--- Applies a layer of 2D noise over the terrain in the defined region.
-- @module worldeditadditions.noise2d

local wea = worldeditadditions

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--- Applies a layer of 2d noise over the terrain in the defined region.
-- @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.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()
	
	local heightmap_old, heightmap_size = worldeditadditions.make_heightmap(
		pos1, pos2,
		manip, area,
		data
	)
	local heightmap_new = worldeditadditions.table.shallowcopy(heightmap_old)
	
	local noisemap = wea.noise.make_2d(noise_params, heightmap_size)
	
	wea.noise.apply_2d(
		heightmap_new,
		noisemap,
		heightmap_size,
		region_height,
		noise_params.apply
	)
	
	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
	worldedit.manip_helpers.finish(manip, data)
	
	return true, stats
end