Distributing Minetest Games

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Revision as of 10:47, 13 January 2023 by ROllerozxa (talk | contribs)
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This page contains (at times very opinionated) notes about taking a Minetest game and distribute it outside of Minetest. It assumes that you know how to compile Minetest from source.

Minetest as an engine itself doesn't have any official means to export a game into a self-contained package with the engine. However as Minetest is free software you can fork the engine to rebrand it and bundle it with the game of your choosing.

General tips

Generally you're able to customise the main menu (at builtin/mainmenu/), which is written in Lua and formspec, however you'd like to suit your game.

Locking down the singleplayer tab to one game

Go into src/defaultsettings.cpp and change default_game to the gameid of your choice. It will now start up on your given game.

To remove the gamebar, it's enough to just remove this code in builtin/mainmenu/tab_local.lua and set the sizes of the buttonbar to 0:

@@ -78,32 +78,8 @@ function singleplayer_refresh_gamebar()
 
 	local btnbar = buttonbar_create("game_button_bar",
 		game_buttonbar_button_handler,
-		{x=-0.3,y=5.9}, "horizontal", {x=12.4,y=1.15})
+		{x=-0.3,y=5.9}, "horizontal", {x=0,y=0})
 
-	for _, game in ipairs(pkgmgr.games) do
-		local btn_name = "game_btnbar_" .. game.id
-
-		local image = nil
-		local text = nil
-		local tooltip = core.formspec_escape(game.title)
-
-		if (game.menuicon_path or "") ~= "" then
-			image = core.formspec_escape(game.menuicon_path)
-		else
-			local part1 = game.id:sub(1,5)
-			local part2 = game.id:sub(6,10)
-			local part3 = game.id:sub(11)
-
-			text = part1 .. "\n" .. part2
-			if part3 ~= "" then
-				text = text .. "\n" .. part3
-			end
-		end
-		btnbar:add_button(btn_name, text, image, tooltip)
-	end
-
-	local plus_image = core.formspec_escape(defaulttexturedir .. "plus.png")
-	btnbar:add_button("game_open_cdb", "", plus_image, fgettext("Install games from ContentDB"))
 end

Rebranding the main menu

Copy the game's menu/ textures into textures/base/pack/.

  • Rename header.png to menu_header.png
  • Rename background.png to menu_bg.png
  • Rename icon.png to logo.png

The main menu branding doesn't support randomised textures (unless you implement that yourself), so you would need to pick one.

Add to the "About" tab

You should keep the Minetest credits list in order to follow Minetest's license regarding attribution, but you may choose to add contributors and developers to the game above it.

In addition to this, you should add some note right above the Minetest credits to credit the engine itself:

local minetest_info = {
	"<GAME> is made possible by the Minetest engine,",
	"which is free software licensed under LGPLv2.1.",
	""
}

Filtering the serverlist

You can filter the serverlist to only show servers running the specified game. Add the following code to builtin/mainmenu/serverlistmgr.lua:

@@ -181,7 +181,18 @@ function serverlistmgr.sync()
 			end
 
 			local retval = core.parse_json(response.data)
-			return retval and retval.list or {}
+
+			local list = {}
+			local kiosk_game = "<gameid of the game>"
+
+			-- Iterate over servers, only keep ones with the valid gameid
+			for _,entry in pairs(retval.list) do
+				if entry.gameid == kiosk_game then
+					table.insert(list, entry)
+				end
+			end
+
+			return list
 		end,
 		nil,
 		function(result)

Replace the kiosk_game variable with the gameid of your game.

Filtering ContentDB packages

ContentDB keeps track of what games a mod is able to support, which can be used to filter the list of packages through the API. This works especially well if the game has a distinct mod ecosystem. Keep in mind that the game needs to be published onto ContentDB for this to work, otherwise you may choose to maintain your own ContentDB instance with a curated set of packages that work with the game.

In builtin/mainmenu/dlg_contentstore.lua, where it constructs an API URL that looks something like this:

"/api/packages/?type=mod&type=game&type=txp&protocol_version=" ..

Add the &game=<author>/<gamepackage> argument onto the URL. For example, Warr1024/nodecore for NodeCore.

Unfortunately texture packs currently do not have the same game compatibility system, so it will be empty when filtering by game name.

Change default settings

You can change the default settings in src/defaultsettings.cpp to better suit your game. You can also tweak settings for particular platforms, for example the Android specific default settings which are inside of a #ifdef __ANDROID__ preprocessor directive.

Windows

Rebranding

To fully change the name of the engine you can change the name of the "project" in CMakeLists.txt. This will change the name of the executable and the name used on the titlebar, among other places. Keep in mind this will also mean you need to rename files in misc/ and the translation files.

To change the icon that's used for Minetest builds on Windows you'll have to replace misc/minetest-icon.ico with your game's icon in the Windows ICO file format.

To make it install your given game instead of Minetest Game, go into CMakeLists.txt and change the line that installs mods/minetest_game to install your game instead. You may also remove things such as the documentation (e.g. lua_api.txt) and devtest. The lines that install this is right around where the game gets installed, just remove those.

Android

This section assumes you already know how to build the Android version of Minetest and how to sign APK files. (TL:DR - Download the Android command-line tools, install the NDK and accept any necessary license terms, then ./gradlew assemblerelease, apksigner and be happy)

Separate package name

First of all you would like to change the package name of the Android app. This will make it separate from the regular Minetest app which has the package name net.minetest.minetest. Change the applicationId in android/app/build.gradle to the package name of your choosing. Package names work like regular Java names which use reverse DNS names, if you don't have a domain name it should be fine to keep net.minetest and only change the last "subdomain" to the game's name.

However if you try to build and install the app right now it will not work. This is because Minetest provides a file provider which needs to be named just like the package name, and will conflict with the regular Minetest app if you have that installed. In android/app/src/main/AndroidManifest.xml and android/app/src/main/java/net/minetest/minetest/GameActivity.java you will have to change the file provider name to reflect your package name.

Rebranding

To change the name of the app to the game's name, edit the label string in android/app/src/main/res/values/strings.xml. To change the icon, replace android/app/src/main/res/mipmap/ic_launcher.png with the icon of the game.

When Gradle bundles assets into an archive, it will copy gameToCopy defined in android/app/build.gradle. By default this is minetest_game so you would want to change the variable to bundle your game instead.

The loading screen background when Minetest extracts assets can be customised too. android/app/src/main/res/drawable/background.png which by default is a basic light blue background will tile if you replace it with something else.

Linux

Linux users are usually more advanced, most of the time they will compile the engine from source for their particular distro and package it for you (the Linux user is a wonderful creature). To give them better desktop integration you should edit misc/net.minetest.minetest.desktop which will give them a application launcher shortcut that accurately reflects the game, including the proper icon.

macOS

TODO

Licensing

As the Minetest engine is licensed under LGPLv2.1, it means that any changes you make to the engine source code need to be made available. This however may not apply to the game you're distributing, which could even be licensed under proprietary terms if you do not make use of any copyleft mods. This isn't legal advice however, and you should consult a lawyer to be absolutely sure.

You can choose to version control your engine fork in Git (which has the added bonus of being able to automatically make builds using CI on your favourite Git host). Alternatively for the absolute minimum necessary you can export your current source tree with modifications as an archive file using something like this:

stashName=`git stash create`; git archive $stashName | gzip > ../cool-game-engine-fork-$(date +'%Y-%m-%d').tar.gz

Make some place where this file is available, and be sure to update it whenever new builds are made. gzip can be replaced with your favourite compression method, if so desired.

Examples

A large portion of the initial version of this page documents changes that were made to the engine for the NodeCore Android app. Its source code is available for download here and can be used as an example if you would like to distribute a game on Android.