Floptle Solar

The engine's space-demo project (see docs/engine-roadmap.md, Workstream D): the long-term goal is a procedurally generated solar system — fly a ship between seeded planets, land, explore, dig, build. This is its first slice.

What's here now

• scenes/planetoid.ron — a little generated planet at the origin with radial gravity (walk all the way around it), a third-person astronaut, and a dig tool.
• terrain/planetoid.1.cfield — the planet itself: a seeded, noise-displaced sphere in the sparse Terrain 2.0 chunk field, with a cave network hidden under the surface. Dig to find it.
• scripts/dig_tool.lua — hold LMB to dig where you aim, Q to pile ground back up (the runtime terrain.* API).

Open the project in the editor and press Play. Controls: WASD + Space (third_person), RMB-drag to look (third_person_camera), LMB dig, Q build.

Life, tools and the material economy

Planets grow their own plants and pay for their own rocks. The whole loop:

mine / harvest  →  suit pack  →  a craft's Cargo Bay  →  land at base
     →  Commerce Depot unloads + sells  →  money  →  research  →  better parts

On foot

key
1	Mining Laser — hold E to cut rock; what comes out depends on the world's archetype, how deep you are, and the ore vein you're standing in
2	Harvest Cutter — hold E to take down the plant you're facing
3	Terrain Spade — E lowers ground, Q raises it. Shaping only: it yields nothing
I	Inventory — the suit pack (45 kg, and mass is the only limit). Click a row to move that stack into a craft's hold or the warehouse when you're standing by one
SPACE / CTRL	swim up / dive, in water

The base buildings are walk-in. The command centre, the assembly gantry and the depot carry a shell collider generated from the model's own geometry rather than one box around the whole thing, so their doorways are doorways — walk in, stand under the roof, and the facility prompt still answers. The power plant and the tracking dish are machines and stay solid. Regenerate a shell (and check that a 2 m astronaut actually fits through the opening) with:

python3 solar/tools/shell_collider.py models/space-kit/hangar_largeA.glb --scale 4.2 --check

The base is a place. It is sited once — around the crew's landing site, after the loading screen hands the world over — and then remembered body-relative in the save (base.body + base.x/y/z), so reloading rebuilds the same colony on the same ground however far you have wandered. It used to be re-cut around wherever the astronaut stood when the terrain first answered, which on a loaded save is the loading hover over the spawn planet's north pole: the buildings went up there and the player woke up hundreds of metres away with nothing to walk up to. If a prompt ever goes missing again, the Console says why — facilities: reports how many are standing and how far the nearest one is.

At the base — the Commerce Depot (the fifth building) unloads any craft parked within 140 m, then sells the warehouse. A material's first sale ever is a discovery: a premium, a point of standing, and usually a part that just became researchable. In the builder, a locked catalogue card shows what it costs and what it wants; clicking it buys the research on the spot.

What generates

• scripts/climate.lua — temperature, moisture, elevation and biome anywhere on any world, from the record the generator publishes (save.world.<name>). Also owns the sea: where it is, and whether you're in it.
• scripts/flora_gen.lua — a world's species, rolled from its seed: silhouette, branch pattern, palette, glow, and what harvesting one gives you. The climate picks which forms a world can grow; the seed makes them unlike anywhere else's.
• scripts/flora_field.lua — streams them in around you, deterministically, so the same ground always grows the same stand. Cut plants regrow.
• scripts/materials.lua / inventory.lua / research.lua — the registry, the containers, and what's still locked.

Tests (offline, no engine needed):

luajit solar/tests/smoke_flora.lua        # climate, species, plant build, scatter, harvest
luajit solar/tests/smoke_resources.lua    # registry, containers, tools, depot, research
luajit solar/tests/smoke_company.lua      # ledger, contracts, deliveries

Regenerating the planet

cargo run --release -p floptle-field --example gen_planetoid -- solar/terrain [seed]

Different seed = different planet (relief, colour patches, caves). Knobs via env: RELIEF=6 CAVES=0 .... A headless render of the current field:

cargo run --release -p floptle-render --example solar_probe

writes solar_orbit.png / solar_surface.png.

Where this is going (roadmap D1–D6)

Planets on Kepler rails + inverse-square gravity + patched conics for the ship, nested reference frames, on-rails time-warp, an orbital trajectory map rendered to a UI viewport, per-planet atmospheres via the Sky stage, water volumes. Each stage lands as an engine feature first — this project is the proving ground.