How it’s built · WebXR for Meta Quest 3

VR Forge

“It works in VR” is the hardest claim a generated project makes, and the easiest to fake: a scene that renders on a monitor can still fail the moment a headset asks for two eyes. VR Forge builds WebXR projects with the same agentic loop as Game Forge, then runs each one in an emulated Quest 3 and measures what happened.

Open VR Forge The shared build loop

31VR briefs: games, simulations and tools
16domain simulations, each naming its model
2eyes measured, not assumed
148unit tests on the app’s services

The VR Forge library: VR briefs such as Rhythm Saber Arena, VR Archery Range and Cockpit Space Flight, each with its pinned three.js version and a Watch for list. — Briefs name their pinned libraries and the mistakes to watch for, such as release velocity taken from a single frame or a scene scaled so the planet is kilometres away.

How a project is checked

BriefA VR game or simulation, with three.js and WebXR add-ons, Rapier physics or Tone audio pinned.
BuildThe shared forge kernel runs the agentic file loop.
Emulated headsetAn emulated Quest 3 (IWER) is installed over navigator.xr in the preview, and the project’s own Enter VR control is clicked.
MeasureDid a session start? How many viewports were drawn in one XR frame?
EvidenceAn eye capture is saved, and the result reads “emulator-verified”, never “verified on Quest 3”.

Design decisions

Simulations with a named model

The sim briefs name the model they must implement, such as IDM and MOBIL for traffic, social forces for crowds, extreme-point packing for pallets, Barnes–Hut for galaxies or Schwarzschild geodesics for a black hole. A vague “make it realistic” cannot be checked; a named model can.

A desktop fallback, checked

Each project declares a non-XR fallback, and the validator checks that it boots and renders. That keeps builds reviewable without a headset, and it is how the showcase plays them in an ordinary browser.

Honest labels

The emulator proves the code path, not the comfort or frame rate on a real device. The app says so, and opening a build on a connected headset is recorded as provenance, not as evidence.

Same kernel as Game Forge

Runs, traces, budgets, pinned libraries and the previewer come from the shared forge kernel. VR adds its own domain and a verification lane.

Problems worth solving

Pose checks pass for broken renderers. The emulator hands every project two correct eye poses, so a monoscopic renderer still looks healthy. The check that works is to record every gl.viewport rectangle set inside one XR frame: two views with one viewport is an error. Two test fixtures that differ only in that block keep the check honest.
Screenshots that hang the page. Rasterising the DOM of a page whose render loop resizes a full-window WebGL canvas every frame blocked the main thread for minutes. VR runs skip it and keep the eye capture as their image.
A regex that froze everything. The module rewriter used a pattern that backtracked exponentially on any exported function with no quote characters. A 1.2 KB matrix helper hung the preview. The pattern is now bounded, with a regression test.
Import maps in a blob preview. Prefix mappings such as three/addons/ are expanded against the project’s files. Otherwise a project works on the headset and fails in the app.

More write-ups

Game Forge Understory Studio Code Morph Lab