| 1 | import type { GameState } from '../game/engine'; |
| 2 | import { makeRng, type Tile } from '../game/tiles'; |
| 3 | import type { SeatId } from '../game/types'; |
| 4 | import { |
| 5 | aimAt, |
| 6 | canThrow, |
| 7 | canThrowFrom, |
| 8 | centreOf, |
| 9 | measure, |
| 10 | type Point, |
| 11 | type TableGeometry, |
| 12 | } from './geometry'; |
| 13 | import { |
| 14 | addBody, |
| 15 | advance as advanceWorld, |
| 16 | createWorld, |
| 17 | liftFor, |
| 18 | reshape, |
| 19 | settled, |
| 20 | stir, |
| 21 | SLIDE_TIME, |
| 22 | type Body, |
| 23 | type Impact, |
| 24 | type Rect, |
| 25 | type World, |
| 26 | } from './physics'; |
| 27 | |
| 28 | const SEATS: SeatId[] = [0, 1, 2, 3]; |
| 29 | |
| 30 | /** |
| 31 | * The tiles in the middle, kept honest against the game state. |
| 32 | * |
| 33 | * This *diffs* rather than listening for events, and that is the whole design. |
| 34 | * A discard is identified by which seat threw it and how many it had thrown |
| 35 | * before — and those keys never shift, because discards are only ever pushed and |
| 36 | * `engine.executeClaim` only ever pops the one on top. So every way the pile can |
| 37 | * change is the same code path: a key that has appeared is a tile to throw in, a |
| 38 | * key that has gone is a tile to take out. Undo, 下一局, a claim, and picking up |
| 39 | * a saved game all fall out of that without the engine knowing this exists. |
| 40 | * |
| 41 | * Nothing here is stored in the game state, so there is no save format to |
| 42 | * change. A pile is rebuilt from the discards it can see, seeded off the hand |
| 43 | * number and each tile's place in it, which is why a refresh mid-hand comes back |
| 44 | * to the pile it had rather than a freshly scattered one. |
| 45 | */ |
| 46 | |
| 47 | /** How long a placed tile is in the air. Long enough to arc over the wall. */ |
| 48 | const PLACE_FLIGHT = 0.62; |
| 49 | /** A flicked tile hops rather than lofts — across the table, not over a wall. */ |
| 50 | const THROW_LIFT = 0.18; |
| 51 | /** Fastest flick we will honour, px/s. Beyond this it is a slip, not a throw. */ |
| 52 | export const MAX_THROW_SPEED = 3600; |
| 53 | /** How long a claimed tile takes to leave the table for the seat taking it. */ |
| 54 | const TAKE_FLIGHT = 0.34; |
| 55 | |
| 56 | /** A tile on its way off the table, no longer part of the pile. */ |
| 57 | interface Leaving { |
| 58 | body: Body; |
| 59 | tx: number; |
| 60 | ty: number; |
| 61 | /** 0 to 1. */ |
| 62 | t: number; |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Whether a tile turns over on its way in. |
| 67 | * |
| 68 | * Off for now. Like `LOB_WHEN_WALLED` below, the tumble is kept whole — the |
| 69 | * flip is a real axis in `physics.ts` and the renderer already squashes the |
| 70 | * tile along it — and this is the only switch that reaches it, so putting it |
| 71 | * back is one word rather than a rewrite. |
| 72 | */ |
| 73 | const TUMBLE: boolean = false; |
| 74 | |
| 75 | /** |
| 76 | * Whether a wall standing in the way turns a discard into a lob over the top |
| 77 | * rather than a flick across the table. |
| 78 | * |
| 79 | * Back on now that the square is a square again. It was off while the wall ran |
| 80 | * along the edges of the middle, where there was nothing much to get over and |
| 81 | * everything read better slid; a square standing in the middle with the pool |
| 82 | * inside it is the other case, and a tile slid flat at it simply bounces off |
| 83 | * and ends up lying outside — which is not where a discard goes. As the square |
| 84 | * is eaten the gaps open and the slide comes back on its own, seat by seat. |
| 85 | */ |
| 86 | const LOB_WHEN_WALLED: boolean = true; |
| 87 | |
| 88 | /** A tile lifted out of a hand and carried about. Drawn, but not simulated. */ |
| 89 | export interface Held { |
| 90 | seat: SeatId; |
| 91 | tile: Tile; |
| 92 | /** Where it came from in that seat's hand, so the caller knows what to play. */ |
| 93 | index: number; |
| 94 | x: number; |
| 95 | y: number; |
| 96 | angle: number; |
| 97 | /** The size it was in the hand — it shrinks to pool size once thrown. */ |
| 98 | w: number; |
| 99 | h: number; |
| 100 | } |
| 101 | |
| 102 | /** A throw that has been let go of, waiting for the discard it belongs to. */ |
| 103 | interface Release { |
| 104 | seat: SeatId; |
| 105 | x: number; |
| 106 | y: number; |
| 107 | angle: number; |
| 108 | w: number; |
| 109 | h: number; |
| 110 | vx: number; |
| 111 | vy: number; |
| 112 | spin: number; |
| 113 | } |
| 114 | |
| 115 | export class TablePool { |
| 116 | world: World | null = null; |
| 117 | geo: TableGeometry | null = null; |
| 118 | /** The tile in somebody's fingers, if any. */ |
| 119 | held: Held | null = null; |
| 120 | /** |
| 121 | * Poke the render loop. Set by ui/Pool.tsx while it is mounted; a gesture |
| 122 | * calls it so a carried tile follows the finger without waiting on a re-render. |
| 123 | */ |
| 124 | wake: () => void = () => {}; |
| 125 | |
| 126 | private table: HTMLElement | null = null; |
| 127 | /** Bodies by `seat:index` into that seat's discards. */ |
| 128 | private entries = new Map<string, Body>(); |
| 129 | private release: Release | null = null; |
| 130 | /** What the wall looked like when we last measured, so we know to re-measure. */ |
| 131 | private measuredAt = ''; |
| 132 | private hand = -1; |
| 133 | /** The tile currently on the table to be claimed, so it can be marked. */ |
| 134 | private newestKey: string | null = null; |
| 135 | /** How many melds each seat had last time, to spot who took a tile. */ |
| 136 | private melds = [0, 0, 0, 0]; |
| 137 | /** Tiles on their way off the table. Drawn, but out of the physics. */ |
| 138 | private leaving: Leaving[] = []; |
| 139 | |
| 140 | // Which seats can throw, as a string, so the seats can re-render when it |
| 141 | // changes. Read through useSyncExternalStore, the same way the game is. |
| 142 | private openness = '----'; |
| 143 | private listeners = new Set<() => void>(); |
| 144 | |
| 145 | attach(table: HTMLElement) { |
| 146 | this.table = table; |
| 147 | this.measuredAt = ''; |
| 148 | } |
| 149 | |
| 150 | detach() { |
| 151 | this.table = null; |
| 152 | this.world = null; |
| 153 | this.geo = null; |
| 154 | this.held = null; |
| 155 | this.release = null; |
| 156 | this.entries.clear(); |
| 157 | this.leaving = []; |
| 158 | this.measuredAt = ''; |
| 159 | } |
| 160 | |
| 161 | subscribe = (cb: () => void) => { |
| 162 | this.listeners.add(cb); |
| 163 | return () => this.listeners.delete(cb); |
| 164 | }; |
| 165 | |
| 166 | /** Which seats have a clear line in, as a string — cheap to compare. */ |
| 167 | getSnapshot = () => this.openness; |
| 168 | |
| 169 | /** Force a re-measure — the window resized, or the layout changed under us. */ |
| 170 | invalidate() { |
| 171 | this.measuredAt = ''; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Whether this seat can flick a tile in, or has to lift it over the wall. |
| 176 | * Unmeasured (or compact, where there is no square) means no. |
| 177 | */ |
| 178 | canThrow(seat: SeatId): boolean { |
| 179 | return this.openness[seat] === 'y'; |
| 180 | } |
| 181 | |
| 182 | /** Where the middle of the table is, for a gesture working out its aim. */ |
| 183 | get poolCentre(): Point | null { |
| 184 | return this.geo ? centreOf(this.geo.pool) : null; |
| 185 | } |
| 186 | |
| 187 | /** Whether a point is already inside the square — a tile dropped there stays. */ |
| 188 | inPool(x: number, y: number): boolean { |
| 189 | const p = this.geo?.pool; |
| 190 | if (!p) return false; |
| 191 | return x >= p.x && x <= p.x + p.w && y >= p.y && y <= p.y + p.h; |
| 192 | } |
| 193 | |
| 194 | /** Whether a tile let go of *here* has a clear line in. Not the same question |
| 195 | * as `canThrow(seat)`: a carried tile is wherever the player took it. */ |
| 196 | canThrowFrom(x: number, y: number): boolean { |
| 197 | return !!this.geo && canThrowFrom(this.geo, { x, y }); |
| 198 | } |
| 199 | |
| 200 | /** Where the pool sits on the table, for the patch of it you can reach into. */ |
| 201 | get poolRect(): Rect | null { |
| 202 | return this.geo?.pool ?? null; |
| 203 | } |
| 204 | |
| 205 | /** |
| 206 | * Push the tiles in the middle about — washing them, the way everybody does |
| 207 | * to a pool of discards while waiting. Purely cosmetic: where a discard is |
| 208 | * lying is not part of the game. |
| 209 | */ |
| 210 | stir(x: number, y: number, vx: number, vy: number) { |
| 211 | if (!this.world || !this.geo) return; |
| 212 | // A finger's worth: about a tile across. |
| 213 | stir(this.world, x, y, vx, vy, this.geo.tile.w * 0.6); |
| 214 | } |
| 215 | |
| 216 | // ---- the tile in your fingers ----------------------------------------- |
| 217 | |
| 218 | /** Lifted out of a hand. From here the canvas draws it, not the DOM. */ |
| 219 | pickUp(held: Held) { |
| 220 | this.held = held; |
| 221 | } |
| 222 | |
| 223 | moveHeld(x: number, y: number, angle?: number) { |
| 224 | if (!this.held) return; |
| 225 | this.held.x = x; |
| 226 | this.held.y = y; |
| 227 | if (angle !== undefined) this.held.angle = angle; |
| 228 | } |
| 229 | |
| 230 | /** Put it back in the hand — the throw was not committed to. */ |
| 231 | cancelHeld() { |
| 232 | this.held = null; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * Let go of it. The body is not made here: the reconciler owns every tile in |
| 237 | * the pool, so this leaves the throw where the next `sync` will find it and |
| 238 | * the caller goes on to call `game.discard`. The held tile stays drawn until |
| 239 | * that happens, so there is no frame with nothing on screen. |
| 240 | */ |
| 241 | throwHeld(vx: number, vy: number, spin: number) { |
| 242 | const h = this.held; |
| 243 | if (!h) return; |
| 244 | const speed = Math.hypot(vx, vy); |
| 245 | const scale = speed > MAX_THROW_SPEED ? MAX_THROW_SPEED / speed : 1; |
| 246 | this.release = { |
| 247 | seat: h.seat, |
| 248 | x: h.x, |
| 249 | y: h.y, |
| 250 | angle: h.angle, |
| 251 | w: h.w, |
| 252 | h: h.h, |
| 253 | vx: vx * scale, |
| 254 | vy: vy * scale, |
| 255 | spin, |
| 256 | }; |
| 257 | } |
| 258 | |
| 259 | // ---- keeping up with the game ---------------------------------------- |
| 260 | |
| 261 | /** Bring the pile in line with the state. Cheap when nothing has changed. */ |
| 262 | sync(state: GameState) { |
| 263 | this.remeasure(state); |
| 264 | const geo = this.geo; |
| 265 | const world = this.world; |
| 266 | if (!geo || !world) return; |
| 267 | |
| 268 | // A new hand is a new pile, and nothing should fly anywhere. |
| 269 | const fresh = state.handNumber !== this.hand; |
| 270 | this.hand = state.handNumber; |
| 271 | |
| 272 | const want = new Set<string>(); |
| 273 | const added: { key: string; seat: SeatId; index: number; tile: Tile }[] = []; |
| 274 | for (const seat of SEATS) { |
| 275 | const discards = state.players[seat].discards; |
| 276 | for (let i = 0; i < discards.length; i++) { |
| 277 | const key = `${seat}:${i}`; |
| 278 | want.add(key); |
| 279 | if (!this.entries.has(key)) added.push({ key, seat, index: i, tile: discards[i] }); |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | const taken: Body[] = []; |
| 284 | for (const [key, body] of this.entries) { |
| 285 | if (want.has(key)) continue; |
| 286 | const at = world.bodies.indexOf(body); |
| 287 | if (at >= 0) world.bodies.splice(at, 1); |
| 288 | this.entries.delete(key); |
| 289 | taken.push(body); |
| 290 | } |
| 291 | |
| 292 | // Exactly one tile off the table is somebody taking it — a 碰, a 吃, a 槓, |
| 293 | // or a discard being taken back. It goes to whoever now has a meld they did |
| 294 | // not have a moment ago, and failing that back to the seat that threw it, |
| 295 | // which is what an undo is. Several at once is the hand ending, and those |
| 296 | // simply go. |
| 297 | const claimer = SEATS.find((q) => state.players[q].melds.length > this.melds[q]); |
| 298 | this.melds = SEATS.map((q) => state.players[q].melds.length); |
| 299 | if (taken.length === 1 && !fresh) { |
| 300 | const to = geo.launch[claimer ?? taken[0].seat]; |
| 301 | if (to) this.leaving.push({ body: taken[0], tx: to.x, ty: to.y, t: 0 }); |
| 302 | } |
| 303 | |
| 304 | // One tile at a time is somebody playing, and it gets thrown. Several at |
| 305 | // once is a pile being rebuilt — a save picked up, an undo, a fresh deal — |
| 306 | // and those tiles were thrown long ago, so they are simply already there. |
| 307 | const rebuilding = fresh || added.length > 1; |
| 308 | for (const a of added) { |
| 309 | this.entries.set(a.key, rebuilding ? this.settle(geo, state, a) : this.launch(geo, state, a)); |
| 310 | } |
| 311 | |
| 312 | // A throw is good for exactly one discard, and the tile it belonged to has |
| 313 | // either just arrived or is never going to. |
| 314 | if (added.length || this.release) { |
| 315 | this.release = null; |
| 316 | this.held = null; |
| 317 | } |
| 318 | |
| 319 | const ld = state.lastDiscard; |
| 320 | this.newestKey = ld ? `${ld.from}:${state.players[ld.from].discards.length - 1}` : null; |
| 321 | } |
| 322 | |
| 323 | /** Run the physics on. Returns impacts worth a sound. */ |
| 324 | advance(seconds: number): Impact[] { |
| 325 | this.carryOff(seconds); |
| 326 | return this.world ? advanceWorld(this.world, seconds) : []; |
| 327 | } |
| 328 | |
| 329 | /** Tiles leaving the table, lifted and carried off to the seat taking them. */ |
| 330 | private carryOff(seconds: number) { |
| 331 | if (this.leaving.length === 0) return; |
| 332 | for (const l of this.leaving) { |
| 333 | l.t = Math.min(1, l.t + seconds / TAKE_FLIGHT); |
| 334 | // Ease out, so it leaves quickly and arrives gently. |
| 335 | const k = 1 - (1 - l.t) * (1 - l.t); |
| 336 | l.body.x += (l.tx - l.body.x) * k * 0.5; |
| 337 | l.body.y += (l.ty - l.body.y) * k * 0.5; |
| 338 | // Up off the table on the way, the way a tile picked up would be. |
| 339 | l.body.z = Math.sin(l.t * Math.PI) * 40; |
| 340 | l.body.angle += seconds * 2.2; |
| 341 | } |
| 342 | this.leaving = this.leaving.filter((l) => l.t < 1); |
| 343 | } |
| 344 | |
| 345 | /** What is on its way off, and how far gone, for the renderer to fade. */ |
| 346 | get departing(): { body: Body; fade: number }[] { |
| 347 | return this.leaving.map((l) => ({ body: l.body, fade: 1 - l.t })); |
| 348 | } |
| 349 | |
| 350 | get bodies(): Body[] { |
| 351 | return this.world?.bodies ?? []; |
| 352 | } |
| 353 | |
| 354 | /** The tile on the table, if there is one — drawn lit, as a lifted tile is. */ |
| 355 | get newest(): Body | null { |
| 356 | return (this.newestKey && this.entries.get(this.newestKey)) || null; |
| 357 | } |
| 358 | |
| 359 | /** |
| 360 | * A tile is still on its way to the middle. The computer players hold off |
| 361 | * while this is true — nobody at a real table reaches across for a tile that |
| 362 | * has not landed, and a 碰 called over one still turning over in the air looks |
| 363 | * like it was snatched out of flight. |
| 364 | */ |
| 365 | get throwInFlight(): boolean { |
| 366 | const b = this.newest; |
| 367 | return !!b && !b.resting; |
| 368 | } |
| 369 | |
| 370 | /** Nothing is moving, so the render loop can stop until something changes. */ |
| 371 | get settled(): boolean { |
| 372 | return !this.held && this.leaving.length === 0 && (!this.world || settled(this.world)); |
| 373 | } |
| 374 | |
| 375 | // ---- measuring --------------------------------------------------------- |
| 376 | |
| 377 | /** |
| 378 | * Re-read the table when the wall's shape has changed or the window has. The |
| 379 | * pile keeps its positions across a re-measure: the wall shrinking does not |
| 380 | * move the tiles already on the felt. |
| 381 | */ |
| 382 | private remeasure(state: GameState) { |
| 383 | const table = this.table; |
| 384 | if (!table) return; |
| 385 | const stamp = `${state.drawnFront}/${state.drawnBack}/${Math.round( |
| 386 | table.clientWidth, |
| 387 | )}x${Math.round(table.clientHeight)}`; |
| 388 | if (stamp === this.measuredAt) return; |
| 389 | |
| 390 | const geo = measure(table, state); |
| 391 | this.measuredAt = geo ? stamp : ''; |
| 392 | this.geo = geo; |
| 393 | if (!geo) { |
| 394 | this.world = null; |
| 395 | this.entries.clear(); |
| 396 | this.setOpenness('----'); |
| 397 | return; |
| 398 | } |
| 399 | // Bounded by the felt, not by the square: what keeps a tile in the middle is |
| 400 | // the stacks still standing, and once they are gone the pool is free to |
| 401 | // spread out through the gap the way a real one does. |
| 402 | if (!this.world) this.world = createWorld(geo.felt, geo.walls); |
| 403 | else reshape(this.world, geo.felt, geo.walls); |
| 404 | // Only here, never per frame: a hundred-odd ray casts is nothing once a |
| 405 | // draw, and a great deal every sixtieth of a second. |
| 406 | this.setOpenness(SEATS.map((s) => (canThrow(geo, s) ? 'y' : '-')).join('')); |
| 407 | } |
| 408 | |
| 409 | private setOpenness(next: string) { |
| 410 | if (next === this.openness) return; |
| 411 | this.openness = next; |
| 412 | for (const cb of this.listeners) cb(); |
| 413 | } |
| 414 | |
| 415 | // ---- putting tiles in ------------------------------------------------- |
| 416 | |
| 417 | /** A tile that is simply there already — a rebuilt pile. */ |
| 418 | private settle( |
| 419 | geo: TableGeometry, |
| 420 | state: GameState, |
| 421 | a: { seat: SeatId; index: number; tile: Tile }, |
| 422 | ): Body { |
| 423 | const rng = this.seeded(state, a); |
| 424 | const { pool } = geo; |
| 425 | // Bunched towards the middle rather than spread evenly to the edges, which |
| 426 | // is what a pool thrown into from four sides actually looks like. |
| 427 | const spread = 0.3; |
| 428 | return addBody(this.world!, { |
| 429 | tile: a.tile, |
| 430 | seat: a.seat, |
| 431 | x: pool.x + pool.w * (0.5 + (rng() - 0.5) * 2 * spread), |
| 432 | y: pool.y + pool.h * (0.5 + (rng() - 0.5) * 2 * spread), |
| 433 | vx: 0, |
| 434 | vy: 0, |
| 435 | z: 0, |
| 436 | vz: 0, |
| 437 | angle: (rng() - 0.5) * Math.PI, |
| 438 | spin: 0, |
| 439 | w: geo.tile.w, |
| 440 | h: geo.tile.h, |
| 441 | atRest: true, |
| 442 | }); |
| 443 | } |
| 444 | |
| 445 | /** A tile arriving now: thrown if somebody threw it, placed over the wall if |
| 446 | * it was tapped, and flat and quick if a bot's wall happens to be open. */ |
| 447 | private launch( |
| 448 | geo: TableGeometry, |
| 449 | state: GameState, |
| 450 | a: { seat: SeatId; index: number; tile: Tile }, |
| 451 | ): Body { |
| 452 | const rng = this.seeded(state, a); |
| 453 | const thrown = this.release?.seat === a.seat ? this.release : null; |
| 454 | |
| 455 | if (thrown) { |
| 456 | // Which of the two ways a tile goes in, decided by what is in its way. |
| 457 | // |
| 458 | // A clear line to the square means it can be *slid* — flat across the |
| 459 | // cloth, at exactly the speed it was let go at, which is what a flick |
| 460 | // wants to be. A standing wall means it has to be *thrown* instead: lifted |
| 461 | // over the top and dropped in, and then the flick's speed decides how far |
| 462 | // across the pool it lands rather than how fast it skates. |
| 463 | // Sliding is the preferred way in, and the question is asked from where |
| 464 | // the tile actually is — a player who carried it out over the square has a |
| 465 | // clear line even though the seat they came from does not. Only a tile |
| 466 | // with nothing but standing wall in front of it has to be lobbed. |
| 467 | const set = this.inPool(thrown.x, thrown.y); |
| 468 | const slide = set || !LOB_WHEN_WALLED || this.canThrowFrom(thrown.x, thrown.y); |
| 469 | let { vx, vy } = thrown; |
| 470 | let vz = 0; |
| 471 | const speed = Math.hypot(vx, vy); |
| 472 | let flipTurns = 0; |
| 473 | let flipOver = 0; |
| 474 | |
| 475 | if (!slide) { |
| 476 | // Lofted over a standing wall. It still has to *land* on the table |
| 477 | // rather than sail off the far side, so there is a ceiling on how fast |
| 478 | // it can cross — but a generous one: a hard throw is meant to reach the |
| 479 | // far wall, come off it and barge through the pile, and only a limp one |
| 480 | // should drop in the middle and stay there. |
| 481 | const centre = centreOf(geo.pool); |
| 482 | const reach = PLACE_FLIGHT + SLIDE_TIME; |
| 483 | const cap = (Math.hypot(centre.x - thrown.x, centre.y - thrown.y) / reach) * 2.4; |
| 484 | const aim = Math.min(speed, cap) / (speed || 1); |
| 485 | vx *= aim; |
| 486 | vy *= aim; |
| 487 | vz = liftFor(PLACE_FLIGHT); |
| 488 | // Long enough in the air to turn over properly, and harder means more. |
| 489 | flipOver = PLACE_FLIGHT; |
| 490 | flipTurns = speed > 1300 ? 2 : 1; |
| 491 | } else if (!set) { |
| 492 | // A skated tile leaves the fingers off the cloth, and turns over on its |
| 493 | // way down — harder means longer in the air and more turns in it. |
| 494 | const hop = THROW_LIFT + Math.min(0.22, (speed / MAX_THROW_SPEED) * 0.28); |
| 495 | vz = liftFor(hop); |
| 496 | flipOver = hop; |
| 497 | flipTurns = speed > 2200 ? 2 : speed > 600 ? 1 : 0; |
| 498 | } |
| 499 | if (!TUMBLE) flipTurns = 0; |
| 500 | |
| 501 | return addBody(this.world!, { |
| 502 | tile: a.tile, |
| 503 | seat: a.seat, |
| 504 | x: thrown.x, |
| 505 | y: thrown.y, |
| 506 | vx, |
| 507 | vy, |
| 508 | z: 0, |
| 509 | vz, |
| 510 | angle: thrown.angle, |
| 511 | spin: thrown.spin, |
| 512 | flipTurns, |
| 513 | flipOver, |
| 514 | // It tumbles across its line of travel, the way a thrown tile does. |
| 515 | flipAxis: Math.atan2(vy, vx), |
| 516 | w: geo.tile.w, |
| 517 | h: geo.tile.h, |
| 518 | // It was drawn at hand size a moment ago; it shrinks on the way down. |
| 519 | scale: thrown.w / geo.tile.w, |
| 520 | }); |
| 521 | } |
| 522 | |
| 523 | // Off the end of the hand, not the middle of it — a tile is thrown from the |
| 524 | // hand holding it, which is the one at the right-hand end of the row. |
| 525 | const from = geo.throwFrom[a.seat] ?? geo.launch[a.seat] ?? centreOf(geo.pool); |
| 526 | const open = !LOB_WHEN_WALLED || this.canThrow(a.seat); |
| 527 | const target = this.aimFor(geo, a.seat, rng); |
| 528 | // Aim for where it comes to *rest*, not where it first touches down: a tile |
| 529 | // keeps sliding after it lands, and SLIDE_TIME is roughly how much further. |
| 530 | const flight = open ? 0.34 + rng() * 0.1 : PLACE_FLIGHT; |
| 531 | const reach = flight + SLIDE_TIME; |
| 532 | |
| 533 | const vx = (target.x - from.x) / reach; |
| 534 | const vy = (target.y - from.y) / reach; |
| 535 | return addBody(this.world!, { |
| 536 | tile: a.tile, |
| 537 | seat: a.seat, |
| 538 | x: from.x, |
| 539 | y: from.y, |
| 540 | vx, |
| 541 | vy, |
| 542 | z: 0, |
| 543 | vz: liftFor(flight), |
| 544 | angle: (rng() - 0.5) * Math.PI, |
| 545 | spin: (rng() - 0.5) * (open ? 7 : 2.5), |
| 546 | // It turns over on its way in, whichever way it is going. |
| 547 | flipTurns: TUMBLE ? 1 : 0, |
| 548 | flipOver: flight, |
| 549 | flipAxis: Math.atan2(vy, vx), |
| 550 | w: geo.tile.w, |
| 551 | h: geo.tile.h, |
| 552 | }); |
| 553 | } |
| 554 | |
| 555 | /** Where a tile from this seat is headed, with a little scatter. */ |
| 556 | private aimFor(geo: TableGeometry, seat: SeatId, rng: () => number): Point { |
| 557 | const base = aimAt(geo, seat) ?? centreOf(geo.pool); |
| 558 | const jitter = Math.min(geo.pool.w, geo.pool.h) * 0.22; |
| 559 | return { x: base.x + (rng() - 0.5) * jitter, y: base.y + (rng() - 0.5) * jitter }; |
| 560 | } |
| 561 | |
| 562 | /** |
| 563 | * A tile's own random stream. Keyed on the hand and its place in that seat's |
| 564 | * discards, so the same tile scatters the same way every time it is rebuilt — |
| 565 | * a refresh mid-hand puts the pile back exactly as it was. |
| 566 | */ |
| 567 | private seeded(state: GameState, a: { seat: SeatId; index: number; tile: Tile }) { |
| 568 | return makeRng(state.handNumber * 7919 + a.seat * 977 + a.index * 31 + a.tile + 1); |
| 569 | } |
| 570 | } |