OpenApparatus Studio (Web)

Browser-based version of OpenApparatus Studio — author, preview, and export OpenApparatus floor plans without installing anything.

The desktop app (Avalonia / .NET 8) remains the reference implementation. This repo is a parallel front-end that runs entirely in the browser, sharing the same generation core via WebAssembly.

Status

Feasibility spike landed. OpenApparatus.Core compiles to WebAssembly and drives a minimal "Generate" page in the browser end-to-end. No editor UI yet, no exporters, no 3D preview. Next milestones: extracting ObjExporter / GltfExporter / JsonExporter / ProjectIO from the desktop Studio assembly into a shared library, then a viewer-quality 2D/3D preview.

Spike measurements (Release publish, .NET 10, 6×6 grid + 3 rectangles)

Metric	Value
Bundle uncompressed	3.2 MB
Bundle gzipped	1.2 MB
Bundle brotli (Cloudflare default)	~1.0 MB
Cold load + first generate (local serve)	~105 ms
Warm-cache generate (mean of 5)	~7 ms
Rooms × doors generated	33 × 33 (32 spanning-tree + 1 outer entrance)

The biggest single asset is dotnet.native.wasm (~370 KB brotli); System.Private.CoreLib and System.Text.Json follow at ~320 KB and ~47 KB. The JSON-over-string interop pattern (see below) costs the System.Text.Json chunk; if it ever matters we can swap to typed-array marshalling.

Architecture (planned)

• UI — React + TypeScript, Vite for the build toolchain
• 2D preview — SVG or <canvas>
• 3D preview — Three.js via @react-three/fiber
• Generation + export — OpenApparatus.Core compiled to WebAssembly via .NET's wasmbrowser workload, called from a thin TS interop wrapper
• Hosting — static site (Cloudflare Pages), eventually under extendedresearch.ca

The Core dependency mirrors how the desktop app consumes it: relative ProjectReference to a sibling openapparatus-core clone, with an MSBuild override for non-standard layouts. When Core ships on NuGet, the local clone requirement goes away.

Development

Requires Node 22+ (see .nvmrc), .NET 10 SDK, and the wasm-tools workload (dotnet workload install wasm-tools).

npm install
npm run build:wasm   # publish .NET → wasm/.../dist + copy into public/_framework/
npm run dev          # http://localhost:5173
npm run build        # production bundle in dist/ (auto-runs build:wasm first)
npm run preview      # serve the production bundle locally

The predev hook runs build:wasm only if public/_framework/ is missing — change C# code? rerun npm run build:wasm manually. The TS/React side hot-reloads as usual.

If OpenApparatus.Core lives somewhere other than the sibling-clone path (e.g. when working inside a worktree), point the build at it:

OPENAPPARATUS_CORE_REPO=/path/to/openapparatus-core npm run build:wasm

Interop pattern (notes from the spike)

OpenApparatus.Wasm/Interop.cs exposes a single [JSExport] static method that returns a JSON string. Object graphs from Core (MultiRoomEnvironment → Room → IRoomShape, Adjacency → Passage polymorphism) cross the JS/WASM boundary as a flat DTO serialized with System.Text.Json source-gen — no attempt to marshal the live CLR objects across. This sidesteps [JSExport]'s limits on arbitrary reference types and keeps the surface trivially evolvable.

Repo layout

openapparatus-studio-web/    ← this repo
openapparatus-studio/        ← desktop app (sibling clone)
openapparatus-core/          ← shared generation core (sibling clone)

License

MIT — see LICENSE.