Adding Rusteal to an existing project

The goal: Rust gameplay in a project that already exists, made from the editor or with C++.

rusteal setup /path/to/YourProject

rusteal setup installs the Rusteal plugins into the project’s Plugins/ and writes a starter rusteal.toml. If the project already has a rusteal.toml, it keeps it.

It does not write the Rust workspace. Create it as rusteal new does (see Project layout):

1. Rust/Cargo.toml, the workspace, listing your crate and bindings, and pinning the Rusteal crates to the CLI’s version (rusteal --version);
2. Rust/<crate>/Cargo.toml, a cdylib depending on rusteal-runtime, bindings and glam;
3. Rust/<crate>/src/lib.rs, with rusteal_runtime::entry!();;
4. in rusteal.toml, [project] crate = "<crate>", the package name of your crate.

The quickest way is to create a blank project with rusteal new next to it and copy its Rust/ directory and the profiles of its Rust/Cargo.toml.

Then build everything once:

cd /path/to/YourProject
rusteal build --all

The project needs a C++ module (Source/<Project>/) for the Unreal Build Tool to build it. A project made from the editor’s Blueprint templates has none: add one from the editor (Tools > New C++ Class, any class) before running the build.

Your existing C++ and Blueprint classes stay as they are, and work next to the Rust ones: Blueprints derive from Rust classes, call their functions and bind their delegates the way they do with C++ classes.