SatelliteMap

SatelliteMap

The map shows the world itself: real relief and shorelines, forest, the paths and fields players have made, buildings, ruins, dungeon entrances and boss altars. Everything is drawn top-down from the data of the world, so your base looks like your base, and the road you paved with the hoe is on the map. The mod draws the whole map, the big one and the small corner one, at any zoom: the game's own map picture is never shown.

What it does

• One picture at every zoom. Up close the map gets as fine as half a metre per pixel; zoomed out it goes all the way to the whole world on one screen. From 8 m per pixel and coarser only relief, water and shores are drawn: buildings and trees are smaller than a pixel there anyway.
• Unexplored land is a clean sheet. The picture never shows what your map does not know yet. Shared exploration from a cartography table counts when the shared map is shown.
• The corner minimap too. It is drawn the same way, around you.
• No empty gaps while loading. While the detailed pieces wait for the server, a quickly drawn relief lies under them.
• The picture is alive. Cut the forest, build a house, lay a road: the map follows. While the map is open, the visible part is re-checked every few minutes. (A map mod can ask for the opposite: a map that shows the land as it was when it was charted, see "Snapshots" below.)
• Icons, marks, pings and map controls are untouched. The picture lies under them.
• No cameras, no screenshots. The relief and the water are computed by the same world generator the game uses, down to the metre. Trees, rocks, building pieces and world locations are drawn from a baked library of their top-down views (about 1100 objects of the game). Lighting and shadows are computed from heights, so a gable roof looks like a gable roof.

Sacrificial stones, burial chambers, tower ruins and boss altars are drawn where they stand, at their own size and rotation, not as symbols laid on top of the map. Shorelines, rivers, the snow line and the forest thinning out as it climbs all come from the world itself.

Multiplayer

The client knows only what is near the player; the rest of the world lives on the server. So the mod has a small server part: the client asks for descriptions of the zones it needs (what stands where, how the ground was painted and levelled), the server answers with a compact packet (about half a kilobyte per 64x64 m zone of forest). Zones come from the middle of the screen outwards; when the client checks them again later, it sends fingerprints and the server replies "unchanged" in a few bytes instead of sending them again.

• Install it on the server and on every client that wants the picture. Clients without the mod just see the usual map; nothing is enforced.
• Without the mod on the server the picture still works, but shows only relief, water and shores: no buildings, paths or forest. The log says so once.
• Single player and self-hosted games need nothing else.

Snapshots

A hand-drawn map should not know about the house somebody built yesterday. For map mods that want this (ParchmentMap does), whoever runs the world — the dedicated server, the host, or your single-player game — can remember what a zone looked like at a given moment:

• When a player charts a zone, the server writes down its description and answers with a snapshot number. The number changes only if the zone has changed since the last snapshot, so untouched forest costs one record no matter how often it is walked.
• The map keeps the numbers, the server keeps the descriptions: <save folder>/satellitemap/<world>.<world id>.zones, next to worlds_local. It only grows when charted places change. Back it up together with the world. If the file is lost, maps fall back to the nearest older snapshot or to the live world, and heal as places are charted again.
• A snapshot never changes, so the client asks for it once and never re-checks it.
• A map without a map mod is not affected: it stays alive as described above.

Settings

BepInEx/config/qua8ion.valheim.satellitemap.cfg

| Section | Setting | Default | Meaning | |---|---|---|---| | Rules | DetailLevel | 3 | How detailed the picture is. 0: relief and water only, 2 m per pixel. 1: a sketch, 2 m per pixel: also paths, fields, buildings, ruins, boss altars. 2: also the forest and large rocks, 1 m per pixel. 3: everything down to bushes, half a metre per pixel. Zoomed far out every level shows relief and water only. The game's own map picture is not shown at any level. On a dedicated server the server's value applies to everyone. | | Debug | DumpMapTiles | false | Save every drawn piece of the map as PNG into BepInEx/cache/SatelliteMap/tiles and log the timings. | | Debug | ServerSelfTest | empty | x,z,radius: a server describes the zones around that point after the world is loaded and writes the packet to BepInEx/cache/SatelliteMap/selftest.bin, then runs the same zones through the request path a client would use, takes snapshots of them, asks them back by number, and logs the result. For checking the server part without a client. |

For other mods

SatelliteMap.SatelliteMapApi (find it by reflection, no build-time dependency needed):

• AddDetailLimit(Func<int> provider): limit the detail level (0-3, where 0 is relief and water only, or -1 for "no opinion right now"). The lowest of the config value and all limits applies.
• NotifyExploredChanged(): tell the mod that the explored part of the map was changed bypassing the game's own methods (or that the snapshot numbers below have changed).
• Survey(int[] zoneXs, int[] zoneYs, Action<int[], int[], int[]> done): the player is charting these zones; done receives the zones and their snapshot numbers. There may be no answer at all (no mod on the server, or older than 0.2.0).