Snowboard Kids

A matching decompilation of Snowboard Kids for Nintendo 64.

This repository does not contain any game assets or assembly whatsoever. An existing copy of the game is required. This project is not a port, to PC or any other platform. It takes a Nintendo 64 rom, extracts assets from it, and combines them with C code we reverse-engineered from the rom, to produce an identical rom. It is explicitly a non-goal for this project to be used for any commercial purpose.

Cloning

Clone this repository, including its submodules:

git clone --recurse-submodules -j8 https://github.com/cdlewis/snowboardkids-decomp.git

Dependencies

The current build is verified on Linux (x86-64). The macOS setup below needs validation with the updated toolchain selection.

System packages:

• make
• git
• python3
• pip3
• clang
• wget and tar (toolchain download)
• binutils-mips-linux-gnu

On Debian/Ubuntu:

sudo apt install make git python3 python3-venv python3-pip clang wget binutils-mips-linux-gnu

On macOS using homebrew. Note that calls below to make should use gmake instead to run the homebrew version.

brew install make python llvm wget tehzz/n64-dev/mips64-elf-binutils
export PATH="$(brew --prefix llvm)/bin:$PATH"
export MAKE=gmake

Build the toolchain:

make -C tools

Install Python dependencies in virtual environment:

python3 -m venv .venv
source .venv/bin/activate
python3 -m pip install -r requirements-build.txt

For optional matching helpers, asm-differ, the permuter, m2c, and task-runner workflows, also install python3 -m pip install -r requirements.txt. Existing development environments can continue using that requirements file.

The build selects tools/ido-recomp/linux or tools/ido-recomp/macos for the host. Set IDO_DIR to use another installed IDO 5.3 toolchain. Linux is verified; the updated macOS selection still needs validation on macOS.

Building

Place your ROM in the repository root using the filename below:

Version	Filename	SHA1
North America (us)	snowboardkids.z64	1583bacc9046a360df8ea4d536942155247e154c
Japan (jp)	snowboardkids.jp.z64	96480c8fa7285d9e850f6ba002e56bcb7ada9796

Build and verify the ROM:

./tools/build-and-verify.sh              # North America (default)
./tools/build-and-verify.sh --version jp

The output is build/snowboardkids.z64 for US or build/jp/snowboardkids.z64 for JP. A successful build prints the output path followed by OK, confirming that its SHA1 matches the original ROM.

For incremental builds, extract once, then run make. Use VERSION=us or VERSION=jp on both commands:

make VERSION=jp extract
make VERSION=jp -j8

Both regions build from shared C and assembly in src/, with VERSION_US and VERSION_JP selecting regional differences. Readable asset tools, progress reporting, and --mode shiftable support US only.

Reverse-engineering notes

• Readable asset extraction explains semantic asset bundles, Blender-friendly GLB models/animations, PNGs, text, replays, audio, safe migration, and byte-exact rebuilding. Start with assets/items/pan/pan.glb and assets/courses/<course>/preview.glb; regenerate GLBs with make asset-previews. All eleven items have named bundles.
• Course asset inventory documents the ten course environments, their ROM ranges, runtime asset roles, and known data layouts.

Contributing

Contributions are most welcome! There are a variety of ways you can assist:

• Fix compiler warnings
• Clean up code: you'll see plenty of hastily decompiled functions that use pointer arithmetic rather than proper struct access. We need help cleaning up these functions.
• Document code: some functions/variables have useful names (rather than func_XXX or D_XXX) but most don't. Some that do are incorrectly named. We need lots of help investigating and documenting what all these functions do.
• Support building the project on more platforms such as Windows or ARM Linux. The current build is verified on Linux; testing the macOS setup would also help.

If you have any additional questions, please reach out on Discord (linked in the header). However please note that, since this is a clean room decompilation, we cannot accept contributions based on leaked source code or from those with proprietary knowledge about the game or related subjects.

Acknowledgements

This project wouldn't be possible without the collective knowledge, tools, and support of the broader decompilation community. Huge thanks to contributors of other N64 decomp projects, the teams behind decomp.me and decomp.dev, and the incredibly helpful discussions happening on Discord. These resources have been invaluable for solving problems, speeding up setup, and staying motivated throughout the process.