529 lines
24 KiB
TypeScript
529 lines
24 KiB
TypeScript
/**
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* @medieval-kit/tavern-sign
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*
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* A wooden board swinging on chains from a forged iron arm on a freestanding
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* timber post.
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*
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* Since literacy was rare, a period sign carried a PICTURE, not TEXT: a garland
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* meant the vintner, a boot the cobbler, a mortar the apothecary. So the model
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* gives the board itself, not the device on it — the consumer attaches whatever
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* they want to `parts.board.anchor`. This is exactly what the protocol's idea
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* of semantic parts is good for.
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*
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* The swing is a different pendulum from the bell's: here the restoring force
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* is not gravity but the friction of two rings. So a sign at rest always hangs
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* STRAIGHT, but once pushed it oscillates for a long time. Put next to the
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* bell's hard, fast damping, the difference between the two reads immediately.
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*
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* DEAD ENDS, so far four rounds of them:
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* 1. The bracket was bolted to a wall the model did not contain, so the
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* whole sign floated. It became a standing post.
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* 2. The brace and the curl were boxes put through `bendGeometry`, which
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* shears a two-level box instead of bending it; both were replaced with
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* `arcBarGeometry`.
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* 3. The post was a stick. A blind critique scored the model 60 and put
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* almost all of the loss below the sign; the cross base, heavy post, cap,
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* collars and knee brace date from that pass, as does the grey-washed oak
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* (the `oak` helper below, with its lightness floor against the
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* renderer's gamma crush).
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* 4. A second blind critique (66) found the pass-3 fixes overshot or
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* half-done, plus real modelling bugs:
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* - The battens were built 8 mm BEHIND the board's back face — floating,
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* and from half the angles they read as a stray strap lying on the
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* front. Battens are gone; the planks now touch at a chamfer-groove
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* seam instead.
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* - The planks were wedge-tapered through their thickness, so the board
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* read as two splayed slabs. They are straight now.
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* - The chain lugs were thicker than the board and ran down its face.
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* Replaced with eye rings half-buried in the board's top edge, and the
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* chain stops above the edge so no link crosses the face.
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* - The cone cap overhung the post like a roof; now a slim pyramid whose
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* base matches the post's cross-section (about half a post-width tall).
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* - The two collars were black blocks a third of a post-width tall,
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* stacked into one collar; now two thin straps (about an eighth), one
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* at the arm, one up where the tie rod anchors, projecting only a few
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* percent past the post faces — which also terminates the rod's top.
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* - The bearer was a stub; it is now a real through-timber about 0.8
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* post-widths across reaching 55% of the arm's length, the arm seats
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* flat on its top face, and the knee brace lands inside its underside.
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* - The hexagonal ring "scroll" is now a C-scroll volute: a 255-degree
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* arc rising off the arm at the tie-rod junction, its free end closed
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* by a forged ball so nothing terminates in the open.
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* - The post dropped from 1:9 to 1:13 width-to-height (the reference is
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* nearer 1:14), the board widened to 1.26:1 with two planks, and every
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* board corner carries the hanging-sign cusp: the edges step in before
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* the corner and a diagonal tab pokes back out to the corner point.
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* - `plankCount` changed MEANING: it now counts the SEAMS, and the board
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* carries plankCount + 1 planks. Do not change it back to a plank
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* count with a default of 2.
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*/
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import type { BufferGeometry } from 'three'
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import {
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arcBarGeometry,
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bandGeometry,
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boxGeometry,
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chamferedBoxGeometry,
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createKitModel,
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createTinter,
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jitter,
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mergeColoured,
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taperedBoxGeometry,
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} from '../core/index.ts'
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export interface TavernSignConfig {
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/** Board width (metres). */
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readonly width: number
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/** Board height (metres). */
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readonly height: number
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/** How far the bracket projects from the post (metres). */
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readonly reach: number
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/** Height of the post the arm is bolted to (metres). */
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readonly postHeight: number
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/** Length of the hanging chain (metres). */
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readonly drop: number
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/** Seams between the boards: the sign carries plankCount + 1 planks. */
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readonly plankCount: number
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/** How fast the swing damps out. */
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readonly damping: number
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readonly seed: number
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}
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export const tavernSignDefaults: TavernSignConfig = {
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// 1.26:1, wider than tall — the reference board is about 1.2:1. The old
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// 0.72 x 0.52 read as roughly square once the corner cusps came off.
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width: 0.78,
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height: 0.62,
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// About 1.5 board widths. At 0.62 the board's inner planks ended flush
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// against the post face and read as clipped by it; now the inner edge
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// clears the post comfortably.
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reach: 1.15,
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postHeight: 2.15,
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// Long enough to see the chain. At 0.12 the board hung almost against the
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// bracket and the five links that connect them were a smudge; the chain is
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// half of what makes a hanging sign read as hanging.
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drop: 0.3,
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// One seam: two planks, which is what the reference board is made of.
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plankCount: 1,
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damping: 0.42,
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seed: 73,
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}
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// The chains are NOT a separate part: they have to swing together with the
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// board, so they live as its `extras` body.
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export type TavernSignParts = 'bracket' | 'board' | 'post'
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export interface TavernSignActions {
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/** Pushes the sign: wind, or someone coming out of the door. */
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push(strength?: number): void
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still(): void
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/** Current swing angle (radians). */
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lean(): number
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}
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export function createModel(overrides: Partial<TavernSignConfig> = {}) {
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let angle = 0
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let velocity = 0
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return createKitModel<TavernSignConfig, 'oak' | 'iron', TavernSignParts, TavernSignActions>({
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id: 'tavern-sign',
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defaults: tavernSignDefaults,
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slots: ['oak', 'iron'],
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build: ({ config, random }) => {
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const tint = createTinter(random)
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// Decades outdoors: rain leaches the tannin out of oak and leaves it
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// grey-brown. The palette's oak is fresh-sawn; every timber tint here is
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// pulled toward grey. The critique called the untreated colour
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// "bright orange-tan" and it was right.
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const oak = (lift = 0, spread = 1) => {
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const c = tint('oak', lift, spread)
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c.offsetHSL(0.004, -0.17, -0.025)
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// Floor the lightness. The renderer's gamma crushes this palette to
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// pure black somewhere around L 0.18, and the tinter's own jitter can
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// land a piece there even from a mild lift -- that is what painted the
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// old battens (and one unlucky foot per seed) as black plastic.
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const hsl = { h: 0, s: 0, l: 0 }
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c.getHSL(hsl)
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if (hsl.l < 0.19) c.setHSL(hsl.h, hsl.s, 0.19)
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return c
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}
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const bar = config.reach * 0.035
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// A slender structural timber: about 1:13 width to height. The first
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// heavy-post pass used 1:9 and the whole sign came out stocky; the
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// reference is nearer 1:14.
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const w = config.postHeight / 13
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// Axis of rotation: the line where the chains leave the arm. The board
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// and the chains are written RELATIVE to this point.
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const pivotY = config.height * 0.5 + config.drop
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const armY = pivotY
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// The post continues well past the ironwork before the cap, the way the
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// reference does, and the tie rod needs the vertical run.
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const postTop = armY + w * 1.6
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const ground = postTop - config.postHeight
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// Board centre along the arm, and where the two chains meet it.
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const zc = config.reach * 0.72
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const hangA = zc - config.width * 0.3
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const hangB = zc + config.width * 0.3
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// --- Post and base -----------------------------------------------------
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const timber: BufferGeometry[] = [chamferedBoxGeometry(
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[w, w],
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[w * 0.92, w * 0.92],
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config.postHeight,
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w * 0.08,
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// The post's foot ends INSIDE the plinth, not on the ground: two
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// ground-touching interpenetrating solids would share coplanar
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// down-facing faces.
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[0, (postTop + ground + w * 0.4) / 2, 0],
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oak(-0.03),
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oak(0.03),
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)]
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// Cap: a slim four-sided pyramid whose base matches the post's
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// cross-section, about half a post-width tall. The old cone overhung the
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// post on every side and read as a fence-post roof.
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const capH = w * 0.55
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timber.push(taperedBoxGeometry(
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[w * 0.945, w * 0.945],
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[w * 0.06, w * 0.06],
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capH,
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[0, postTop - 0.02 + capH / 2, 0],
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oak(-0.02),
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oak(-0.05),
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))
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// The cross base: a centre plinth, four feet radiating on the ground
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// axes, four angled struts. This is the bottom third of the reference.
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//
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// Ground contact is divided so no two down-facing faces overlap in the
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// ground plane: the FEET stand on the ground at four disjoint patches,
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// and the plinth they all embed into rides 6 mm up, hidden behind them.
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const footH = w * 0.75
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const footW = w * 0.88
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const rIn = w * 0.55 // feet start inside the plinth
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const rOut = w * 2.3 // and reach over two post-widths out
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timber.push(chamferedBoxGeometry(
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[w * 1.55, w * 1.55],
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[w * 1.42, w * 1.42],
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footH * 1.2,
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w * 0.06,
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[0, ground + 0.006 + footH * 0.6, 0],
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oak(-0.02),
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))
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for (const [axis, sign] of [['x', 1], ['x', -1], ['z', 1], ['z', -1]] as const) {
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const len = rOut - rIn
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const foot = chamferedBoxGeometry(
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axis === 'x' ? [footH, footW] : [footW, footH],
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axis === 'x' ? [footH * 0.88, footW * 0.88] : [footW * 0.88, footH * 0.88],
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len,
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footH * 0.14,
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[0, 0, 0],
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oak(jitter(random, 0.025), 0.6),
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)
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// Built standing, then laid over so the chamfered end points outward.
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if (axis === 'x') foot.rotateZ(-sign * Math.PI / 2)
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else foot.rotateX(sign * Math.PI / 2)
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const mid = rIn + len / 2
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foot.translate(axis === 'x' ? sign * mid : 0, ground + footH / 2, axis === 'z' ? sign * mid : 0)
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timber.push(foot)
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// Strut: from a fifth of the way up the post down to the outer end of
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// this foot. Both end caps terminate inside their solids.
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const s = w * 0.38
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const top = { r: w * 0.3, y: ground + config.postHeight * 0.19 }
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const bot = { r: rOut - w * 0.4, y: ground + footH * 0.5 }
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const run = bot.r - top.r
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const rise = top.y - bot.y
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const len2 = Math.hypot(run, rise)
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const lean = Math.atan2(-run, rise)
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const strut = boxGeometry([s * 0.92, len2, s], [0, 0, 0], oak(jitter(random, 0.02), 0.6))
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if (axis === 'x') strut.rotateZ(-sign * lean)
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else strut.rotateX(sign * lean)
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strut.translate(
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axis === 'x' ? sign * (top.r + bot.r) / 2 : 0,
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(top.y + bot.y) / 2,
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axis === 'z' ? sign * (top.r + bot.r) / 2 : 0,
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)
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timber.push(strut)
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}
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// Bearer: the through-timber the arm actually rests on. About 0.8
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// post-widths across, poking out a little behind the post and reaching
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// 55% of the arm's length in front; the arm seats flat on its top face.
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const armH = bar * 1.5
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const armW = bar * 0.9
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const bearerW = w * 0.8
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const bearerH = w * 0.68
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const bearerTop = armY - armH / 2 + 0.004
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const bearerY = bearerTop - bearerH / 2
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const backZ = -w * 0.9
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// Just short of the inner chain: at 0.55 reach the bearer's end swallowed
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// the inner chain's top link.
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const frontZ = config.reach * 0.47
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const bearer = chamferedBoxGeometry(
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[bearerW, bearerH],
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[bearerW * 0.96, bearerH * 0.96],
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frontZ - backZ,
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w * 0.05,
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[0, 0, 0],
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oak(-0.02),
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)
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bearer.rotateX(Math.PI / 2) // stand it on its side: length now along +Z
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bearer.translate(0, bearerY, (frontZ + backZ) / 2)
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timber.push(bearer)
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// The knee brace: a quarter arc from the post face out to the bearer's
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// underside. One end cap inside the post, the other rises into the
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// bearer; nothing terminates in the open.
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const braceR = Math.max(w * 0.9, Math.min(w * 2.1, frontZ - w * 0.3))
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const brace = arcBarGeometry(
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braceR, w * 0.32, -Math.PI / 2, 0, 6, [0, 0, 0],
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oak(0.02, 0.5),
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)
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// Built in XY; -90 degrees about Y carries +X into +Z, standing the arc
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// in the plane the bracket occupies.
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brace.rotateY(-Math.PI / 2)
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brace.translate(0, bearerY - bearerH / 2 + 0.02, 0)
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timber.push(brace)
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// --- Ironwork ----------------------------------------------------------
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const iron: BufferGeometry[] = []
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// The arm: a flat strap seated on the bearer's top face, its back end
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// buried in the post (it stops short of the post's back face).
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iron.push(boxGeometry(
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[armW, armH, config.reach + w * 0.4],
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[0, armY, (config.reach - w * 0.4) / 2],
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tint('iron', 0.02, 0.7),
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))
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// Forged diamond finial at the tip, slightly proud of the bar the way a
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// hammered spear-end spreads.
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const tipL = w * 0.5
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const tip = taperedBoxGeometry(
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[armW * 1.2, armH * 1.35],
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[armW * 0.12, armH * 0.12],
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tipL,
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[0, 0, 0],
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tint('iron', 0.04, 0.7),
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)
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tip.rotateX(Math.PI / 2) // point it along +Z
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tip.translate(0, armY, config.reach - 0.01 + tipL / 2)
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iron.push(tip)
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// Two thin straps around the post — about an eighth of a post-width
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// tall, projecting a few percent past the faces. One clamps the arm
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// where it enters the post, one up top anchors the tie rod.
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const bandH = bar * 0.65
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const rodTopY = postTop - w * 0.35
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iron.push(boxGeometry([w, bandH, w], [0, rodTopY, 0], tint('iron', -0.04, 0.7)))
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iron.push(boxGeometry([w, bandH * 1.1, w], [0, armY, 0], tint('iron', -0.06, 0.7)))
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// The shallow diagonal tie rod, from the upper strap down into the arm
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// at the scroll junction.
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const scrollZ = config.reach * 0.8
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{
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const t = { y: rodTopY, z: w * 0.28 }
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const b = { y: armY + armH * 0.2, z: scrollZ }
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const len = Math.hypot(t.y - b.y, b.z - t.z)
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const rod = boxGeometry([bar * 0.55, len, bar * 0.55], [0, 0, 0], tint('iron', 0, 0.7))
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// atan2 of (dz, dy) ALONG the rod, top to bottom: getting the y term
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// backwards mirrors the slope and the rod climbs into free air past
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// the arm instead of dropping from the post top onto it.
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rod.rotateX(Math.atan2(b.z - t.z, b.y - t.y))
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rod.translate(0, (t.y + b.y) / 2, (t.z + b.z) / 2)
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iron.push(rod)
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}
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// The C-scroll volute where the rod meets the arm: a 255-degree arc
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// rising off the arm and curling back over itself. Its lower end is
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// buried in the arm; its free end is closed by a forged ball, so neither
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// end terminates in the open. The old closed hexagonal ring read as a
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// washer, not a scroll.
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const rS = w * 0.32
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const scroll = arcBarGeometry(
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rS, bar * 0.6, -Math.PI * 0.44, Math.PI * 0.97, 8, [0, 0, 0],
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tint('iron', 0.05, 0.7),
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)
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scroll.rotateY(-Math.PI / 2)
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scroll.translate(0, armY + rS * 0.9, scrollZ)
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iron.push(scroll)
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iron.push(boxGeometry(
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[bar * 1.1, bar * 1.1, bar * 1.1],
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[0, armY + rS * 0.99, scrollZ - rS],
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tint('iron', 0.02, 0.7),
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))
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// --- Chains ------------------------------------------------------------
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// They have to swing TOGETHER with the board, hence the board's `extras`
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// body. Were they a separate part, the chain would stay bolt upright
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// while the board swung.
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//
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// The COUNT is fixed and the RADIUS is derived, not the other way round.
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// Deriving the count from `drop` guaranteed the links overlap, but it also
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// made the triangle count depend on a continuous slider — which meant the
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// showcase could not morph this model and had to fall back to visibly
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// stepped rebuilds. Fixing the count and growing the links instead keeps
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// both properties: always interlocked, always the same topology.
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const linkCount = 5
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const linkRadius = Math.max(bar * 0.9, (config.drop / (linkCount - 1)) * 0.62)
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const eyeR = linkRadius * 0.9
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// The chain stops ABOVE the board's top edge; the eye ring bridges the
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// last link to the board. Letting the last link reach the edge itself
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// put its lower arc through the board's face from both sides.
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const chainSpan = Math.max(0.01, config.drop - eyeR * 1.2)
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const links: BufferGeometry[] = []
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for (const side of [-1, 1]) {
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const hangZ = side < 0 ? hangA - zc : hangB - zc
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for (let i = 0; i < linkCount; i += 1) {
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// The first link wraps the arm and the last threads the board's eye,
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// so the chain is a real connection rather than two things at
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// roughly the same height.
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const y = -chainSpan * (i / (linkCount - 1))
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const ring2 = bandGeometry(linkRadius, 0, bar * 0.6, bar * 0.35, 6,
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tint('iron', jitter(random, 0.05), 0.7), { inner: true })
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// Each link is indexed a little differently about its own axis, so
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// consecutive interlocking links never leave coplanar facets. The
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// offset is deterministic so the seeded stream is untouched.
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ring2.rotateY(i * 0.37 + side * 0.19)
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// Successive links must pass through at right angles — that is what a
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// chain is.
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ring2.rotateX(i % 2 === 0 ? Math.PI / 2 : 0)
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ring2.rotateZ(i % 2 === 0 ? 0 : Math.PI / 2)
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ring2.translate(0, y, hangZ)
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links.push(ring2)
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}
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// The eye: a ring standing in the board's own plane, its lower half
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// buried in the board's top edge, its upper half threading the last
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// chain link. This replaces the old lugs, which were thicker than the
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// board and ran down its face.
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const eye = bandGeometry(eyeR, 0, bar * 0.55, bar * 0.35, 6,
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tint('iron', 0.03, 0.7), { inner: true })
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eye.rotateZ(Math.PI / 2)
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eye.translate(0, -config.drop + eyeR * 0.35, hangZ)
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links.push(eye)
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}
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// --- Board -------------------------------------------------------------
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// Two planks (by default) touching at a chamfer-groove seam, with the
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// hanging-sign cusp cut into all four corners: the outer edges step in a
|
|
// tenth of the board width before the corner, and a diagonal tab pokes
|
|
// back out to the corner point, leaving a concave notch either side.
|
|
const W = config.width
|
|
const H = config.height
|
|
const t = Math.max(0.02, H * 0.05)
|
|
const planks = Math.max(1, Math.round(config.plankCount) + 1)
|
|
const plankH = H / planks
|
|
const n = Math.min(W * 0.09, plankH * 0.42)
|
|
const boardTop = -config.drop
|
|
// Half-width of the shadow gap either side of a plank seam. The seam is
|
|
// an actual groove: the planks pull back a hair and a darker strip sits
|
|
// recessed behind the gap, bridging them. Tint jitter alone was not
|
|
// enough — one seed put the two planks at the same value and the board
|
|
// read as a single slab.
|
|
const g = 0.002
|
|
const board: BufferGeometry[] = []
|
|
for (let i = 0; i < planks; i += 1) {
|
|
const y0 = boardTop - H + i * plankH
|
|
const y1 = y0 + plankH
|
|
const cutTop = i === planks - 1
|
|
const cutBottom = i === 0
|
|
// Alternate the planks light/dark on purpose so the seam always
|
|
// separates two visibly different boards, whatever the seed does.
|
|
const c = oak((i % 2 === 0 ? -0.055 : 0.05) + jitter(random, 0.012))
|
|
// Two boards cut from two trees: the light plank is warmer as well as
|
|
// lighter, so the seam separates two visibly different timbers.
|
|
if (i % 2 === 1) c.offsetHSL(0.012, 0.05, 0)
|
|
// A hair of per-plank thickness difference: it marks the single real
|
|
// seam with a faint step without cutting a groove that could be
|
|
// miscounted as another plank.
|
|
const tp = t * (1 - i * 0.012)
|
|
const yLo = cutBottom ? y0 : y0 + g
|
|
const yHi = cutTop ? y1 : y1 - g
|
|
const aLow = yLo + (cutBottom ? n : 0)
|
|
const aHigh = yHi - (cutTop ? n : 0)
|
|
if (i > 0) {
|
|
// The seam strip: darker, recessed behind both plank faces, and
|
|
// overlapping both planks so the board stays one connected body.
|
|
// Sitting only 1.3 mm behind the faces: any deeper and the lower
|
|
// plank's lit top face fills the slit and the seam reads LIGHT.
|
|
board.push(boxGeometry([t * 0.91, 0.02, W * 0.985], [0, y0, 0], oak(-0.2)))
|
|
}
|
|
// The plank body. Plain and straight through its thickness: the old
|
|
// wedge taper made the front faces splay and the board read as two
|
|
// non-coplanar slabs, and a chamfered body left a groove where the
|
|
// corner-cut strip joins it, which read as a third plank seam.
|
|
board.push(boxGeometry([tp, aHigh - aLow, W], [0, (aLow + aHigh) / 2, 0], c))
|
|
for (const [edge, cut] of [[1, cutTop], [-1, cutBottom]] as const) {
|
|
if (!cut) continue
|
|
const yEdge = edge > 0 ? y1 : y0
|
|
// The outer-edge strip: its inner cross-section matches the body
|
|
// exactly (flush, invisible joint) and it tapers to W - 2n at the
|
|
// outer edge, so each corner is cut by a 45-degree facet.
|
|
board.push(taperedBoxGeometry(
|
|
edge > 0 ? [tp, W] : [tp * 0.99, W - 2 * n],
|
|
edge > 0 ? [tp * 0.99, W - 2 * n] : [tp, W],
|
|
n,
|
|
[0, yEdge - edge * n / 2, 0], c,
|
|
))
|
|
for (const side of [-1, 1] as const) {
|
|
// The cusp point: a small pointed diamond on the corner diagonal,
|
|
// base buried in the strip, tip reaching exactly the original
|
|
// corner. It stays inside the board's rectangle instead of
|
|
// poking past it.
|
|
const theta = edge > 0 ? side * Math.PI / 4 : Math.PI - side * Math.PI / 4
|
|
const tipTab = taperedBoxGeometry(
|
|
[tp * 0.92, n * 0.95], [tp * 0.45, n * 0.12], n, [0, 0, 0], c,
|
|
)
|
|
tipTab.rotateX(theta)
|
|
tipTab.translate(
|
|
0,
|
|
yEdge - Math.cos(theta) * n * 0.5,
|
|
side * W / 2 - Math.sin(theta) * n * 0.5,
|
|
)
|
|
board.push(tipTab)
|
|
}
|
|
}
|
|
}
|
|
|
|
return {
|
|
post: { slot: 'oak' as const, geometry: mergeColoured(timber) },
|
|
bracket: { slot: 'iron' as const, geometry: mergeColoured(iron) },
|
|
board: {
|
|
slot: 'oak' as const,
|
|
geometry: mergeColoured(board),
|
|
// The origin is the point on the ARM the chains hang from, not the
|
|
// post's centre line: the swing action rotates about this origin,
|
|
// and rotating about anywhere else sweeps the chain tops off the
|
|
// bar they are looped through.
|
|
origin: [0, pivotY, zc] as const,
|
|
extras: [{ slot: 'iron' as const, geometry: mergeColoured(links) }],
|
|
},
|
|
}
|
|
},
|
|
|
|
actions: ({ parts }) => {
|
|
parts.board.anchor.rotation.z = angle
|
|
return {
|
|
push: (strength = 1) => {
|
|
// Reinforces the existing motion instead of resetting it: successive
|
|
// pushes should accumulate the way a real wind does.
|
|
velocity += (velocity >= 0 ? 1 : -1) * 1.6 * strength
|
|
},
|
|
still: () => { angle = 0; velocity = 0; parts.board.anchor.rotation.z = 0 },
|
|
lean: () => angle,
|
|
}
|
|
},
|
|
|
|
update: (dt, { parts, getConfig }) => {
|
|
const step = Math.min(0.05, Math.max(0, dt))
|
|
if (step === 0) return
|
|
if (Math.abs(angle) < 1e-5 && Math.abs(velocity) < 1e-5) return
|
|
// A SOFTER pendulum than the bell's: weak restoring force, little damping.
|
|
// This is what the long, lazy swing of a heavy board looks like.
|
|
velocity += -angle * 11 * step - velocity * getConfig().damping * step
|
|
angle += velocity * step
|
|
// Limit: the board must stop before it hits the arm.
|
|
const limit = 0.55
|
|
if (Math.abs(angle) > limit) {
|
|
angle = Math.sign(angle) * limit
|
|
velocity *= -0.4
|
|
}
|
|
parts.board.anchor.rotation.z = angle
|
|
},
|
|
}, overrides)
|
|
}
|