SHEET 20 · Games
SWYF Unreal
The browser ski game re-hosted in Unreal Engine 5.8 on Linux and Android — same bakes, same deterministic sim, 35k lines of C++, 3.4 ms a frame on a 4090, one cooked level that plays 59 mountains
3.4 ms frame59 maps35k lines C++UE 5.8.2 engine2026localGames
About
A native port of Skiride. The same resort bundles the web engine decodes — a 4097² height lattice, 277,428 tree records, pistes and lifts from OpenStreetMap — are bridged into Unreal by a stdlib Python script that checks every asset's byte count and SHA-256 and keeps the vertical datums explicit. At runtime a procedural-mesh terrain with GPU LOD morph, instanced forests with per-tier LOD ladders, catenary lifts and buildings are built from the bundle; the skier is re-implemented on a fixed-step simulation with the web game's loft tables and air-flail kinematics. The web game's operations simulator runs unchanged inside the packaged build through an embedded QuickJS.
Maps beyond Sunlight download from the CDN, verify, convert on a worker and cache — Everest with a 3,390 m drop, Vail with 33 lift routes. The multiplayer client speaks the Ski With Your Friends relay in an 88-byte wire record with 100 ms interpolation; two clients on one relay agree to 2 cm. Nine CPU optimisations in the performance audit were each proven bit-identical against an exact-digest oracle before their timing was believed. A Unity port preceded it and lasted one day.
Key features
- 01Packaged Linux x86-64 and Android arm64/x86-64; tested on the host, a Galaxy S24 Ultra and an API 36 emulator
- 02Winter forest 3.41 ms median at 1080p Epic on the RTX 4090; phone soak 7,200 frames without a crash, worst frame 60.6 ms
- 03Bridge script verifies byte counts and SHA-256 for every asset and writes provenance alongside the content
- 04Engine-free Simulation layer built twice: inside Unreal and as native CTest suites
- 05Ops simulator JavaScript executed by an embedded QuickJS-NG through a runtime bridge
- 06Map switcher: 59 maps from one cooked level; synthesised fall lines where a map has no routes
- 07Multiplayer: hello-first WebSocket client, reconnect ladder, 20/5/2 Hz upload cadence, dead reckoning ≤250 ms
- 08Nine preservation-proven optimisations: 2,880 filter cases, 24,000 collision motions, 10.25 M audio samples bit-identical
- 0926 Unreal automation tests, 20 native CTest suites, 100 Python tests, 14 validators; 461 deterministic motion captures
Gallery
recording · still
Nearby
SHEET 19 · Games
Ski With Your Friends
The consumer brand of Skiride: one relay, 20 Hz pose replication, eight per lobby, voice that fades with distance — separated from the xyzski monorepo at a pinned commit and live on its own domain since 2026-09-17
2026live20 hz relay8 players lobby
SHEET 18 · Terrain & GIS
xyzski
58 real ski mountains in a browser tab — USGS terrain, OSM lifts, LiDAR forests, a GPU terrain renderer at 60 fps, a patrol shift you can ski inside, and an embed any resort drops in with one tag
2026live58 resorts17.4 ms soak p95
SHEET 17 · Games
xyzdisc
Browser 3D disc golf on real Colorado courses — 0.7 m LiDAR ground, aerial imagery, crown-detected forests, a physics flight model and PDGA stances; 9 venues, 18 layouts, 5,400 unit cases, live at xyzdg.com
2026live9 venues18 layouts