Jet Moto 2 Recompiled

A native PC build of Jet Moto 2: Championship Edition (PlayStation, 1998, SCUS-94167), made by statically recompiling the game's MIPS code to C# with RecompOne. No emulator and no BIOS. Bring your own disc - this repository and its releases contain no game code or data.

Status

Early release, tested on Windows 11 x64 only.

Works	Not tested yet
Boot logos, title and menus	Sound and CD music (never listened to)
Attract demo	Memory card saving
A full player-controlled race (tried on Slickrock Gorge)	The other 19 tracks, season modes
Keyboard input, cheats menu	Two-player, gamepads

Known oddity: on the 640x480 menu screens the artwork runs off the right edge. It has not been compared against real hardware.

Install

You need Windows x64, the .NET 10 SDK (winget install Microsoft.DotNet.SDK.10) and your own dump of the USA Championship Edition disc.

1. Download the release zip and extract it.
2. Copy your disc image (.cue + 17 .bin tracks, Redump names) into disc\.
3. Run JetMoto2.exe. The first run recompiles the game from your disc and builds it, which takes a few minutes; after that the same exe just starts the game. JetMoto2.exe --rebuild forces a rebuild.

After an update the launcher notices the new version and rebuilds once on its own, keeping your settings, cheats and memory cards.

With Quiver Launcher, install the tile, open its folder, do step 2 and press Play.

Enhancements

All under System > Settings > Display, and on by default:

• 60 fps. The game renders at 30 fps; RecompOne interpolates in-between frames (the frame-rate setting goes higher, up to your monitor's refresh rate). Before v0.1.5 this only affected the menus, not races, so races still looked like 30 fps whatever the setting said.
• PGXP. Removes the PS1's wobbling polygons and warping textures. Interpolation needs it on.
• Widescreen races (16:10, 16:9, 21:9 or off). The 3D view shows more to each side at the same scale; the HUD stays in the middle 4:3 and the pre-drawn menus stay 4:3. (v0.1.3 and v0.1.4 squeezed the 3D view to 3/4 width and left holes in the left edge; fixed in v0.1.5.)
• 4x internal resolution (adjustable 1x to 8x).

Measured on a 15 W Intel laptop, PGXP plus 60 fps costs no extra CPU over stock.

Auto Centering fix

The game's own Options > Auto Centering: Off never fully worked: the steering code levels the bike on two axes, and the setting only switched off one of them. With this port, Off really means off. This can be turned back to the original behaviour under Settings > Display ("Auto Centering Off means fully off"). Nothing changes when Auto Centering is On.

Controls

Default keyboard: Z Cross (thrust), X Circle, A Square, S Triangle (turbo), Enter Start, Right Shift Select, arrow keys. Rebind under System > Settings. F1 hides the menu bar.

Cheats

Cheats in the top menu bar; choices are saved in build\cheats.json.

• Infinite Turbo - verified in a race.
• Infinite Grapple - same record layout as the turbo cheat, not exercised in play yet.
• Apply to CPU riders too

Published GameShark codes for SCUS-94167 are for the 1997 Jet Moto 2 and do not fit this disc: Championship Edition is a different build under the same serial and those addresses land on program code. The addresses used here were found in this build (see patches/Cheats.cs).

Building from source

git clone --recursive https://github.com/goodshepherd23/JetMoto2-Recomp

Put the disc in disc\, then either run the launcher project (dotnet run --project tools/Launcher) or:

dotnet build RecompOne/RecompOne.Recompiler -c Release
RecompOne/RecompOne.Recompiler/bin/Release/net10.0/recompone.exe config/JetMoto2.json
python tools/apply_fixups.py .
dotnet build JetMoto2Recomp.csproj -c Release -o build

.vscode/ has matching tasks and an F5 debug config for VS Code.

What this game needed

• Overlay load addresses. RecompOne's --autoconfigure guesses them from the code and gets this game wrong. The real ones come from the game's own loader: BIN/JM2SHELL.BIN loads at 0x800C10B8 and each of the twenty per-track BIN files at 0x801020B8. tools/FuncMapGen builds the config and function maps with those, and tools/fix_funcmaps.py repairs function starts the linear sweep misplaces. The results are committed in config/.
• CdReadSync must report drive status 0x22 or the game's file loader retries forever (patches/CdPatches.cs).
• StoreImage is replaced for VRAM outside the frame buffers (patches/GpuPatches.cs). The menus upload a palette and read it straight back to build their glowing cursors; RecompOne's GL renderer answers a same-frame readback with stale VRAM, which turned the race-type cursor into green speckles and the track-dial pointer into a grey square.
• Auto Centering (patches/AutoCentering.cs): func_80153858 corrects two angle errors with thruster nudges when they pass the threshold at GP+0x4C8; the Options flag (copied to GP+0x4A0) only gates the first. While the flag is off, the threshold is raised for the duration of that function, the only place it is read.
• Frame pacing (patches/FramePacing.cs): the race loop caps itself at 30 fps by calling VSync(0) repeatedly until enough time has passed. RecompOne publishes a frame on every VSync, so every other one was empty and its interpolator never had two frames to blend. The first wait of each frame now asks for both vblanks at once.
• Widescreen culling. The polygon renderer func_801051BC drops polygons whose screen X are all below 0, which cut holes into the left margin. That one test sits inside a very large function, so config/fixups.json edits it in the generated C# after recompiling (tools/apply_fixups.py; the launcher does the same) to read Widescreen.CullLeft, which is 0 unless widescreen is on.
• libpad replacements are disabled: the game uses PadInit/PadRead, so its own libpad runs against the emulated controller port.

Credits and disclosure

• RecompOne by flaffy and contributors (MIT), pinned as a submodule and used unmodified.
• Jet Moto 2 is by SingleTrac / 989 Studios / Sony Computer Entertainment America. This project is not affiliated with or endorsed by them.
• This port was made with heavy AI assistance (Claude). RecompOne's maintainers do not accept AI-written contributions and do not support ports made this way, so please do not report problems with this project to them. Use this repository's issues instead.

MIT licensed (the code in this repository; not the game).