mitch030504--Wiicompiled_VR_Frame/README.md

WiiCompiled VR for the Steam Frame

Mario Kart Wii in VR on Valve's Steam Frame, running natively on SteamOS: a fork of WiiCompiled OpenXR VR (itself built on WiiCompiled), the static recompilation of Mario Kart Wii to native code. There is no emulator, interpreter or JIT at runtime: your own disc is translated to C++ and compiled for the Frame's ARM64 CPU, and it renders through SteamVR's OpenXR runtime.

Important

There is no Nintendo code, no assets and no game data anywhere in this project. You need your own legally dumped copy of the PAL version of the game; the translation runs on your machine against your disc image, and nothing is uploaded.

Warning

Beta. It runs on a Steam Frame: SteamVR, both eyes at the panels' 2160x2160, the Frame's controllers, 120 Hz with every game frame shown, and foveation that follows your eyes. It is not finished: images still double in races and on the HUD, and the foveation tracks the right eye less well than the left (see Known issues). Reports with the run log move it forward (see Reporting problems).

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Quick start

This is the whole way from your disc to playing in the headset, building on an x86_64 Linux PC. The first build takes a few hours, most of it compiling Dawn under emulation; later builds reuse it. Other ways to build covers a faster machine and the Frame itself.

You need:

• a Steam Frame with Developer Mode on (Steam Settings → System → Enable Developer Mode, then set a user password), on the same network as your PC;
• your own clean PAL RMCP01 disc image of Mario Kart Wii (ISO, WBFS, RVZ, ...);
• an x86_64 Linux PC with about 20 GB free and 16 GB of memory or more.

The PC commands below work in bash, zsh and fish.

Note

Nobody here will tell you where to get the game. Dumping your own disc is on you, and links to game files won't be provided or tolerated. For the same reason there is no ready-built game to download: releases hold the source, and the game is always built from your own disc.

1. Set up ARM64 emulation on the PC

sudo pacman -S --needed podman qemu-user-static qemu-user-static-binfmt   # Arch, CachyOS
sudo systemctl restart systemd-binfmt
podman run --rm --platform linux/arm64 docker.io/library/debian:trixie uname -m

The last command must print aarch64. On Debian or Ubuntu install podman qemu-user-static binfmt-support instead. If podman complains about subordinate ids, run sudo usermod --add-subuids 100000-165535 --add-subgids 100000-165535 $USER and log in again.

2. Get the code and extract your disc

mkdir -p ~/wiicompiled; cd ~/wiicompiled
git clone https://github.com/mitch030504/Wiicompiled_VR_Frame.git
curl -fL -o nodtool https://github.com/encounter/nod/releases/download/v2.0.0-alpha.10/nodtool-linux-x86_64
chmod +x nodtool
./nodtool extract "/path/to/Mario Kart Wii.wbfs" disc-extract
mkdir -p Wiicompiled_VR_Frame/Assets
cp disc-extract/sys/main.dol disc-extract/files/rel/StaticR.rel Wiicompiled_VR_Frame/Assets/

disc-extract must hold sys/ and files/ directly; keep it, the game reads it when it runs.

3. Build, inside an ARM64 container

podman run -it --name wiicompiled-frame --platform linux/arm64 -v ~/wiicompiled:/work docker.io/library/debian:trixie bash

Then, in the container's bash prompt:

apt-get update && apt-get install -y --no-install-recommends \
    ca-certificates curl git python3 xz-utils unzip file pkg-config g++ binutils libicu-dev zlib1g-dev \
    libvulkan-dev libx11-dev libx11-xcb-dev libxcb1-dev libxext-dev libxrandr-dev libxinerama-dev \
    libxcursor-dev libxi-dev libxss-dev libxtst-dev libxkbcommon-dev libwayland-dev wayland-protocols \
    libdecor-0-dev libegl-dev libgl-dev libgles-dev libdrm-dev libgbm-dev libasound2-dev libpulse-dev \
    libpipewire-0.3-dev libudev-dev libdbus-1-dev libusb-1.0-0-dev
cd /work/Wiicompiled_VR_Frame
Launcher/prepare-portable-tools.sh --arch aarch64 --destination /work/tools   # clang 22, CMake, Ninja
T=/work/tools/toolchain-aarch64/bin
curl -fsSL https://dot.net/v1/dotnet-install.sh | bash -s -- --channel 8.0 --install-dir /work/dotnet
Launcher/build-dawn-linux.sh --work-dir /work/dawn --cc $T/clang --cxx $T/clang++ \
    --cmake $T/cmake --ninja $T/ninja --jobs 4 2>&1 | tee -a /work/dawn.log
Launcher/local-build.sh --output-dir /work/out --cc $T/clang --cxx $T/clang++ --fuse-ld lld \
    --cmake $T/cmake --ninja $T/ninja --dotnet /work/dotnet/dotnet --parallel 4 \
    --openxr --dawn-package /work/dawn/package --headset steam_frame 2>&1 | tee -a /work/game.log
exit

• Dawn is done when it prints Patched Dawn for Linux ready, the game when it prints MKWCBUILD:OUTPUT=/work/out.
• --jobs 4 and --parallel 4 suit 16 GB of memory. Compiles take more memory under emulation, and 16 at once froze a 16 GB laptop. Use 8 with 32 GB.
• If it stops, podman start -ai wiicompiled-frame gets you back in. Run cd /work/Wiicompiled_VR_Frame; T=/work/tools/toolchain-aarch64/bin, then the step that stopped: both scripts resume.

4. Install on the Frame

The easiest way is Frame Control: set up its connection to the Frame, then drag ~/wiicompiled/out onto Send to Frame. Name it WiiCompiled and keep Launches on WiiCompiled. It adds the game to your Steam library, in ~/devkit-game/WiiCompiled/ on the Frame.

Then copy the disc over and, on a first install, tell the game where it is (Frame Control's SSH key answers to frame; use steamos@<frame-ip> otherwise):

ssh frame mkdir -p wiicompiled
scp -r ~/wiicompiled/disc-extract frame:wiicompiled/disc
ssh frame 'mkdir -p ~/.local/share/WiiCompiled && printf "[paths]\ndvd_root = \"/home/steamos/wiicompiled/disc\"\n" > ~/.local/share/WiiCompiled/Config.toml'

Without Frame Control, scp -r ~/wiicompiled/out frame:wiicompiled/ and start ~/wiicompiled/out/WiiCompiled from a terminal in the Frame's Desktop Mode, with SteamVR running.

5. Play

Start WiiCompiled from the library in the headset. Open the settings panel with the left shoulder button, go to the VR tab and set the recommended settings.

Updating

Pull the new code, rebuild, and replace only the executable. Copying to a new name and moving it into place works even while an old copy is open:

cd ~/wiicompiled/Wiicompiled_VR_Frame && git pull
podman start -ai wiicompiled-frame
# in the container: cd /work/Wiicompiled_VR_Frame; T=/work/tools/toolchain-aarch64/bin, then the
# build-dawn-linux.sh and local-build.sh lines from step 3 (only what changed is rebuilt), then exit
scp ~/wiicompiled/out/WiiCompiled frame:devkit-game/WiiCompiled/WiiCompiled.new
ssh frame 'cd ~/devkit-game/WiiCompiled && chmod 755 WiiCompiled.new && mv -f WiiCompiled.new WiiCompiled'

Recommended settings

All of these are in the headset's settings panel (left shoulder button, VR tab) and in ~/.local/share/WiiCompiled/Config.toml. Quit the game before editing the file; it writes its settings back when it closes.

Setting	Value	Why
[vr] render_scale	1.25	Scales SteamVR's recommended eye size, 1728x1728 on the Frame: 1.25 is the panels' native 2160x2160, which the Frame renders in 9 to 11 ms a frame with medium foveation.
[vr] foveation	medium	off shades every pixel and costs the most. See Known issues if images double.
[vr] repeat_frames	true (default)	Without it SteamVR halves the game's rate and fills refreshes itself.
[vr] frame_interpolation_fps	0	Rendering in-between frames needs 120 eye pairs a second, which made things worse on the Frame.
[video] resolution_multiplier	2	The game's own frame, which the eyes are made from. 4x is far too heavy for the Frame's GPU.

Keep SteamVR's refresh rate at 120 Hz. Motion Smoothing makes no difference to this game.

Controls

The Frame's controllers are bound through their own profile, so the left D-pad works:

Frame controller	Wii Remote mode	Gamepad mode
Right A	A	South (A)
Right B	C (look behind)	East (B)
Right trigger	B	Right trigger
Right stick up / down	1 / 2	Right stick
Left View	+ (pause)	Start
Left shoulder	Settings panel	North (Y)
Left D-pad	Wii Remote D-pad	D-pad
Left stick, left trigger	Nunchuk stick, Z	Left stick, left trigger
Grips, stick clicks, motion, aim	as on Quest Touch (OPENXR.md, Controllers)	as on Touch
Right X, Y, menu and shoulder	unbound	unbound

Known issues

• Doubled images in races and on the HUD, worst while racing, sometimes in the right eye only. Both eyes get the same frames, so a doubling in one eye points at foveation: the Frame's driver (Turnip) draws a foveated screen tile at lower resolution and scales it back up, and each eye's density maps change with its gaze. Try foveation Off if it bothers you, and report whether it helped.
• Foveation follows the right eye less well than the left. Convergence on near content (the HUD screen at 2 m, the cockpit) is not yet corrected for.
• VR frame interpolation is not recommended on the Frame.
• The Quest app's steamFrame flavour cannot show a picture in the Frame's Android layer (below). Use the native build.

Troubleshooting

Logs. Each run gets a folder under ~/.local/share/WiiCompiled/Logs/ on the Frame, holding console.log and, after a crash, crash_sigsegv.txt. A working start logs, in order:

1. OpenXR initialized: runtime 'SteamVR/OpenXR';
2. Dawn will create its device through the runtime;
3. Fragment density maps: enabled;
4. OpenXR Vulkan swapchains ready ... same-queue native eye copies;
5. display refresh rate 120 Hz requested, then OpenXR session state -> FOCUSED;
6. OpenXR interaction profiles: left /interaction_profiles/valve/frame_controller_valve;
7. OpenXR eye gaze: available, then tracking.

The first one missing says where it stopped. Linux Vulkan OpenXR requires a Dawn built with Aurora's patches means the game was built without --dawn-package.

Smoothness. With [diagnostics] openxr_logging = true, the log gets a pacing line every second:

ssh frame 'cd ~/.local/share/WiiCompiled/Logs && d=$(ls -t | head -1) && grep -h "xr-diag\] 1.0" "$d/console.log" | tail -5'

A healthy race reads predicted-rate=120.0Hz, new=60 repeat=60 and late=0. Fewer than 60 new frames means the GPU is over budget: lower render_scale or resolution_multiplier.

Crashes. console.log then names the faulting thread and gives its pc and a backtrace as module+offset. On the build machine, addr2line -f -C -e Wiicompiled_VR_Frame/native-build/WiiCompiled 0x<offset> turns an offset in WiiCompiled into a function: the executable is not stripped.

Building. A build that freezes the machine has run out of memory: lower --jobs or --parallel. A missing CMake package means installing its -dev package in the container and running the same command again.

Other ways to build

On the Frame itself. SteamOS's root file system is read-only, but it ships podman. Over SSH:

mkdir -p ~/wiicompiled && cd ~/wiicompiled
git clone https://github.com/mitch030504/Wiicompiled_VR_Frame.git
podman run -it --name wiicompiled-frame -v ~/wiicompiled:/work:Z docker.io/library/debian:trixie bash

It is native ARM64, so no emulation, but the Frame has less memory and cooling than a PC. Extract your disc as in step 2, with nodtool-linux-aarch64 instead of nodtool-linux-x86_64, copy main.dol and StaticR.rel into Assets/, and run step 3's commands in the container. The game lands in ~/wiicompiled/out.

With Docker on a stronger machine (a server, for example). The same container and commands work, and much faster with more cores and memory. Copy ~/wiicompiled over without Dawn's build tree, and run the build detached so a closed SSH session does not stop it:

rsync -a --exclude dawn/build --exclude 'dawn/dawn-*' --exclude disc-extract \
    ~/wiicompiled/ root@<server>:/srv/wiicompiled/        # from the PC
docker run -d --name wiicompiled-frame --platform linux/arm64 -v /srv/wiicompiled:/work \
    debian:trixie bash -c 'bash /work/build-game.sh >> /work/game.log 2>&1'

build-game.sh holds step 3's apt-get line and local-build.sh command, with --parallel 8 for 32 GB. docker start wiicompiled-frame runs it again after an update.

On some hosts, for example Unraid 7 with kernel 6.18, binfmt_misc registrations are per container. tonistiigi/binfmt --install arm64 then reports success, but Debian answers exec format error. Register qemu on the host instead, with the P flag the tonistiigi build of qemu expects. Without it, every program loses its first argument, and uname -m prints Linux:

docker create --name qemu-src tonistiigi/binfmt
docker cp qemu-src:/usr/bin/qemu-aarch64 /usr/local/bin/qemu-aarch64
docker rm qemu-src
echo ':qemu-aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-aarch64:POCF' > /proc/sys/fs/binfmt_misc/register
docker run --rm --platform linux/arm64 debian:trixie uname -m   # aarch64

Unraid keeps /usr/local/bin in memory, so repeat this after a reboot.

How it works

• Same-device rendering. SteamVR's OpenXR runtime creates the Vulkan instance and device that Dawn (Aurora's WebGPU layer) renders with, through Aurora's patches to Dawn (aurora-main/patches/dawn). Each eye is copied into SteamVR's swapchain on Dawn's own queue, so nothing is shared between GPU devices. This is the PC's Vulkan backend (runtime/src/vr/openxr_vulkan_win32.cpp), compiled for Linux. Dawn links statically, so the patched Dawn is built once (Launcher/build-dawn-linux.sh). Its aurora-dawn.json declares the Vulkan hook and density map ABIs that Aurora compiles against.
• Headset only. The game neither shows nor finishes rendering a desktop window, and is compiled for the Frame's Cortex-X4 cores (-mcpu=cortex-x4, overridable with --cpu).
• Every refresh from the game. The game draws 60 frames a second. When it handed SteamVR only those, SteamVR ran it at half rate and made up every other refresh itself, even with Motion Smoothing off. With [vr] repeat_frames, the pacing thread waits for the next frame until 1.5 ms before SteamVR's next wake, then resubmits the last frame at the pose it was rendered for. SteamVR turns that to the current head pose.
• Eye-tracked foveation. XR_EXT_eye_gaze_interaction gives the gaze, which runtime/include/vr/eye_gaze.h turns into each eye's view. Aurora picks a fragment density map centred on the gaze, snapped to cells of about 3 degrees (aurora-main/lib/gfx/foveation.hpp), and keeps up to 128 per eye. Each map has a memory block of its own: Turnip reads a map through a host mapping, and Dawn's buffer uploads unmap the shared blocks they sub-allocate from. That crashed the game when a race restarted, until each map got its own block.
• 120 Hz. [vr] refresh_rate (default 120 on the Frame, 0 keeps the headset's own) is asked of SteamVR through XR_FB_display_refresh_rate. SteamVR only offers the rate set in its own settings.

The Android flavour

The Quest app also has a steamFrame flavour (android/Build-Quest.ps1 -Headset frame), for the Frame's Android layer, Lepton. It builds and starts in VR there, but cannot show a picture. The Android backend hands each eye from Dawn's device to its own OpenXR device through VK_ANDROID_external_memory_android_hardware_buffer and sync fds, and Lepton's Turnip has neither, nor VK_KHR_external_memory_fd. The native build needs no sharing, which is why it is the one to play. docs/quest-port.md covers the Android build.

Reporting problems

Open an issue on this repository with:

• what you did and what you saw (which eye, where in the picture, racing or menus);
• the run's console.log (and crash_sigsegv.txt after a crash) from ~/.local/share/WiiCompiled/Logs/ on the Frame;
• or, for a build problem, the last lines of the failing step.

Problems that also happen on a PC or a Quest belong upstream, in WiiCompiled OpenXR VR.

From upstream

The fork keeps everything WiiCompiled OpenXR VR does; its README covers it in full. In the headset that means:

• Menus and unsupported scenes on a head-locked virtual screen, and races in immersive stereo.
• A first-person cockpit whose steering wheel or handlebar turns with your steering, and hand steering by heurazy: grab the wheel with the tracked controllers and turn it.
• The settings panel in the headset (render scale, foveation, refresh rate, controls), saved to Config.toml on the spot.
• Physics identical to the original game, proven by ghosts that sync across Wii, Dolphin and WiiCompiled.
• Retro Rewind as its own statically translated profile.

The PC (Windows D3D12 and Vulkan) and Meta Quest builds are still here and unchanged; see OPENXR.md and docs/quest-port.md. For those, use upstream's WheelWizard VR instead of this fork.

A note on related projects

WiiCompiled, WiiCompiled OpenXR VR, Wheel Wizard, Retro Rewind and this fork are developed independently, each with its own rules. What applies here does not automatically apply there, and vice versa. Check each project's own CONTRIBUTING and README files.

FAQ

Is this an emulator? No. Everything is compiled to native ARM64 code before you press play. At runtime nothing emulates a Wii CPU or GPU.

Do you provide the game, or a ready-built binary? No. Nothing in this repo contains Nintendo code or assets, and the translated game is never shipped: it is built from your own disc, a one-time cost on your machine.

Which game version works? Clean PAL RMCP01. Other regions and modified executables are rejected.

Why not install the Quest APK on the Frame? The Frame runs it in Lepton, whose graphics driver cannot share images between the two GPU devices the Android backend uses, so it shows nothing. The native build uses one device and needs no sharing.

Can it run on other SteamOS or Linux ARM64 devices? Leave out --headset steam_frame and pass --cpu for your CPU to get a generic Linux VR build; it needs an OpenXR runtime with XR_KHR_vulkan_enable2. Untested.

AI usage

AI coding tools were used during development of this project. All translated output is verified against real hardware behavior and most importantly, physics accuracy is proven synced across Wii, Dolphin, and WiiCompiled (see FAQ).

Credits

• inkwreck - making the logo
• aurora - the GX rendering/windowing backend this project's whole graphics layer sits on. MIT licensed.
• Dawn - Google's WebGPU implementation, powering aurora's Direct3D, Vulkan and OpenGL backends.
• OpenXR - the Khronos cross-platform API used by the experimental VR renderer.
• WiiCompiled OpenXR VR by iChris4 and WiiCompiled by patchzyy - the projects this fork is built on.
• heurazy - the VR cockpit's turning steering wheel and hand steering, ported from mario-kart-wii-VR-port (GPL-3.0).
• Dolphin Emulator - an invaluable reference for Wii hardware behavior during development, plus the source of the free DSP coefficient ROM and the unmodified default WiiConnect24 bootstrap tree bundled with the runtime.
• Retro Rewind by ZPL and team - the mod distribution this project supports.
• Wheel Wizard - the mod manager this project integrates with as a launch backend.
• nod - nodtool, the disc image extractor.
• DolphinXR - the Steam Frame controller profile's input paths.
• Frame Control by saphid - installing the game into the Frame's Steam library, and its notes on how the Frame's software fits together.
• Everyone in the static recompilation community.

Bundled third-party components and their licenses live in THIRD-PARTY-NOTICES.md.

License

WiiCompiled is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License, version 3 as published by the Free Software Foundation.

WiiCompiled is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Any mkwii distribution making use of WiiCompiled must be licensed under GPL v3.0.

Not affiliated with, endorsed by, or associated with Nintendo. Mario Kart Wii is a trademark of Nintendo. No Nintendo intellectual property is contained in, distributed with, or obtainable through this project.