Compile Rust to ASM.js

[bvssvni]

Collect some information about how to compile Rust to ASM.js and interop with WebGL and user events.

[bvssvni]

rust-lang/rust#2235

• Status of compiling Rust with emscripten
• Seems to be problems with atomic instructions

[bvssvni]

https://github.com/hannobraun/rum

• A project with goal of developing HTML5 games in Rust
• Not actively maintained