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CI / test cartopolis (push) Has started running
feat(render): sunbeams through cloud gaps and past buildings
The light shafts never drew what people mean by sunbeams. They are
bevy's volumetric fog cut by the sun's shadow map, and the cloud deck
casts no shadow; around the viewer they are deliberately faint. Shafts
on against off over Groningen at a low sun (Deck, 2026-09-29) was a
smooth warm wash and no beam anywhere.
Sun rays are a screen-space pass over the finished frame (a
FullscreenMaterial on the camera, before tonemapping): each pixel walks
toward the sun's screen position and gathers what is bright near the
sun, so gaps in the clouds become streaks and cloud bases and buildings
cut them. What counts as bright is measured against the sky round the
sun, so dusk casts beams as noon does. No depth is read; the app has no
prepass on purpose, and an occluder only has to be darker than the sky.
Three versions inside the cloud shader were built and measured first
and all read as nothing: averaging the deck along the arc to the sun,
darkening the shadowed columns, and tracing each view ray's columns up
to the deck. The last is physically right and fails for that reason:
the deck's clouds are kilometres across, so a column's lit fraction
changes over tens of degrees and draws a gradient, not a beam.
Its own switch, Settings > Graphics > Sun rays (AppPrefs::sun_rays),
on by default on any hardware adapter and not gated on shadows. About
1 ms a frame on the Deck at 540x1000.
A social map of the real world: see how a place is built, and talk about it with the people who are there.
A walkable 3D copy of the real world, built from open public data and shared between everyone looking at it. Runs in the browser, on the desktop and on Android. Free, open source, self-hostable.
Public infrastructure
- Built from the registers — buildings from BAG and 3DBAG, ground from AHN, street trees, lighting and paving from the national and municipal object registers, PDOK aerial photography, live transit.
- Every building has a card — year built, use, units, floor area, status, monument listing, addresses. Walk in and its storeys are there.
- The world around it — real sun, real weather, routing on foot, by bike or by car, and one continuous space from a doorway to orbit.
Sharing a place
- Talk where you stand — avatars, local chat scoped by distance, proximity voice, world chat, end-to-end encrypted private chats.
- Point at it — a link opens your exact view in the browser or the app; saved places with photos and map pins.
- Put something there — place and script objects and 3D models, swap a building for an IFC model, export and import content over an HTTP API.
- Moderation — blocking, reporting and account deletion, enforced on the server; a web console for accounts and data pipelines.
For residents, communities, municipalities and governments, and planners and architects.
Screenshots
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| Canal ring | Ring road tunnel by DUO |
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| Main station and rail yard | Grote Markt and Martinitoren |
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| Forum Groningen | Building card: the town hall |
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| Groningen from 3 km | The city from 1.2 km up |
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| Eemshaven | Eemshaven from the Wadden Sea |
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| Meeting on the Grote Markt | Earth from orbit |
Generated with cargo shots from docs/shots.toml.
Where it works
Map, sky, weather, routing and the shared world: anywhere on Earth. Register detail (measured buildings and their records, relief, street objects, aerial photos, transit): the Netherlands, plus municipal data where a city publishes it. Elsewhere the ground is flat and buildings come from OpenStreetMap. Each register is one pipeline in crates/atlas.
Written in Rust on Bevy.
Try it
- Browser — cartopolis.org. Needs WebGPU.
- Desktop — Linux and Windows on the releases page, or build from source (macOS too). Published binaries need AVX2 and FMA (~2013+).
- Android — APK at cartopolis.org/apk (arm64, Android 9+). The full client, least tested of the three (notes).
Running from source
cargo run -p cartopolis
Starts offline. Sign in to a server from ☰ ▸ Sign in….
cargo run -p cartopolis -- --connect <host> # split mode: connect to a live sim (TLS)
cargo run -p cartopolis -- --offline # no sim: single user, no auth or persistence
cargo run -p cartopolis_simulator # the sim server, standalone
Needs Rust, a C compiler and a GPU driver; see the development guide. Run git lfs install before cloning — assets are in Git LFS and some are compiled in.
Documentation
- User manual — controls, getting around, authoring, the developer panel.
- Changelog — what changed, per release.
- Development guide — prerequisites, dev loop, tests, code map, conventions, CI.
- Server guide — deploying the sim and the self-hosted geo services.
docs/notes/— constraints and measurements;CLAUDE.mdKnown issues is the trap list.
Architecture
| Crate | Role |
|---|---|
cartopolis_core |
Shared protocol types and tile/coordinate math |
cartopolis_geo |
Bevy-free map geodata: MVT decode, road classes, tree scatter, the routing graph |
cartopolis_e2ee |
End-to-end encrypted private chats (MLS); the server relays sealed bytes it cannot open |
cartopolis_simulator |
The shared-world server (Tokio + SQLite): avatars, chat, voice, objects, accounts; no Bevy |
cartopolis_atlas |
The register pipelines (BAG, 3DBAG, AHN, BGT, …), the terrain server and the operator web console |
cartopolis |
Bevy client — rendering, ECS systems, UI |
cartopolis_android |
The Android app shell around the client |
big_space |
Vendored floating-origin fork, for planet-scale coordinates |
Licence
Source: MIT OR Apache-2.0 (LICENSE). Data, avatars and font carry their own terms; LICENSE-THIRD-PARTY.md is the canonical notice list (the credits below mirror it — add new sources there).
Credits
- Engine — built with Bevy.
- Floating origin —
big_spaceby Aevyrie, MIT OR Apache-2.0. Vendored here as a fork ported to the Bevy release we track. - Avatar characters — Quaternius Ultimate Modular Men/Women, CC0. Consider supporting the work on Patreon.
- Map data — © OpenStreetMap contributors, under the ODbL. Building detail and POIs come from Overpass, place search and reverse geocoding from Nominatim — both self-hosted, and usable against the public instances under the OSMF usage policies.
- Vector tiles — VersaTiles, in the Shortbread schema. Self-hosted mirror of their OSM-derived planet build.
- Buildings (LoD2.2) — 3DBAG by the 3D geoinformation group, TU Delft, CC BY 4.0 — derived from the Kadaster's BAG registry and AHN, both via PDOK. Netherlands only.
- Aerial photography — Beeldmateriaal Nederland, served as Luchtfoto RGB by PDOK, CC BY 4.0. Netherlands only.
- Street objects — street trees, lighting and containers from gemeente Groningen open data, CC BY 4.0. Groningen only.
- Elevation — AHN height rasters (DTM/DSM), served by PDOK, CC0. Netherlands only.
- Public transport — live departures and vehicle positions from OVapi, the open key-free feed of Dutch NDOV operator data. Netherlands only.
- Weather — forecasts from MET Norway, CC BY 4.0, and global cloud cover from the NOAA Global Forecast System, public domain.
- Night sky — star positions and magnitudes from the HYG Database v4.1 by David Nash, CC BY-SA 4.0 — a compilation of the Hipparcos, Yale Bright Star and Gliese catalogs.
- Type — Plus Jakarta Sans by Tokotype, SIL Open Font License 1.1.