Playing Minecraft in split screen on PC and other funny stories

A few weeks ago I felt a sudden urge to play some Minecraft with my brother. We both have accounts on minecraft.net, but my PC is the only one in our household capable of running it smoothly. Besides, we prefer the same-room multiplayer, preferably hot-seat (like in Worms) or split screen (so many hours lost on Left 4 Dead), so regular Minecraft multiplayer was out of the question.

I started looking into available options. Minecraft didn't have a split screen option, unlike the upcoming XBox 360 version. Searching for mods that added the functionality revealed no results. Then I remembered of a method of playing another game, Borderlands, in semi-splitscreen. It was based on running two instances of a game in a window, and connecting to each other in LAN. Add a bunch of scripts, boarder-less (no pun intended) windows, and you have yourself a playable game.

So, if I could run and control two instances of Minecraft, after connecting to the same server I would have some real world, first class, same room multiplayer fun. I could even connect a second monitor and play it really comfortably.

The quest was on finding a way to control both instances separately. Minecraft didn't support joypad input, and I haven't found a mod that does that neither. Other possible solutions included programs like Joy2Key and xpadder to map the joypad buttons and axes into keyboard and mouse input. But doing so would not resolve the problem because only one window can receive keyboard and mouse input at a time, and having two windows open, only one would be focused. Having found no available solution to the problem, I decided to try and develop one myself.

UPDATE: This post is outdated and should be treated only as a curiosity and a piece of (my) history. If  you're interested in downloading and installing the Minecraft Joypad / Split Screen mod, please head to the mod page, or the Minecraft Forums thread.

Thanks to the hard work of guys and gals at the Minecraft Coder Pack, everyone who is interested in modifying Minecraft to suit their needs with basic knowledge of Java and game development can jump right in. They provide the facilities to decompile and deobfuscate the Minecraft classes, an Eclipse workspace with the debug profile set and ready, and utilities to pack everything back. I really couldn't be impressed more. Everything works out of the box, and the level of de-obfuscation is admirable. Not all method and field names are mapped though, so be prepared for a healthy dose of debugging. Although there are some resources on the net regarding Minecraft modding, if you stray a bit from the known waters (adding blocks, mobs, textures) you're pretty much on your own. I plan an additional blog post regarding the technicalities about what I have learned on Minecraft insides, but for now I present you the 

Minecraft Joypad Mod

The mod allows you to control the Minecraft using the standard OS-recognizable joypad (should work an all OSes). It's in a very rough state, but with a bit of luck and determination on your side it should let you play Minecraft with a joypad. It receives a global joypad input, so it works even if the window has no focus. This effectively lets you play Minecraft in a "split screen". Just run two instances of it, one using the keyboard and mouse, other with a joypad. Resize and/or arrange the windows the way you want to, and rock away. Windows' 7 Snap feature helps a bit, although not as much as the second monitor ;). You can also use software like Auto Window Manager if you wish to. If you want to play locally run the server beforehand. You can also connect to any multiplayer game.

Here's how it looks like:

Basic feature list:

- plays Minecraft using a joypad

- works in both single and multi player

- provides basic means of configuration through the config file

- allows for unlimited (?) number of joypads - yes you should get that 6-player split screen going

- compatible with Minecraft 1.2.5

- all basic features of Minecraft work (including Mining and crafting ;)) - movement, destroying and placing blocks, inventory, chests, crafting, furnace, brewing etc

- lots of fun

UPDATE: It's has been updated to 1.3.2: http://retro-hack.blogspot.com/2012/09/minecraft-joypad-mod-v0113.html

Cons:

- a bit hard to set up ;)

- requires a joypad with 2 analog sticks, d-pad and a few buttons.

- broken keyboard input - you can't use keyboard and joypad for the input at the same time

- main menu not working - you'll need the help from the second player to start the game

- camera sometimes runs in circles by itself at the beginning of the game (stops when you move the analog stick)

- probably not compatible with other mods

I plan on improving upon all of the above, if there is enough public interest.

Setting up

First of all you need a 4-axis joypad which is registered by the OS (check the control panel), and a PC that can handle multiple instances of Minecraft running simultaneously.

Next, you need to prepare a separate portable copy of Minecraft, so you don't screw over you regular Minecraft copy with my mod. You'll need a launcher jar, and this bat file. In case the bat file is unavailable here are it's contents:

set APPDATA=%CD%
java -cp bin\minecraft.jar net.minecraft.LauncherFrame
pause

Create an empty directory on the desktop. Place a bat file inside it. Create an empty directory named 'bin' alongside the bat file, and copy the launcher jar to it. Run the bat file. Log in to minecraft.net. It will download a copy of Minecraft to your folder on the desktop. Afterwards, you can always run the bat file to play it.

So, now you have a clean working copy of Minecraft. Download my mod, and apply it to your copy. Installation is pretty straightforward, as far as mod installation on Minecraft goes - open minecraft.jar with the 7-zip, add my modified classses, remove META-INF. Only difference being that the minecraft.jar is located in Desktop/yourdir/.minecraft/bin instead of %APPDATA%/.minecraft/bin.

Run 'run.bat' it should start the game. It'll print the information about the detected joypads and their layout to the console. The typical output should look like:

Loading: net.java.games.input.DirectAndRawInputEnvironmentPlugin
Minecraft joypad mod v0.6 by Ljubomir Simin
Found 1 controller(s) in total.
Found controller XUSB Gamepad (Controller) (0)
It has  10 buttons.
Button 0, Button 0
Button 1, Button 1
Button 2, Button 2
Button 3, Button 3
Button 4, Button 4
Button 5, Button 5
Button 6, Button 6
Button 7, Button 7
Button 8, Button 8
Button 9, Button 9
It has  5 axes.
Axis 0, Y Axis
Axis 1, X Axis
Axis 2, Y Rotation
Axis 3, X Rotation
Axis 4, Z Axis
Loading configuration file, using joypad no. 0 XUSB Gamepad (Controller)

You can read your joypad name and index (in parenthesis), button and axes counts and names. 

Start the game, create a new world. Walk around, test the controls. They'll probably be suboptimal. Don't worry, you can change them in the file named 'options.txt' in the .minecraft dir.

There's the meaning of button mapping:

joyNo:0 // number of joypad, -1 == no joypad, 0 = first joypad
joyCameraAxisX:3 // axis used for camera movement
joyCameraAxisY:2 // axis used for camera movement
joyMovementAxisX:1 // axis used for player movement
joyMovementAxisY:0 // axis used for player movement
joyCameraSensitivity:20 // camera sensitivity, between 1 and a few hundreds. Other values should provide funny results.
joyCameraInvertY:false // invert camera
joy_joy.attack:5 // attack. normally left mouse click
joy_joy.use:4 // use. normally right click
joy_joy.jump:0 //jump
joy_joy.sneak:8 //sneak
joy_joy.drop:6 //drop one item
joy_joy.inventory:7 // open/close the inventory
joy_joy.interact:2 //interact. like right clicking but without placing blocks
joy_joy.guiLeftClick:5 //used for left click in inventory. might be same as attack. normally left click
joy_joy.guiRightClick:4 //used for right click in inventory. might be same as use. normally right click

You can tweak the settings to match your preference.

UPDATE: Configuration has been simplified in the newest version: http://retro-hack.blogspot.com/2012/09/minecraft-joypad-mod-v0113.html

Notable improvements

When I first started to work on joypad support for Minecraft my goal was to implement it the quick 'n dirty way. As I worked on it though it became obvious there is no quick way. So I took some time and developed a few improvements specific to controller input. 

Firstly, all GUI screens support d-pad navigation. It means you can interact with all containers in game, be it player inventory, crafting bench, furnace, etc. This is not done by mouse emulation, it's hooked into game logic for selecting items, and hand-tweaked for each GUI screen to achieve sensible controls.

Secondly, I've added the 'interact' functionality. Back at the day one could burn own house down while trying to open the chest with a bucket full of lava. Nowadays it's not an issue anymore but it can still be a bit inconvenient if you miss a mob or lever and place a block instead of interacting with an entity. That's why I have added the 'interact' functionality. I behaves like a right mouse click, but can't be used for placing blocks. Think of it like an 'use' button in many other games, used for opening the doors, activating switches and interacting with the mobs. I usually map it to the "square" button on my controller.

Final words

Try it out it you think it's interesting. It's a bit tricky to set up, but I hope that won't be an obstacle to many. This is my first Minecraft mod and contribution, and I'll try to improve it as much as my free time allows it. I depend on your feedback though, so please feel free to comment it, and show to all your friends ;)

Wish you loads of fun.

Cheers!

DOWNLOAD Minecraft Joypad Mod