Dexterous Developer

An experimental hot reload system for the bevy game engine. Inspired by DGriffin91's Ridiculous bevy hot reloading - adding the ability to re-load arbitrary systems, and the ability to transform resource/component structures over time.

Fuller documentation is available at: https://lee-orr.github.io/dexterous_developer/

Features

• Define the reloadable areas of your game explicitly - which can include systems, components and resources (w/ some limitations)
• Reset resources to a default or pre-determined value upon reload
• serialize/deserialize your reloadable resources & components, allowing you to evolve their schemas so long as they are compatible with the de-serializer (using rmp_serde)
• mark entities to get removed on hot reload
• run systems after hot-reload
• create functions to set-up & tear down upon either entering/exiting a state or on hot reload
• only includes any hot reload capacity in your build when you explicitly enable it - such as by using the CLI launcher

Known issues

• Won't work on mobile or WASM, and only tested on Windows
• events and states still need to be pre-defined

Installation

Grab the CLI by running: cargo install dexterous_developer_cli. If you don't want to use the cli - there is more info in the docs.

You'll be able to run the dexterous verion of your code by running dexterous_developer_cli in your terminal.

In your Cargo.toml add the following:

[lib]

name = "lib_THE_NAME_OF_YOUR_GAME"

path = "src/lib.rs"

crate-type = ["rlib", "dylib"]



[dependencies]

bevy = "0.11"

dexterous_developer = "0.0.4"

serde = "1" # If you want the serialization capacities

If your game is not a library yet, move all your main logic to lib.rs rather than main.rs. Then, in your main.rs - call the bevy_main function:

fn main() {
    lib_NAME_OF_YOUR_GAME::bevy_main();
}

and in your lib.rs, your main function should become:

#[hot_bevy_main]
pub fn bevy_main(initial_plugins: impl InitialPlugins) {
    App::new()
        .add_plugins(initial_plugins.initialize::<DefaultPlugins>()) // You can use either DefaultPlugins or MinimnalPlugins here, and use "set" on this as you would with them
    // Here you can do what you'd normally do with app
    // ... and so on
}

If you have a plugin where you want to add reloadable elements, add the following in the file defining the plugin:

impl Plugin for MyPlugin {
    fn build(&self, app: &mut App) {
        app
            .setup_reloadable_elements::<reloadable>();
    }
}

#[dexterous_developer_setup]
fn reloadable(app: &mut ReloadableAppContents) {
    app
        .add_systems(Update, this_system_will_reload);
}

For the best results, you'll want to add the following to your .cargo/config.toml:

# Add the contents of this file to `config.toml` to enable "fast build" configuration. Please read the notes below.



# NOTE: For maximum performance, build using a nightly compiler

# If you are using rust stable, remove the "-Zshare-generics=y" below.



[target.x86_64-unknown-linux-gnu]

linker = "clang"

rustflags = ["-Clink-arg=-fuse-ld=lld", "-Zshare-generics=y"]



# NOTE: you must install [Mach-O LLD Port](https://lld.llvm.org/MachO/index.html) on mac. you can easily do this by installing llvm which includes lld with the "brew" package manager:

# `brew install llvm`

[target.x86_64-apple-darwin]

rustflags = [

    "-C",

    "link-arg=-fuse-ld=/usr/local/opt/llvm/bin/ld64.lld",

    "-Zshare-generics=y",

]



[target.aarch64-apple-darwin]

rustflags = [

    "-C",

    "link-arg=-fuse-ld=/opt/homebrew/opt/llvm/bin/ld64.lld",

    "-Zshare-generics=y",

]



[target.x86_64-pc-windows-msvc]

linker = "rust-lld.exe"

rustflags = ["-Zshare-generics=n"]



# Optional: Uncommenting the following improves compile times, but reduces the amount of debug info to 'line number tables only'

# In most cases the gains are negligible, but if you are on macos and have slow compile times you should see significant gains.

#[profile.dev]

#debug = 1



# Enable a small amount of optimization in debug mode

[profile.dev]

opt-level = 1



# Enable high optimizations for dependencies (incl. Bevy), but not for our code:

[profile.dev.package."*"]

opt-level = 3



[profile.dev.package.gfx-backend-vulkan]

opt-level = 3

debug-assertions = false