From C to Browser: WebAssembly

Compiling native code to run in the browser.

The Challenge

MiniRT started as a C ray tracer using the minilibx graphics library. The goal was simple: get it running in a browser without requiring users to install anything.

Traditional approaches would have been:

• JavaScript reimplementation — Months of work, potential performance loss
• Native plugin — Dead technology, security concerns
• Server-side rendering — Latency, no interactivity

WebAssembly offered a fourth path.

The Compilation

Emscripten handles the heavy lifting. It compiles C to WASM while providing JavaScript bindings for browser APIs:

C Source → LLVM IR → Emscripten → WebAssembly + JS Glue

The key insight is that minilibx (the graphics library) had already been ported to work with raylib. And raylib had been compiled to WebAssembly before. The question wasn’t whether it was possible — it was whether I could wire it all together correctly.

What Gets Compiled

The WASM build produces four files:

Virtual Filesystem

Emscripten creates a virtual filesystem. Pre-bundled scene files are embedded at compile time and available at their original paths when the WASM runs.

Result

A fully interactive ray tracer running at near-native speeds in any modern browser. The same C code, compiled once, runs everywhere.