| 1 | /** |
| 2 | * The collider overlay: every boundary the physics actually uses, drawn in thin |
| 3 | * red over the table. |
| 4 | * |
| 5 | * Everything the tiles bounce off is *measured* off the DOM rather than written |
| 6 | * down anywhere — the felt is where the four strips leave off, the wall is |
| 7 | * seventy-odd real elements — so the only honest way to check a bounce is to |
| 8 | * draw the boxes in the same coordinate space the tiles are drawn in. A bounce |
| 9 | * that looks wrong is either a box in the wrong place or a box you had not |
| 10 | * thought about, and this tells you which. |
| 11 | * |
| 12 | * On with `?colliders` in the address bar, or `colliders()` from the console |
| 13 | * while a hand is running — which is the point of it, since the thing you want |
| 14 | * to look at is usually already skidding across the table. |
| 15 | */ |
| 16 | |
| 17 | import { FIXED_DT, type Impact } from '../table/physics'; |
| 18 | |
| 19 | const params = typeof location === 'undefined' ? null : new URLSearchParams(location.search); |
| 20 | |
| 21 | let on = !!params?.has('colliders'); |
| 22 | |
| 23 | /** |
| 24 | * Stop dead on contact. `?colliders&pause=1`, or `pause()` from the console. |
| 25 | * |
| 26 | * A bounce is four or five milliseconds long and the interesting part is the |
| 27 | * one frame where the two rectangles are touching, which is exactly the frame |
| 28 | * you cannot see. This holds the world there — the physics stops on the fixed |
| 29 | * step that resolved the contact and drops the rest of the frame, so what is on |
| 30 | * screen is where the tile actually touched rather than where it had got to by |
| 31 | * the time the frame ended. |
| 32 | * |
| 33 | * Space carries on, → takes one step, ↑ takes ten. |
| 34 | */ |
| 35 | let pauseOnHit = params?.get('pause') !== null && params?.get('pause') !== '0'; |
| 36 | let held = false; |
| 37 | let pending = 0; |
| 38 | |
| 39 | const listeners = new Set<() => void>(); |
| 40 | |
| 41 | export const showingColliders = () => on; |
| 42 | |
| 43 | /** Toggle, or set. Returns what it ended up as, so the console says it back. */ |
| 44 | export function toggleColliders(next = !on): boolean { |
| 45 | on = next; |
| 46 | if (!on) { |
| 47 | held = false; |
| 48 | pending = 0; |
| 49 | } |
| 50 | for (const cb of listeners) cb(); |
| 51 | return on; |
| 52 | } |
| 53 | |
| 54 | /** Repaint when it changes — a settled table is not drawing frames otherwise. */ |
| 55 | export function onCollidersChange(cb: () => void): () => void { |
| 56 | listeners.add(cb); |
| 57 | return () => { |
| 58 | listeners.delete(cb); |
| 59 | }; |
| 60 | } |
| 61 | |
| 62 | const wake = () => { |
| 63 | for (const cb of listeners) cb(); |
| 64 | }; |
| 65 | |
| 66 | /** |
| 67 | * Where contacts have just happened. |
| 68 | * |
| 69 | * The overlay draws the boxes the physics holds, so anything it collides with |
| 70 | * is on screen by construction — which makes the useful question the other one: |
| 71 | * *did* it collide, and where? A cross sitting in open felt with no box under it |
| 72 | * is a bounce off something that is not a collider at all, and that is a |
| 73 | * different bug from a box in the wrong place. |
| 74 | */ |
| 75 | const MARKS = 24; |
| 76 | let marks: { x: number; y: number; kind: string; age: number }[] = []; |
| 77 | |
| 78 | export function noteImpacts(impacts: Impact[]) { |
| 79 | if (!on || !impacts.length) return; |
| 80 | for (const i of impacts) { |
| 81 | marks.push({ |
| 82 | x: i.x, |
| 83 | y: i.y, |
| 84 | kind: i.into !== undefined ? `seat ${i.into}` : i.edge ? i.edge : '', |
| 85 | age: 0, |
| 86 | }); |
| 87 | } |
| 88 | if (marks.length > MARKS) marks = marks.slice(-MARKS); |
| 89 | } |
| 90 | |
| 91 | /** Ages them a frame and hands back what is still worth drawing. */ |
| 92 | export function recentImpacts(step: boolean) { |
| 93 | if (step) for (const m of marks) m.age++; |
| 94 | marks = marks.filter((m) => m.age < 90); |
| 95 | return marks; |
| 96 | } |
| 97 | |
| 98 | export const pausingOnHit = () => on && pauseOnHit; |
| 99 | export const isHeld = () => held; |
| 100 | |
| 101 | /** Arm or disarm the freeze. Turning it off lets go of whatever it is holding. */ |
| 102 | export function pause(next = !pauseOnHit): boolean { |
| 103 | pauseOnHit = next; |
| 104 | if (!next) resume(); |
| 105 | return pauseOnHit; |
| 106 | } |
| 107 | |
| 108 | /** Freeze here, and say what on. */ |
| 109 | export function holdOn(impacts: Impact[]) { |
| 110 | held = true; |
| 111 | const what = impacts |
| 112 | .map((i) => { |
| 113 | const where = `(${Math.round(i.x)}, ${Math.round(i.y)})`; |
| 114 | if (i.into !== undefined) return `seat ${i.into}'s tiles at ${where}`; |
| 115 | if (i.edge) return `the ${i.edge} edge at ${where}`; |
| 116 | return `something at ${where}`; |
| 117 | }) |
| 118 | .join(', '); |
| 119 | console.log(`[colliders] held on ${what} — space to carry on, → one step, ↑ ten`); |
| 120 | } |
| 121 | |
| 122 | /** Let it run again. */ |
| 123 | export function resume() { |
| 124 | held = false; |
| 125 | pending = 0; |
| 126 | wake(); |
| 127 | } |
| 128 | |
| 129 | /** Take `n` fixed steps and stop again. */ |
| 130 | export function stepOn(n = 1) { |
| 131 | if (!held) return; |
| 132 | pending += n; |
| 133 | wake(); |
| 134 | } |
| 135 | |
| 136 | /** How much the frozen loop owes, in seconds, taken as it is asked for. */ |
| 137 | export function owedTime(): number { |
| 138 | const n = pending; |
| 139 | pending = 0; |
| 140 | return n * FIXED_DT; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Space to carry on, → for one step, ↑ for ten. Only while the overlay is up, |
| 145 | * so this cannot get in the way of an actual game. |
| 146 | */ |
| 147 | export function keyHeld(e: KeyboardEvent): boolean { |
| 148 | if (!on || !held) return false; |
| 149 | if (e.key === ' ') resume(); |
| 150 | else if (e.key === 'ArrowRight') stepOn(1); |
| 151 | else if (e.key === 'ArrowUp') stepOn(10); |
| 152 | else return false; |
| 153 | return true; |
| 154 | } |
| 155 | |
| 156 | declare global { |
| 157 | interface Window { |
| 158 | colliders?: (next?: boolean) => boolean; |
| 159 | pause?: (next?: boolean) => boolean; |
| 160 | resume?: () => void; |
| 161 | stepOn?: (n?: number) => void; |
| 162 | /** The live pool, for poking at from the console. Dev builds only. */ |
| 163 | pool?: unknown; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | if (typeof window !== 'undefined') { |
| 168 | window.colliders = toggleColliders; |
| 169 | window.pause = pause; |
| 170 | window.resume = resume; |
| 171 | window.stepOn = stepOn; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Hand the console the pool itself, so `pool.world.walls` and `pool.geo` can be |
| 176 | * read against what is drawn. The overlay draws the world's own copy rather than |
| 177 | * a fresh measurement on purpose — if the two ever disagree it is the world that |
| 178 | * is stale, and that is a thing you want to be able to catch. |
| 179 | */ |
| 180 | export function exposePool(pool: unknown) { |
| 181 | if (import.meta.env.DEV && typeof window !== 'undefined') window.pool = pool; |
| 182 | } |