rust-sdl2-emscripten/README.md

rust-sdl2-emscripten

This is an experimental repository while testing a Rust + SDL2 project built with Emscripten.

• hello-rust-sdl2-wasm - A bit of a weird repository, I'm not sure that the creator knows Rust that well, but it compiles. Note that the asmjs-unknown-emscripten target is deprecated, and you should use wasm32-unknown-emscripten instead. You'll need to change all the files, flags etc. to make it match.

• build.sh - One of the core files in this repository, it builds the project with Emscripten. Note all the flags available for modifying the behavior of the build.

Goals

• Automatic Builds
  • Web Assembly (Emscripten)
  • Windows
  • MacOS
  • Linux
  • This ensures that the project can iterate safely and be inspected in a safe environment, free from errors. Helps ensure errors are isolated to the machine or build script.
• SDL2 Extensions
  • Image
  • Mixer
  • TTF
  • GFX
  • All of these libraries are common and necessary for a lot of projects. Ensuring they work is important.
• Example of External Javascript Interop
  • The basic ability to provide some kind of Javascript binding would be important for a decent web-based project or game.
  • The ability to use localStorage, fetch, or some browser-only API would be important.

Concept

• A decent codebase without extras or warnings. Straightforward build process for Windows, Linux, and WASM.
  • Note: Cross-compiling for Windows is a bit of a pain, but it's possible. That said, GitHub Actions can handle Windows builds natively.
  • While SDL2 has annoying as fuck lifetimes, Emscripten callback loop imbibes even worse static lifetimes that are damn near impossible to satisfy.
• A simple example of a game loop, input handling, and rendering.
  • Pausing functionality, native-only quit.
  • FPS counter toggle (TTF example).
• Sprites with Atlas
• Resizable Canvas
• Javascript Interop
  • LocalStorage
  • Fetch

Resources

• KyleMiles/Rust-SDL-Emscripten-Template/
  • Has some special javascript interop code
• gregbuchholz/RuSDLem
  • One of the few with a demo available.
• tung/ruggrogue
  • A very large game example, great codebase, documentation, online player.
• arskiy/chess
  • Image usage, decent code example
  • Has more advanced javascript config and examples to look at.
• deckarep/flappy-rust
  • Image + Mixer Usage, possibly GFX & TTF
• aelred/tetris
  • Contains multiple sub-projects, including a web server. Uses SDL2 TTF & Mixer.
  • Most recent development (3 months ago).
  • Custom font loading, packed inside the binary (WASM) instead of .data file, or external file.
  • Advanced Emscripten bindings for Javascript (fetch, GET/POST)
  • No Asyncify, uses emscripten_set_main_loop callback instead.
  • See the REST functions for Emscripten.
• coderedart/rust-sdl2-wasm
  • This is mostly interesting because it has an egui implementation; egui is very cool for demos, developer tooling, debug menus, and so on.
  • The only thing I don't understand is where SDL2 is; there is almost no real code referencing SDL2 except a SDL2Backend provided by the egui crate. Weird.
  • While devoid of anything particularly interesting for my own needs, it has a demo here