Implement more of the noise command backend

It's still not hooked up yet though, and there's no command parsing 
logic either

worldeditadditions/lib/noise/apply_2d.lua

@@ -0,0 +1,38 @@
+
+--- Applies the given noise field to the given heightmap.
+-- Mutates the given heightmap.
+-- @param	heightmap		number[]			A table of ZERO indexed numbers representing the heghtmap - see worldeditadditions.make_heightmap().
+-- @param	noise			number[]			An table identical in structure to the heightmap containing the noise values to apply.
+-- @param	heightmap_size	{x:number,z:number}	A 2d vector representing the size of the heightmap.
+-- @param	region_height	number				The height of the defined region.
+-- @param	apply_mode		string				The apply mode to use to apply the noise to the heightmap.
+-- @returns	bool[,string]	A boolean value representing whether the application was successful or not. If false, then an error message as a string is also returned describing the error that occurred.
+function worldeditadditions.noise.apply_2d(heightmap, noise, heightmap_size, region_height, apply_mode)
+	if type(apply_mode) ~= "string" then
+		return false, "Error: Expected string value for apply_mode, but received value of type "..type(apply_mode)
+	end
+	
+	local percent = tonumber(apply_mode:match("^(%d+)%%$"))
+	
+	for z = heightmap_size.z - 1, 0, -1 do
+		for x = heightmap_size.x - 1, 0, -1 do
+			local i = (z * heightmap_size.x) + x
+			
+			if apply_mode == "add" then
+				heightmap[i] = heightmap[i] + noise[i]
+			elseif apply_mode == "multiply" then
+				heightmap[i] = heightmap[i] * noise[i]
+			elseif percent then
+				-- Rescale from 0 - 1 to -1 - +1
+				local rescaled = (noise[i] * 2) - 1
+				-- Rescale to match the percentage specified
+				rescaled = rescaled * region_height * percent
+				heightmap[i] = rescaled
+			else
+				return false, "Error: Unknown apply_mode '"..apply_mode.."'"
+			end
+		end
+	end
+	
+	return true
+end

worldeditadditions/lib/noise/engines/perlin.lua

@@ -1,8 +1,5 @@
 local wea = worldeditadditions
 
--- original code by Ken Perlin: http://mrl.nyu.edu/~perlin/noise/
--- Port from this StackOverflow answer: https://stackoverflow.com/a/33425812/1460422
-
 
 local function BitAND(a, b) --Bitwise and
 	local p, c = 1, 0
@@ -29,10 +26,15 @@ local function grad(hash, x, y, z)
 	return ((h and 1) == 0 and u or - u) + ((h and 2) == 0 and v or - v)
 end
 
+--- Perlin noise generation engine.
+-- Original code by Ken Perlin: http://mrl.nyu.edu/~perlin/noise/
+-- Port from this StackOverflow answer: https://stackoverflow.com/a/33425812/1460422
+-- @class
+local Perlin = {}
+Perlin.__index = Perlin
 
-wea.noise.perlin = {}
-wea.noise.perlin.p = {}
-wea.noise.perlin.permutation = {
+Perlin.p = {}
+Perlin.permutation = {
 	151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140,
 	36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148, 247, 120,
 	234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33,
@@ -50,28 +52,36 @@ wea.noise.perlin.permutation = {
 	115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93, 222, 114, 67, 29,
 	24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180
 }
-wea.noise.perlin.size = 256
-wea.noise.perlin.gx = {}
-wea.noise.perlin.gy = {}
-wea.noise.perlin.randMax = 256
+Perlin.size = 256
+Perlin.gx = {}
+Perlin.gy = {}
+Perlin.randMax = 256
 
---- Creates a new perlin instance.
--- @return	perlin	A new perlin instance.
-function wea.noise.perlin.new()
+--- Creates a new Perlin instance.
+-- @return	Perlin	A new perlin instance.
+function Perlin.new()
 	local instance = {}
-	setmetatable(instance, wea.noise.perlin)
+	setmetatable(instance, Perlin)
 	instance:load()
 	return instance
 end
 
-function wea.noise.perlin:load()
+--- Initialises this Perlin instance.
+-- Called automatically by the constructor - you do NOT need to call this
+-- yourself.
+function Perlin:load()
 	for i = 1, self.size do
 		self.p[i] = self.permutation[i]
 		self.p[255 + i] = self.p[i]
 	end
 end
 
-function wea.noise.perlin:noise( x, y, z )
+--- Returns a noise value for a given point in 3D space.
+-- @param	x	number	The x co-ordinate.
+-- @param	y	number	The y co-ordinate.
+-- @param	z	number	The z co-ordinate.
+-- @returns	number		The calculated noise value.
+function Perlin:noise( x, y, z )
 	local X = BitAND(math.floor(x), 255) + 1
 	local Y = BitAND(math.floor(y), 255) + 1
 	local Z = BitAND(math.floor(z), 255) + 1
@@ -98,3 +108,5 @@ function wea.noise.perlin:noise( x, y, z )
 		lerp(u, grad(self.p[AB + 1], x, y - 1, z - 1),
 	grad(self.p[BB + 1], x - 1, y - 1, z - 1))))
 end
+
+return Perlin

worldeditadditions/lib/noise/init.lua

@@ -0,0 +1,12 @@
+worldeditadditions.noise = {}
+
+-- The command itself
+dofile(worldeditadditions.modpath.."/lib/noise/noise2d.lua")
+
+-- Dependencies
+dofile(worldeditadditions.modpath.."/lib/noise/apply_2d.lua")
+dofile(worldeditadditions.modpath.."/lib/noise/make_2d.lua")
+dofile(worldeditadditions.modpath.."/lib/noise/params_apply_default.lua")
+
+-- Noise generation engines
+dofile(worldeditadditions.modpath.."/lib/noise/engines/perlin.lua")

worldeditadditions/lib/noise/make_2d.lua

@@ -11,15 +11,13 @@
 -- @param	size	Vector	An x/y vector representing the size of the noise area to generate.
 -- @param	params	table|table<table>	A table of noise params to use to generate the noise. Values that aren't specified are filled in automatically. If a table of tables is specified, it is interpreted as multiple octaves of noise to apply in sequence.
 function worldeditadditions.noise.make_2d(size, params)
-	params = worldeditadditions.noise.params_apply_default(params)
-	
 	local result = {}
 	
 	local generator;
 	if params.algorithm == "perlin" then
 		generator = worldeditadditions.noise.perlin.new()
 	else -- We don't have any other generators just yet
-		return false, "Error: Unknown noise algorithm '"..params.."'."
+		return false, "Error: Unknown noise algorithm '"..params.."' (available algorithms: perlin)."
 	end
 	
 	for x=params.offset.x, params.offset.x+size.x do

worldeditadditions/lib/noise/noise.lua

@@ -1,5 +0,0 @@
-worldeditadditions.noise = {}
-
-dofile(worldeditadditions.modpath.."/lib/noise/noise_params.lua")
-dofile(worldeditadditions.modpath.."/lib/noise/make_2d.lua")
-dofile(worldeditadditions.modpath.."/lib/noise/engines/perlin.lua")

worldeditadditions/lib/noise/noise2d.lua

@@ -1,6 +1,8 @@
 --- Applies a layer of 2D noise over the terrain in the defined region.
 -- @module worldeditadditions.noise2d
 
+local wea = worldeditadditions
+
 -- ███    ██  ██████  ██ ███████ ███████ ██████  ██████
 -- ████   ██ ██    ██ ██ ██      ██           ██ ██   ██
 -- ██ ██  ██ ██    ██ ██ ███████ █████    █████  ██   ██
@@ -10,10 +12,14 @@
 -- @param	pos1			Vector	pos1 of the defined region
 -- @param	pos2			Vector	pos2 of the defined region
 -- @param	noise_params	table	A noise parameters table. Will be passed unmodified to PerlinNoise() from the Minetest API.
-function worldeditadditions.noise2d(pos1, pos2, noise_params)
+function worldeditadditions.noise.noise2d(pos1, pos2, noise_params)
 	pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	local region_height = pos1.y - pos2.y
 	-- pos2 will always have the highest co-ordinates now
 	
+	-- Fill in the default params
+	noise_params = worldeditadditions.noise.params_apply_default(noise_params)
+	
 	-- Fetch the nodes in the specified area
 	local manip, area = worldedit.manip_helpers.init(pos1, pos2)
 	local data = manip:get_data()
@@ -25,14 +31,25 @@ function worldeditadditions.noise2d(pos1, pos2, noise_params)
 	)
 	local heightmap_new = worldeditadditions.table.shallowcopy(heightmap_old)
 	
-	local perlin_map = PerlinNoiseMap(noise_params, heightmap_size)
+	local noisemap = wea.noise.make_2d(noise_params, heightmap_size)
 	
-	-- TODO: apply the perlin noise map here
+	wea.noise.apply_2d(
+		heightmap_new,
+		noisemap,
+		heightmap_size,
+		region_height,
+		noise_params.apply
+	)
 	
-	local stats = { added = 0, removed = 0 }
+	local success, stats = wea.apply_heightmap_changes(
+		pos1, pos2,
+		area, data,
+		heightmap_old, heightmap_new,
+		heightmap_size
+	)
+	if not success then return success, stats end
 	
 	-- Save the modified nodes back to disk & return
-	-- No need to save - this function doesn't actually change anything
 	worldedit.manip_helpers.finish(manip, data)
 	
 	return true, stats

worldeditadditions/lib/noise/params_apply_default.lua

@@ -1,14 +1,23 @@
+local wea = worldeditadditions
+
 --- Makes sure that the default settings are all present in the given params table.
 -- This way not all params have to be specified by the user.
 -- @param	params	table	The params table generated from the user's input.
 -- @return	table	A NEW table with all the missing properties filled in with the default values.
 function worldeditadditions.noise.params_apply_default(params)
 	local params_default = {
+		-- How to apply the noise to the heightmap. Different values result in
+		-- different effects:
+		-- - The exact string "add": Noise values are added to each heightmap pixel.
+		-- - The exact string "multiply": Each heightmap pixel is multiplied by the corresponding noise value.
+		-- - A string in the form of digits followed by a percent sign (e.g. "40%"), then the noise will is remapped from the range 0 - 1 to the range -1 - +1, and then for each pixel in the heightmap will be altered at most the given percentage of the total height of the defined region.
+		apply = "40%",
+		-- The backend noise algorithm to use
 		algorithm = "perlin",
 		-- Zooms in and out
-		scale = vector.new(1, 1, 1),
+		scale = wea.Vector3.new(1, 1, 1),
 		-- Offset the generated noise by this vector.
-		offset = vector.new(0, 0, 0),
+		offset = wea.Vector3.new(0, 0, 0),
 		-- Apply this exponent to the resulting noise value
 		exponent = 1,
 		-- Multiply the resulting noise value by this number. Changes the "strength" of the noise

worldeditadditions/utils/terrain.lua

@@ -92,7 +92,7 @@ end
 -- @param	heightmap_old	number[]	The original heightmap from worldeditadditions.make_heightmap.
 -- @param	heightmap_new	number[]	The new heightmap containing the altered updated values. It is expected that worldeditadditions.table.shallowcopy be used to make a COPY of the data worldeditadditions.make_heightmap for this purpose. Both heightmap_old AND heightmap_new are REQUIRED in order for this function to work.
 -- @param	heightmap_size	vector	The x / z size of the heightmap. Any y value set in the vector is ignored.
--- 
+-- @returns	bool, string|{ added: number, removed: number }	A bool indicating whether the operation was successful or not, followed by either an error message as a string (if it was not successful) or a table of statistics (if it was successful).
 function worldeditadditions.apply_heightmap_changes(pos1, pos2, area, data, heightmap_old, heightmap_new, heightmap_size)
 	local stats = { added = 0, removed = 0 }
 	local node_id_air = minetest.get_content_id("air")