refactor log registration.

rename log and sapling textures to be more clear. rewrite node
registration code to account for this, and to be overall cleaner.

mods/bg_tree/node.lua

@@ -1,39 +1,35 @@
 local modname = minetest.get_current_modname()
 
-blockgame.register_node(modname .. ":log", {
-	description = "Log",
-	tiles = {
-		modname .. "_log_top.png",
-		modname .. "_log_top.png",
-		modname .. "_log.png",
-	},
-	groups = {
+local function reg_log (name, def)
+	def = def or {}
+
+	def.description = def.description or "Log"
+
+	local texture = def.texture or name
+	def.tiles = blockgame.underride(def.tiles, {
+		modname .. "_" .. texture .. "_top.png",
+		modname .. "_" .. texture .. "_top.png",
+		modname .. "_" .. texture .. ".png",
+	})
+
+	def.groups = blockgame.underride(def.groups, {
 		woody = 1,
-	},
-})
-blockgame.register_node(modname .. ":log_alive", {
-	description = "Living Log",
-	tiles = {
-		modname .. "_log_top.png",
-		modname .. "_log_top.png",
-		modname .. "_log.png",
-	},
+		supports_leaves = 1,
+	})
+
+	blockgame.register_node(modname .. ":" .. name, def)
+end
+
+reg_log("log")
+reg_log("log_alive", {
 	groups = {
-		woody = 1,
 		planty = 1,
 	},
+	texture = "log",
 	drop = modname .. ":log",
 })
-
-blockgame.register_node(modname .. ":sapling", {
-	description = "Growing Log",
-	tiles = {
-		modname .. "_log_top_alive.png",
-		modname .. "_log_top_alive.png",
-		modname .. "_log_alive.png",
-	},
+reg_log("sapling", {
 	groups = {
-		woody = 1,
 		planty = 1,
 	},
 	drop = modname .. ":log",