Check for each node's existence

If the specified node does not exist, the air node is used instead.
Grows on's default is changed to air node.
Update README.

README.md

@@ -14,9 +14,11 @@ MIT License (code) and CC BY-SA 3.0 (media) (see LICENSE file)
 2. Change `sflat.Y_ORIGIN` to adjust first layer's pos (default: 1).
 3. Change `sflat.BLOCKS` to adjust the composition of the world (code: layers from bottom to top;biome,decoration) (examples available).
 
+Note: If the specified node does not exist, the air node will be used.
+
 ## Modify existing world
 1. Open `superflat.txt` file in your world's folder.
-2. Do like opening `parameter.lua` file.
+2. Do like editing `parameter.lua` file.
 
 ## List of biomes
 - Frozen River

README.txt

@@ -14,9 +14,11 @@ MIT License (code) and CC BY-SA 3.0 (media) (see LICENSE file)
 2. Change sflat.Y_ORIGIN to adjust first layer's pos (default: 1).
 3. Change sflat.BLOCKS to adjust the composition of the world (code: layers from bottom to top;biome,decoration) (examples available).
 
+Note: If the specified node does not exist, the air node will be used.
+
 ## Modify existing world
 1. Open superflat.txt file in your world's folder.
-2. Do like opening parameter.lua file.
+2. Do like editing parameter.lua file.
 
 ## List of biomes
 - Frozen River

decoration.lua

@@ -14,6 +14,7 @@ sflat.decoration = sflat.decoration or {}
 sflat.decoration.list = {}
 
 local c_air = minetest.get_content_id("air")
+local c_ignore = minetest.get_content_id("ignore")
 
 function sflat.decoration.generate(minp, maxp, LAYERS, data, area, seed, pr)
 	local biome = sflat.biome.list[sflat.options.biome]
@@ -41,7 +42,7 @@ end
 function sflat.decoration.register(param)
 	sflat.decoration.list[param.name] = {
 		chance = param.chance or 1024,
-		grows_on = param.grows_on or "default:dirt_with_grass",
+		grows_on = param.grows_on or "air",
 		grow = param.grow or function() return nil end
 	}
 end
@@ -97,14 +98,13 @@ sflat.biome.register({
 
 -- Decoration definition
 
-local c_ignore = minetest.get_content_id("ignore")
+local c_dirt_grass = sflat.get_content_id("default:dirt_with_grass")
-local c_dirt_grass = minetest.get_content_id("default:dirt_with_grass")
+local c_tree = sflat.get_content_id("default:tree")
-local c_tree = minetest.get_content_id("default:tree")
+local c_leaves = sflat.get_content_id("default:leaves")
-local c_leaves = minetest.get_content_id("default:leaves")
+local c_apple = sflat.get_content_id("default:apple")
-local c_apple = minetest.get_content_id("default:apple")
+local c_jungletree = sflat.get_content_id("default:jungletree")
-local c_jungletree = minetest.get_content_id("default:jungletree")
+local c_jungleleaves = sflat.get_content_id("default:jungleleaves")
-local c_jungleleaves = minetest.get_content_id("default:jungleleaves")
+local c_snow = sflat.get_content_id("default:snow")
-local c_snow = minetest.get_content_id("default:snow")
 
 -- leaves
 local function add_leaves(data, vi, c_leaf, other)
@@ -233,15 +233,15 @@ sflat.decoration.register({
 
 -- small plants
 
-local c_cactus = minetest.get_content_id("default:cactus")
+local c_cactus = sflat.get_content_id("default:cactus")
-local c_dry_shrub = minetest.get_content_id("default:dry_shrub")
+local c_dry_shrub = sflat.get_content_id("default:dry_shrub")
-local c_papyrus = minetest.get_content_id("default:papyrus")
+local c_papyrus = sflat.get_content_id("default:papyrus")
-local c_junglegrass  = minetest.get_content_id("default:junglegrass")
+local c_junglegrass  = sflat.get_content_id("default:junglegrass")
-local c_grass_1 = minetest.get_content_id("default:grass_1")
+local c_grass_1 = sflat.get_content_id("default:grass_1")
-local c_grass_2 = minetest.get_content_id("default:grass_2")
+local c_grass_2 = sflat.get_content_id("default:grass_2")
-local c_grass_3 = minetest.get_content_id("default:grass_3")
+local c_grass_3 = sflat.get_content_id("default:grass_3")
-local c_grass_4 = minetest.get_content_id("default:grass_4")
+local c_grass_4 = sflat.get_content_id("default:grass_4")
-local c_grass_5 = minetest.get_content_id("default:grass_5")
+local c_grass_5 = sflat.get_content_id("default:grass_5")
 local c_grasses = {c_grass_1, c_grass_2, c_grass_3, c_grass_4, c_grass_5}
 
 -- dry shrub
@@ -327,12 +327,12 @@ sflat.decoration.register({
 })
 
 
-local c_dandelion_white = minetest.get_content_id("flowers:dandelion_white")
+local c_dandelion_white = sflat.get_content_id("flowers:dandelion_white")
-local c_dandelion_yellow = minetest.get_content_id("flowers:dandelion_yellow")
+local c_dandelion_yellow = sflat.get_content_id("flowers:dandelion_yellow")
-local c_geranium = minetest.get_content_id("flowers:geranium")
+local c_geranium = sflat.get_content_id("flowers:geranium")
-local c_rose = minetest.get_content_id("flowers:rose")
+local c_rose = sflat.get_content_id("flowers:rose")
-local c_tulip = minetest.get_content_id("flowers:tulip")
+local c_tulip = sflat.get_content_id("flowers:tulip")
-local c_viola = minetest.get_content_id("flowers:viola")
+local c_viola = sflat.get_content_id("flowers:viola")
 local c_flowers = {c_dandelion_white, c_dandelion_yellow, c_geranium, c_rose, c_tulip, c_viola}
 
 -- flowers
@@ -349,7 +349,7 @@ sflat.decoration.register({
 	end
 })
 
-local c_ice = minetest.get_content_id("default:ice")
+local c_ice = sflat.get_content_id("default:ice")
 
 -- ice spikes
 sflat.decoration.register({

init.lua

@@ -11,6 +11,15 @@ sflat.options = {
 	decoration = false
 }
 
+local c_air = minetest.get_content_id("air")
+function sflat.get_content_id(name)
+	local id = c_air
+	if minetest.registered_nodes[name] then
+		id = minetest.get_content_id(name)
+	end
+	return id
+end
+
 dofile(minetest.get_modpath("superflat") .. "/parsetext.lua")
 dofile(minetest.get_modpath("superflat") .. "/parameter.lua")
 dofile(minetest.get_modpath("superflat") .. "/decoration.lua")

parsetext.lua

@@ -26,7 +26,7 @@ function sflat.parsetext(text)
 		if node ~= nil and amount ~= nil then
 			if amount == "" then amount = 1 end
 			y = y + amount
-			layers[#layers + 1] = {node, minetest.get_content_id(node), y}
+			layers[#layers + 1] = {node, sflat.get_content_id(node), y}
 		end
 	end
 	return layers