Unleashed Recompiled: PC port of the Xbox 360 version of Sonic Unleashed

[OuterVale]

This is one of the most impressive things I've seen in a while. It isn't traditional emulation, and it isn't a decompilation.

It is a static recompilation of the Xbox 360 version. It required a ton of low-level re-handling of things from the 360's Xenon CPU and Xenos GPU.

Not only is it the game running natively on PC, it has also been modded to support all manner of tweaks and enhancements that are manageable in-game, and mod support.

Really impressive stuff.

Release trailer: https://www.youtube.com/watch?v=TJreGbVPDx0

[perching_aix]

> It isn't traditional emulation, and it isn't a decompilation. It is a static recompilation of the Xbox 360 version.

And all its real benefits come from the countless manual changes made to it, such as rewriting the rendering code. This is because at its core, especially for now, there's no meaningful technological difference between what the tool they used does vs what an emulator does.

Applications on the X360 were barred from self-modifying, so an emulator can/will statically (ahead-of-time) recompile the executable before jumping to it. Whether this is actually what Xenia (the x360 emu) does or if they JIT / hybrid it to get rid of the lengthy precomp, idk, but RPCS3 (the ps3 emu) where this exact same situation also applies does do this, even via LLVM, so there really is 0 difference. (On the PS3 though, there's also SPU code, which can and does self modify, so that needs JITing).

[aquova]

As a fan of the game, I just built it and got it working for myself. It's really impressive and is running great on my machine. I realize (with dread) that the game is about 17 years old now, but I eagerly awaited it release back in the day, and it was one of first games that I still think of as "modern". Rewatching the opening movie, I'm not sure you could easily distinguish it from a modern CGI cutscene.

[Borealid]

This is conceptually similar to Ship of Harkinian ( https://www.shipofharkinian.com/ ). If someone cares enough about a particular game to put this level of tailored work into it, wonderful.

There is a down side, though: because emulators handle a much wider variety of games, they get better feature sharing for things like save states, shaders, controller bindings, etc. With libretro things even go a step beyond that and different systems' games can all share the same launcher UI and the same support for things like RetroAchievements!

So a recompiled version is better from a performance standpoint, and might have more game-specific quality of life features, but it also means more development time is devoted to that particular game.

[LorenDB]

Similar Sonic projects include SA2 Redux[0] and Project 06[1].

[0]: https://gamejolt.com/games/SA2R/939490

[1]: https://youtube.com/c/ChaosX (best link as there is no official website)

[ronjouch]

And similar recomp projects include Zelda { Ocarina of Time, Majora's Mask } and Starfox.

- https://github.com/HarbourMasters/Shipwright

- https://github.com/HarbourMasters/2ship2harkinian

- https://github.com/HarbourMasters/Starship

[louhike]

SA2 redux looks more like a remake than a recomp. I didn’t know the project though and it seems promising!

[robbiet480]

It's already available on macOS too, runs pretty well https://github.com/squidbus/UnleashedRecomp/actions/runs/136...

[heavensteeth]

Every time MattKC uploads[0], his video's subject matter appears on HN a few hours later. I'm beginning to think it's not a coincidence :)

[0]: https://www.youtube.com/watch?v=lMGu6Ng_3yA

[OuterVale]

In this case the post was made a few days ago, but didn't get the traction it arguably deserved so was given a second chance.

[no_time]

Am I understanding right that this is basically an ahead of time xbox360 emulator?

Absolutely fascinating.

[dharmab]

It's not emulation. It's recompiled to the target device's native machine code. It also required a lot of additional low-level, per game programming to make stuff like graphics and sound work correctly.

[remix2000]

Compared to the og recompiler <https://github.com/rexdex/recompiler>, this is super basic and only matches patterns specific to a single compiler rather than devising a CFG as one would expect with such a tool. I wasn't able to analyze, let alone "recompile" even the basic "dolphin" demo.

[DeathArrow]

It's the first time I hear about static recompilation. I didn't know you can recompile something to run on a different architecture and OS.