# kit The vale's surfaces and its ground — the two things every other `vale` submodule needs. ## Exports - `kit.mintMaterials()` — mints the fourteen vale materials (ragstone, limestone, lichen, slate, iron, brass, yew, bark, turf, gravel, water, void, distance, rook) from `film.PAL`. Idempotent. - `kit.id(name)` — the dotted identity of one of them, which is how a `Model` wears it. `kit.has(name)` asks whether it has been minted yet. - `kit.ground(x, z)` — **the** height function. The terrain mesh, the path, the monuments and the yews all sample this one function, so nothing in the vale floats or sinks. Banks rise quadratically either side of the avenue, the floor lifts toward the lodge gate, and there is a crest behind the chapel as well as the far one at 900 m. - `kit.pathY(z)`, `kit.gutterY(z, t)` — the metalled avenue and the water standing in its gutter. - `kit.qAxis`, `kit.qYaw`, `kit.qMul` — an entity's `rotation` is a quaternion table; these are the three constructors the vale needs. ## Anchors it honours `kit.ground(0, 0)` is 0 (`film.PLACES.chapelDoor`) and `kit.ground(0, 96)` is 1.2 (`film.PLACES.lodgeGate`) exactly — the far shoulder and ridge terms are held off the vale floor so those two stay true.

# geom The mesh lathe the `vale` slice of *Sexton's Bell* is built with. A builder accumulates one triangle stream — positions, normals, uvs, indices — under a transform stack, and mints it as a `.mesh` asset. One merged mesh per material is the unit of geometry here: four hundred monuments become three draws rather than four hundred entities. ## Exports - `geom.builder()` — a fresh builder. - `geom.trs(tx, ty, tz, yaw, pitch, roll, sx, sy, sz)` / `geom.compose(a, b)` — transforms; `b:push(m)` / `b:pop()` / `b:at(...)` stack them. - `geom.ring(n, r, rot)` — a regular n-gon in the XZ plane, for lofts. On a builder: `vert`, `face`, `tri`, `quad`, `box`, `pier`, `polyFan`, `extrudeZ`, `extrudeY`, `loft`, `grid`, `tris`, `mint`. ## Conventions - Emitters are **flat-shaded** by default: every face owns its vertices, which is what dressed stone wants. `loft` takes `smooth = true` (the yews, the urns, the ridge treeline) and `grid` is always smooth. - A face's front is the side its three vertices turn counter-clockwise as seen from. `quad`/`tri`/`box` derive the normal from the winding they are given, so those two can never disagree; `polyFan`, `loft(smooth)`, `grid` and the `extrudeY` caps write normals of their own, so their winding is chosen from the outline's signed area rather than assumed. - `extrudeZ` and `polyFan` take an outline wound either way and still come out facing outward. - `mint(identity, name, folder, force)` asks `asset.exists` rather than resolving a handle from a computed name, so a mesh identity built by concatenation never becomes an unpublishable reference on the content that wears it.

# film The shared clock, the storm and the slice registry for Sexton's Bell — the 95-second, 14-shot demo in this world. Every build slice requires this module; it is the only place the film's time, weather, palette and storm table are written down. ## Exports - `film.FPS` / `film.DT` / `film.DURATION` / `film.FRAMES` — 24, 1/24, 95.0, 2280. - `film.now()` / `film.frame()` / `film.isPlaying()` — where the film is. - `film.seekTo(t)` / `film.seekToFrame(n)` / `film.reset()` / `film.play()` / `film.pause()` / `film.run()` / `film.step()` — the transport. `step()` is called once per rendered frame by the `FilmDirector` component and by nothing else. - `film.register(slice)` / `film.buildAll()` / `film.built(name)` / `film.missing()` / `film.slices()` — the registry. - `film.SHOTS` / `film.shotAt(t)` — the fourteen shots and their boundaries. - `film.STROKES` / `film.strobe(t)` / `film.thunderAt(i)` / `film.gap(i)` / `film.strokeAt(t)` — the storm. `strobe(t)` is the single lightning envelope everything reads; nobody writes their own. - `film.rain(t)` / `film.wind(t)` / `film.windDir(t)` / `film.wetness(t)` / `film.gas(t)` / `film.lantern(t)` — the shared weather and practical ramps. - `film.rand(seed, i)` / `film.noise(seed, x)` — the only randomness a slice may use. - `film.PAL` / `film.NAMES` / `film.PLACES` — palette, shared entity names, world anchors. ## Usage ```luau local film = require("demo.film") local function update(t) local level, stroke = film.strobe(t) -- ... a pure function of t, and of nothing else end ``` ## Notes - Every slice's `update(t)` is a pure function of absolute film time. No accumulation, no `dt`, no `math.random`, no wall clock. That purity is what makes `seekTo(t)` reproduce a frame exactly, which is what lets the film be recorded twice for the same result. - Guard a slice's `build()` on its sentinel entity being alive, never on a module-local flag: module state survives an edit/play flip and entities do not. - The full design is `/zero/source/design/spec.md`.