Hello there !
My friend and me played Minecraft since years on our private server. The problem is, he broke his computer recently.
So, considering I have a powerful PC (GTX 1060 6gb, i5 4440) and two screens, I thought about both of us playing on a different screen. But, as you know, Minecraft doesn't support local co-op...
Are there any kind of mods or tools to do this ?
I precise that we both bought Minecraft, but my friend lost his password and forgot his mail adress, so he can only play on a cracked version...
The only mod I know of at the moment that does so is the 'Joypad mod' which allows controller support and splitscreen on the same screen (similar splitscreen to Minecraft on console, but the controller support for this mod is a slightly bit worse than Minecraft console which always surprised me), but most of the time when I try to find the mod again, I remember it has a 'ad site' blocking access to download it so I give up/get turned away on getting the mod these days when developers do that. It's just awkward and wrong/dodgey. And the only other mod I know of that does controllers is MCGamePad for 1.8 but it doesn't give you the splitscreen feature your looking for.
It depends on the version of the game too. I think Joypad has mostly been available for current versions such as 1.7.10, 1.8 and 1.9 version which I remember using but afterwards it didn't update any further so 1.9 and before versions it seems for the controller/splitscreen Java Edition experience.
But that's the answer I can give for now of mods that allow co-op on one monitor/screen.
Edit: After checking a document I had with information on downloads for the mod 1.11 versions were made, and even a GitHub/source code link let me know there is a 1.12 version, but again, all the downloads led to an ad site so... That's unfortunate.
I also have information from January 2017 towards the mod as well as download links (again led to ad sites so dangerous). But that's all I have of things regarding the mod since I don't have a .jar file of the mod left when I thought I did. Sigh.
You can edit your minecraft profile file to make it load a 'guest' account, skipping authentification. I've forgotten how to do so though (can confirm it works at least), and I don't think the mods would like me explaining it hahah.
Try a google search for it. Something like "how to start minecraft offline mode".