World sounds are local: fade with distance and pan (distant sizzles snapped constantly)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/DESIGN.md

@@ -177,6 +177,12 @@ above, including:
 
 - **Fewer, smaller messages.** Molds show only a small percentage, red when blocked or spoiled and gold when a casting waits for F; details are in the hover panel. Bars dropping, blocked molds and set castings no longer pop up cards or toasts. Fan heat is a red marker on the fan; melted tubes and machines get a short red label where they were. Status lines are one short sentence. The owner found the messages too large and too many.
 
+- **World sounds are local.** Sounds from the world (water sizzling on hot metal or lava, and
+  any other event with a place) fade with distance from the view and pan left or right; they go
+  silent one screen width off-screen. The owner heard a constant snapping that followed the bot
+  in an older world but not in a new one. Most likely the sizzle: in a test, a lava and water
+  contact far from the bot sizzled about 580 times a minute, all played at full volume.
+
 ## Ideas not built yet
 
 - **Concrete**, as a stronger wall material from rubble.

docs/PROJECT_MAP.md

@@ -354,9 +354,9 @@ Smooth look: a WebGL2 pass that turns the per-grain buffers drawWorld fills (col
 - functions: smCompile, smoothAvailable, smUpload, smoothDraw, smoothPace
 - variables: SM, SM_VS, SM_FS, smBytes
 
-### src/ui/audio.js (209 lines)
+### src/ui/audio.js (228 lines)
 Audio: chiptune effects and generative music that changes with depth. Everything is synthesized with WebAudio, no samples.
-- functions: auInit, auVolumes, rateOk, tone, noiseBurst, playSfx, auAmbient, mtof, zoneForDepth, scaleNote, musicScheduler
+- functions: auInit, auVolumes, rateOk, tone, noiseBurst, sfxPlace, playSfx, auAmbient, mtof, zoneForDepth, scaleNote, musicScheduler
 - variables: AU, SFX, ZONES
 
 ### src/ui/state.js (67 lines)

docs/agent-log.md

@@ -4,6 +4,23 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-23: world sounds are local (Claude Code, with Codex)
+
+Note: "there is a sound effect that seems to happen randomly but constantly… maybe the sound
+effects are not local?" The owner then confirmed a new world is quiet.
+
+- Measured headlessly over 5 game minutes: a fresh world emits no sounds; a lava and water
+  contact 720+ grains from the bot emitted 2,889 sizzles (about 580 a minute), and `events.js`
+  played every one at full volume. The sizzle (`heat.js` boiling and quenching) is the only sim
+  sound with a position.
+- `src/ui/audio.js`: `sfxPlace(x, y)` gives gain (1 in view, 0 one view width beyond it) and
+  pan; `playSfx(name, arg, x, y)` skips silent ones before the rate limit and plays the rest
+  through a gain and stereo panner (`AU.bus`). `src/ui/events.js` passes positions.
+  `docs/DESIGN.md`, `docs/PROJECT_MAP.md`.
+- `test/play.py`: far off-screen is silent, on screen plays, just off-screen is quieter and
+  panned. All 11 headless suites, `play.py` and `t_smooth.py` pass.
+- Open: not tested against the owner's own save; the owner checks by ear.
+
 ## 2026-10-23: fewer, smaller messages (Claude Code, with Codex)
 
 Note: "lets change the engot mold and other status messages. they are way too large and just too

src/ui/audio.js

@@ -75,7 +75,7 @@ function tone(freq, dur, opts = {}) {
   g.gain.exponentialRampToValueAtTime(v, t + a);
   g.gain.setValueAtTime(v, t + Math.max(a, dur - rel));
   g.gain.exponentialRampToValueAtTime(0.0001, t + dur);
-  o.connect(g); g.connect(opts.bus || AU.sfx);
+  o.connect(g); g.connect(opts.bus || AU.bus || AU.sfx);
   o.start(t); o.stop(t + dur + 0.02);
 }
 function noiseBurst(dur, opts = {}) {
@@ -87,7 +87,7 @@ function noiseBurst(dur, opts = {}) {
   if (opts.sweep) f.frequency.exponentialRampToValueAtTime(opts.sweep, t + dur);
   const g = ctx.createGain(); const v = opts.vol || 0.08;
   g.gain.setValueAtTime(v, t); g.gain.exponentialRampToValueAtTime(0.0001, t + dur);
-  s.connect(f); f.connect(g); g.connect(opts.bus || AU.sfx);
+  s.connect(f); f.connect(g); g.connect(opts.bus || AU.bus || AU.sfx);
   s.start(t, Math.random() * 1.5); s.stop(t + dur + 0.02);
 }
 const SFX = {
@@ -118,7 +118,26 @@ const SFX = {
   sale() { if (!AU.ctx) return; const t = AU.ctx.currentTime; [784, 988, 1175, 1568].forEach((f, k) => tone(f, 0.09, { wave: 'p25', vol: 0.05, at: t + k * 0.06 })); },
   discover() { if (!rateOk('disc', 500)) return; const t = AU.ctx && AU.ctx.currentTime; tone(880, 0.06, { wave: 'p25', vol: 0.04, at: t }); tone(1175, 0.1, { wave: 'p25', vol: 0.04, at: t + 0.06 }); },
 };
-function playSfx(name, arg) { if (!AU.ctx || !SFX[name]) return; try { SFX[name](arg); } catch (e) { /* ignore */ } }
+function sfxPlace(x, y) {
+  if (typeof R === 'undefined' || !R.bw) return { gain: 1, pan: 0 };
+  const dx = Math.max(R.vx0 - x, 0, x - R.vx0 - R.bw), dy = Math.max(R.vy0 - y, 0, y - R.vy0 - R.bh);
+  return { gain: Math.max(0, 1 - Math.hypot(dx, dy) / R.bw), pan: Math.max(-1, Math.min(1, (x - R.vx0 - R.bw / 2) / (R.bw / 2))) * 0.6 };
+}
+function playSfx(name, arg, x, y) {
+  if (!AU.ctx || !SFX[name]) return;
+  const place = typeof x === 'number' && typeof y === 'number' ? sfxPlace(x, y) : null;
+  if (place && place.gain < 0.02) return;
+  const prev = AU.bus; let gain, pan;
+  try {
+    if (place) {
+      gain = AU.ctx.createGain(); pan = AU.ctx.createStereoPanner();
+      gain.gain.value = place.gain; pan.pan.value = place.pan;
+      gain.connect(pan); pan.connect(AU.sfx); AU.bus = gain;
+    }
+    SFX[name](arg);
+  } catch (e) { /* ignore */ }
+  finally { AU.bus = prev; if (gain || pan) setTimeout(() => { if (gain) gain.disconnect(); if (pan) pan.disconnect(); }, 1500); }
+}
 
 // Ambient layer driven by what is on screen.
 function auAmbient(info) {

src/ui/events.js

@@ -11,7 +11,7 @@ function drainEvents() {
       const m = MILESTONES.find(x => x.id === e.id);
       if (m && !['bit1', 'bit2', 'bit3', 'tank'].includes(m.id)) { showCard({ kind: 'Milestone', title: m.title, body: [m.msg, m.reward], accent: 'milestone' }); playSfx('milestone'); }
     } else if (e.t === 'cast_ready') {
-      playSfx('cast');
+      playSfx('cast', undefined, e.x, e.y);
     } else if (e.t === 'upgrade') {
       playSfx('upgrade'); if (SET.shake) R.shake = 1.4;
       showCard({ kind: e.kind === 'bit' ? 'Drill bit upgraded' : 'Bag upgraded', title: e.kind === 'bit' ? BIT_TIERS[e.tier].name : TANK_TIERS[e.tier].name, accent: 'milestone',
@@ -36,7 +36,7 @@ function drainEvents() {
     }
     else if (e.t === 'claim_paid') { showCard({ kind: 'Claim', title: 'The land is yours', accent: 'milestone', hold: 1.5, body: ['You have paid off the claim on this land.', 'Keep filling orders: bigger buyers bring bigger ones. The ledger has bigger goals too.'] }); playSfx('milestone'); }
     else if (e.t === 'sprout') { showCard({ kind: 'Discovery', title: 'A sapling', swatch: ACORN, body: ['An acorn on soil under open sky has sprouted.', 'It grows into a tree in about a minute and a half. Keep the space above it clear.'] }); playSfx('discover'); }
-    else if (e.t === 'sfx') { if (e.s) playSfx(e.s, e.a); }
+    else if (e.t === 'sfx') { if (e.s) playSfx(e.s, e.a, e.x, e.y); }
     else if (e.t === 'toast') { if (e.text) toast(e.text); }
   }
 }

test/play.py

@@ -26,6 +26,17 @@ with sync_playwright() as p:
     pg.wait_for_timeout(500)
     ev = pg.evaluate
     ev("window._maxStatus = ''; const _ss = setStatus; setStatus = function (s, k) { if (s && s.length > _maxStatus.length) _maxStatus = s; return _ss(s, k); }; 0")
+    # World effects use the view, and inaudible ones must not throttle nearby sounds.
+    ev("auInit(); window._noiseCalls = 0; window._noiseBurst = noiseBurst; noiseBurst = function (...args) { _noiseCalls++; return _noiseBurst(...args); }; 0")
+    try:
+        far = ev("(() => { const n = _noiseCalls; AU.last.sizzle = 0; const x = R.vx0 + R.bw * 3, y = R.vy0 + R.bh / 2; playSfx('sizzle', 0, x, y); return [_noiseCalls - n, sfxPlace(x, y).gain, AU.last.sizzle]; })()")
+        check('a sound far off-screen is silent', far == [0, 0, 0], far)
+        near = ev("(() => { const n = _noiseCalls; AU.last.sizzle = 0; const x = R.vx0 + R.bw / 2, y = R.vy0 + R.bh / 2; playSfx('sizzle', 0, x, y); return [_noiseCalls - n, sfxPlace(x, y).gain, AU.bus == null]; })()")
+        check('a sound on screen plays', near == [1, 1, True], near)
+        quiet = ev('sfxPlace(R.vx0 + R.bw * 1.5, R.vy0 + R.bh / 2)')
+        check('a sound just off-screen is quieter', 0 < quiet['gain'] < 1 and quiet['pan'] > 0, quiet)
+    finally:
+        ev('noiseBurst = _noiseBurst; delete window._noiseBurst; delete window._noiseCalls; 0')
     look = sys.argv[2] if len(sys.argv) > 2 else 'pixel'
     check('a new game starts fully zoomed in', ev('SET.zoom') == 12, ev('SET.zoom'))
     # Ctrl+W closes the tab; with a world open the browser must ask first