cooped

A multiplayer, collaboratively-editable FPS with Quake-style convex brushes, in-game editing (Sauerbraten "press E"), and baked HDR radiosity. Runs on desktop and in the browser.

See DESIGN.md for the full architecture (render DESIGN.html with the command at the bottom for a nicer read).

Status

Milestones 1–5 + 7 done: dual-target engine (desktop + browser) · convex-brush CSG + lit rendering · in-game editor (E-toggle, grid, select, Sauerbraten scroll push/pull, undo) · Quake-style player physics (walk/jump on brushes) · collaborative editing over the network with a dedicated server speaking ENet (native) and WebRTC (browser) in one process.

Prerequisites

• CMake ≥ 3.20, a C++20 compiler, and Ninja (or Make).
• Git (dependencies are fetched at configure time via CMake FetchContent).
• Network access on the first configure (to clone SDL3 + bgfx).
• For the web build: the Emscripten SDK. A local checkout is vendored at ./emsdk/ (gitignored); activate it with source ./emsdk/emsdk_env.sh.

Build & run — desktop

cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build
./build/cooped

You should see a dark window titled "cooped — milestone 1" with the active renderer name (Vulkan/GL/Metal/D3D depending on platform) printed in the corner. Esc or closing the window quits.

Build & run — browser (WebAssembly)

source ./emsdk/emsdk_env.sh
emcmake cmake -S . -B build-web -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build-web --target cooped     # build only our target (see note below)
emrun build-web/cooped.html                 # or serve the dir over http and open cooped.html

The same scene renders via WebGL2 in the tab.

Multiplayer (collaborative editing)

The server is authoritative and relays edit ops; native clients use ENet, browser clients use WebRTC (with WebSocket signaling on port + 1).

# 1) server (ENet udp:27500, signaling ws:27501)
./build/cooped_server

# 2) native client(s)
./build/cooped 127.0.0.1            # or  ./build/cooped <host> [port]

# 3) browser client — serve the web build over plain HTTP so ws:// is allowed
python3 -m http.server 8000 -d build-web
#   open http://localhost:8000/cooped.html  (auto-connects to ws://localhost:27501)

Edits on any client (create/delete/move/scroll push-pull) sync to all the others. Running a client with no argument (or the public HTTPS site with no ?server=) stays single-player.

Public server over TLS (wss://)

An https page (e.g. GitHub Pages) can only open a wss:// signaling socket. Give the server a TLS cert + key and it serves wss on port + 1:

./build/cooped_server 27500 /path/fullchain.pem /path/privkey.pem   # e.g. Let's Encrypt

Then point the deployed client at it: https://vampirefrog.github.io/cooped/?server=wss://YOURHOST:27501 (the host must present a browser-trusted cert; self-signed won't work for wss).

Why --target cooped for the web build: bgfx.cmake also defines bimg_encode (the offline texture-compression encoder), which uses x86 CRC32 intrinsics that don't exist on wasm. We don't link it, so building only the cooped target skips it. The web build also enables -msimd128 (in CMakeLists.txt) because bx/bgfx pass SSE flags that Emscripten requires wasm SIMD alongside.

Dependency versions

Pinned in CMakeLists.txt:

• SDL3 — release-3.2.30
• bgfx — via bgfx.cmake master (pin to a specific commit for fully reproducible builds)
• ENet v1.3.18 and libdatachannel v0.24.3 (native only; the server's transports)

Later milestones add Recast/Detour, Embree, Jolt, xatlas, etc. (also via FetchContent).

Conventions

Right-handed, Z-up, floating-point world units at Quake scale. See DESIGN.md §17.

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To regenerate the styled design doc preview:

pandoc DESIGN.md -s --embed-resources --metadata title="cooped — Design Document" \
  -H /tmp/cooped-style.html -o DESIGN.html