splatter-tennis/zombies.js

// The splatter phase: shamblers, gore decals, particles. The ball is the weapon;
// tennis scoring keeps running via gameplay.splatPoint. Zombies advance toward
// your baseline — one crossing it is a point for THEM.
// (zombies <-> gameplay is a runtime-only import cycle, same pattern as input.)

import { TUNE, COURT } from './config.js';
import { G, P, ball, sendBoy, setupPoint } from './state.js';
import { splat, moan, pock, voice, boom, swish, shriek, aww, sfx } from './audio.js';
import { splatPoint, cheer, spentBall, resolveInterlude } from './gameplay.js';

export const zombies = []; // {x, z, v, walkT, variant: 'a'|'b'|'c'}
export const gore = [];    // lawn decals {x, z, r, a}  — the flat ground layer
export const piles = [];   // 3D-ish gore mounds {x, z, size 1..4, seed} — grow where kills cluster
export const parts = [];   // splatter particles {x, y, z, vx, vy, vz, t, dark}
export const pellets = []; // machine-gun rounds during a horde {x, y, z, vx, vz, t}
export const extras = [];  // triple-serve side balls {x, y, z, vx, vy, vz, pow, t} — ballistic clones

let spawnT = 1.5, moanT = 3;

export function spawnZombie(x, z, variant) {
  const ramp = 1 + Math.min(1.5, G.splatT / 70); // they get faster the longer you survive
  const zb = { x, z, v: TUNE.zSpeed * ramp * (0.8 + Math.random() * 0.4), walkT: Math.random() * 9,
               homeOff: (Math.random() * 2 - 1) * 0.8, variant }; // personal lane offset so they don't stack into a column
  if (variant === 'f') { zb.v = Math.min(TUNE.runnerVMax, zb.v * TUNE.runnerSpeed); shriek(); } // shriek = the fairness contract; capped so late runners stay reactable
  if (variant === 'a' || variant === 'b') zb.hp = TUNE.shamblerHp; // classic shamblers take a wound before they drop — only the runner is one-shot glass
  if (variant === 'g') { zb.v *= 0.55; zb.hp = TUNE.bruteHp; } // slow, but soaks hits
  if (variant === 's') zb.shieldT = 0;                         // chair up; > 0 = seconds of stagger left
  zombies.push(zb);
}

// which shambler steps out next: the roster grows one type per set (runner: set 1 game 3+,
// brute: set 2, shield: set 3). Fixed random slots so the classics stay the crowd.
function pickVariant() {
  const tier = G.sets[0] + G.sets[1], r = Math.random();
  if (tier >= 2 && r < 0.15) return 's';
  if (tier >= 1 && r >= 0.15 && r < 0.30) return 'g';
  if ((tier >= 1 || G.runGames >= 2) && r >= 0.30 && r < 0.42
      && !zombies.some(z => z.variant === 'f')) return 'f'; // at most one runner alive
  return Math.random() < 0.5 ? 'a' : 'b';
}

// core kill: remove the zombie, spawn its gore/pile/particles, score. No ball coupling —
// shared by ball hits, machine-gun pellets, melee swipes, and extra (multi-serve) balls.
// how absurdly a variant dies: classics splash, the advanced roster DETONATES
const GORE_MUL = { a: 1, b: 1, f: 1.8, s: 2.5, g: 4, r: 3 };

function killZombie(i, quiet) {
  const zb = zombies[i];
  const mul = GORE_MUL[zb.variant] || 1;
  zombies.splice(i, 1);
  if (G.interlude && zb.variant === 'r') resolveInterlude('P'); // regicide ends the duel your way — any weapon counts
  const stains = Math.round(Math.sqrt(mul)); // advanced kills splash a scatter of stains, not one puddle
  for (let k = 0; k < stains; k++) {
    gore.push({ x: zb.x + (k ? (Math.random() * 2 - 1) * 0.9 : 0), z: zb.z + (k ? (Math.random() * 2 - 1) * 0.9 : 0),
                r: (0.45 + Math.random() * 0.35) * Math.sqrt(mul), a: 0.85 });
    if (gore.length > 40) gore.shift();
  }
  const pl = piles.find(p => Math.hypot(p.x - zb.x, p.z - zb.z) < 0.6); // stack up where kills cluster
  if (pl) pl.size = Math.min(4, pl.size + Math.round(mul / 2 + 0.5));
  else { piles.push({ x: zb.x, z: zb.z, size: Math.min(4, Math.round(mul / 2 + 0.5)), seed: Math.random() * 1e4, blobs: null, builtSize: 0 });
         if (piles.length > 30) piles.shift(); }
  const n = Math.round(30 * mul); // base bumped 24 -> 30, then the multiplier goes to work
  for (let k = 0; k < n; k++) { const dark = k >= n * 2 / 3; parts.push({ // ~1/3 dark & long-lived: settling gore
    x: zb.x, y: 0.9, z: zb.z,
    vx: (Math.random() * 2 - 1) * 3.5, vy: 1 + Math.random() * 3.5, vz: (Math.random() * 2 - 1) * 3.5,
    t: dark ? 0.6 + Math.random() * 0.6 : 0.4 + Math.random() * 0.4, dark,
  }); }
  splat();
  sfx('headshot-' + (Math.random() < 0.5 ? 1 : 2), 0.6); // random headshot crack layered on the gore burst
  sendBoy(zb.x, zb.z);            // a boy sprints out to mop
  if (!G.horde && !G.clearing) splatPoint('P', quiet); // horde = survival, clearing = mopping up an already-won game — neither scores
}

// a small dark spatter the instant a multi-hit shambler is wounded — subtle impact pop, NOT the
// kill spray (the ongoing thin trickle is bleed()'s job). Kept low per the settled blood feel.
function woundBurst(zb) {
  for (let k = 0; k < 5; k++) parts.push({
    x: zb.x + (Math.random() * 2 - 1) * 0.15, y: 1.4, z: zb.z,
    vx: (Math.random() * 2 - 1) * 1.6, vy: 0.6 + Math.random() * 1.4, vz: (Math.random() * 2 - 1) * 1.6,
    t: 0.35 + Math.random() * 0.3, dark: Math.random() < 0.6 });
}

// swishing the racket cleaves every shambler in reach — it's the panic button for when they're
// already on top of you, so it stays a full sweep. TUNE.meleeCool is the brake that stops it
// from being the default attack. (the racket-zombie boss shrugs melee off entirely)
export function meleeSwipe(x, z, range) {
  let hit = 0;
  for (let i = zombies.length - 1; i >= 0; i--) {
    const zb = zombies[i];
    if (!zb || zb.variant === 'r') continue; // !zb: killZombie can sweep the court mid-loop
    if (Math.hypot(zb.x - x, zb.z - z) < range) { killZombie(i, !!G.horde); hit++; }
  }
  if (hit) swish(0.35);
  return hit;
}

function splatter(i, fanfare = true) { // the MAIN ball hit a zombie
  killZombie(i, !!G.horde);
  ball.vx *= TUNE.zPierce; ball.vz *= TUNE.zPierce; // keep enough pace to plow through the next
  if (!fanfare) return;           // machine-gun pellets splatter but skip the streak fanfare / bomb meter
  ball.kills++;                   // this shot's running streak
  // escalating multi-kill fanfare — one shot, ≥2 zombies
  if (ball.kills === 2) { G.flash = { text: 'DOUBLE KILL', t: 0.9 }; cheer(1.6, 0.45); voice('double_kill', 0.4); }
  else if (ball.kills === 3) { G.flash = { text: 'TRIPLE KILL', t: 0.9 }; cheer(2.2, 0.6); voice('triple_kill', 0.4); }
  else if (ball.kills >= 4) { G.flash = { text: `MASSACRE ×${ball.kills}`, t: 0.9 }; cheer(2.8, 0.7); voice('unbelievable', 0.4); }
}

// ---- horde wave: dense spawns + an auto-firing machine-gun racket (pellets, not the match ball)
function spawnHordeZombie() { // all from the far baseline, across the court — never off-screen at the sides
  spawnZombie((Math.random() * 2 - 1) * 5, -1.5 - Math.random(), Math.random() < 0.5 ? 'a' : 'b');
}
function firePellet() {
  const a = (Math.random() * 2 - 1) * 4 * Math.PI / 180, s = 26; // ±4° spread, straight up-court (-z)
  pellets.push({ x: P.x, y: 0.9, z: P.z, vx: Math.sin(a) * s, vz: -Math.cos(a) * s, t: 1.2 });
  pock(0.25, 1400); // rapid fire tick; if it clips on device, gate to every 2nd pellet
}
export function spawnRacketZombie() { // one takes up residence on the far court — an opponent, of sorts
  zombies.push({ x: (Math.random() * 2 - 1) * 2.5, z: 3.5, v: 0, walkT: Math.random() * 9,
    variant: 'r', side: 'O', facing: 1, pose: 'idle', poseT: 0, swingT: -1, swingCool: 0, runT: 0, hp: TUNE.racketHp });
}
function endHorde() {
  G.horde = null; pellets.length = 0;
  if (!zombies.some(z => z.variant === 'r')) spawnRacketZombie(); // survive the wave → a racket zombie stays
  setupPoint();                    // serve loop resumes; any zombies still standing are yours to mop up
  voice('quiet_dark', 0.5, 0.85);
}
function tickHorde(dt) {
  const h = G.horde;
  h.t -= dt;
  if ((h.spawnT -= dt) <= 0) { spawnHordeZombie(); h.spawnT = 1 / TUNE.hordeRate; }
  if ((h.mgT -= dt) <= 0) { firePellet(); h.mgT = 1 / TUNE.mgRate; }
  if (h.t <= 0) endHorde();
}

// bomb ball: everything inside bombRadius splatters at once (each kill still ++ball.kills so
// the Phase-2 fanfare escalates), plus a crater — big stain, size-3 pile, extra particles, boom.
export function explode(x, z) {
  for (let i = zombies.length - 1; i >= 0; i--) // backwards: splatter() splices (and can sweep) the array
    if (zombies[i] && Math.hypot(zombies[i].x - x, zombies[i].z - z) < TUNE.bombRadius) splatter(i);
  gore.push({ x, z, r: 1.6, a: 1, scorch: true }); if (gore.length > 40) gore.shift(); // the crater — near-permanent
  gore.push({ x, z, r: 1.4, a: 0.9 }); if (gore.length > 40) gore.shift();
  const pl = piles.find(p => Math.hypot(p.x - x, p.z - z) < 0.6);
  if (pl) pl.size = Math.min(4, pl.size + 3);
  else { piles.push({ x, z, size: 3, seed: Math.random() * 1e4, blobs: null, builtSize: 0 }); if (piles.length > 30) piles.shift(); }
  for (let k = 0; k < 40; k++) parts.push({
    x, y: 0.6, z, vx: (Math.random() * 2 - 1) * 6, vy: 1 + Math.random() * 5, vz: (Math.random() * 2 - 1) * 6,
    t: 0.5 + Math.random() * 0.7, dark: k % 2 === 0,
  });
  G.hitstop = 0.18; boom();
  G.shake = { t: 0.35, mag: 6 };  // camera kick
  G.boomFlash = 0.08;             // one white frame
  if (G.idleT - G.lastOrderT > 3) { voice('order', 0.35); G.lastOrderT = G.idleT; } // the umpire loses composure
}

// wounded zombies bleed from every open wound — a fine, sparse trickle (a small spurt from the
// neck stump on the headless boss). Anchors are approximate body offsets [x, y, rise]; most
// frames a wound drips nothing, and the tight spread keeps each thread thin. Bounded low.
function bleed(zb) {
  if (parts.length > 90) return;
  let wounds;
  if (zb.variant === 'g' && zb.hp < TUNE.bruteHp) wounds = [[-0.3, 1.95, 1.1]];              // brute: torn-off arm
  else if (zb.variant === 'r' && zb.hp <= 1)      wounds = [[0.05, 1.5, 2.4], [0.4, 1.15, 0.9]]; // headless: neck spurt + torn arm
  else if (zb.variant === 'r' && zb.hp === 2)     wounds = [[0.4, 1.2, 1.0]];                 // racket: torn-off arm
  else if ((zb.variant === 'a' || zb.variant === 'b') && zb.hp < TUNE.shamblerHp) wounds = [[0.28, 1.35, 0.85]]; // shambler: gashed shoulder
  else return;
  for (const w of wounds) {
    if (Math.random() > 0.4) continue; // sparse: most frames this wound emits nothing
    parts.push({
      x: zb.x + w[0] + (Math.random() * 2 - 1) * 0.03, y: w[1] + (Math.random() * 2 - 1) * 0.03, z: zb.z + (Math.random() * 2 - 1) * 0.03,
      vx: (Math.random() * 2 - 1) * 0.3, vy: w[2] * (0.6 + Math.random() * 0.5), vz: (Math.random() * 2 - 1) * 0.28,
      t: 0.3 + Math.random() * 0.3, dark: Math.random() < 0.55 });
  }
}

export function updateZombies(dt) {
  moanT -= dt;
  if (moanT <= 0) { moan(); moanT = 2.5 + Math.random() * 4; }

  if (G.mode === 'splatter') { // transition spawns are scripted, not timed
    G.splatT += dt;
    if (G.horde) tickHorde(dt); // horde: dense spawns + machine gun, ignores the cap
    else if (G.mgT > 0 && G.phase === 'rally') { // machine-gun tin: horde firepower, regular rules
      G.mgT -= dt;
      if ((G.mgCool -= dt) <= 0) { firePellet(); G.mgCool = 1 / TUNE.mgRate; }
      if (G.mgT <= 0) setupPoint(); // ammo dry — the serve loop resumes
    }
    if (!G.horde && !G.changeover && !G.interlude && !G.clearing) { // breathers, duels AND the mop-up after a won game get a quiet court (no new spawns)
      spawnT -= dt;
      // the spawn director: the match's age (games finished) sets both crowd size and tempo
      const cap = Math.min(TUNE.zMaxCap, TUNE.zMax + G.runGames);
      if (spawnT <= 0 && zombies.length < cap) {
        spawnZombie((Math.random() * 2 - 1) * 4.8, -1.5 - Math.random(), pickVariant());
        spawnT = Math.max(TUNE.zSpawnMin, TUNE.zSpawnEvery - G.runGames * TUNE.zSpawnStep);
      }
    }
  }

  // ponytail: crude swept collision — grow the contact window by half the distance the ball
  // covers this frame. A full-draw smash moves ~0.7 m per frame (1.6 m on a 25 fps device, where
  // main.js clamps dt), which is wider than a shambler, so a discrete point test tunnels straight
  // through bodies. Upgrade to a real segment-vs-circle test if the fudge ever reads as a phantom
  // hit; at these speeds and radii it doesn't.
  const ballSweep = ball.active ? Math.hypot(ball.vx, ball.vz) * dt * 0.5 : 0;

  for (let i = zombies.length - 1; i >= 0; i--) {
    const zb = zombies[i];
    if (!zb) continue; // a bomb detonation splices several out mid-loop and can gut the array under us
    zb.walkT += dt;
    zb.z += zb.v * dt;
    bleed(zb); // open wounds bleed every frame they're standing

    if (zb.shieldT > 0) zb.shieldT -= dt; // staggered chair comes back up when this runs out
    if (zb.variant === 'r') { /* the racket boss holds station — its AI owns its x */ }
    else if (G.mode === 'splatter' && zb.z > COURT.netZ) { // on YOUR half they close in — each on its own lane, not a column
      const tx = P.x + zb.homeOff;
      zb.x += Math.sign(tx - zb.x) * Math.min(Math.abs(tx - zb.x), zb.v * 0.7 * dt)
            + Math.sin(zb.walkT * 2.3) * 0.25 * dt; // shamble wobble — the approach reads organic, not tracked
    } else
      zb.x += Math.sin(zb.walkT * 1.7) * 0.15 * dt; // far half: aimless shamble
    if (G.mode === 'splatter' && Math.hypot(zb.x - P.x, (zb.z - P.z) * 0.75) < TUNE.eatenR + (zb.variant === 'g' ? 0.2 : 0)) { // z weighted down: depth is foreshortened, so a head-on shambler eats you when it LOOKS on top of you
      gore.push({ x: P.x, z: P.z, r: 0.9, a: 0.9 });
      for (let k = 0; k < 30; k++) parts.push({
        x: P.x, y: 1.1, z: P.z,
        vx: (Math.random() * 2 - 1) * 4.5, vy: 1 + Math.random() * 4, vz: (Math.random() * 2 - 1) * 4.5,
        t: 0.5 + Math.random() * 0.5,
      });
      splat(1);
      voice('game_set_massacre', 0.8); aww(1); // the run is over — the crowd groans
      G.mode = 'eaten'; ball.active = false; G.flash = null; // zombies keep shambling for ambience
      G.horde = null; pellets.length = 0; extras.length = 0; G.mgT = 0; // everything stops; the eaten screen takes over
      try { // the run is over — settle it against the best (games survived, sets as tiebreak)
        const b = JSON.parse(localStorage.splatterBest || 'null') || { games: 0, sets: 0 };
        G.newBest = G.runGames > b.games; // beat it → the summary crows about it
        if (G.newBest) { b.games = G.runGames; b.sets = G.sets[0]; localStorage.splatterBest = JSON.stringify(b); }
        G.best = b;
      } catch (e) { G.best = null; } // private mode etc. — the summary just skips the best line
    }
    if (ball.active && ball.lastHit === 'P' && ball.y < 1.9) {
      const d = Math.hypot(ball.x - zb.x, ball.z - zb.z);
      if (d < (zb.variant === 'g' ? 0.75 : 0.55) + ballSweep) { // the brute is a bigger target
        if (ball.bomb) { // detonate on first contact, whatever the pace
          explode(ball.x, ball.z); ball.bomb = false;
          spentBall(); break; // zombies mutated — stop this frame's loop
        }
        if (ball.flame) { // burns through anything it touches — no quality gate, no chair, no pace tax
          if (zb.variant === 'r') { // the boss only takes a wound
            zb.hp--; splat(0.5);
            if (zb.hp <= 0) { splatter(i); } continue;
          }
          const vx0 = ball.vx, vz0 = ball.vz;
          splatter(i); ball.vx = vx0; ball.vz = vz0; // undo splatter's pierce tax: full pace through the lane
          continue;
        }
        if (zb.variant === 'r') { // mini-boss: splat-quality wounds it; soft balls it rallies (racketAI)
          if ((ball.pow || 0) >= TUNE.zSplatQ) {
            zb.hp--; splat(0.5); pock(0.6, 300);
            ball.vx *= 0.3; ball.vz *= 0.3; ball.lastHit = 'X'; // spent on the hit
            if (zb.hp <= 0) { splatter(i); continue; }         // killing blow: full gore + point
          }
          continue; // soft balls pass through, for the AI to return
        }
        if (zb.variant === 'g') { // brute: soaks splat-quality hits, never staggers back
          if ((ball.pow || 0) >= TUNE.zSplatQ) {
            zb.hp--; splat(0.5); pock(0.6, 220);
            ball.vx *= 0.3; ball.vz *= 0.3; ball.lastHit = 'X';
            if (zb.hp <= 0) { splatter(i); continue; } // timber
          } else { pock(0.6, 300); ball.vx *= 0.6; ball.vz *= 0.6; ball.lastHit = 'X'; } // soft ball bounces off
          continue;
        }
        if (zb.variant === 's' && ball.vz < 0 && !(zb.shieldT > 0)) { // chair up, ball at its face: BLOCKED
          zb.shieldT = TUNE.shieldDown; // ...but the block staggers it — the chair drops, kill window opens
          zb.z -= TUNE.zPushback * 0.5;
          pock(0.9, 1800); // wooden clank
          ball.vx *= 0.4; ball.vz *= -0.2; ball.lastHit = 'X'; // ball caroms off the chair, spent
          continue;
        }
        if (zb.variant === 'f') { splatter(i); continue; } // the sprinter is GLASS — any touch, any quality, it bursts
        if (zb.variant === 'a' || zb.variant === 'b') { // classic shamblers soak a splat-quality wound before they drop
          if ((ball.pow || 0) >= TUNE.zSplatQ) {
            if (--zb.hp <= 0) { splatter(i); continue; }              // the second splat is the killing blow
            woundBurst(zb); splat(0.5); pock(0.6, 280);              // first splat: a bloody wound, not a death
            zb.z -= TUNE.zPushback * 0.5; ball.vx *= 0.3; ball.vz *= 0.3; ball.lastHit = 'X'; continue; // ball spent on the wound
          }
          zb.z -= TUNE.zPushback; pock(0.6, 300); ball.vx *= 0.6; ball.vz *= 0.6; ball.lastHit = 'X'; continue; // soft ball just staggers
        }
        // chair-down shield zombies (and anything hit from behind) obey the normal rules:
        if ((ball.pow || 0) >= TUNE.zSplatQ) { splatter(i); continue; }
        zb.z -= TUNE.zPushback; // weak sitters only stagger them
        pock(0.6, 300);
        ball.vx *= 0.6; ball.vz *= 0.6; ball.lastHit = 'X'; // spent — one stagger per ball
      }
    }
    if (zb.z >= COURT.L + 0.7) { zombies.splice(i, 1); if (G.mode !== 'eaten' && !G.horde && !G.clearing) splatPoint('O'); } // it reached your baseline (during a mop-up, a straggler that reaches the line just despawns — no point for them)
  }

  for (let i = pellets.length - 1; i >= 0; i--) { // machine-gun rounds: flat, fast, one-shot kills
    const pe = pellets[i];
    pe.t -= dt; pe.x += pe.vx * dt; pe.z += pe.vz * dt;
    let hit = false;
    for (let j = zombies.length - 1; j >= 0; j--) {
      const zb = zombies[j];
      if (!zb || zb.variant === 'r') continue;
      if (Math.hypot(zb.x - pe.x, zb.z - pe.z) < (zb.variant === 'g' ? 0.75 : 0.55)) {
        if (zb.hp > 1) { zb.hp--; pock(0.5, 260); } // brutes AND shamblers soak pellets — wound, don't kill
        else killZombie(j, true);
        hit = true; break;
      }
    }
    if (hit || pe.t <= 0) pellets.splice(i, 1);
  }

  for (let i = extras.length - 1; i >= 0; i--) { // triple-serve side balls: full ballistic clones
    const e = extras[i];
    e.t -= dt; e.vy -= TUNE.gravity * dt;
    e.x += e.vx * dt; e.y += e.vy * dt; e.z += e.vz * dt;
    if (e.y <= 0 && e.vy < 0) { e.y = 0; e.vy = -e.vy * TUNE.bounceY; e.vx *= TUNE.bounceXZ; e.vz *= TUNE.bounceXZ; }
    let dead = e.t <= 0 || Math.abs(e.x) > 7.5 || e.z < -2 || e.z > 25.5;
    if (!dead && e.y < 1.9) for (let j = zombies.length - 1; j >= 0; j--) {
      const zb = zombies[j];
      if (!zb || zb.variant === 'r') continue; // side balls pass the boss; !zb: kills can sweep mid-loop
      if (Math.hypot(zb.x - e.x, zb.z - e.z) < (zb.variant === 'g' ? 0.75 : 0.55)
                                               + Math.hypot(e.vx, e.vz) * dt * 0.5) { // same sweep: clones inherit the smash pace
        if (zb.variant === 's' && e.vz < 0 && !(zb.shieldT > 0)) { zb.shieldT = TUNE.shieldDown; pock(0.9, 1800); } // chair blocks these too
        else if (e.pow >= TUNE.zSplatQ || zb.variant === 'f') {
          if (zb.hp > 1) { zb.hp--; splat(0.4); } // wounds brutes AND shamblers
          else killZombie(j, !!G.horde);
        } else { zb.z -= TUNE.zPushback; pock(0.5, 300); }
        dead = true; break; // a side ball is spent on its first touch
      }
    }
    if (dead) extras.splice(i, 1);
  }

  for (let i = parts.length - 1; i >= 0; i--) {
    const p = parts[i];
    p.t -= dt; p.vy -= 14 * dt;
    p.x += p.vx * dt; p.y += p.vy * dt; p.z += p.vz * dt;
    if (p.y < 0) { p.y = 0; p.vy = 0; p.vx *= 0.5; p.vz *= 0.5; }
    if (p.t <= 0) parts.splice(i, 1);
  }

  const boy = G.boy; // the boy mops any gore he passes over
  for (let i = gore.length - 1; i >= 0; i--) {
    const d = gore[i];
    if (boy && Math.abs(boy.x - d.x) < 0.7 && Math.abs(boy.z - d.z) < 1.2) d.a -= dt * (d.scorch ? 0.16 : 1.6); // craters scar the lawn 10× longer
    if (d.a <= 0) gore.splice(i, 1);
  }
  for (let i = piles.length - 1; i >= 0; i--) { // piles shave far slower than stains — net growth wins
    const pl = piles[i];
    if (boy && Math.abs(boy.x - pl.x) < 0.7 && Math.abs(boy.z - pl.z) < 1.2) pl.size -= dt * 0.25;
    if (pl.size <= 0.3) piles.splice(i, 1);
  }
}