Settlements were static -- every town grew with one global rate to the same
habitability cap (frozen in Live World), so they grew "the same amount
everywhere". Now stepCivilization(dtHours, liveTime) is environment-driven and
time-varying. All drivers are deterministic functions of (region, year, seed),
so step-back replays them with no new saved/snapshot state (population is
already snapshotted).
- Differentiated growth: rate scales with habitability (fertile boom, marginal
crawl); capacity K = maxPop * habitability * siteQuality * conditions.
- Site quality: max city size varies by an order of magnitude with location --
a great river (log-scaled discharge) or coast hosts a metropolis, a dry inland
cell a town (civSiteVariety). This spreads final sizes ~8-9x instead of all
saturating equally.
- Conditions (per ~20deg region, per year): multi-year droughts (worse in arid
regions), year-to-year harvests (bigger swings inland), rare cold years, river
floods, and the existing volcano ash. Regional, so different parts of a
continent have different fortunes.
- Storms kill directly: a system within its radius of a town deals deaths scaled
by strength (hurricanes x civHurricaneDeathMult) -- a parked hurricane can gut
a coastal city. Reads the already-snapshotted storms().
- Famine: accelerated loss when food < population; sustained drought / acute
disaster can collapse a settlement to ruins (revives when conditions return).
- Viewer: markers withered-tinted by hardship (3D + 2D), cell-info "drought/
conditions" line, and cause-attributed kind=3 events ("Hurricane X devastates
Y", "Famine shrinks Y to a Town", tier up/down/abandon).
New civ* knobs (self-describing config -> no save bump). test_civ extended:
sizes vary widely (not uniform), bad-year declines, a hurricane over a town
kills its population. All 10 suites pass; GUI build clean. Docs updated.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Two features (the ecoregions layer was authored locally and was still
uncommitted; civilization Step 2 builds on top and is intermingled in shared
files, so they land together):
Ecoregions (v19, PlanetEcoregions.*, key E):
- generateEcoregions() flood-fills cells sharing biome + land/water context +
productivity band into named ecological provinces (dominant flora/fauna/funga
+ per-kind productivity), a separate sEcoRng. ColorMode::Ecoregion + an Eco
tab + cell-info dominants. Saved v19 (v18 geography reshuffle salt already in).
Civilizations Step 2 (v20, PlanetCiv.*, keys U/I):
- computeHabitability(): derived per-cell food/livability (climate comfort +
water access (rivers/lakes/coast) + food (flora/fauna + ecoregion
productivity), gated by freezing winters / high terrain). ColorMode::
Habitability (key I).
- placeSettlements() (key U, "the dawn"): one-time greedy placement on the best
well-spaced fertile cells (separate sCivRng; named from the continent's
NameGen bank). The set is fixed, so the only mutable per-step state is each
settlement's population.
- stepCivilization(): logistic growth toward K = civMaxPopulation*habitability,
cut where an active volcano ashes the area, so settlements grow / decline /
are abandoned (floored at 1 so a site can revive). Tiers village->town->city.
Runs in liveAdvance; detectLiveEvents logs kind=3 events.
- Step-back snapshots only the population vector (WeatherSnapshot.settlementPop).
3D + 2D tier-sized markers + city/town labels, a Civ tab, cell-info line.
buildGeometry() clears settlements on reseed. Save v20; sCellSettlement
rebuilt on load. civ* config knobs.
New test_ecoregions.cpp + test_civ.cpp; all 10 headless suites pass; GUI build
clean. CLAUDE.md / design-notes / BUILD.md updated (roadmap Step 2 done).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
