Emscripten-generated JavaScript glue is not just a tiny loader. It can implement parts of SDL, OpenGL, OpenAL, POSIX compatibility, filesystem emulation, stdout/stderr handling, memory setup, and browser/Node environment behavior.

  • SDL maps to Canvas, input events, timing, and media APIs.
  • OpenGL calls are translated to WebGL/WebGL2 where possible.
  • OpenAL maps to Web Audio concepts.
  • Generated HTML often loads the JS glue, writes stdout to a textarea, and includes a canvas for graphics.
  • Modularized builds expose factories that fetch, compile, instantiate, and run the WASM file.