Tip

If you're going to build the port in a Docker container, the only dependency is Docker itself. All the dependencies listed below are required for compiling the port on the host machine.

Rust toolchain with the Switch patches (link)
Rust nightly toolchain (the nightly channel). The cargo binary will be loaded from it, since the patched toolchain miss it. Any other toolchain, even if it's nightly (like nightly-2025-10-24), won't work
Switch toolchain by devkitPro (install the switch-dev package)
libclang-dev (on Debian; for other distros, find a package that provides libclang.so)
Clang (it provides some header files, such as stddef.h)

Standard build

Compile a debug build:

./build.sh

Compile an optimized (release) build:

./build.sh -r

All flags not listed in the help message are passed to the cargo build command (in this example, the -vv and -j3 flags will be passed to cargo build):

./build.sh -r -vv -j3

Building in a Docker container

To build in a Docker container, enter the drshorizon folder. Then run:

./build.sh --docker

This will build the port in a Docker container. The cargo cache and project directory will be mounted from the host, so the build artifacts can be found in the target folder, just as they would be in a regular build.

If you have Docker Compose installed, the script will run it using config params from composer.yaml. The created container will be removed on exit.

Otherwise the script will build the container image with docker build and run it via docker run. If you want to use precompiled docker image, specify its name in the RUSTSWITCH_IMAGE environment variable (i.e. ghcr.io/doukutsu-rs/drshorizon-build-env:latest).

If you want to force build via Docker Compose, specify --docker-mode:

./build.sh --docker-mode compose

Notes for maintainers

The dependency on Clang is caused by the deko3d-sys crate, which ignores the presence of GCC/glibc headers.
The toolchain intended for use in a container should be built on a Debian Bookworm virtual machine, since this is the version used by the devkitPro image.

Building the toolchain on newer systems will result in the toolchain’s libraries being linked against a newer version of glibc than the one present in the container, which in turn will make it impossible to build the port using this toolchain, as it will crash with a segfault.

Attempting to build the toolchain inside the container results either in compilation errors or in the generation of artifacts that cannot be run/loaded properly (they crash with core dump).

Maintaining Docker image

Since the CI workflow for automatically building the Docker image and uploading it to the registry isn't configured yet, you'll need to do this manually.

Versioning

The Docker image version is independent of the version of doukutsu-rs and the Horizon port.

The major version number should be incremented only if the introduced changes make it impossible to compile previous versions with the updated image.

The minor version number should be incremented when updating container dependencies (the base image or a patched toolset), but previous versions of the port should still be compilable.

The patch number may be incremented when some metadata is changed or when other minor changes are made.

Building image

Ensure that Docker Buildx plugin is installed.
Enter directory where the Dockerfile is located (currently it's drshorizon).
Build the image and link it to the latest tag (replace ${VERSION} with the new version of the image):
```
docker buildx build --provenance=false \
   -t ghcr.io/doukutsu-rs/drshorizon-build-env:latest \
   -t ghcr.io/doukutsu-rs/drshorizon-build-env:${VERSION} .
```
The --provencance=false argument disables generation of provenance attestation, since this attestation generates useless unknown/unknown platform on Github Packages page of the image.

Pushing image to registry

Generate personal access token (classic) with at least write:packages permission.
Authenticate into the Github Containers registry with your Github username and the access token:
```
docker login ghcr.io
```

Push the image (replace ${VERSION} with the new version of the image):

docker push ghcr.io/doukutsu-rs/drshorizon-build-env:${VERSION}
docker push ghcr.io/doukutsu-rs/drshorizon-build-env:latest

README.md Unescape Escape

Known issues

Build

Dependencies (for local build)