make shrubs and moss furnace burnable and remove ws values saving, l got a memory error

src/mapgen_v6.lua

@@ -36,27 +36,11 @@ local function do_ws_func(a, x)
 	local n = x/(16000)
 	local y = 0
 	for k=1,1000 do
-		y = y + 1000*(math.sin(math.pi * k^a * n)/(math.pi * k^a))
+		y = y + 1000*math.sin(math.pi * k^a * n)/(math.pi * k^a)
 	end
 	return y
 end
 
-local ws_lists = {}
-local function get_ws_list(a,x)
-        ws_lists[a] = ws_lists[a] or {}
-        local v = ws_lists[a][x]
-        if v then
-                return v
-        end
-        v = {}
-        for x=x,x + (80 - 1) do
-		local y = do_ws_func(a, x)
-                v[x] = y
-        end
-        ws_lists[a][x] = v
-        return v
-end
-
 
 local plantlike_ids = {}
 local function is_plantlike(id)
@@ -365,11 +349,7 @@ minetest.register_on_generated(function(minp, maxp, seed)
 			if test > 0 then
 				local maxh = math.floor(test*10)%10+1
 				if maxh ~= 1 then
-					if not wsz then
-						wsz = get_ws_list(5, z0)
-						wsx = get_ws_list(2, x0)
-					end
-					local h = math.floor(wsx[x]+wsz[z]*5)%10+1
+					local h = math.floor( do_ws_func(2, x) + do_ws_func(5, z)*5)%10+1
 					if h ~= 1 then
 						-- search for nearby snow
 						y = y+1

src/nodes.lua

@@ -157,6 +157,7 @@ minetest.register_node("snow:moss", {
 	},
 	is_ground_content = true,
 	groups = {crumbly=3, attached_node=1},
+	furnace_burntime = 3,
 })
 
 -- Shrub(s)
@@ -178,6 +179,7 @@ nodedef = {
 		type = "fixed",
 		fixed = {-0.3, -0.5, -0.3, 0.3, -5/16, 0.3},
 	},
+	furnace_burntime = 5,
 }
 minetest.register_node("snow:shrub", table.copy(nodedef))
 
@@ -185,6 +187,7 @@ nodedef.tiles = {"snow_shrub.png^snow_shrub_covering.png"}
 nodedef.inventory_image = "snow_shrub.png^snow_shrub_covering.png"
 nodedef.wield_image = "snow_shrub.png^snow_shrub_covering.png"
 nodedef.drop = "snow:shrub"
+nodedef.furnace_burntime = 3
 minetest.register_node("snow:shrub_covered", nodedef)