Initial commit

.gitignore

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+*~
+*.png

README.md

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+we_env
+======
+
+Tools to aid the forming of "natural" terrain by hand using [WorldEdit](https://github.com/Uberi/Minetest-WorldEdit)'s brush.
+This is more of a proof of concept and might be merged into WorldEdit in the future.
+
+![](https://i.imgur.com/O7PodOm.jpg)
+
+## Command reference
+
+* `//fall`
+Make all gravity-affected nodes in the current selection fall down.
+Unlike the usual "punch to cause fall" this works en masse.
+
+* `//populate`
+Convert terrain (`default:dirt` only) in current selection to look like "real" terrain.
+Meaning: Add grass on top and change deeper nodes to stone.
+
+* `//smooth`
+Smooth terrain (`default:dirt` only) in the current selection.
+This uses an exponentially weighted moving average (EWMA) and should be ran 1 or 2 times to produce good results.

depends.txt

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+worldedit
+worldedit_commands

init.lua

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+local mh = worldedit.manip_helpers
+
+---------------------------------------------
+-- manipulations
+---------------------------------------------
+
+local function fall(pos1, pos2)
+	local pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	local dim = vector.subtract(pos2, pos1) -- technically incorrect but cba to fix
+	if dim.y == 0 then return 0 end
+
+	local manip, area = mh.init(pos1, pos2)
+	local data = manip:get_data()
+
+	local count = 0
+	local stride = {x=1, y=area.ystride, z=area.zstride}
+	local offset = vector.subtract(pos1, area.MinEdge)
+	local c_air = minetest.get_content_id("air")
+	for x = 0, dim.x do
+		local index_x = offset.x + x + 1 -- +1 for 1-based indexing
+		for z = 0, dim.z do
+			local index_z = index_x + (offset.z + z) * stride.z
+
+			local y = 0
+			local fall_height = 0
+			while y < dim.y do
+				local index = index_z + (offset.y + y) * stride.y
+				local ndef = minetest.registered_nodes[minetest.get_name_from_content_id(data[index])]
+				local did_fall = false
+				if ndef ~= nil then
+					if ndef.groups.falling_node ~= nil and fall_height > 0 then
+						-- move all nodes above down by `fall_height`
+						-- FIXME: move meta & param2 too
+						for y2 = y, dim.y do
+							local index2 = index_z + (offset.y + y2) * stride.y
+							data[index2 - stride.y * fall_height] = data[index2]
+							data[index2] = c_air
+						end
+						count = count + (dim.y - y)
+						did_fall = true
+					elseif not ndef.walkable then
+						fall_height = fall_height + 1
+					else -- walkable and won't fall
+						fall_height = 0
+					end
+				end
+
+				if did_fall then
+					-- restart processing from node above the one that fell
+					y = y - fall_height + 1
+					fall_height = 0
+				else
+					y = y + 1
+				end
+			end
+		end
+	end
+
+	mh.finish(manip, data)
+	return count
+end
+
+local function populate(pos1, pos2)
+	local pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	local dim = vector.subtract(pos2, pos1) -- technically incorrect but cba to fix
+
+	local manip, area = mh.init(pos1, pos2)
+	local data = manip:get_data()
+
+	local stride = {x=1, y=area.ystride, z=area.zstride}
+	local offset = vector.subtract(pos1, area.MinEdge)
+
+	local count = 0
+	local c_air = minetest.get_content_id("air")
+	local c_dirt = minetest.get_content_id("default:dirt")
+	local c_grass = minetest.get_content_id("default:dirt_with_grass")
+	local c_stone = minetest.get_content_id("default:stone")
+	for x = 0, dim.x do
+		local index_x = offset.x + x + 1 -- +1 for 1-based indexing
+		for z = 0, dim.z do
+			local index_z = index_x + (offset.z + z) * stride.z
+
+			local y = dim.y
+			local last_was_air = false
+			local depth = 0
+			while y >= 0 do
+				local index = index_z + (offset.y + y) * stride.y
+				if data[index] == c_dirt then
+					depth = depth + 1
+					if last_was_air then
+						data[index] = c_grass
+						count = count + 1
+					elseif depth > 3 then
+						data[index] = c_stone
+						count = count + 1
+					end
+				else
+					depth = 0
+				end
+
+				last_was_air = data[index] == c_air
+				y = y - 1
+			end
+		end
+	end
+
+	mh.finish(manip, data)
+	return count
+end
+
+local print2d = function(name, w, h, index) -- for debugging
+	local max = 1
+	for y = 0, h-1 do
+	for x = 0, w-1 do
+		max = math.max(max, index(x, y))
+	end
+	end
+	max = math.ceil(max)
+	local s = "##" .. name .. "\n" .. w .. "," .. h .. ":"
+	for y = 0, h-1 do
+	for x = 0, w-1 do
+		local n = (1 - index(x, y) / max) * 255
+		assert(n >= 0 and n <= 255)
+		s = s .. string.format("%02x", math.floor(n))
+	end
+	end
+	print(s)
+end
+
+local EWMA_alpha = 0.6
+local WEIGHT = {orig=0.5, x=0.25, z=0.25}
+local function smooth(pos1, pos2)
+	local pos1, pos2 = worldedit.sort_pos(pos1, pos2)
+	local dim = vector.add(vector.subtract(pos2, pos1), 1)
+	if dim.x < 2 or dim.y < 2 or dim.z < 2 then return 0 end
+
+	local manip, area = mh.init(pos1, pos2)
+	local data = manip:get_data()
+
+	local stride = {x=1, y=area.ystride, z=area.zstride}
+	local offset = vector.subtract(pos1, area.MinEdge)
+	local c_air = minetest.get_content_id("air")
+	local c_dirt = minetest.get_content_id("default:dirt")
+
+	-- read heightmap from data
+	local heightmap = {}
+	local hstride = {x=1, z=dim.x}
+	for x = 0, dim.x-1 do
+		for z = 0, dim.z-1 do
+			heightmap[x + (z * hstride.z) + 1] = 0
+		end
+	end
+	for x = 0, dim.x-1 do
+		local index_x = offset.x + x + 1 -- +1 for 1-based indexing
+		for z = 0, dim.z-1 do
+			local index_z = index_x + (offset.z + z) * stride.z
+
+			local y = dim.y-1
+			while y >= 0 do
+				if data[index_z + (offset.y + y) * stride.y] ~= c_air then
+					heightmap[x + (z * hstride.z) + 1] = y + 1
+					break
+				end
+				y = y - 1
+			end
+		end
+	end
+
+	-- calculate EWMA for each x/z slice
+	-- TODO: calculate reverse and average to remove x+/z+ bias
+	local slice_x, slice_z = {}, {}
+	for x = 0, dim.x-1 do
+		local res = {}
+		local last = heightmap[x + 1]
+		res[1] = last
+		for z = 1, dim.z-1 do
+			local h = heightmap[x + (z * hstride.z) + 1]
+			last = EWMA_alpha * h + (1 - EWMA_alpha) * last
+			res[z+1] = last
+		end
+		slice_x[x+1] = res
+	end
+	for z = 0, dim.z-1 do
+		local res = {}
+		local last = heightmap[(z * hstride.z) + 1]
+		res[1] = last
+		for x = 1, dim.x-1 do
+			local h = heightmap[x + (z * hstride.z) + 1]
+			last = EWMA_alpha * h + (1 - EWMA_alpha) * last
+			res[x+1] = last
+		end
+		slice_z[z+1] = res
+	end
+
+	--[[print2d("heightmap", dim.x, dim.z, function(x, z)
+		return heightmap[x + (z * hstride.z) + 1]
+	end)
+	print2d("ewma_x", dim.x, dim.z, function(x, z)
+		return slice_x[x+1][z+1]
+	end)
+	print2d("ewma_z", dim.x, dim.z, function(x, z)
+		return slice_z[z+1][x+1]
+	end)--]]
+
+	-- adjust actual heights based on results
+	local count = 0
+	for x = 0, dim.x-1 do
+		local index_x = offset.x + x + 1 -- +1 for 1-based indexing
+		for z = 0, dim.z-1 do
+			local index_z = index_x + (offset.z + z) * stride.z
+
+			local old_height = heightmap[x + (z * hstride.z) + 1]
+			local new_height = math.floor(
+				old_height * WEIGHT.orig +
+				slice_x[x+1][z+1] * WEIGHT.x +
+				slice_z[z+1][x+1] * WEIGHT.z
+			)
+
+			if old_height > new_height then
+				-- need to delete nodes
+				local y = old_height-1
+				while y >= new_height do
+					local index = index_z + (offset.y + y) * stride.y
+					if data[index] == c_dirt then data[index] = c_air end
+
+					count = count + 1
+					y = y - 1
+				end
+			elseif old_height < new_height then
+				-- need to add nodes
+				local y = old_height
+				while y <= new_height-1 do
+					local index = index_z + (offset.y + y) * stride.y
+					if data[index] == c_air then data[index] = c_dirt end
+
+					count = count + 1
+					y = y + 1
+				end
+			end
+		end
+	end
+
+	mh.finish(manip, data)
+	return count
+end
+
+---------------------------------------------
+-- chat commands
+---------------------------------------------
+
+minetest.register_chatcommand("/fall", {
+	params = "",
+	description = "Apply gravity to all falling nodes in current WorldEdit region",
+	privs = {worldedit=true},
+	func = function(name, param)
+		local pos1, pos2 = worldedit.pos1[name], worldedit.pos2[name]
+		if pos1 == nil or pos2 == nil then
+			worldedit.player_notify(name, "no region selected")
+			return nil
+		end
+		local count = fall(pos1, pos2)
+		worldedit.player_notify(name, count .. " nodes updated")
+	end,
+})
+
+minetest.register_chatcommand("/populate", {
+	params = "",
+	description = "Populate dirt in current WorldEdit region",
+	privs = {worldedit=true},
+	func = function(name, param)
+		local pos1, pos2 = worldedit.pos1[name], worldedit.pos2[name]
+		if pos1 == nil or pos2 == nil then
+			worldedit.player_notify(name, "no region selected")
+			return nil
+		end
+		local count = populate(pos1, pos2)
+		worldedit.player_notify(name, count .. " nodes updated")
+	end,
+})
+
+minetest.register_chatcommand("/smooth", {
+	params = "",
+	description = "Smooth terrain (dirt) in current WorldEdit region",
+	privs = {worldedit=true},
+	func = function(name, param)
+		local pos1, pos2 = worldedit.pos1[name], worldedit.pos2[name]
+		if pos1 == nil or pos2 == nil then
+			worldedit.player_notify(name, "no region selected")
+			return nil
+		end
+		local count = smooth(pos1, pos2)
+		worldedit.player_notify(name, count .. " nodes updated")
+	end,
+})

parse2d.py

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+#!/usr/bin/env python3
+from PIL import Image
+from collections import namedtuple
+from binascii import unhexlify
+import sys
+
+# parses debug output from print2d() and creates PNGs
+Parsed = namedtuple("Parsed", ['w', 'h', 's'])
+parsed = {}
+
+state = None
+for line in sys.stdin:
+	line = line.rstrip("\r\n")
+	if state is not None:
+		dim, data = line.split(":")
+		tmp = dim.split(",")
+		w, h = int(tmp[0]), int(tmp[1])
+		parsed[state] = Parsed(w, h, data)
+
+	if line.startswith("##"):
+		state = line[2:]
+	else:
+		state = None
+
+for name, p in parsed.items():
+	#print("len(s)=%r w*h=%d" % (len(p.s), p.w * p.h))
+	img = Image.frombytes("L", (p.w, p.h), unhexlify(p.s))
+	img.save(name + ".png")