emscripten-core/emscripten

Emscripten is a compiler tool that takes programs written in C or C++ and translates them into WebAssembly so they can run in a web browser. WebAssembly (often shortened to "wasm") is a format that allows code originally written for desktop computers to run on the web at near-native speed, meaning programs that traditionally only worked as installed desktop applications can now work directly in a browser tab. The way it works: Emscripten uses a compiler infrastructure called LLVM to transform C/C++ source code into WebAssembly output. That output can then run in any modern web browser, in Node.js (a server-side JavaScript environment), or in standalone WebAssembly runtimes. It also provides compatibility layers for popular graphics and input APIs like OpenGL and SDL2, which are widely used in game development and multimedia applications. This makes it possible to port complex native applications, the README mentions examples like the Unity game engine and Google Earth, to run on the web without rewriting them. You would use Emscripten when you have an existing C or C++ program, such as a game, a physics simulation, an image processing library, or any performance-heavy tool, and you want it to run in a browser without requiring users to download anything. It also supports integration with other languages that target LLVM, such as Rust. Emscripten is open source under permissive licenses.