Initial commit

.gitignore

@@ -0,0 +1 @@
+textures

.luacheckrc

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+globals = {"texgen"}
+read_globals = {"minetest", "modlib", "Settings"}

Readme.md

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+# Texture Generator (`texgen`)
+
+Dynamically generates a texture pack for your current game in the `textures` directory.
+
+## Features
+
+* Compatible with virtually all mods and games
+* Easy texture pack generation, no complex installation
+* Server-side (mod-based) texture pack; textures can be accessed by other mods
+
+## Instructions
+
+Just fire up the mod and configure it to your liking. It might throw an error message as it updates its `mod.conf` to depend on all enabled mods. Simply retry after that.
+
+### Downloading palettes
+
+You can use the `/download_palette <url>` chatcommand to download a PNG palette file, for example `/download_palette https://lospec.com/palette-list/zughy-32-1x.png`.
+
+See `/help download_palette` for details on its usage.
+
+Requires the `server` priv. Only available if `texgen` is added to `secure.http_mods`.
+
+**WARNING: Enabling this feature poses a minor security risk.**
+
+## Configuration
+
+<!--modlib:conf:2-->
+### `average`
+
+Replace each texture with a single pixel of its weighted average RGB color
+
+* Type: boolean
+* Default: `false`
+
+### `invert`
+
+Invert the RGB colors
+
+* Type: boolean
+* Default: `false`
+
+### `monochrome`
+
+Convert RGB to monochrome (greyscale)
+
+* Type: boolean
+* Default: `false`
+
+### `palette`
+
+#### `dithering`
+
+Dithering method to use
+
+* Type: string
+* Default: `floyd_steinberg`
+* Possible values:
+  * sierra
+  * stucke
+  * sierra_lite
+  * jarvis_judice_ninke
+  * floyd_steinberg
+  * none
+  * two_row_sierra
+  * burkes
+  * atkinson
+
+#### `name`
+
+Name of the palette to use (without extension)
+
+* Type: string
+* Default: `apollo`
+* Possible values:
+  * soggy-newspapers
+  * apollo
+  * zughy-32
+  * aap-64
+  * pico-8
+  * resurrect-64
+
+
+### `saturate`
+
+Increase or decrease saturation by a factor
+
+* Type: number
+* Default: `1`
+* &gt;= `0.1`
+* &lt;= `10`
+<!--modlib:conf-->
+
+## Links
+
+* [GitHub](https://github.com/appgurueu/texgen) - sources, issue tracking, contributing
+* [Discord](https://discord.gg/ysP74by) - discussion, chatting
+* [Minetest Forum](https://forum.minetest.net/viewtopic.php?f=9&t=28115) - (more organized) discussion
+* [ContentDB](https://content.minetest.net/packages/LMD/texgen) - releases (downloading from GitHub is recommended)
+
+## License
+
+Code written by Lars Müller (appgurueu) and licensed under the MIT license; builtin Minetest media licensed under various free Creative Commons licenses as well as the Apache 2 license (see `LICENSE.txt` in the `builtin` folder for details and attribution).
+
+The palettes are (for copyright reasons shuffled) versions of palettes available on [Lospec](https://lospec.com/):
+
+* Adigun A. Polack's "AAP-64"
+* AdamCYounis' "Apollo"
+* Lexaloffle Games' "PICO-8"
+* Kerrie Lake's "Resurrect 64"
+* Walking's "Soggy Newspapers"
+* Zughy's "Zughy 32"

average_color.lua

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+-- Average color, weighted by alpha and calculated in linear RGB colorspace
+return function(png)
+	-- TODO make colorspecs extend vectors
+	local avg_color = modlib.vector.new{r = 0, g = 0, b = 0}
+	local total_alpha = 0
+	for _, color in ipairs(png.data) do
+		color = modlib.minetest.colorspec.from_number(color)
+		-- Squared average
+		avg_color = modlib.vector.add(avg_color, modlib.vector.multiply_scalar(
+			modlib.vector.pow_scalar({r = color.r, g = color.g, b = color.b}, 2), color.a))
+		total_alpha = total_alpha + color.a
+	end
+	if total_alpha == 0 then total_alpha = 1 end -- Avoid division by zero
+	-- Round & convert back to colorspec
+	avg_color = modlib.minetest.colorspec.new(avg_color:divide_scalar(total_alpha)
+		:apply(math.sqrt):add_scalar(0.5):floor())
+	return avg_color
+end

builtin/LICENSE.txt

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+
+License of Minetest textures and sounds
+---------------------------------------
+
+This applies to textures and sounds contained in the main Minetest
+distribution.
+
+Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
+http://creativecommons.org/licenses/by-sa/3.0/
+
+textures/base/pack/refresh.png is under the Apache 2 license
+https://www.apache.org/licenses/LICENSE-2.0.html
+
+Textures by Zughy are under CC BY-SA 4.0
+https://creativecommons.org/licenses/by-sa/4.0/
+
+textures/base/pack/server_public.png is under CC-BY 4.0, taken from Twitter's Twemoji set
+https://creativecommons.org/licenses/by/4.0/
+
+Authors of media files
+-----------------------
+Everything not listed in here:
+Copyright (C) 2010-2012 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+ShadowNinja:
+  textures/base/pack/smoke_puff.png
+
+paramat:
+  textures/base/pack/menu_header.png
+  textures/base/pack/next_icon.png
+  textures/base/pack/prev_icon.png
+  textures/base/pack/clear.png
+  textures/base/pack/search.png
+
+rubenwardy, paramat:
+  textures/base/pack/start_icon.png
+  textures/base/pack/end_icon.png
+
+erlehmann:
+  misc/minetest-icon-24x24.png
+  misc/minetest-icon.ico
+  misc/minetest.svg
+  textures/base/pack/logo.png
+
+JRottm:
+  textures/base/pack/player_marker.png
+
+srifqi:
+  textures/base/pack/chat_hide_btn.png
+  textures/base/pack/chat_show_btn.png
+  textures/base/pack/joystick_bg.png
+  textures/base/pack/joystick_center.png
+  textures/base/pack/joystick_off.png
+  textures/base/pack/minimap_btn.png
+
+Zughy:
+  textures/base/pack/cdb_add.png
+  textures/base/pack/cdb_clear.png
+  textures/base/pack/cdb_downloading.png
+  textures/base/pack/cdb_queued.png
+  textures/base/pack/cdb_update.png
+  textures/base/pack/cdb_viewonline.png
+
+appgurueu:
+  textures/base/pack/server_incompatible.png
+
+License of Minetest source code
+-------------------------------
+
+Minetest
+Copyright (C) 2010-2018 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Irrlicht
+---------------
+
+This program uses IrrlichtMt, Minetest's fork of
+the Irrlicht Engine. http://irrlicht.sourceforge.net/
+
+ The Irrlicht Engine License
+
+Copyright © 2002-2005 Nikolaus Gebhardt
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute
+it freely, subject to the following restrictions:
+
+   1. The origin of this software must not be misrepresented; you
+      must not claim that you wrote the original software. If you use
+	  this software in a product, an acknowledgment in the product
+	  documentation would be appreciated but is not required.
+   2. Altered source versions must be plainly marked as such, and must
+      not be misrepresented as being the original software.
+   3. This notice may not be removed or altered from any source
+      distribution.
+
+
+JThread
+---------------
+
+This program uses the JThread library. License for JThread follows:
+
+Copyright (c) 2000-2006  Jori Liesenborgs (jori.liesenborgs@gmail.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.
+
+Lua
+---------------
+
+Lua is licensed under the terms of the MIT license reproduced below.
+This means that Lua is free software and can be used for both academic
+and commercial purposes at absolutely no cost.
+
+For details and rationale, see https://www.lua.org/license.html .
+
+Copyright (C) 1994-2008 Lua.org, PUC-Rio.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+Fonts
+---------------
+
+Bitstream Vera Fonts Copyright:
+
+  Copyright (c) 2003 by Bitstream, Inc. All Rights Reserved. Bitstream Vera is
+  a trademark of Bitstream, Inc.
+
+Arimo - Apache License, version 2.0
+  Digitized data copyright (c) 2010-2012 Google Corporation.
+
+Cousine - Apache License, version 2.0
+  Digitized data copyright (c) 2010-2012 Google Corporation.
+
+DroidSansFallBackFull:
+
+  Copyright (C) 2008 The Android Open Source Project
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.

dithering.lua

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+-- Simple error diffusion dithering
+-- TODO use HSV/HSL for dithering closer to human perception
+
+local matrices = {
+	none = {
+		fraction = 0
+	},
+	floyd_steinberg = {
+		fraction = 1/16,
+		{x_off = 1,         7};
+		{x_off = -1,  3, 5, 1};
+	},
+	jarvis_judice_ninke = {
+		fraction = 1/48,
+		{x_off = 1,            7, 5};
+		{x_off = -2,  3, 5, 7, 5, 3};
+		{x_off = -2,  1, 3, 5, 3, 1};
+	},
+	stucke = {
+		fraction = 1/42,
+		{x_off = 1,            8, 4};
+		{x_off = -2,  2, 4, 8, 4, 2};
+		{x_off = -2,  1, 2, 4, 2, 1};
+	},
+	atkinson = {
+		fraction = 1/8,
+		{x_off = 1,         1, 1};
+		{x_off = -1,  1, 1, 1   };
+		{x_off = 0,      1      };
+	},
+	burkes = {
+		fraction = 1/42,
+		{x_off = 1,            8, 4};
+		{x_off = -2,  2, 4, 8, 4, 2};
+	},
+	sierra = {
+		fraction = 1/16,
+		{x_off = 1,            4, 3};
+		{x_off = -2,  1, 2, 3, 2, 1};
+	},
+	sierra_lite = {
+		fraction = 1/4,
+		{x_off = 1,         2},
+		{x_off = -1,  1, 1   },
+	},
+	two_row_sierra = {
+		fraction = 1/32,
+		{x_off = 1,            5, 3},
+		{x_off = -2,  2, 4, 5, 4, 2},
+		{x_off = -1,     2, 3, 2   },
+	},
+}
+texgen.dithering_methods = matrices
+
+local clamp = modlib.math.clamp
+return function(method)
+	local matrix = assert(matrices[method])
+	return function(png, closest_color)
+		local width = png.width
+		local diffused_errors = {}
+		local zero_err = {r = 0, g = 0, b = 0}
+		for index, color in ipairs(png.data) do
+			local x, y = (index - 1) % width, math.floor((index - 1) / width)
+			color = modlib.minetest.colorspec.from_number(color)
+			local diff_err = diffused_errors[index] or zero_err
+			diffused_errors[index] = nil
+			local col_err = {
+				r = clamp(color.r + diff_err.r, 0, 255),
+				g = clamp(color.g + diff_err.g, 0, 255),
+				b = clamp(color.b + diff_err.b, 0, 255)
+			}
+			local new_color = closest_color(col_err)
+			png.data[index] = modlib.minetest.colorspec.new{
+				r = new_color.r,
+				g = new_color.g,
+				b = new_color.b,
+				a = color.a -- keep alpha
+			}:to_number()
+			-- Diffuse error
+			local weight = matrix.fraction * color.a / 255
+			if weight > 0 then
+				local err = {
+					r = weight * (new_color.r - col_err.r),
+					g = weight * (new_color.g - col_err.g),
+					b = weight * (new_color.b - col_err.b)
+				}
+				for y_off, row in ipairs(matrix) do
+					local ey = y + y_off - 1
+					for x_off, factor in ipairs(row) do
+						local ex = x + row.x_off + x_off - 1
+						local idx = ey * width + ex
+						local derr = diffused_errors[idx] or {r = 0, g = 0, b = 0}
+						derr.r = derr.r + factor * err.r
+						derr.g = derr.g + factor * err.g
+						derr.b = derr.b + factor * err.b
+						diffused_errors[idx] = derr
+					end
+				end
+			end
+		end
+	end
+end

download_palette.lua

@@ -0,0 +1,39 @@
+local http = ...
+local palettes = modlib.mod.get_resource"palettes"
+minetest.register_chatcommand("download_palette", {
+	params = "<url>",
+	description = "Download a palette to use for generating textures",
+	privs = {server = true},
+	func = function(name, url)
+		local palette_name = url:match"/([A-Za-z0-9-_]+)%.png$"
+		if not (url:match"^https://" and palette_name) then
+			return false, "URL must be a valid HTTPS URL with a filename consisting of ASCII letters, digits, hyphens and underscores and ending in a .png extension." -- luacheck: ignore
+		end
+		http.fetch({
+			url = url,
+			method = "GET"
+		}, function(res)
+			local failure = (res.timeout and "Timeout") or (not res.succeeded and ("HTTP Status Code %d"):format(res.code))
+			if failure then
+				minetest.chat_send_player(name, ("Downloading from URL %s failed: %s"):format(url, failure))
+				return
+			end
+			local stream = modlib.text.inputstream(res.data)
+			local status, res_or_err = pcall(modlib.minetest.decode_png, stream)
+			if stream:read(1) then
+				status, res_or_err = false, "EOF expected"
+			end
+			if status then
+				-- Rewrite & store PNG
+				local png = res_or_err
+				modlib.minetest.convert_png_to_argb8(png)
+				modlib.table.shuffle(png.data) -- for copyright reasons
+				modlib.file.write(modlib.file.concat_path{palettes, palette_name .. ".png"},
+					modlib.minetest.encode_png(png.width, png.height, png.data))
+				minetest.chat_send_player(name, ("Palette %s added to palettes!"):format(palette_name))
+			else
+				minetest.chat_send_player(name, ("PNG image from URL %s is invalid: %s"):format(url, res_or_err))
+			end
+		end)
+	end
+})

init.lua

@@ -0,0 +1,130 @@
+local modname = "texgen"
+local modpath = minetest.get_modpath(modname)
+
+-- Rewrite mod.conf on startup
+do
+	local conf = Settings(modpath .. "/mod.conf")
+	conf:set("name", modname)
+	conf:set("description", "Dynamically generated texture packs")
+	conf:set("depends", "modlib")
+	local to_depend = {}
+	local to_dep_list = {}
+	for _, modname in pairs(minetest.get_modnames()) do to_depend[modname] = true end -- luacheck: ignore
+	local opt_dep_str = conf:get"optional_depends" or ""
+	for opt_depend in opt_dep_str:gmatch"[^%s,]+" do
+		table.insert(to_dep_list, opt_depend)
+		to_depend[opt_depend] = nil
+	end
+	to_depend.texgen = nil -- no circular dependency
+	to_depend.modlib = nil -- modlib is already a hard dependency
+	if next(to_depend) or not modlib then
+		for dep in pairs(to_depend) do table.insert(to_dep_list, dep) end
+		conf:set("optional_depends", table.concat(to_dep_list, ", "))
+		conf:write()
+		error"mod.conf updated to optionally depend on all enabled mods, please restart the game"
+	end
+end
+
+assert(modlib.version >= 94, "update modlib to version rolling-94 or newer")
+
+-- Register palette downloading command if HTTP API is available
+local http = minetest.request_http_api()
+if http then
+	assert(loadfile(modlib.mod.get_resource"download_palette.lua"))(http)
+end
+
+local texture_path = modpath .. "/textures/"
+if minetest.rmdir then
+	-- Clear texture directory on startup
+	minetest.rmdir(texture_path, true)
+end
+minetest.mkdir(texture_path)
+
+local function get_path(filename)
+	local path
+	local mod = modlib.minetest.media.mods[filename]
+	if mod == modname then -- media overridden by this mod
+		local overridden_paths = modlib.minetest.media.overridden_paths[filename]
+		if not overridden_paths then return end
+		path = overridden_paths[#overridden_paths]
+	else
+		path = modlib.minetest.media.paths[filename]
+	end
+	return path
+end
+
+texgen = {} -- HACK only use the mod namespace to expose the dithering methods to the schema...
+local dithering = modlib.mod.include"dithering.lua" -- sets texgen.dithering_methods
+local conf = modlib.mod.configuration()
+texgen = nil -- ...delete it afterwards
+
+local palette, dither
+if conf.palette.name then
+	palette = modlib.mod.include"palette.lua"(conf.palette.name)
+	dither = dithering(conf.palette.dithering)
+end
+local saturate, monochrome, invert = conf.saturate, conf.monochrome, conf.invert
+local average
+if conf.average then
+	average = modlib.mod.include"average_color.lua"
+end
+
+local function read_convert_png(path)
+	local file = assert(io.open(path, "rb"))
+	local png = modlib.minetest.decode_png(file)
+	assert(not file:read(1), "EOF expected")
+	file:close()
+	modlib.minetest.convert_png_to_argb8(png)
+	return png
+end
+
+local clamp = modlib.math.clamp
+local function transform_png(filename, path)
+	local png = read_convert_png(path)
+	if palette then
+		dither(png, palette)
+	end
+	modlib.table.map(png.data, function(color_num)
+		local color = modlib.minetest.colorspec.from_number(color_num)
+		if saturate ~= 1 then
+			-- See https://alienryderflex.com/saturation.html
+			local P = math.sqrt(0.299 * color.r^2 + 0.587 * color.g^2 + 0.114 * color.b^2)
+			local res = modlib.vector.apply({
+				r = clamp((color.r - P) * saturate + P + 0.5, 0, 255),
+				g = clamp((color.g - P) * saturate + P + 0.5, 0, 255),
+				b = clamp((color.b - P) * saturate + P + 0.5, 0, 255),
+			}, math.floor)
+			color.r, color.g, color.b = res.r, res.g, res.b
+		end
+		if invert then
+			color.r, color.g, color.b = 255 - color.r, 255 - color.g, 255 - color.b
+		end
+		if monochrome then
+			local brightness = math.floor(0.299 * color.r + 0.587 * color.g + 0.114 * color.b + 0.5)
+			color.r, color.g, color.b = brightness, brightness, brightness
+		end
+		return color:to_number()
+	end)
+	local width, height, data = png.width, png.height, png.data
+	if average then
+		width, height, data = 1, 1, {average(png):to_number()}
+	end
+	modlib.file.write(modlib.file.concat_path{modpath, "textures", filename},
+		modlib.minetest.encode_png(width, height, data))
+end
+
+for filename in pairs(modlib.minetest.media.paths) do
+	local _, ext = modlib.file.get_extension(filename)
+	if ext == "png" then
+		local path = get_path(filename)
+		-- May be (only) overridden media from this mod, which does not have a path (as it was deleted)
+		if path then transform_png(filename, path) end
+	end
+end
+-- Builtin textures aren't provided by mods and are thus unknown to modlib; provide them through this mod
+for _, filename in ipairs(minetest.get_dir_list(modlib.file.concat_path{modpath, "builtin"}, false)) do
+	-- Don't override builtin overrides by other mods
+	if filename:match"%.png$" and not (modlib.minetest.media[filename] and modlib.minetest.overridden_paths[filename]) then
+		transform_png(filename, modlib.file.concat_path{modpath, "builtin", filename})
+	end
+end

mod.conf

@@ -0,0 +1,5 @@
+name = texgen
+title = Texture Generator
+author = appguru(eu)
+description = Dynamically generated texture packs
+depends = modlib

palette.lua

@@ -0,0 +1,42 @@
+local function relative_color_distance(color, other_color)
+	-- See https://www.compuphase.com/cmetric.htm
+	local redmean = (color.r + other_color.r) / 2
+	-- Omits the square root as this only has to be relative
+	return (2 + redmean/256) * (color.r-other_color.r)^2
+		+ 4 * (color.g-other_color.g)^2
+		+ (2 + (255 - redmean)/256) * (color.b-other_color.b)^2
+end
+local palettes = modlib.mod.get_resource"palettes"
+return function(name)
+	local path = modlib.file.concat_path{palettes, name .. ".png"}
+	local file = assert(io.open(path, "rb"))
+	local png = modlib.minetest.decode_png(file)
+	assert(not file:read(1), "EOF expected")
+	file:close()
+	modlib.minetest.convert_png_to_argb8(png)
+	local colors = {}
+	for _, color in pairs(png.data) do
+		-- TODO ignore colors with alpha 0?
+		local rgb = color % 0x1000000
+		colors[rgb] = true
+	end
+	local palette_colors = {}
+	for colornum in pairs(colors) do
+		table.insert(palette_colors, modlib.minetest.colorspec.from_number(colornum))
+	end
+	return function(color)
+		-- Find closest color using a linear search; a k-d-tree can't be employed here because the metric isn't euclidean
+		local closest_color = palette_colors[1]
+		local closest_distance = relative_color_distance(color, closest_color)
+		for i = 2, #palette_colors do
+			local palette_color = palette_colors[i]
+			local distance = relative_color_distance(color, palette_color)
+			-- TODO deal with same distances through random choice?
+			if distance < closest_distance then
+				closest_color = palette_color
+				closest_distance = distance
+			end
+		end
+		return closest_color
+	end
+end

schema.lua

@@ -0,0 +1,48 @@
+local palettes = {}
+for _, filename in ipairs(minetest.get_dir_list(modlib.mod.get_resource"palettes", false)) do
+	local palette = filename:match"(.+)%.png$"
+	if palette then palettes[palette] = true end
+end
+return {
+	type = "table",
+	entries = {
+		palette = {
+			type = "table",
+			entries = {
+				name = {
+					type = "string",
+					description = "Name of the palette to use (without extension)",
+					values = palettes,
+					default = "apollo"
+				},
+				dithering = {
+					type = "string",
+					description = "Dithering method to use",
+					values = texgen.dithering_methods,
+					default = "floyd_steinberg"
+				}
+			}
+		},
+		saturate = {
+			type = "number",
+			description = "Increase or decrease saturation by a factor",
+			range = {min = 0.1, max = 10},
+			default = 1
+		},
+		monochrome = {
+			type = "boolean",
+			description = "Convert RGB to monochrome (greyscale)",
+			default = false
+		},
+		invert = {
+			type = "boolean",
+			description = "Invert the RGB colors",
+			default = false
+		},
+		average = {
+			type = "boolean",
+			description = "Replace each texture with a single pixel of its weighted average RGB color",
+			default = false,
+		}
+	}
+}

settingtypes.txt

@@ -0,0 +1,19 @@
+# Replace each texture with a single pixel of its weighted average RGB color
+texgen.average (Texgen Average) bool false
+
+# Invert the RGB colors
+texgen.invert (Texgen Invert) bool false
+
+# Convert RGB to monochrome (greyscale)
+texgen.monochrome (Texgen Monochrome) bool false
+
+# Increase or decrease saturation by a factor
+texgen.saturate (Texgen Saturate) float 1 0.100000 10.000000
+
+[texgen.palette]
+
+# Dithering method to use
+texgen.palette.dithering (Texgen Palette Dithering) enum floyd_steinberg sierra,stucke,sierra_lite,jarvis_judice_ninke,floyd_steinberg,none,two_row_sierra,burkes,atkinson
+
+# Name of the palette to use (without extension)
+texgen.palette.name (Texgen Palette Name) enum apollo soggy-newspapers,apollo,zughy-32,aap-64,pico-8,resurrect-64