asm.js/wasm support

[icefoxen]

Should happen eventually!

[icefoxen]

SDL windowing and events isn't quite a drop-in solution but does appear to work.

Audio is going to probably require adding a backend to cpal, see RustAudio/cpal#92

gfx-rs: kvark says that people have made gfx-rs work with WebGL but it's not well formalized.

[icefoxen]

Blockers:

• Resources and files
• Audio
• SDL GL context attributes: emscripten-core/emscripten#4425
• gfx-rs support: When I try to run a hacked-up test program I get tons of the following errors: bad name in getProcAddress: glWhateverThing

[kvark]

@icefoxen gfx-0.17 runs on WebGL, but a few tweaks are required in the environment. See (from gfx-rs/gfx#1681):

In Emscripten configuration, set USE_WEBGL2=1. I did it by just modifying "emscripten/src/settings.js" directly (from where it's installed).

[beatgammit]

Since ggez is using winit now, the SDL bit is irrelevant, right? Aside from that, is the list above accurate?

[icefoxen]

Yeah, but winit support for wasm32-unknown is still experimental last I checked. And the stable version of ggez still uses SDL2, so.

[icefoxen]

Currently, here are the crates that need to support wasm:

• slice_deque: gnzlbg/slice_deque#60 (though minimp3, which is easy to get rid of by disabling the mp3 feature in `rayon)
• bzip2, used by zip, again easy to feature out
• shared_library: used by glutin and by osmesa-sys which is used by glutin
• winit: rust-windowing/winit#395
• cpal via rodio builds but won't actually do anything: RustAudio/cpal#212

[kvark]

Worth noting this project that has a dedicated WebGL backend on GGEZ: http://github.com/not-fl3/good-web-game

[ozkriff]

Note that good-web-game is not really GGEZ's backend, but a separate web-targeted engine with a similar API that @not-fl3 uses for his prototypes.

Zemeroth uses good-web-game for its web version as a quick-n-dirty immediate solution until a proper WASM support arrives to GGEZ (there're no plans of making good-web-game some kind of official GGEZ backend).

The currently implemented subset of GGEZ API is quite limited and while it may be used for something else that Zemeroth, it will probably require a lot of work to do (contributions are welcome ;) ).