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The History of Nucleus Coop and Splitscreen.me

The Beginning#

The story of Splitscreen.me starts with a splitscreening tool, made by the Brazillian game and software developer Lucas Assislar in August/September 2012, only a few weeks after Borderlands 2's release. The app was originally created to split screen Borderlands 2, as there was not any way to play that game split screen on PC at the time. The app was called "Borderlands 2 SplitScreen Tool" at the time; fast-forward a year in August 2013 Lucas made this post. The app already had support for multiple games, and because of that, the app name "Borderlands 2 SplitScreen Tool" didn't really fit anymore. Therefore the project was renamed to SplitPlay. SplitPlay was really buggy, so a lot of people were still using the original tool for borderlands 2.

In 2014 Lucas Assislar made his first Youtube video about the project, showcasing Borderlands 2 in split screen. 4 days later he made another video showcasing Borderlands: The Pre-Sequel. The video was a hit, and is currently sitting at around 68k views.

Rebranding to Nucleus Co-op#

Behind the scenes Lucas started working on another rebranding of the app, this time it was going to be called Nucleus Co-op. Lucas made version 1 of Nucleus Co-op in October 2015, but didn't like the result. He rebuilt it in version 2.0, and in December 2015 this version was released. The release was very buggy and only had support for the two previously mentioned borderlands games. In terms of functionality, Nucleus Co-op was a downgrade compared to SplitPlay. But the groundwork for the project was made.

Lucas continued to improve Nucleus Co-op over the next few months, and new features were added in each release. Perhaps the first notable update came in September 2016 with the release of Alpha 4(September 26. 2016). Along with the already supported games from the previous version, this release brought support(although very buggy) for Borderlands 1, and a new fundamental change to how the games' handlers were made. In earlier version of Nucleus, the handlers were made using C#, and were only available inside the system. This was problematic, since it meant that if you wanted to add a game, you had to fork the entire app in order to add it. Alpha 4 however brought the JavaScript engine into the mix, which meant that you could simply make a JavaScript handler and add it to the app. This meant that it would be easier for others to help with the project. It also made it easier for Lucas to add handlers, or make small changes to the existing ones without changing ( and potentially messing up) the main application.

Alpha 5(October 11. 2016) and Alpha 6(October 19. 2016) focused on improving Borderlands 1 support, along with quality of life upgrades to the app. Alpha 7(March 21. 2017) redesigned the UI, brought close to perfect splitscreening of all the Borderlands games released at the time, Saints Row 3 got added as working, and the javascript engine got improved. This was also around the time where the first people started joining in and making their own scripts.

On August 9. 2017, r-mach shared his addition of don't starve together in a reddit post. A few days after this reddit post, r-mach reached out to Lucas, and they decided that Lucas would continue on the app, and r-mach would be doing the web stuff. r-mach created the old website nucleuscoop.com, and he later created basic a basic API for handlers. He also created a wiki together with Lucas. Even though the API was 99% finished, the wiki and API never saw the light of day.

Alpha 8(August 27. 2017) brought a big change as well, arguably even more so than Alpha 4, d1maxa and r-mach made some improvements, and added some games. Several bugs were also fixed. This version broke Saints Row 3, but it added 4 new games to the list, and the first Cod game was added to the "What kinda works" list. In Alpha 9(August 5. 2018) the engine got reworked once again, The game handlers now needed to be downloaded from an external website, unlike the included javascript(.js) handlers that had been before. At this time Lucas Assislar's latest release is the Alpha 10(February 1. 2019) version, which had a reworked UI. With this version admin privileges were not needed at app startup(unlike before), and in his own words "XInput library will setup the game's window, for WAYYY faster scaling". The handlers also got changed in this version, now the .js handler file would have to be placed inside a .nc(zip-file) file in order to be read by Nucleus.

Lucas had long been struggling with mental health problems, and personal matters. And largely because of this he stopped working on the project after the release of Alpha 10 and went silent. R-mach, the main website developer at the time, also went silent after that release, also due to personal matters. This is the reason the old wiki and API, which I mentioned earlier, never got finished.

Enter SplitScreenDreams#

On the surface it seemed like Nucleus Co-op had died, and there was little to no information regarding where the project was at, and where it was headed. But behind the scenes two enthusiasts had started working individually on making split screen handlers/scripts, for the app. They soon found out about each other, and they made a private Discord server called "SplitScreenDreams" on April 24. 2019.

One of the two enthusiasts, called Talos91, invited another enthusiast called dr.oldboi(dr.oldboi#8752 on Discord) to the server very shortly after. These three started working together on making split screen scripts for Nucleus Co-op. The SplitScreenDreams server started growing, and Talos91 would often post guides on reddit about how to play new games in split screen with Nucleus. At the time of writing this (August 04. 2021), SplitScreenDreams has made handlers for over 500 games, almost 400 of which are published on the hub, and downloadable from within the Nucleus Coop app. These handlers were made thanks to cooperation between almost 100 people, but the majority of the handlers, were made by co-creator of SplitScreenDreams, Talos91.

The Nucleus Co-op Zerofox Mod#

Most of todays supported games however, would not be possible if it weren't for Zerofox bringing new life into the project, with his fork of the Alpha 8 version, called "Alpha 8 Zerofox mod".

Zerofox had first seen the split screen project back in it's infancy just before it's rebranding from SplitPlay to Nucleus Co-op. He stumbled upon it when trying to find games he could play in split screen on his PC. At the time (as mentioned earlier) SplitPlay was very much in early development, so he didn't look any further into it at the time. Fast-forward to 2019, he went on a quest again to find a way to split screen games. This is when he stumbled upon one of Talos91's reddit posts. The post was a guide to playing Dead Rising 2 in split screen. There he referenced Nucleus Co-op which Zerofox remembered from his earlier encounter with the app. And because of this guide Zerofox had his first real experience with Nucleus Co-op. It was after this that Zerofox really got into Nucleus Co-op. In July 2019, after reading Talos' post, and reading up more of his guides/posts, Zerofox read about a "secret" Discord channel where this stuff was being worked on. He sent Talos a PM on reddit saying that he wanted to help out, to which Talos responded with an invite to the SplitScreenDreams Discord server.

After trying out Nucleus and learning more about it, Zerofox saw there were a few major barriers. Having modded games and consoles since his childhood, and a few big mods behind him, he thought that he could fix those barriers relatively easily. So he started working on a few Quality of Life upgrades to the app. That was originally all that he intended to do. However as he got to using Nucleus more and more, and talking with the other members of the SplitScreenDreams discord, he started to realize the potential Nucleus Co-op had. So he expanded the "mod" by adding a few thing here and there according to community feedback and his own ideas. Those "few things here and there" added up to a lot of things, and with a lot of support from the community he branded his mod "Zerofox Alpha 8 mod" and released it on August 1. 2019.

In this relatively short time, Zerofox had made it possible for the community to add support for a lot of games that were previously impossible to split screen through Nucleus Co-op. However there were a few things missing, and multiple mouse and keyboard support was one of them. There had been attempts earlier by Lucas to add Keyboard and Mouse (KBM) support to Nucleus, but it only allowed for 1 KBM, not multiple. And besides, it was quite buggy and didn't always work as intended. While Zerofox was working on Nucleus Co-op he heard about Universal Split Screen(USS). He took a look at it, and was instantly amazed. While I was interviewing Zerofox he said: "The code, design and execution was very impressive. It was more of the "big picture" idea I had for Nucleus. I truly believed USS was the future." USS had support for multiple keyboards and mice, which was a dream come true for Zerofox. Not only that, the tool was generally powerful with a lot of other powerful features. The problem was the setup, even though USS was more powerful than Nucleus in a lot of aspects, it required a much more tedious setup. Zerofox wanted the functionality and power of USS, but the convenience of Nucleus Co-op. So that is what he set out to do with his mod, he found a new source of inspiration in USS to improve his own Nucleus Co-op mod.

r-mach, the same guy who made the NucleusCoop.com website, joined the SplitScreenDreams Discord some time after Zerofox. He had heard someone talking about this mysterious "SplitScreenDreams" Discord server in the official Nucleus Co-op server, then called "Distro". When r-mach found out about the server he immediately wrote to Lucas explaining that someone had continued splitscreening games with Nucleus Co-op, and urged him to come back and see for himself. In the message he wrote "DUDE THERE'RE PEOPLE DOING AMAZING THINGS, LETS COME BACK IN!" Lucas didn't answer the message.

In October/November 2019, after some time developing the mod and having added a lot of new features, Zerofox started talking with r-mach. Zerofox talked to r-mach about wanting to take the mod further and build something new from scratch as a standalone, new and improved... and under a different name. r-mach suggested combining forces with USS. Which brings us to the story of how USS and developer Ilyaki joined the Nucleus Co-op team.

The Origins of Universal Split Screen (USS)#

Going a bit back in time, to before Nucleus Co-op started gaining traction again, another developer called Ilyaki was also looking into split screen. This other developer also came from the modding scene. In 2018 he had made a mod for Stardew Valley, the mod redirected controller input between instances, much like Nucleus Co-op. He even added KBM support, and moved onto porting the mod to Terraria, as it was running under the same engine. After a brief stunt called Battle Royalley(a battle royale mod for Stardew Valley), he once again returned to split-screening games. Ilyaki had heard of Nucleus Co-op before, but he was more interested in getting support for multiple keyboards and mice than controllers, and with his background with keyboard and mouse modding he had a good starting point. So he started to work on his own project, Universal Split Screen, also know as USS. Ilyaki had initially thought it would be as simple as splitting input as he'd done before and sending input to each game with something like AutoHotKey. It turned out to be much harder than that, much thanks to the overcomplicated input model of Windows, and the different methods used for different games. He was able to get some rather limited results by just forwarding Windows input messages around, but it didn't seem to be a magic formula he had hoped for. Luckily Ilyaki made a breakthrough when he started using something called EasyHook. With EasyHook's function hooking, he was able to easily modify the input that applications were recieving. And after about 3 months of testing, he arrived at USS 1.0.0(July 16. 2019). He was finally sucessful in splitting games, and assigning keyboards and mice to the instances with his app. Ilyaki made a post(Universal Split Screen released) on the r/localmultiplayergames subreddit on July 17. 2019, telling about USS and what it had achieved so far. Less than 2 hours later Talos91 commented on the post asking what was the advantages over Nucleus Co-op, to which Ilyaki responded "The main advantages are multiple keyboard/mouse/controller support, and compatibility with many games." Soon thereafter Talos91 invited him to join the SplitScreenDreams Discord, where Ilyaki met the split screen community. Ilyaki had joined SplitScreenDreams before Zerofox, but when Zerofox joined, and presented his mod... Ilyaki saw the potential. ZeroFox's mod had incredible automation features and simple user setup, compared to USS's entirely manual approach.

Nucleus Co-op and USS join forces#

After r-mach suggesting Ilyaki and Zerofox should join forces, Zerofox started talking to the developer of USS, Ilyaki. Ilyaki agreed to help out with Zerofox's mod, and they have been working together ever since. Ilyaki has since brought multi-KBM support to Nucleus Co-op, along with a lot more features for scripters.

Rebranding to Splitscreen.me#

r-mach started working on the new website(Splitscreen.me) and the hub(splitscreen.me/hub). After it's creation lots of contributions have been made to the website by the community. Today the website has documentation which is ever expanding and the hub has almost 400 public handlers, and close to 500,000 handler downloads.

Before we end this story, we would like to thank the entire community for helping develop, script, suggest features, report bugs, manage Discord and Reddit servers, post guides, and everything else you do to make this community so much better! The story of Splitscreen.me is far from over, and we hope you will help us make a comeback in split screen gaming for PC. Join the split screen revolution!

More coming soon...#

A big thanks to all the people(listed below) who helped piece together the history of Splitscreen.me, this would not have been possible without you guys!#

Written by Snailed lt

In association with: Talos91, dr.oldboi, Lucas Assislar, Zerofox, r-mach, Gaz, Ilyaki, anonymous SplitScreenDreams creator