506d07be5d
Roads are a jittered 7x7 grid with ~a quarter of the edges thinned out, kept connected. The loops are the point: "take a different road" is not a decision without alternative routes. Every metre driven adds heat to that segment; all roads shed it slowly. Crossing a threshold escalates Clear -> Patrol -> Barricade -> Turret, each of which puts real obstructions on the tarmac. Hysteresis stops a road on a boundary from rebuilding its barricade every few seconds. Level changes are deferred while the car is on the segment. Building a barricade around the player would spawn a static collider inside the chassis, and the player is meant to discover escalation by returning to a road, not by watching it assemble behind them. Checkpoint positions are seeded from the segment id, so a stretch of road always fortifies in the same place — recognising it is part of learning the map. Scenery now avoids the tarmac and the car spawns at a junction. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
121 lines
5.3 KiB
Markdown
121 lines
5.3 KiB
Markdown
# Drive Between the Lines — prototype
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Endless driving survival game.
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- **Phase 0** — a drivable car with persistent wear that is felt through the wheel.
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- **Phase 1** — a road network whose roads remember being driven, and escalate.
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## Running
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```bash
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npm run dev
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```
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Then open http://localhost:5173. Append `?seed=anything` to regenerate the world —
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seeds may be numbers or words.
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| | |
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|---|---|
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| `W` / `S` | throttle / brake-reverse |
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| `A` / `D` | steer |
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| `Space` | handbrake (rear wheels only) |
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| `R` | respawn the car — **does not** repair it |
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```bash
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npm test # sim + headless physics
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npm run build # typecheck + production bundle
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```
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## Road heat
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Every metre driven on a road adds heat to that segment; every road everywhere
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sheds it slowly. Cross a threshold and the road escalates:
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`Clear → Patrol → Barricade → Turret`
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- **Patrol** parks a vehicle on the verge. The road narrows.
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- **Barricade** puts concrete across it, leaving a gap you have to slow for.
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- **Turret** adds a tower overlooking the checkpoint.
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Roughly four traversals take a road from clear to turret; an untouched road
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cools off in about four minutes. Both numbers are in `sim/heat.ts` and both are
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guesses meant to be tuned.
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Three things are deliberate:
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- **No AI yet.** The props are stationary hazards. Escalation currently means the
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road gets slower and more expensive to get wrong, which is enough to test the
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phase's real question.
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- **Changes never happen on the road you are on.** They are deferred until you
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leave. Otherwise a barricade would spawn a static collider inside your car —
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and you are supposed to discover escalation by *coming back*, not by watching
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it assemble behind you.
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- **A checkpoint's position is seeded from its segment**, so a given stretch of
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road always fortifies in the same place. Recognising it is part of learning
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the map.
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The road network is a jittered grid with roughly a quarter of its edges removed,
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keeping the whole thing connected. The loops are the point: "take a different
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road this time" is not a decision unless alternative routes exist.
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## Layout
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The one rule worth keeping: **`src/sim/` imports neither three.js nor Rapier.**
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Phases 1–4 (heat, regions, front lines, quests) are all simulation, and keeping
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them engine-free is what makes them unit-testable and fast-forwardable — you can
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run a hundred simulated days in milliseconds to tune an escalation curve without
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ever opening a browser.
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```
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src/
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sim/ pure model — roads, heat, world generation, condition → handling
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physics/ Rapier world, raycast vehicle, input → wheel forces
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render/ three.js scene, roads, chase camera
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core/ fixed-timestep loop, seeded RNG, keyboard
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ui/ debug HUD
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carSpec.ts shared car dimensions, so body and mesh cannot drift apart
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heatProps.ts integration layer: heat levels → colliders + meshes
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```
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`heatProps.ts` sits at the top level on purpose — it is the one module allowed to
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touch both Rapier and three.js, because it owns objects that must exist in both
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or neither. Its tests run headless: three.js scene graphs work fine in Node, so
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"the barricade's collider was removed along with its mesh" is a unit test.
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Data flows one way: `sim` → `physics` → `render`. Condition reaches the physics
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layer already digested into a `Handling` by `deriveHandling`, so there is exactly
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one place where "how broken the car is" turns into "how it drives".
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## Notes on the state of it
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- **The car handles like a placeholder.** Suspension, grip, and engine numbers in
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`physics/physics.ts` and `sim/car.ts` are first guesses that pass a smoke test,
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not something tuned by feel. That tuning *is* Phase 0's verification gate.
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- **Wear rates are deliberately aggressive** so decline is visible in minutes
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rather than hours. Turn them down in `applyWear` once the curve reads right.
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- **No interpolation** between physics steps. Fine at 60 Hz; revisit if the step
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rate changes.
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- **Condition and heat are not yet persisted** across reloads. IndexedDB comes
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with the campaign layer.
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- **Heat has no diegetic signal at a distance.** You learn a road is hot by
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arriving at the checkpoint. The brief wants it readable from patrol density and
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wreckage before you commit — that needs the enemy presence Phase 5 brings.
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- **The heat HUD lines are debug scaffolding.** The brief is explicit that no
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numeric heat meter ships; they exist to tune the curve and should come out.
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- **Bundle:** ~2.7 MB raw / ~945 KB gzipped, dominated by Rapier's WASM, which
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`rapier3d-compat` inlines as base64. Switching to the non-compat `@dimforge/rapier3d`
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package serves the WASM as a separate file (~570 KB gzipped, compiled in
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parallel with the JS) at the cost of extra Vite plugin config. Worth doing
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before anyone but you plays it; not worth doing now.
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## Next
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Phase 1's gate: **you catch yourself avoiding a road because of its history, not
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its distance.** That cannot be checked by a test — it needs you driving the same
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routes for a while and noticing what you start doing.
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If it fails, the likely culprits, in order: escalation is too slow to matter
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within a session (`METRES_PER_HEAT`), decay is so fast that nothing accumulates
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(`DECAY_PER_SECOND`), or the props are not actually inconvenient enough to route
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around. Tune before building Phase 2 on top.
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