Minetest-WorldEditAdditions/worldeditadditions/lib/noise/make_2d.lua

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local wea = worldeditadditions

-- Generate a flat array of 2D noise.
-- Written with help from https://www.redblobgames.com/maps/terrain-from-noise/
-- @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, start_pos, params)
	local result = {}
	
	for i, layer in ipairs(params) do
		local generator
		if layer.algorithm == "perlin" then
			generator = wea.noise.engines.Perlin.new()
		elseif layer.algorithm == "sin" then
			generator = wea.noise.engines.Sin.new()
		else -- We don't have any other generators just yet
			return false, "Error: Unknown noise algorithm '"..tostring(layer.algorithm).."' in layer "..i.." of "..#params.." (available algorithms: perlin)."
		end
		
		for x = 0, size.x do
			for y = 0, size.z do
				local i = y*size.x + x
				
				local noise_x = (x + 100000+start_pos.x+layer.offset.x) * layer.scale.x
				local noise_y = (y + 100000+start_pos.z+layer.offset.z) * layer.scale.z
				local noise_value = generator:noise(noise_x, noise_y, 0)
				
				if type(result[i]) ~= "number" then result[i] = 0 end
				result[i] = result[i] + (noise_value ^ layer.exponent) * layer.multiply + layer.add
			end
		end
		
	end
	
	-- We don't round here, because otherwise when we apply it it'll be inaccurate
	
	return true, result
end