Change leaf decay to use groups

mods/nc_api/item_groupdump.lua

@@ -82,6 +82,8 @@ local groups = {
 	is_stack_only = "(specific) a bare item stack as a node",
 	lava = "(specific) source or flowing pumwater",
 	leaf_decay = "decays into its leaf_decay_as items if not connected to tree trunk",
+	leaf_decay_support = "nodes that stop leaves from decaying (tree trunks)",
+	leaf_decay_transmit = "nodes that transmit leaf decay stoppage through them (leaves)",
 	leafy = "(deprecated) loose leaves",
 	lens_glow_start = "(specific) glowing lenses in warm-up state",
 	lode_cobble = "(specific) lode cobble or loose lode cobble",

mods/nc_tree/grow_node.lua

@@ -112,7 +112,8 @@ minetest.register_node(modname .. ":tree_bud", {
 			flammable = 12,
 			fire_fuel = 6,
 			falling_node = 1,
-			scaling_time = 80
+			scaling_time = 80,
+			leaf_decay_support = 1
 		},
 		crush_damage = 1,
 		sounds = nodecore.sounds("nc_tree_woody"),
@@ -137,7 +138,8 @@ minetest.register_node(modname .. ":leaves_bud", {
 			fire_fuel = 2,
 			green = 4,
 			scaling_time = 90,
-			leaf_decay = 1
+			leaf_decay = 1,
+			leaf_decay_transmit = 1
 		},
 		treeable_to = true,
 		drop = "",

mods/nc_tree/leafdecay.lua

@@ -5,8 +5,6 @@ local math_random
     = math.random
 -- LUALOCALS > ---------------------------------------------------------
 
-local modname = minetest.get_current_modname()
-
 local hashpos = minetest.hash_node_position
 
 local queue = {}
@@ -73,15 +71,15 @@ end
 
 local cache = {}
 
+local leaf_decay_support = nodecore.group_expand("group:leaf_decay_support", true)
+local leaf_decay_transmit = nodecore.group_expand("group:leaf_decay_transmit", true)
 local function check_decay(pos, node)
 	local hash = hashpos(pos)
 	local found = cache[hash]
 	if found and minetest.get_node(found).name == found.name then return true end
 	return nodecore.scan_flood(pos, 5, function(p)
 			local n = minetest.get_node(p).name
-			if n == modname .. ":tree"
-			or n == modname .. ":tree_bud"
-			or n == "ignore" then
+			if n == "ignore" or leaf_decay_support[n] then
 				while p.prev do
 					p.name = minetest.get_node(p).name
 					cache[hashpos(p.prev)] = p
@@ -89,10 +87,7 @@ local function check_decay(pos, node)
 				end
 				return true
 			end
-			if n == modname .. ":leaves"
-			or n == modname .. ":leaves_bud" then
-				return
-			end
+			if leaf_decay_transmit[n] then return end
 			return false
 		end
 	) or nodecore.leaf_decay(pos, node)

mods/nc_tree/node.lua

@@ -55,7 +55,8 @@ minetest.register_node(modname .. ":tree", {
 			fire_fuel = 6,
 			log = 1,
 			falling_node = 1,
-			scaling_time = 80
+			scaling_time = 80,
+			leaf_decay_support = 1
 		},
 		crush_damage = 1,
 		sounds = nodecore.sounds("nc_tree_woody"),
@@ -95,7 +96,8 @@ minetest.register_node(modname .. ":leaves", {
 			fire_fuel = 2,
 			green = 3,
 			scaling_time = 90,
-			leaf_decay = 1
+			leaf_decay = 1,
+			leaf_decay_transmit = 1
 		},
 		alternate_loose = {
 			tiles = {fade(modname .. "_leaves_dry.png")},