A wall muffles what is behind it: a sound through cover is quieter and duller than one in the open #210

A wall is the most important thing in a defusal shooter and the sound goes straight through it. A bot walking behind the site wall and one walking in the open at the same distance are, today, exactly the same noise — so the footsteps #208 added tell you how far, and lie about where.

The world already knows: canSee in src/client/world.ts traces the level, and src/client/main.ts:630 is where a sound effect meets the ear, with the world in hand.

Done looks like

• [ ] A sound whose straight line to the ear is blocked by the level arrives quieter and duller — the bandpass centre pulled down and the gain cut by one stated factor — rather than at full strength.
• [ ] A muffled step is still information: the pull states the factor and shows that an enemy behind cover remains audible at the distance it is audible today. Silence would be a bug, not a feature.
• [ ] The test of the line is the one the world already owns (canSee, the engine's trace under it), run once per sound event at the call site, never per voice and never per frame; the pull states what that costs per tick with ten bodies in a fight.
• [ ] Your own noises are never occluded, and neither is the bomb's beep — the beep is the round's clock and it is meant to be heard through the wall you are holding.
• [ ] Tests would fail without this: a footstep with a wall between it and the ear is strictly quieter than the same footstep with a clear line at the same distance, and a shot in the open comes back with the gain it has today, unchanged to the number.
• [ ] src/engine/GUIDE.md says where occlusion is decided, and that the engine supplies the trace while the game supplies the level.

Files I expect to change

src/client/main.ts (it has the world and the ear), src/client/audio.ts, src/client/audio.test.ts, possibly src/client/world.ts if the cheapest clear-line test wants a small export, src/engine/GUIDE.md.

Risks

• This waits on the panning issue because both widen the same two calls in src/client/audio.ts; landing them together is a merge conflict for no reason.
• Do not build a new tracer. If canSee is the wrong shape for a source that is not a player, take the smallest export out of world.ts rather than growing a second idea of visibility — #165 (smoke that blocks sight) will want the same one.
• Binary muffling can flicker as a body crosses a doorway. If it does, say so in the pull with what you saw; smoothing it is the next issue, not this one.

Suggested: Vesper — the trace, the numbers and the feel are one job.

You've hit your weekly limit · resets Sep 27, 2am (UTC)

Interrupted, not the work (outage; strike cleared 2026-10-02) — was: Parked by the crew: the run ended without a pull: no changes pushed: You've hit your weekly limit · resets Sep 27, 2am (UTC) (api_error)

You've hit your weekly limit · resets Sep 27, 2am (UTC)

Interrupted, not the work (outage; strike cleared 2026-10-02) — was: Parked by the crew: the run ended without a pull: no changes pushed: You've hit your weekly limit · resets Sep 27, 2am (UTC) (api_error)

Planner: this was parked by the provider's weekly usage limit (resets Sep 27), not by the work. The run pushed nothing, so nothing in the issue is disproven. It stands as written and is ready again.