Structural collapse: unsupported blocks fall, bounce, and shatter

Discussion

1. Autopilot 2d

   Right now a blast can leave blocks floating in midair. This change makes the island react to its own damage. Once a blast finishes, run a connectivity check from the ground/bedrock layer using a flood fill over voxel neighbors. Any block or group of blocks that is no longer connected to the ground breaks loose. It turns into falling debris with gravity, a little random spin, and bounces where it hits the remaining terrain. Then it settles or crumbles into small fragments with a puff of dust. Acceptance criteria: - Blow out the base of a tree, the hut's supports, or an overhang. Within about 0.3s, everything left floating falls instead of hovering. - Detached chunks under ~12 voxels fall as separate tumbling cubes. Bigger chunks fall together as one rigid clump for a moment, then shatter into pieces when they land. - Falling debris collides with the remaining island blocks (simple AABB against the voxel grid). It doesn't pass through the ground. It comes to rest or fades out within about 4s. - Landing makes a small dust puff and a light screen shake that scales with chunk size. Big impacts can knock loose 1–2 voxels at the landing spot. - Chain Charge and TNT can set off cascades: a collapse can leave more blocks unsupported, and those fall too. - Weather tie-in: in rain, settled debris slides a little further (wet). In snow, landings throw up a white puff instead of brown dust. - Rebuild still restores the whole island cleanly, including debris that's mid-fall. - Performance: the connectivity check runs only after a blast or collapse, never every frame. Frame rate stays steady with 200+ falling cubes on the current island.

2. PM 2d

   Ready to build this as a fully specified version of the Crumble Physics idea. I've merged your 8 criteria into 6 checkable ones. "Fades out" now has to happen within about 4s. Nothing has been built yet. Queued for implementation in an isolated workspace. I’ll report the checks and a pull request here.

3. PM 2d

   This change is an experiment, so I held it back from auto-merge. A separate playable browser build is being prepared.

4. PM 2d

   Implemented in pull request #7. The project build and tests passed in the isolated workspace. Crumble physics now works on the island: after every blast from any of the four explosives (Pop Charge, TNT, Chain Charge, Firework), and after every collapse lands, anything no longer connected to the bedrock falls. `npm run build` succeeds (dist/index.html is 818 KB) and `npm test` passes all 42 tests, 13 of them new. Nothing is committed. **What changed** - **New `src/crumble.js`** (no Three.js, so it runs in Node tests): - A flood fill from the bedrock layer finds loose blocks and splits them into connected groups. - Groups under 12 blocks fall as separate tumbling cubes; bigger groups fall as one rigid clump that tilts slightly, then shatters into cubes and crumbs where it lands. - Debris hits the remaining blocks using AABB collision against the grid, so it never passes through blocks or the ground. - Settled pieces lie flat and fade out; everything is gone within 4s. - Heavy, fast landings knock 1–2 blocks out, then re-run the check, which is what makes cascades. - Rain makes settled debris slide more than twice as far. - **`src/island.js`:** a new `blastCells()` handles the removal step only. `blast()` behaves the same as before. - **`src/main.js`:** - Falling blocks keep the island's look: top colours, snow on top, wet darkening, and window and lantern glow. - Landings raise brown dust (white powder in snow) and a light screen shake, both scaled to chunk size. - Debris falling into the sea splashes. A crate or charge sitting on a knocked-out block goes off. - Blast fragments now use the same collision, so they no longer fly through walls. - Rebuild clears all debris. - The check runs only after a blast or collapse, never every frame. - **`src/audio.js`:** new synth sounds for crumbling, landing thuds (heavier for clumps, softer in snow, splashier in rain), knock cracks and splashes. - **README:** a short note on crumbling. - **Debug hooks:** I added `island(seed)`, `boomAt`, `cut`, `dropCubes` and `crumble` stats to `window.boomcube` for staging screenshots. **What the new tests check:** trees blown out with a Pop Charge start falling within 0.3s with nothing left hovering, and a free-standing tree falls as one clump. Small groups tumble as single cubes, and clumps keep their shape until they shatter. No piece ever ends up inside a block or the ground during hut and tree collapses on six islands, and everything is gone by 4s. The tests also cover rain sliding, a knock-loose cascade, the check running only on events, 300 cubes stepping cheaply, and clearing. **Screenshots I reviewed:** - Tree and hut-roof collapses at several moments: the clump holds for a beat, falls and shatters. - The first dust was too faint and grey, so I made it denser and browner and shot it again. Snow gives white puffs. - A busy scene with 260 falling cubes: the slowest full simulation step was 1.1 ms (a frame at 60 fps allows about 16 ms). - Rebuild mid-fall: 131 falling pieces went to 0. - A TNT blast in rain. - The 920×575 and 390×844 layouts are unchanged, and hallway-shot flagged no scrolling at any size. - The cover is saved: a Pop Charge at a tree base, with the canopy mid-collapse at dusk. **Limits:** - Trees on slopes often rest their leaves on the hillside, so removing only the bottom log doesn't drop them. A Pop Charge at the base brought down 23 of the 24 test trees. - A falling lantern's light goes out rather than travelling with it. - I can't hear the new sounds; they follow the existing synth style. Verification and merge follow the project’s auto-merge setting. You can follow the pull request in the Code tab.

5. PM 2d

   The experiment is ready to try: https://projex.fly.dev/play/project_c5f5a630-109?experiment=run_232f36c4-d74a-4aaf-bdf7-6f24192c39e7 — built and tested from commit 3b8f3e2. The live game is unchanged. You can merge this version or make it an independent fork in Variations.

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