Minecraft – Is it possible to run the new Minecraft launcher v1.6.1 in the browser

First of all, the new "launcher" is just a native wrapper arround the old java-based one

We're going to be rolling out a new launcher* soon, and I'd like to get your help getting some general testing first!

*Technically it's not a whole new launcher, it's just a native wrapping around what we have now. The ugly white loading screen at the start has gone, users no longer need to have Java installed (we'll maintain our own version of Java which we'll keep up to date and correct for your OS), and it should handle a whole bunch of failcases much better than before.

We will be creating this for both Windows and OSX, but we only have the Windows one for testing right now. We hope to get the OSX one for testing very early next year, which again will remove lots of current issues OSX users have getting the game (wrong java or no java). You'll notice I haven't said linux... we may or may not make a native one for linux later, we're just not sure if they need it. We're not dropping support for linux or anything crazy like that, they will still play fine as they do now.

There will also be an installer available, so new users will just install the game and have icons where they'd expect, solving lots of issues we've had in the past with "well, where's the game?!". Right now I'm just testing the actual native launcher itself though, so wherever you run it it will put a few files in that folder - again, that won't be an issue with the installer.

If you encounter any bugs, have any comments or complaints, or just generally want to talk about life and stuff please comment and let me know your thoughts!

Download the new launcher, run it in its own folder (makes no real difference but easier to clean up later) and let me know your feedback please! <3

Source: Mojang post on the subject

However, the wrapper downloads it's own JRE to use (as of this writing, it is oracle Java 8), which can cause improvements for users who were running older, and possibly 32-bit java environments.

General Notes

(I'm sorry for any spelling-, grammar- and wording-errors and over-complicated expressions and explanations, English is not my native language...)

I managed to get Minecraft running on my ARM-Chromebook; however, it may not work for future releases (perhaps you will have to modify the scripts, perhaps it won't work at all).

The Launcher I last tried this method with was 1.6.61 and the Minecraft version was 1.9.2.

Knowing a bit of how to write bash scripts is recommendable; do NOT use my script for learning bash, I'm not good at it and you shouldn't learn bad coding practices. (This code is probably acceptable but don't use it for learning just to be sure.)

Do this at your own risk. (I don't think that anything can go wrong really; anyway, backups are always a good idea.)

My actual Answer

Working Principle

The MC-Launcher does the authentication stuff with the Mojang-Server, the updates (including library updates), profile management and then passes the required arguments to the MC-Client. The MC-Launcher also passes the library paths to the Client. By writing a java-wrapper-script we can modify the library paths passed to the client.

Choosing a newer proprietary edition of Java (optional)

As of what I heard Java 8 brings some notable performance improvements to the ARM platform. By using the version directly from Oracle you won't get automatic updates though.

You can download the proprietary Java 8 here. Go to the downloads page (the link might change from time to time which is why I didn't link directly there), choose to accept the licence and download the version you need (in my case "Linux ARM 32 Soft Float ABI"). Extract the tar file whereever you want to store it on your computer (e.g. in ~/proprietary_java/).

Starting the Launcher

If you downloaded Java 8 and didn't install it in any way (only unpacked the archive somewhere) you can launch the launcher by running e.g.

~/proprietary_java/jdk1.8.0_77/bin/java -jar ~/<path-to-the-minecraft-launcher>. (You may need to change the path accordingly when a newer version of Java is released at some point. You may also want to write a custom .desktop file or launch script for this.)

The Java Wrapper

This is where my solution gets a bit hacky (not in a good way). You can use this script but you may need to modify the paths:

#!/bin/bash
ARGS=$@
#echo $ARGS > /tmp/args_original #uncomment for debugging

JAVA=$HOME/proprietary_java/jdk1.8.0_77/bin/java
JAVA_LIB_SETTING="-Djava.library.path="
JAVA_LIB_PATH="$HOME/MC_libs"

MC_ORIG_LWJGL="$HOME/.minecraft/libraries/org/lwjgl/lwjgl/lwjgl/2.9.4-nightly-20150209/lwjgl-2.9.4-nightly-20150209.jar"
MC_ORIG_LWJGL_UTIL="$HOME/.minecraft/libraries/org/lwjgl/lwjgl/lwjgl_util/2.9.4-nightly-20150209/lwjgl_util-2.9.4-nightly-20150209.jar"
MC_ARM_LWJGL="$HOME/proprietary_java/MC_libs/lwjgl.jar"
MC_ARM_LWJGL_UTIL="$HOME/proprietary_java/MC_libs/lwjgl_util.jar"

ARGS=$(echo $ARGS | sed "s|$MC_ORIG_LWJGL|$MC_ARM_LWJGL|g" | sed "s|$MC_ORIG_LWJGL_UTIL|$MC_ARM_LWJGL_UTIL|g" )
ARGS=$(echo $ARGS | sed "s|-Djava.library.path=[a-zA-Z0-9_\/\\\.-]\+|$JAVA_LIB_SETTING$JAVA_LIB_PATH |g") #magic ;-)
# the magic seems to eat the space-character though; this is why it's added after JAVA_LIB_PATH (I'm not good at regex)

#"[a-zA-Z0-9_\/\\\.-]\+" explained:
# match a-z and A-Z and 0-9 and '_' and '/' and '\' and '.' and '-' (this must be at the end it seems).
# "\+": escape the '+'; match this pattern multiple times.
#   (this means: start at "-Djava.library.path=" and stop replacing at the first space that occurs)

#echo $ARGS > /tmp/args_modified #uncomment for debugging

$JAVA $ARGS

Save this script e.g. as java_wrapper and make the file executable (e.g. chmod +x java_wrapper)

Explanation:

ARGS=$@: get the arguments passed to the wrapper (more or less the arguments passed to the MC-Client). We do this since we want to modify those and "ARGS" is a little more self-explanatory than "$@"

echo $ARGS > /tmp/args_original: this puts all the arguments to the file /tmp/args_original. This is useful when the game doesn't launch anymore - some paths may have changed and you may need to replace a few paths. Using this you can see which paths you need to replace - more on this soon.

JAVA=$HOME/proprietary_java/jdk1.8.0_77/bin/java: The path to the Java-executable.

JAVA_LIB_SETTING="-Djava.library.path=": This is how java wants to get the library paths. The MC-Launcher passes them like this. Maybe this will change at some point (probably not) and then you'll need to find out how Minecraft tells Java where to look for these libraries. (Uncomment echo $ARGS > /tmp/args_original and have a look at /tmp/args_original and search for something that looks like passing libraries; I'm sorry, I can't provide anything more clear (I did it like this) but maybe someone can provide a proper how-to in the comments?)

JAVA_LIB_PATH="$HOME/MC_libs": Compile libopenal and liblwjgl as mentioned here and put the files lwjgl/libs/linux/liblwjgl.so, lwjgl/libs/lwjgl.jar, lwjgl/libs/lwjgl_util.jar and openal-soft-1.15.1/build/libopenal.so.1.15.1 (remove the ".1.15.1" from libopenal.so) in a directory you want to use (e.g. ~/MC_libs in my example)

MC_ORIG_LWJGL=: This is the original path to lwjgl.jar as it is passed by the launcher. This will probably change at some point (uncomment the lines for debugging then and search for something like "lwjgl.jar" in /tmp/args_original)

MC_ORIG_LWJGL_UTIL: This is the original path to lwjgl_util.jar as it is passed by the launcher. This will probably change at some point (uncomment the lines for debugging then and search for something like "lwjgl_util.jar" in /tmp/args_original)

MC_ARM_LWJGL: This is the path to the lwjgl.jar that you compiled (as described in my "JAVA_LIB_PATH=" description)

MC_ARM_LWJGL_UTIL: This is the path to the lwjgl_util.jar that you compiled (as described in my "JAVA_LIB_PATH=" description)

ARGS=$(echo $ARGS | sed "s|$MC_ORIG_LWJGL|$MC_ARM_LWJGL|g" | sed "s|$MC_ORIG_LWJGL_UTIL|$MC_ARM_LWJGL_UTIL|g" ): Here we change the first few things in the arguments: We replace the path $MC_ORIG_LWJGL with $MC_ARM_LWJGL and $MC_ORIG_LWJGL_UTIL with $MC_ARM_LWJGL_UTIL.

ARGS=$(echo $ARGS | sed "s|-Djava.library.path=[a-zA-Z0-9_\/\\\.-]\+|$JAVA_LIB_SETTING$JAVA_LIB_PATH |g") #magic ;-): Here we replace the library path (which is something that actually may change at some point) with our library path; we replace the specified path after "-Djava.library.path=". I hope you don't have any spaces in there, I'm not good with regular expressions (that's what the "[a-zA-Z0-9_/\.-]+"-thingy is called).

echo $ARGS > /tmp/args_modified: Uncomment this line if you want to see what we get after our modifications to ARGS. This can be useful for finding out what you got wrong in the paths. (I needed this very often for the regex ^^)

$JAVA $ARGS: Call the version of Java we specified at the top and pass the modified arguments of the MC-Launcher to it.

Making the Launcher run our wrapper

Launch the MC-Launcher, log in (if needed) and edit the current profile: In the section "Java Settings (Advanced)" check the option "Executable" and change the path to our Java-wrapper-script.

Now it's finally time to test our wrapper! Launch the MC-Launcher and start minecraft as usual. That's it! If it doesn't work you'll get a few error messages which will hopefully explain what's wrong... You then may need to change a few paths. (Let's hope it's not more than that.) And if it works: Have Fun!

Feel free to ask anything, in some cases I may be able to provide an answer - if not I hope that someone else can.