen = 80,
+		fill_ratio = 0.009,
+		noise_threshold = 2.0,
+		flags = "all_floors",
+		y_min = mcl_vars.mg_overworld_min,
+		y_max = mcl_vars.mg_overworld_max,
+		decoration = "mcl_mushrooms:mushroom_red",
+	})
+	minetest.register_decoration({
+		deco_type = "simple",
+		place_on = {"group:material_stone"},
+		sidelen = 80,
+		fill_ratio = 0.009,
+		noise_threshold = 2.0,
+		y_min = mcl_vars.mg_overworld_min,
+		y_max = mcl_vars.mg_overworld_max,
+		decoration = "mcl_mushrooms:mushroom_brown",
+	})
+
 	-- Mossy cobblestone boulder (3×3)
 	minetest.register_decoration({
 		deco_type = "schematic",

mods/MAPGEN/mcl_mapgen_core/init.lua

@@ -1720,7 +1720,7 @@ local function generate_tree_decorations(minp, maxp, seed, data, param2_data, ar
 end
 
 -- Generate mushrooms in caves manually.
--- Minetest's API does not support decorations in caves yet. :-(
+-- only v6. minetest supports cave decos via "all_floors" flag now
 local function generate_underground_mushrooms(minp, maxp, seed)
 	local pr_shroom = PseudoRandom(seed-24359)
 	-- Generate rare underground mushrooms
@@ -1756,7 +1756,6 @@ end
 -- Generate Nether decorations manually: Eternal fire, mushrooms, nether wart
 -- (only v6)
 local function generate_nether_decorations(minp, maxp, seed)
-	if mg_name == "v6" then
 	local pr_nether = PseudoRandom(seed+667)
 
 	if minp.y > mcl_vars.mg_nether_max or maxp.y < mcl_vars.mg_nether_min then
@@ -1816,7 +1815,6 @@ local function generate_nether_decorations(minp, maxp, seed)
 			minetest.set_node(bpos, {name = "mcl_nether:nether_wart"})
 		end
 	end)
-	end
 end
 
 minetest.register_on_generated(function(minp, maxp, blockseed)
@@ -2200,10 +2198,24 @@ end
 local function basic_node(minp, maxp, blockseed)
 	if mg_name ~= "singlenode" then
 		-- Generate special decorations
+		if mg_name == "v6" then
 			generate_underground_mushrooms(minp, maxp, blockseed)
 			generate_nether_decorations(minp, maxp, blockseed)
+		end
 		generate_structures(minp, maxp, blockseed, minetest.get_mapgen_object("biomemap"))
 	end
 end
 
 mcl_mapgen_core.register_generator("main", basic, basic_node, 1, true)
+
+mcl_mapgen_core.register_generator("structures",nil, function(minp, maxp, blockseed)
+	local gennotify = minetest.get_mapgen_object("gennotify")
+	local pr = PseudoRandom(blockseed + 42)
+	for _,struct in pairs(mcl_structures.registered_structures) do
+		for _, pos in pairs(gennotify["decoration#"..struct.deco_id] or {}) do
+			local realpos = vector.offset(pos,0,-1,0)
+			minetest.remove_node(realpos)
+			mcl_structures.place_structure(realpos,struct,pr)
+		end
+	end
+end, 100, true)

mods/MAPGEN/mcl_structures/api.lua

@@ -53,17 +53,8 @@ function mcl_structures.register_structure(name,def,nospawn) --nospawn means it
 			y_max = def.y_max,
 			y_min = def.y_min
 		})
-		local deco_id = minetest.get_decoration_id("mcl_structures:deco_"..name)
-		minetest.set_gen_notify({decoration=true}, { deco_id })
-		minetest.register_on_generated(function(minp, maxp, blockseed)
-			local gennotify = minetest.get_mapgen_object("gennotify")
-			local pr = PseudoRandom(blockseed + 42)
-			for _, pos in pairs(gennotify["decoration#"..deco_id] or {}) do
-				local realpos = vector.offset(pos,0,-1,0)
-				minetest.remove_node(realpos)
-				mcl_structures.place_structure(realpos,def,pr)
-			end
-		end)
+		def.deco_id = minetest.get_decoration_id("mcl_structures:deco_"..name)
+		minetest.set_gen_notify({decoration=true}, { def.deco_id })
 	end
 	minetest.register_node(":"..structblock, {drawtype="airlike", walkable = false, pointable = false,groups = sbgroups})
 	def.structblock = structblock