Nebula

Nebula runs Super Mario Galaxy natively on Windows. You need your own copy of the game.

The released version is 1.0.2. This branch (main) is Nebula 2, in development and not released: much of this page describes it. What 1.0.2 has and what is coming in 2.0 are listed separately below.

Download · Controls · Building from source · Architecture

Not affiliated with or endorsed by Nintendo.

Project status

• Released: Nebula 1.0.2. Playable from start to finish with the North American disc (RMGE01). Setup translates the game's PowerPC code to C++ and compiles it on your PC.
• In development: Nebula 2 (this branch). The game is built as native code from the Petari decompilation, with more discs, controllers and features (below). It is not released; you can build it from source. Bugs remain; see Known issues.

How Nebula was made

Nebula's host, renderer, installer, tests and documentation were written with AI coding agents (Anthropic's Claude), directed, reviewed and tested by the project's author. The game's own logic, Mario's physics included, is the Petari decompilation by SMGCommunity, compiled for the PC with the changes a 64-bit, little-endian host needs.

How it works

Nebula 2 (this branch; 1.0.2 works differently, see Project status):

1. Game module (native/). Petari's game code, JSystem, NW4R and RVLFaceLib, compiled with clang into smg_game.dll.
2. Host (runtime/, native/host). NebulaNative.exe loads the module and gives it its services: typed records drawn with Direct3D 12 or Vulkan, voices mixed and played, controllers and a real Wii Remote, the game's files from the store, saves, and the frame clock.
3. Setup and launcher (installer/, C#; crates/nebula-import, Rust). Nebula-Setup.exe reads your disc image, checks that it is the supported release and packs its files for Nebula; Nebula.exe starts the game.

Features

In the released version (1.0.2)

• Keyboard and mouse, Xbox controllers, the Switch Pro and Switch 2 Pro Controllers (USB), remappable. Switch controllers point with the gyro and tilt for the Star Ball and ray surfing; vibration follows the Wii Remote's motor.
• Aspect ratios from 4:3 to 32:9, internal resolution up to 16x, frame rates above 60.
• Anti-aliasing (SMAA, FXAA), AMD FidelityFX FSR 1 and NVIDIA DLSS upscaling, anisotropic filtering, optional per-pixel lighting.
• In-game settings menu (F1, View + Menu on Xbox, Minus + Plus on Switch).
• Text speed: dialogue and Rosalina's storybook at the original pace, 2x or 3x.
• English, French or Spanish, the languages of the North American disc.
• Saves in %LOCALAPPDATA%\Nebula\saves, with export, import and Dolphin saves (see Saves).

In development for 2.0 (not released)

None of these are in 1.0.2. They are in this branch and change until 2.0 is released.

• The European (RMGP01) and Japanese (RMGJ01) discs and all their languages (Languages).
• The game built natively from the Petari decompilation: no compiling during install; a Vulkan renderer beside Direct3D 12.
• More controllers: PlayStation (DualShock 4, DualSense, DualSense Edge), the Steam Controller and generic HID controllers; gyro pointing and tilt on any controller with motion sensors.
• MSAA, AMD FSR 3, ambient occlusion.
• Skippable cutscenes (+ during a cutscene) and Quit to desktop on the file select.
• 34 achievements, each with a pop-up when it is reached. From the Gateway's Grand Star on, a Luma near Mario's start in the Comet Observatory shows them all: tabs, filters and play stats.
• Instant text speed.
• Mii import for the file icons from a Wii, DS, 3DS, Wii U, Switch, Mii Studio or Mii Creator. Settings > GENERAL

  IMPORT MIIS, or put the files in the miis folder next to the settings; imported files are kept there and read at every start.

• Mods: one .luma file for a mod, on every version of the game. LumaLink converts Riivolution mods and texture packs to it, and its guide shows how to make one: models, textures, levels, music, cutscenes, galaxies, and native plugins with hooks. Import from Settings > MODS or drop a file on the game window. Among enabled mods the higher one wins a file or texture. Raw mods, disc files and texture packs in the mods folder still work.
• Nebula's own text (its buttons, questions and achievements) in all 14 of the game's languages, changeable or translatable by a mod: docs/MODDING_NEBULA_TEXT.md.
• When Nebula stops, an error code (docs/ERROR_CODES.md) naming the cause and a report in %LOCALAPPDATA%\Nebula\crashes.

Requirements

• Super Mario Galaxy, revision 0, as an ISO, RVZ or extracted folder: North America (RMGE01) for 1.0.2; Europe (RMGP01) and Japan (RMGJ01) too in 2.0 (in development)
• Windows 10 (version 1803 or newer) or Windows 11, 64-bit
• A GPU with Direct3D 12 support
• A CPU with AVX2 (2.0)
• 8 GB of RAM; for 1.0.2, 16 GB of free disk space and an internet connection during installation, about 5.5 GB afterwards

Install

1. Download Nebula-Setup.exe from the latest release. The file is not code-signed, so Windows SmartScreen shows "Unknown publisher"; choose More info, then Run anyway.
2. Select your game and choose Install.
3. Start Nebula from the Start menu.

Setup installs 1.0.2, the released version. Setup also updates, repairs and uninstalls. Updates are signed; Setup checks the signature against the public key built into it before installing. Each update keeps the version before it: Nebula Setup > Restore the previous version goes back to it (and forward again the same way).

Languages

1.0.2 plays the North American disc in English, French or Spanish. Nebula 2 (in development) plays the North American (RMGE01), European (RMGP01) and Japanese (RMGJ01) discs, each in the languages on it. Setup names a disc's languages before importing it. The game starts in your system's language where the disc has it (else English; Japan's disc in Japanese), and the language setting offers the disc's languages (and those a mod adds). Nebula's own menus follow the game's language.

Disc	Languages
North America, RMGE01	English, French, Spanish
Europe, RMGP01	English, French, German, Spanish, Italian (GameTDB)
Japan, RMGJ01	Japanese
Korea, RMGK01	Korean (GameTDB); not supported yet

GameTDB lists no Wii disc in Chinese; Simplified Chinese came with the NVIDIA Shield TV release in China (RNVW01). The Korean release's code also names a Simplified Chinese folder (Language.cpp); no Korean disc has been read here to see whether it holds one.

Saves

Saves are kept in %LOCALAPPDATA%\Nebula\saves, laid out like the Wii's internal memory: each release keeps its own save, as on the Wii, in title\00010000\<title>\data\GameData.bin (1.0.2 also writes the Wii Menu's banner.bin beside it; 524d4745 North America; in 2.0 also 524d4750 Europe and 524d474a Japan). Move saves with the launcher's Advanced tab:

• Export saves… writes Nebula-Saves-<date>.zip with everything the game reads.
• Import saves… takes such a zip, another zip or folder of Nebula saves, or a save from Dolphin. Your current saves are moved to saves-backup-<date> beside them first. Close the game before importing or exporting.

To bring a save over from Dolphin, right-click Super Mario Galaxy in Dolphin, choose Open Wii Save Folder, then in Nebula choose Advanced, Import saves…, From a folder… and select that folder. A save goes to the installed disc's release; Nebula and Dolphin use the same save format.

Building from source

docs/BUILDING.md covers the tools, building the game module, the host and Setup, and running the tests.

Known issues

• 1.0.2: some players report the game closing when Mario enters or leaves water in some galaxies (Beach Bowl, Sea Slide, Bonefin, Deep Dark, Freezeflame).
• Heavy background CPU load can make the audio skip.
• HD replacement movies at 4K need hardware video decoding.

Report problems on the issue tracker. If Nebula closed unexpectedly, attach its crash report from %LOCALAPPDATA%\Nebula\crashes.

License

Nebula is licensed under the GNU General Public License v3.0 only (LICENSE). Third-party code and its licenses are listed in THIRD-PARTY-NOTICES.md and docs/PROVENANCE.md.

Nebula builds on the Petari decompilation (SMGCommunity), Aurora, Dusklight, SMAA, AMD FidelityFX, NVIDIA Streamline and the nod disc library.

"Super Mario Galaxy", "Wii" and "Nintendo" are trademarks of Nintendo.