0018 – Datadisk wildlife overlays and cover / ambient music

Status:

Accepted by the project owner and implemented in the working trees

Date:

2026-10-18

Context

A datadisk can pin real terrain (ADR 0013, 0017) and play place music, but wild flora and fauna still come only from the seeded biome map. Historical disks such as Gilgamesh need date palms and reeds around Uruk without changing the whole planet’s climate. Cover art also had no soundtrack; travel on the plains had no default track outside place radii.

Decision

  • A place may declare wildlife with weighted flora / fauna catalog ids, optional radius_m and density. Inside that radius the server picks scenery and land animals from those weights instead of the global biome table; clear and water rules are unchanged. An entry may set waterside: true so it only spawns within about 60 m of patch water, a river or the sea (crocodiles, waterfowl, gulls).

  • The manifest may name cover_music (logo jingle while the cover shows) and ambient_music (default background outside place music). Both are track ids from music/*.yaml. The world announcement includes their media URLs when set.

Consequences

  • Gilgamesh (and similar disks) can describe Early Dynastic plant and animal lists in research notes and encode them as overlays without a full climate rebuild.

  • Clients play the cover jingle with the cover image and fall back to ambient travel music.