Minetest-WorldEditAdditions/worldeditadditions/lib/noiseapply2d.lua

local wea_c = worldeditadditions_core
local Vector3 = wea_c.Vector3

---
-- @module worldeditadditions

-- ███    ██  ██████  ██ ███████ ███████  █████  ██████  ██████  ██   ██    ██ ██████  ██████
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-- ██ ██  ██ ██    ██ ██ ███████ █████   ███████ ██████  ██████  ██     ████    █████  ██   ██
-- ██  ██ ██ ██    ██ ██      ██ ██      ██   ██ ██      ██      ██      ██    ██      ██   ██
-- ██   ████  ██████  ██ ███████ ███████ ██   ██ ██      ██      ███████ ██    ███████ ██████

--- Similar to cubeapply, except that it takes 2 positions and randomly keeps changes based on a noise pattern.
-- Takes a backup copy of the defined region, runs the given function, and then
-- restores the bits that aren't above the noise threshold.
-- @param	pos1	Vector3		The 1st position defining the region boundary
-- @param	pos2	Vector3		The 2nd positioon defining the region boundary 
-- @param	func	function	The function to call that performs the action in question. It is expected that the given function will accept no arguments.
function worldeditadditions.noiseapply2d(pos1, pos2, threshold, scale, func)
	local time_taken_all = wea_c.get_ms_time()
	pos1, pos2 = Vector3.sort(pos1, pos2)
	if not threshold then threshold = 0.5 end
	-- pos2 will always have the highest co-ordinates now
	
	-- Fetch the nodes in the specified area
	local manip_before, area_before = worldedit.manip_helpers.init(pos1, pos2)
	local data_before = manip_before:get_data()
	
	local time_taken_fn = wea_c.get_ms_time()
	func()
	time_taken_fn = wea_c.get_ms_time() - time_taken_fn
	
	local manip_after, area_after = worldedit.manip_helpers.init(pos1, pos2)
	local data_after = manip_after:get_data()
	
	local size2d = pos2 - pos1 + Vector3.new(1, 1, 1)
	-- print("DEBUG pos1", pos1, "pos2", pos2, "size2d", size2d)
	local success, noise = worldeditadditions.noise.make_2d(size2d, pos1, {
		algorithm = "perlinmt",
		scale = scale
	})
	if not success then return success, noise end
	
	for z = pos2.z, pos1.z, -1 do
		for y = pos2.y, pos1.y, -1 do
			for x = pos2.x, pos1.x, -1 do
				local i_before = area_before:index(x, y, z)
				local i_after = area_after:index(x, y, z)
				
				local i_noise = (z-pos1.z)*size2d.x + (x-pos1.x)
				
				-- Roll everything where the noise function returns less than 0.5
				if noise[i_noise] < threshold then
					data_after[i_after] = data_before[i_before]
				end
			end
		end
	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_after, data_after)
	
	time_taken_all = wea_c.get_ms_time() - time_taken_all
	return true, { all = time_taken_all, fn = time_taken_fn }
end