Merge lane-h: ghost replay (record/save/replay best run) + title screen

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
type-two 2026-07-18 11:48:46 +10:00
commit 874fe076cb
9 changed files with 1113 additions and 0 deletions

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demos/lane-h.html Normal file
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<!doctype html>
<html lang="en">
<head><meta charset="utf-8" /><title>BLOBBO lane h demo — ghost + title</title>
<style>
html,body{margin:0;height:100%;overflow:hidden;background:#0a0c18;font-family:system-ui,sans-serif}
#app{width:100%;height:100%}
#legend{position:fixed;bottom:12px;right:12px;padding:9px 12px;border-radius:8px;
background:rgba(20,24,40,.72);color:#eaf2ff;font-size:12px;line-height:1.55;pointer-events:none;z-index:5}
#legend b{color:#ffd60a}
#legend .k{display:inline-block;min-width:14px;padding:1px 5px;margin-right:6px;border-radius:4px;
background:#354569;color:#fff;font-weight:600;text-align:center}
</style></head>
<body>
<div id="app"></div>
<div id="legend">
<b>Lane H — ghost + title</b><br>
Title → PLAY starts run 1 (records). Later runs replay the ghost.<br>
<span class="k">G</span>wipe saved ghost<br>
<span class="k">R</span>restart the run<br>
<span class="k">P</span>print state snapshot
</div>
<script type="module" src="/src/demo/lane-h.ts"></script>
</body>
</html>

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/**
* Lane H demo ghost replay + title screen.
*
* Self-contained (no game.ts): a scripted "run" drives a ball around a 20s
* circle. The title card gates the start (and emits ui:play). Run 1 records the
* path; every later run replays the saved ghost racing the live ball around the
* SAME deterministic circle, so the translucent ghost should sit right on top
* of the solid ball. The recorder persists the best to localStorage, so a page
* reload comes back with the ghost already armed on the title.
*
* Debug keys (browser):
* G wipe the saved ghost from localStorage (blobbo:ghost)
* R restart the run immediately
* P print a one-line state snapshot to the console
*
* A live "drift" readout compares the replayed ghost against the true circle in
* real time; the rigorous numeric check is verify-drift.ts (bundle + node).
*/
import * as THREE from 'three'
import type { Blob, World } from '../contracts'
import { defaultModifiers } from '../contracts'
import { installTitle } from '../ui/title'
import { installGhost } from '../ghost/install'
import { clearGhost, hasGhost, loadGhost, sampleAt, type GhostSample, type GhostTrack } from '../ghost/format'
// ---- the deterministic scripted path (a ball on a circle) -----------------
const R = 8 // circle radius (m)
const CY = 1.0 // ride height (m)
const RUN_SECONDS = 20
const OMEGA = (2 * Math.PI) / RUN_SECONDS
const BLOB_RADIUS = 0.5
function pathAt(t: number, out: GhostSample): GhostSample {
const th = OMEGA * t - Math.PI / 2 // start near (0,·,-R)
out.x = R * Math.cos(th)
out.y = CY
out.z = R * Math.sin(th)
out.scale = 1 + 0.15 * Math.sin(2 * OMEGA * t) // gentle pulse to exercise scale replay
return out
}
export function buildLaneH(world: World): {
blob: Blob
beginRun: () => void
wipeGhost: () => void
} {
const { scene, physics, rapier } = world
// ---------------------------------------------------------------- scenery
const floor = new THREE.Mesh(
new THREE.CircleGeometry(R + 4, 64),
new THREE.MeshStandardMaterial({ color: '#3a4a63', roughness: 0.95 }),
)
floor.rotation.x = -Math.PI / 2
floor.receiveShadow = true
scene.add(floor)
// the racing line, drawn on the floor so the circle is obvious
const ring = new THREE.Mesh(
new THREE.RingGeometry(R - 0.12, R + 0.12, 96),
new THREE.MeshBasicMaterial({ color: '#ffd60a', side: THREE.DoubleSide }),
)
ring.rotation.x = -Math.PI / 2
ring.position.y = 0.02
scene.add(ring)
// start marker
const startMark = new THREE.Mesh(
new THREE.BoxGeometry(0.4, 0.05, 2.4),
new THREE.MeshBasicMaterial({ color: '#FF6EB4' }),
)
startMark.position.set(0, 0.03, -R)
scene.add(startMark)
// ---------------------------------------------------------------- the "blob"
// A Lane-H-owned stand-in shaped like the frozen Blob: the recorder reads the
// root group's position + scale. A kinematic body is created only to satisfy
// the Blob type (never stepped; the group is driven directly).
const group = new THREE.Group()
group.position.set(0, CY, -R)
scene.add(group)
const mesh = new THREE.Mesh(
new THREE.SphereGeometry(BLOB_RADIUS, 32, 24),
new THREE.MeshStandardMaterial({ color: '#F5F5F7', roughness: 0.4, emissive: '#ffcaa8', emissiveIntensity: 0.15 }),
)
mesh.castShadow = true
group.add(mesh)
// little eyes so the live ball reads as Blobbo, for contrast with the ghost
const eyeMat = new THREE.MeshStandardMaterial({ color: '#1a1a22', roughness: 0.5 })
const eyeGeo = new THREE.SphereGeometry(BLOB_RADIUS * 0.16, 12, 10)
for (const side of [-1, 1]) {
const eye = new THREE.Mesh(eyeGeo, eyeMat)
eye.position.set(side * BLOB_RADIUS * 0.34, BLOB_RADIUS * 0.32, BLOB_RADIUS * 0.9)
group.add(eye)
}
const body = physics.createRigidBody(
rapier.RigidBodyDesc.kinematicPositionBased().setTranslation(0, CY, -R),
)
const blob: Blob = { group, mesh, body, modifiers: defaultModifiers() }
// ---------------------------------------------------------------- run driver
let running = false
let runT = 0
let runNo = 0
let best: number | null = null
let ghostThisRun = false
let liveTrack: GhostTrack | null = null
let maxDrift = 0
const scratchA: GhostSample = { x: 0, y: 0, z: 0, scale: 1 }
const scratchB: GhostSample = { x: 0, y: 0, z: 0, scale: 1 }
let nextTimer = 0
// Driver runs as a fixed-step System added BEFORE installGhost, so the
// recorder samples this frame's updated group position (insertion order).
world.addSystem({
update(dt: number): void {
if (!running) return
runT += dt
const tt = Math.min(runT, RUN_SECONDS)
pathAt(tt, scratchA)
group.position.set(scratchA.x, scratchA.y, scratchA.z)
group.scale.setScalar(scratchA.scale)
if (runT >= RUN_SECONDS) {
running = false
const time = RUN_SECONDS
const isBest = best == null || time < best
if (isBest) best = time
world.events.emit('race:finished', { time, best })
toast(`🏁 run ${runNo}${time.toFixed(2)}s${ghostThisRun ? ` · ghost drift ${maxDrift.toFixed(3)}m` : ' (recording)'}`)
// auto-loop into the next run
window.clearTimeout(nextTimer)
nextTimer = window.setTimeout(beginRun, 2200)
}
},
})
// ---------------------------------------------------------------- ghost wiring
installGhost(world, blob, { radius: BLOB_RADIUS })
// Live drift readout: replayed ghost vs the true circle at the same race time.
// Registered AFTER installGhost so the ghost has advanced this frame.
world.onFrame(() => {
if (!running || !ghostThisRun || !liveTrack) return
sampleAt(liveTrack, runT, scratchB) // what the ghost replays
pathAt(runT, scratchA) // ground truth
const d = Math.hypot(scratchA.x - scratchB.x, scratchA.y - scratchB.y, scratchA.z - scratchB.z)
if (d > maxDrift) maxDrift = d
})
function beginRun(): void {
window.clearTimeout(nextTimer)
runT = 0
running = true
runNo++
maxDrift = 0
ghostThisRun = hasGhost()
liveTrack = ghostThisRun ? loadGhost() : null
// snap live ball to the start so recording starts clean
pathAt(0, scratchA)
group.position.set(scratchA.x, scratchA.y, scratchA.z)
group.scale.setScalar(scratchA.scale)
world.events.emit('race:started', {})
toast(ghostThisRun ? `run ${runNo} — 👻 racing your ghost` : `run ${runNo} — recording…`)
}
function wipeGhost(): void {
clearGhost()
toast('👻 ghost wiped')
updateHud()
}
// ---------------------------------------------------------------- HUD + toast
const hud = document.createElement('div')
hud.style.cssText =
'position:fixed;top:12px;left:14px;z-index:20;pointer-events:none;' +
'font:600 14px ui-monospace,Menlo,monospace;color:#eaf2ff;background:rgba(16,20,34,.7);' +
'padding:10px 13px;border-radius:10px;line-height:1.55'
document.body.appendChild(hud)
function updateHud(): void {
hud.innerHTML =
`<b style="color:#ffd60a">BLOBBO — Lane H ghost demo</b><br>` +
`run ${runNo}${running ? `${Math.min(runT, RUN_SECONDS).toFixed(2)}s` : ''}<br>` +
`ghost: ${hasGhost() ? `saved ✓${ghostThisRun ? ' · replaying' : ''}` : 'none'}<br>` +
`${ghostThisRun ? `live drift: ${maxDrift.toFixed(3)}m (< ${BLOB_RADIUS}m radius)<br>` : ''}` +
`<span style="opacity:.7">keys: G wipe ghost · R restart · P snapshot</span>`
}
world.onFrame(updateHud)
let toastEl: HTMLDivElement | null = null
let toastTimer = 0
function toast(msg: string): void {
if (!toastEl) {
toastEl = document.createElement('div')
toastEl.style.cssText =
'position:fixed;bottom:22px;left:50%;transform:translateX(-50%);z-index:20;pointer-events:none;' +
'font:700 15px ui-monospace,Menlo,monospace;color:#16264a;background:#ffd60a;' +
'padding:9px 16px;border-radius:10px;box-shadow:0 6px 18px rgba(0,0,0,.4)'
document.body.appendChild(toastEl)
}
toastEl.textContent = msg
toastEl.style.opacity = '1'
window.clearTimeout(toastTimer)
toastTimer = window.setTimeout(() => {
if (toastEl) toastEl.style.opacity = '0'
}, 2600)
}
function snapshot(): Record<string, unknown> {
return {
run: runNo,
running,
t: +runT.toFixed(2),
hasGhost: hasGhost(),
replaying: ghostThisRun,
maxDriftM: +maxDrift.toFixed(4),
pos: [+group.position.x.toFixed(2), +group.position.y.toFixed(2), +group.position.z.toFixed(2)],
}
}
addEventListener('keydown', (e) => {
if (e.code === 'KeyG') wipeGhost()
else if (e.code === 'KeyR') beginRun()
else if (e.code === 'KeyP') console.log('[lane-h]', JSON.stringify(snapshot()))
})
return { blob, beginRun, wipeGhost }
}
// --------------------------------------------------------------- bootstrap
if (typeof document !== 'undefined') {
const { createWorld } = await import('../world')
const world = await createWorld(document.getElementById('app')!)
world.camera.position.set(0, 16, 20)
world.onFrame(() => world.camera.lookAt(0, 0.5, 0))
const h = buildLaneH(world)
// Title in front. Hand it a short boot promise to show the loading blob dot
// before PLAY (the real world is already booted; this just exercises the
// loading state). ui:play kicks off the first run exactly once.
const boot = new Promise<void>((res) => setTimeout(res, 700))
const title = installTitle(world, { ready: boot })
title.done.then(() => {
console.log('[lane-h] ui:play received — starting run 1')
h.beginRun()
})
world.start()
console.log('[lane-h] ready — click PLAY, then keys: G wipe ghost · R restart · P snapshot')
}

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/**
* Ghost track storage + sampling the pure, headless-testable core shared by
* the recorder (writes), the player (reads) and the title (reads best time).
*
* No three / no DOM here beyond guarded btoa/atob/localStorage, so the drift
* verifier (verify-drift.ts) can bundle + run this exact code under `node`.
*
* Wire storage is int16 centimetres (position) + int16 milli-units (uniform
* scale), base64 of the raw Int16Array inside a tiny JSON envelope in
* localStorage key `blobbo:ghost`. A full 5-minute run is ~48KB base64, well
* under the ~200KB budget.
*/
export const GHOST_KEY = 'blobbo:ghost'
export const RECORD_HZ = 15
export const MAX_SECONDS = 300 // ~5 min recording cap
export const MAX_SAMPLES = MAX_SECONDS * RECORD_HZ // 4500
export const FLOATS_PER_SAMPLE = 4 // x, y, z, uniformScale
export const POS_SCALE = 100 // metres -> int16 centimetres (±327.67 m range)
export const SIZE_SCALE = 1000 // uniform scale -> int16 milli-units (±32.767)
export interface GhostTrack {
time: number // recorded run time (seconds)
hz: number // sample rate
count: number // number of samples stored
data: Int16Array // interleaved [x_cm, y_cm, z_cm, scale_milli] * count
}
export interface GhostSample {
x: number
y: number
z: number
scale: number
}
// clamp to int16 so one wild sample can never corrupt the buffer / overflow
const i16 = (n: number): number => Math.max(-32768, Math.min(32767, Math.round(n)))
/** Quantise the first `count` samples of a flat Float32 buffer into int16s. */
export function quantize(src: Float32Array, count: number): Int16Array {
const out = new Int16Array(count * FLOATS_PER_SAMPLE)
for (let i = 0; i < count; i++) {
const o = i * FLOATS_PER_SAMPLE
out[o] = i16(src[o] * POS_SCALE)
out[o + 1] = i16(src[o + 1] * POS_SCALE)
out[o + 2] = i16(src[o + 2] * POS_SCALE)
out[o + 3] = i16(src[o + 3] * SIZE_SCALE)
}
return out
}
/**
* Linear-interpolate the track at race-time `t` (seconds), writing into `out`
* (reused to avoid per-frame allocation). Clamps at both ends: before the run
* it sits at the start sample, after the run it freezes on the finish sample.
*/
export function sampleAt(track: GhostTrack, t: number, out: GhostSample): GhostSample {
const { data, count, hz } = track
if (count === 0) {
out.x = out.y = out.z = 0
out.scale = 1
return out
}
const f = Math.max(0, Math.min(count - 1, t * hz))
const i0 = Math.floor(f)
const i1 = Math.min(count - 1, i0 + 1)
const a = f - i0
const o0 = i0 * FLOATS_PER_SAMPLE
const o1 = i1 * FLOATS_PER_SAMPLE
out.x = (data[o0] + (data[o1] - data[o0]) * a) / POS_SCALE
out.y = (data[o0 + 1] + (data[o1 + 1] - data[o0 + 1]) * a) / POS_SCALE
out.z = (data[o0 + 2] + (data[o1 + 2] - data[o0 + 2]) * a) / POS_SCALE
out.scale = (data[o0 + 3] + (data[o1 + 3] - data[o0 + 3]) * a) / SIZE_SCALE
return out
}
// ---- base64 <-> bytes (chunked so btoa never blows the arg limit) ----------
const B64_CHUNK = 0x8000
function bytesToB64(bytes: Uint8Array): string {
let bin = ''
for (let i = 0; i < bytes.length; i += B64_CHUNK) {
bin += String.fromCharCode(...bytes.subarray(i, i + B64_CHUNK))
}
return btoa(bin)
}
function b64ToBytes(b64: string): Uint8Array {
const bin = atob(b64)
const bytes = new Uint8Array(bin.length)
for (let i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i)
return bytes
}
// ---- envelope -------------------------------------------------------------
interface GhostPayload {
v: number // schema version
t: number // run time (s)
hz: number // sample rate
n: number // sample count
b: string // base64 of the interleaved int16 buffer
}
export function encodeGhost(track: GhostTrack): string {
const view = new Uint8Array(track.data.buffer, track.data.byteOffset, track.data.byteLength)
const payload: GhostPayload = {
v: 1,
t: track.time,
hz: track.hz,
n: track.count,
b: bytesToB64(view),
}
return JSON.stringify(payload)
}
export function decodeGhost(json: string): GhostTrack | null {
try {
const p = JSON.parse(json) as Partial<GhostPayload>
if (!p || p.v !== 1 || typeof p.b !== 'string') return null
const bytes = b64ToBytes(p.b)
// ensure an even byte length for Int16Array
const len16 = Math.floor(bytes.byteLength / 2)
const data = new Int16Array(bytes.buffer, bytes.byteOffset, len16)
const count = typeof p.n === 'number' ? p.n : Math.floor(len16 / FLOATS_PER_SAMPLE)
return {
time: typeof p.t === 'number' ? p.t : count / RECORD_HZ,
hz: typeof p.hz === 'number' && p.hz > 0 ? p.hz : RECORD_HZ,
count,
data,
}
} catch {
return null
}
}
// ---- localStorage (guarded so this module stays runnable headless) --------
function store(): Storage | null {
try {
return typeof localStorage !== 'undefined' ? localStorage : null
} catch {
return null
}
}
/** Persist a track. Returns false if storage is unavailable or the write threw. */
export function saveGhost(track: GhostTrack): boolean {
const s = store()
if (!s) return false
try {
s.setItem(GHOST_KEY, encodeGhost(track))
return true
} catch {
return false
}
}
export function loadGhost(): GhostTrack | null {
const s = store()
if (!s) return null
const raw = s.getItem(GHOST_KEY)
return raw ? decodeGhost(raw) : null
}
export function clearGhost(): void {
store()?.removeItem(GHOST_KEY)
}
export function hasGhost(): boolean {
return !!store()?.getItem(GHOST_KEY)
}
/** Cheap read of just the saved run time (for the title), without decoding samples. */
export function ghostTime(): number | null {
const s = store()
if (!s) return null
const raw = s.getItem(GHOST_KEY)
if (!raw) return null
try {
const p = JSON.parse(raw) as Partial<GhostPayload>
return typeof p.t === 'number' ? p.t : null
} catch {
return null
}
}

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/** Lane H — ghost replay. Public surface for integration + the demo. */
export { installGhost, type GhostHandles } from './install'
export { GhostRecorder } from './recorder'
export { GhostPlayer, type GhostPlayerOptions } from './player'
export {
GHOST_KEY,
RECORD_HZ,
clearGhost,
ghostTime,
hasGhost,
loadGhost,
saveGhost,
sampleAt,
quantize,
type GhostSample,
type GhostTrack,
} from './format'

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/**
* installGhost wires a recorder + player to the race events. Integration
* calls this once, after the blob exists:
*
* installGhost(world, blob)
*
* The recorder captures every run and persists the best; the player replays the
* saved best on the next race. Both self-subscribe to race:started/finished.
*/
import type { Blob, World } from '../contracts'
import { GhostRecorder } from './recorder'
import { GhostPlayer, type GhostPlayerOptions } from './player'
export interface GhostHandles {
recorder: GhostRecorder
player: GhostPlayer
}
export function installGhost(
world: World,
blob: Blob,
opts: GhostPlayerOptions = {},
): GhostHandles {
const recorder = new GhostRecorder(world, blob)
world.addSystem(recorder)
const radius = opts.radius ?? (blob as { radius?: number }).radius ?? 0.5
const player = new GhostPlayer(world, { ...opts, radius })
return { recorder, player }
}

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/**
* GhostPlayer if a saved ghost exists, spawns a translucent, physics-free
* "past self" on `race:started` and replays the recorded track in race time
* with linear interpolation, then despawns on `race:finished` (or the next
* respawn, which re-fires race:started and resets it).
*
* Interpolation runs on the RENDER frame (onFrame) for smoothness; the track
* itself was sampled deterministically at 15Hz. The ghost is deliberately
* NOT-you: ghostly desaturated white, ~0.35 opacity, faint emissive, a slight
* vertical bob.
*
* Consumes: race:started, race:finished. Emits: nothing.
*/
import * as THREE from 'three'
import type { World } from '../contracts'
import { loadGhost, sampleAt, type GhostSample, type GhostTrack } from './format'
const GHOST_OPACITY = 0.35
const BOB_AMPLITUDE = 0.06 // metres
const BOB_RATE = 4 // rad/s
export interface GhostPlayerOptions {
/** Visual radius; match the blob so the overlap reads true. Default 0.5. */
radius?: number
}
export class GhostPlayer {
private group: THREE.Group | null = null
private track: GhostTrack | null = null
private playing = false
private t = 0
private bob = 0
private readonly radius: number
private readonly out: GhostSample = { x: 0, y: 0, z: 0, scale: 1 }
private readonly mats: THREE.Material[] = []
private readonly geos: THREE.BufferGeometry[] = []
constructor(
private readonly world: World,
opts: GhostPlayerOptions = {},
) {
this.radius = opts.radius ?? 0.5
world.events.on('race:started', () => this.spawn())
world.events.on('race:finished', () => this.despawn())
world.onFrame((dt) => this.update(dt))
}
private build(): THREE.Group {
const r = this.radius
const g = new THREE.Group()
const bodyGeo = new THREE.SphereGeometry(r, 32, 24)
const bodyMat = new THREE.MeshStandardMaterial({
color: '#eaf6ff',
emissive: '#bfe6ff',
emissiveIntensity: 0.5,
roughness: 0.35,
metalness: 0.0,
transparent: true,
opacity: GHOST_OPACITY,
depthWrite: false, // translucent: don't occlude the real blob behind it
})
const body = new THREE.Mesh(bodyGeo, bodyMat)
g.add(body)
// Simple eyes so it reads as a blob (not a soap bubble), slightly less sheer.
const eyeGeo = new THREE.SphereGeometry(r * 0.16, 12, 10)
const eyeMat = new THREE.MeshStandardMaterial({
color: '#2a3a48',
transparent: true,
opacity: Math.min(1, GHOST_OPACITY + 0.25),
depthWrite: false,
})
for (const side of [-1, 1]) {
const eye = new THREE.Mesh(eyeGeo, eyeMat)
eye.position.set(side * r * 0.34, r * 0.32, r * 0.9)
g.add(eye)
}
g.renderOrder = 2 // composite over the opaque scene
this.mats.push(bodyMat, eyeMat)
this.geos.push(bodyGeo, eyeGeo)
return g
}
private spawn(): void {
this.track = loadGhost()
if (!this.track || this.track.count < 2) {
this.track = null // no ghost yet (e.g. first run ever)
return
}
if (!this.group) {
this.group = this.build()
this.world.scene.add(this.group)
}
this.group.visible = true
this.t = 0
this.bob = 0
this.playing = true
this.place() // snap to the start pose immediately, no one-frame pop
}
private despawn(): void {
this.playing = false
if (this.group) this.group.visible = false
}
private place(): void {
if (!this.group || !this.track) return
sampleAt(this.track, this.t, this.out)
const bob = Math.sin(this.bob * BOB_RATE) * BOB_AMPLITUDE
this.group.position.set(this.out.x, this.out.y + bob, this.out.z)
this.group.scale.setScalar(this.out.scale || 1)
}
private update(dt: number): void {
if (!this.playing) return
this.t += dt
this.bob += dt
this.place()
}
/** Fully tear down (scene node + GPU resources). */
dispose(): void {
if (this.group) {
this.world.scene.remove(this.group)
this.group = null
}
for (const m of this.mats) m.dispose()
for (const geo of this.geos) geo.dispose()
this.mats.length = 0
this.geos.length = 0
this.playing = false
}
}

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/**
* GhostRecorder records the blob root's position + uniform scale at 15Hz
* between `race:started` and `race:finished`, and on a new best writes a
* quantised, base64 track to localStorage `blobbo:ghost`.
*
* It is a fixed-step System (added via installGhost) so the 15Hz grid is
* deterministic (every 4th 60Hz step) rather than tied to render cadence.
*
* Consumes: race:started, race:finished {time,best}. Emits: nothing.
*/
import type { Blob, System, World } from '../contracts'
import {
FLOATS_PER_SAMPLE,
MAX_SAMPLES,
RECORD_HZ,
quantize,
saveGhost,
type GhostTrack,
} from './format'
export class GhostRecorder implements System {
private readonly buf = new Float32Array(MAX_SAMPLES * FLOATS_PER_SAMPLE)
private count = 0
private acc = 0
private recording = false
private readonly period = 1 / RECORD_HZ
constructor(
private readonly world: World,
private readonly blob: Blob,
) {
world.events.on('race:started', () => this.begin())
world.events.on('race:finished', (p) => this.finish(p))
}
private begin(): void {
this.count = 0
this.acc = 0
this.recording = true
this.capture() // anchor sample at t = 0
}
private capture(): void {
if (this.count >= MAX_SAMPLES) {
this.recording = false // 5-minute cap reached; keep what we have
return
}
// The blob root (group) carries world position (synced to the rigid body
// each fixed step) and the `size` uniform scale — exactly what we replay.
const g = this.blob.group
const o = this.count * FLOATS_PER_SAMPLE
this.buf[o] = g.position.x
this.buf[o + 1] = g.position.y
this.buf[o + 2] = g.position.z
this.buf[o + 3] = g.scale.x
this.count++
}
update(dt: number): void {
if (!this.recording) return
this.acc += dt
while (this.acc >= this.period) {
this.acc -= this.period
this.capture()
if (!this.recording) break
}
}
private finish(p?: { time?: number; best?: number }): void {
if (!this.recording) return
this.recording = false
this.capture() // pin the exact finish pose
const time = p?.time ?? this.count / RECORD_HZ
const best = p?.best
// game.ts sets `best` to the new time BEFORE emitting on a record, so a new
// best arrives as time === best. `<=` catches that; a slower run has
// best < time and is skipped.
const isBest = best == null || time <= best + 1e-6
if (!isBest || this.count < 2) return
const track: GhostTrack = {
time,
hz: RECORD_HZ,
count: this.count,
data: quantize(this.buf, this.count),
}
saveGhost(track)
}
}

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/**
* Numeric acceptance for Lane H: ghost replay drift vs the recorded path must be
* < one blob radius at all sample points. This mirrors the demo's deterministic
* circle, records it at 15Hz through the REAL quantize(), then replays it
* through the REAL sampleAt() and reports the worst-case position error.
*
* Not imported by any entry (headless-only). Run it with:
* node_modules/.bin/esbuild src/ghost/verify-drift.ts --bundle --platform=node \
* --format=esm --outfile=/tmp/verify.mjs && node /tmp/verify.mjs
*/
import {
FLOATS_PER_SAMPLE,
RECORD_HZ,
quantize,
sampleAt,
type GhostSample,
type GhostTrack,
} from './format'
// --- the exact same path the demo drives (ball on a circle) ---
const R = 8
const CY = 1.0
const RUN_SECONDS = 20
const OMEGA = (2 * Math.PI) / RUN_SECONDS
const BLOB_RADIUS = 0.5
function pathAt(t: number, out: GhostSample): GhostSample {
const th = OMEGA * t - Math.PI / 2
out.x = R * Math.cos(th)
out.y = CY
out.z = R * Math.sin(th)
out.scale = 1 + 0.15 * Math.sin(2 * OMEGA * t)
return out
}
// --- record at 15Hz exactly as GhostRecorder does (grid times i/hz) ---
const count = Math.floor(RUN_SECONDS * RECORD_HZ) + 1
const buf = new Float32Array(count * FLOATS_PER_SAMPLE)
const s: GhostSample = { x: 0, y: 0, z: 0, scale: 1 }
for (let i = 0; i < count; i++) {
pathAt(i / RECORD_HZ, s)
const o = i * FLOATS_PER_SAMPLE
buf[o] = s.x
buf[o + 1] = s.y
buf[o + 2] = s.z
buf[o + 3] = s.scale
}
const track: GhostTrack = { time: RUN_SECONDS, hz: RECORD_HZ, count, data: quantize(buf, count) }
// --- replay and measure drift ---
const truth: GhostSample = { x: 0, y: 0, z: 0, scale: 1 }
const ghost: GhostSample = { x: 0, y: 0, z: 0, scale: 1 }
function driftAt(t: number): number {
pathAt(t, truth)
sampleAt(track, t, ghost)
return Math.hypot(truth.x - ghost.x, truth.y - ghost.y, truth.z - ghost.z)
}
// (a) exactly at every recorded sample point (the acceptance wording)
let maxAtSamples = 0
let worstSampleT = 0
for (let i = 0; i < count; i++) {
const t = i / RECORD_HZ
const d = driftAt(t)
if (d > maxAtSamples) {
maxAtSamples = d
worstSampleT = t
}
}
// (b) densely between samples too (interpolation error), 1ms resolution
let maxDense = 0
let worstDenseT = 0
for (let t = 0; t <= RUN_SECONDS; t += 0.001) {
const d = driftAt(t)
if (d > maxDense) {
maxDense = d
worstDenseT = t
}
}
// scale error, for completeness
let maxScaleErr = 0
for (let t = 0; t <= RUN_SECONDS; t += 0.001) {
pathAt(t, truth)
sampleAt(track, t, ghost)
maxScaleErr = Math.max(maxScaleErr, Math.abs(truth.scale - ghost.scale))
}
const rawBytes = track.data.byteLength
const b64Bytes = Math.ceil(rawBytes / 3) * 4
console.log('--- Lane H ghost drift verification ---')
console.log(`samples: ${count} @ ${RECORD_HZ}Hz storage: ${rawBytes} B int16 → ~${b64Bytes} B base64`)
console.log(`blob radius (budget): ${BLOB_RADIUS} m`)
console.log(`max drift at sample points : ${maxAtSamples.toFixed(4)} m (t=${worstSampleT.toFixed(3)}s)`)
console.log(`max drift densely (1ms) : ${maxDense.toFixed(4)} m (t=${worstDenseT.toFixed(3)}s)`)
console.log(`max scale error : ${maxScaleErr.toFixed(5)}`)
const pass = maxDense < BLOB_RADIUS && maxAtSamples < BLOB_RADIUS
console.log(pass ? `PASS — drift < ${BLOB_RADIUS} m everywhere` : 'FAIL — drift exceeds one blob radius')
if (!pass) throw new Error('ghost drift exceeds one blob radius')

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/**
* installTitle the five-second onboarding card + the audio gate.
*
* Full-screen overlay on boot: bold CSS bubble-letter BLOBBO wordmark with
* rainbow paint-drip accents, a one-line pitch, a three-row controls card, and
* a fat PLAY button. If the world is still booting (a `ready` promise was
* handed in), PLAY is replaced by a wobbling "loading…" blob dot until it
* resolves.
*
* On the first click / keypress / gamepad button it emits **`ui:play`** exactly
* once (synchronously, inside the user gesture, so a listening AudioContext can
* unlock), fades the overlay out and never shows it again.
*
* No external fonts or assets everything is inline CSS. Readable on any
* background thanks to the dimming backdrop.
*/
import type { World } from '../contracts'
import { PALETTE } from '../contracts'
import { ghostTime, hasGhost } from '../ghost/format'
export interface TitleOptions {
/** Resolves when Rapier/world finished booting. While pending: loading state. */
ready?: Promise<unknown>
}
export interface TitleHandle {
/** Resolves once the player has started (ui:play fired). */
done: Promise<void>
/** Force-remove the overlay (teardown / tests). Does not emit ui:play. */
remove(): void
}
const STYLE_ID = 'blobbo-title-style'
const DRIP_COLORS = [PALETTE.red, PALETTE.yellow, PALETTE.green, PALETTE.blue, PALETTE.pink]
function injectStyle(): void {
if (document.getElementById(STYLE_ID)) return
const el = document.createElement('style')
el.id = STYLE_ID
el.textContent = `
#blobbo-title{position:fixed;inset:0;z-index:1000;display:flex;flex-direction:column;
align-items:center;justify-content:center;gap:26px;padding:24px;box-sizing:border-box;
background:radial-gradient(120% 120% at 50% 30%,rgba(24,30,54,.72),rgba(10,12,24,.92));
backdrop-filter:blur(3px);-webkit-backdrop-filter:blur(3px);
font-family:'Comic Sans MS','Chalkboard SE','Baloo 2',system-ui,sans-serif;
color:#fff;text-align:center;opacity:1;transition:opacity .4s ease}
#blobbo-title.hide{opacity:0;pointer-events:none}
.blobbo-word{display:flex;gap:.01em;line-height:1;
font-weight:900;font-size:clamp(58px,15vw,168px);filter:drop-shadow(0 8px 14px rgba(0,0,0,.45))}
.blobbo-word span{position:relative;color:#fff;
-webkit-text-stroke:.085em #16264a;paint-order:stroke fill;
text-shadow:0 .05em 0 #16264a,0 .11em .02em rgba(0,0,0,.4);
transform:rotate(var(--rot,0deg));
animation:blobbo-pop .5s cubic-bezier(.2,1.5,.4,1) both;animation-delay:var(--d,0s)}
.blobbo-drip{position:absolute;left:50%;bottom:.04em;width:.15em;height:.2em;
transform:translateX(-50%);background:var(--c,#fff);border-radius:0 0 55% 55%/0 0 70% 70%;
box-shadow:0 .05em 0 var(--c,#fff);z-index:-1;
animation:blobbo-drip 2.8s ease-in-out infinite;animation-delay:var(--dd,0s)}
@keyframes blobbo-pop{from{transform:translateY(.25em) rotate(var(--rot,0deg)) scale(.6);opacity:0}
to{transform:translateY(0) rotate(var(--rot,0deg)) scale(1);opacity:1}}
@keyframes blobbo-drip{0%,100%{transform:translateX(-50%) scaleY(1)}55%{transform:translateX(-50%) scaleY(1.7)}}
.blobbo-pitch{font-size:clamp(17px,3.2vw,26px);font-weight:700;letter-spacing:.02em;
color:#eaf2ff;text-shadow:0 2px 6px rgba(0,0,0,.6);margin-top:-6px}
.blobbo-controls{display:flex;flex-wrap:wrap;gap:10px 18px;justify-content:center;
background:rgba(255,255,255,.1);border:1px solid rgba(255,255,255,.16);border-radius:14px;
padding:12px 18px;font-family:ui-monospace,Menlo,monospace;font-size:15px;font-weight:600}
.blobbo-controls .row{display:flex;align-items:center;gap:8px;white-space:nowrap}
.blobbo-controls .key{display:inline-block;min-width:20px;padding:2px 8px;border-radius:6px;
background:#33436b;color:#fff;box-shadow:0 2px 0 rgba(0,0,0,.4);text-align:center}
.blobbo-best{font-family:ui-monospace,Menlo,monospace;font-size:15px;font-weight:700;
color:#ffd60a;min-height:1.2em}
.blobbo-play{cursor:pointer;border:none;font-family:inherit;font-weight:900;
font-size:clamp(24px,5vw,40px);color:#16264a;letter-spacing:.04em;
padding:.35em 1.3em;border-radius:999px;
background:linear-gradient(180deg,#fff,#ffe14d);
box-shadow:0 8px 0 #b98a00,0 12px 24px rgba(0,0,0,.4);
transform:translateY(0);transition:transform .08s ease,box-shadow .08s ease;
animation:blobbo-breathe 2.2s ease-in-out infinite}
.blobbo-play:hover{transform:translateY(-2px)}
.blobbo-play:active{transform:translateY(6px);box-shadow:0 2px 0 #b98a00,0 4px 10px rgba(0,0,0,.4)}
@keyframes blobbo-breathe{0%,100%{scale:1}50%{scale:1.05}}
.blobbo-loading{display:flex;flex-direction:column;align-items:center;gap:12px;
font-family:ui-monospace,Menlo,monospace;font-size:16px;font-weight:700;color:#eaf2ff}
.blobbo-dot{width:34px;height:34px;border-radius:50%;
background:radial-gradient(circle at 35% 30%,#fff,#bfe6ff 60%,#7ab6e6);
animation:blobbo-wobble 1s ease-in-out infinite}
@keyframes blobbo-wobble{0%,100%{transform:translateY(0) scale(1,1)}
25%{transform:translateY(-10px) scale(.92,1.1)}
55%{transform:translateY(0) scale(1.15,.85)}
75%{transform:translateY(-4px) scale(.96,1.05)}}
.blobbo-hint{font-family:ui-monospace,Menlo,monospace;font-size:12px;color:rgba(234,242,255,.65)}
`
document.head.appendChild(el)
}
function buildWordmark(): HTMLElement {
const word = document.createElement('div')
word.className = 'blobbo-word'
word.setAttribute('aria-label', 'BLOBBO')
const letters = 'BLOBBO'.split('')
// deterministic-ish tilts + a few drips so it reads hand-made, not random.
const tilts = [-5, 4, -3, 6, -4, 3]
const dripAt = new Set([0, 2, 4]) // under B, O, B
letters.forEach((ch, i) => {
const span = document.createElement('span')
span.textContent = ch
span.style.setProperty('--rot', `${tilts[i]}deg`)
span.style.setProperty('--d', `${i * 0.06}s`)
if (dripAt.has(i)) {
const drip = document.createElement('span')
drip.className = 'blobbo-drip'
drip.style.setProperty('--c', DRIP_COLORS[i % DRIP_COLORS.length])
drip.style.setProperty('--dd', `${i * 0.35}s`)
span.appendChild(drip)
}
word.appendChild(span)
})
return word
}
function buildControls(): HTMLElement {
const box = document.createElement('div')
box.className = 'blobbo-controls'
const rows: Array<[string, string]> = [
['WASD / stick', 'move'],
['Space / A', 'jump'],
['R / Start', 'restart'],
]
for (const [keys, action] of rows) {
const row = document.createElement('div')
row.className = 'row'
const k = document.createElement('span')
k.className = 'key'
k.textContent = keys
const a = document.createElement('span')
a.textContent = action
row.append(k, a)
box.appendChild(row)
}
return box
}
export function installTitle(world: World, opts: TitleOptions = {}): TitleHandle {
injectStyle()
const overlay = document.createElement('div')
overlay.id = 'blobbo-title'
overlay.appendChild(buildWordmark())
const pitch = document.createElement('div')
pitch.className = 'blobbo-pitch'
pitch.textContent = 'Race. Get painted. Paint is power.'
overlay.appendChild(pitch)
overlay.appendChild(buildControls())
// saved best + ghost status
const best = document.createElement('div')
best.className = 'blobbo-best'
if (hasGhost()) {
const t = ghostTime()
best.textContent = t != null ? `best ${t.toFixed(2)}s · 👻 ghost ready` : '👻 ghost ready'
}
overlay.appendChild(best)
// action slot: either the loading blob or the PLAY button
const slot = document.createElement('div')
overlay.appendChild(slot)
const hint = document.createElement('div')
hint.className = 'blobbo-hint'
overlay.appendChild(hint)
document.body.appendChild(overlay)
// ---- lifecycle -----------------------------------------------------------
let armed = false // becomes true once boot completes → input can start play
let started = false
let resolveDone: () => void = () => {}
const done = new Promise<void>((res) => (resolveDone = res))
const showLoading = (): void => {
slot.innerHTML = ''
const box = document.createElement('div')
box.className = 'blobbo-loading'
const dot = document.createElement('div')
dot.className = 'blobbo-dot'
const label = document.createElement('div')
label.textContent = 'loading…'
box.append(dot, label)
slot.appendChild(box)
}
const playBtn = document.createElement('button')
playBtn.className = 'blobbo-play'
playBtn.type = 'button'
playBtn.textContent = 'PLAY'
const showPlay = (): void => {
slot.innerHTML = ''
slot.appendChild(playBtn)
hint.textContent = 'click PLAY · or press any key · or a gamepad button'
}
// ---- the single start path ----------------------------------------------
const start = (): void => {
if (!armed || started) return
started = true
cleanup()
// Emit synchronously within the user gesture so audio can unlock here.
world.events.emit('ui:play')
overlay.classList.add('hide')
resolveDone()
// remove from DOM after the fade so it can never reappear or catch input
window.setTimeout(() => overlay.remove(), 450)
}
// input wiring (removed on start so ui:play can only fire once)
const onKey = (e: KeyboardEvent): void => {
if (e.repeat) return
start()
}
const onClick = (): void => start()
let padRaf = 0
const pollPad = (): void => {
if (started) return
const pads = typeof navigator !== 'undefined' && navigator.getGamepads ? navigator.getGamepads() : null
if (pads) {
for (const p of pads) {
if (!p || !p.connected) continue
if (p.buttons.some((b) => b.pressed)) {
start()
return
}
break
}
}
padRaf = requestAnimationFrame(pollPad)
}
const cleanup = (): void => {
window.removeEventListener('keydown', onKey)
playBtn.removeEventListener('click', onClick)
if (padRaf) cancelAnimationFrame(padRaf)
}
playBtn.addEventListener('click', onClick)
const arm = (): void => {
if (armed) return
armed = true
showPlay()
window.addEventListener('keydown', onKey)
padRaf = requestAnimationFrame(pollPad)
}
if (opts.ready) {
showLoading()
hint.textContent = 'waking up the physics…'
opts.ready.then(arm, arm) // arm even if boot rejects; the game decides what to do
} else {
arm()
}
return {
done,
remove(): void {
cleanup()
overlay.remove()
},
}
}