rednoise (WebAssembly)

A WebAssembly build of the RedNoise CPU software renderer. It compiles the C++23 engine to WASM with Emscripten and exposes a small JavaScript API that renders a Wavefront OBJ into an RGBA pixel buffer.

Four render modes are available: wireframe, rasterised, raytraced, and pathtraced.

Install

npm install rednoise

Usage (Node)

import { readFileSync } from "node:fs";
import { createRenderer } from "rednoise";

const obj = readFileSync("model.obj", "utf8");
const renderer = await createRenderer();

const width = 640;
const height = 480;
const rgba = renderer.render({ obj, mode: "raytraced", width, height });
// rgba is a Uint8ClampedArray of width * height * 4 bytes (RGBA).

console.log("rednoise version:", renderer.version());

Usage (browser)

import { createRenderer } from "rednoise";

const renderer = await createRenderer();
const rgba = renderer.render({ obj: objText, mode: "raytraced", width: 640, height: 480 });

const canvas = document.querySelector("canvas");
canvas.width = 640;
canvas.height = 480;
const ctx = canvas.getContext("2d");
ctx.putImageData(new ImageData(rgba, 640, 480), 0, 0);

render options

| option | default | meaning | | --------- | ------------- | --------------------------------------------------------- | | obj | (required) | OBJ file contents as a string | | mode | "raytraced" | wireframe, rasterised, raytraced, or pathtraced | | width | 640 | output width in pixels | | height | 480 | output height in pixels | | samples | 64 | per-pixel samples (path tracer only) | | camZ | 4.0 | camera z position; the camera looks at the origin |

How OBJ loading works

The engine's loadOBJ reads a file by path. Under WebAssembly there is no host filesystem, so the wrapper writes the OBJ text you pass into Emscripten's MEMFS (an in-memory filesystem) and loads it from there. Because a companion .mtl file is not written alongside it, materials are not resolved and faces use their default colour, matching the headless native behaviour.

Building locally

The dist/ folder is produced by Emscripten and is not checked into git; it is built in CI before publishing. To build it yourself you need the Emscripten SDK (emsdk) installed and activated so that emcc is on your PATH:

bash build.sh

This produces dist/rednoise.mjs and dist/rednoise.wasm.

License

MIT