transcience/docs/ROADMAP.md

# Status and roadmap

**Read this first when picking up work.** It maps every feature in the design
brief to its current state and the files that implement it, so you can find the
relevant code without re-reading the whole project.

Art and audio source packs, and their licence status, are recorded in
[ASSETS.md](ASSETS.md) — the packs themselves are not in git.

Design decisions that are already settled — and the reasoning behind them — live
in [DECISIONS.md](DECISIONS.md). Check there before asking the user something
that may already have an answer.

Legend: **done** · **partial** (works, with a stated gap) · **todo** (not started)

## Verification surface

What "everything passes" currently means. Numbers move; the shape does not.

| Gate | Covers | Runtime |
| --- | --- | --- |
| `tools/check.sh` | every script parses and type-checks | ~5s |
| `tools/test.sh` | 266 GUT tests, no SceneTree | ~3s |
| `tools/smoke.sh` | 16 assertions over a real ENet socket: handshake, auth, character creation and persistence, portal, escape, hard kill, polite disconnect | ~40s |
| `diag_prediction.tscn` | client-prediction gap, with injected clock drift | ~10s |
| `diag_progression.tscn` | kill → xp → level → health, death → retire → roster, swap guards | ~10s |
| `diag_loot.tscn` | drop → snapshot → pick up → persist → use → drop, and both loot visibilities on the wire | ~10s |

The three diagnostics exist because the smoke test structurally cannot reach
what they cover: bots are poor shots (so they neither level up nor produce
drops), and a listen server cannot drift its own clock against itself.

---

## Stage 1 — World and exploration · *done*

| Feature | State | Where |
| --- | --- | --- |
| Tile grid: movement / bullet / sight blocking | done | [src/sim/map_grid.gd](../src/sim/map_grid.gd) |
| Dungeon generation from (seed, depth) | done | [src/sim/map_gen.gd](../src/sim/map_gen.gd) |
| Hand-authored boss arenas and hub | done | [src/content/rooms.gd](../src/content/rooms.gd) |
| Walls, pillars, pits, barricades | done | `MapGrid.Kind` + the three `BLOCKS_*` tables |
| Enemies placed per room at creation | done | `Instance._populate()` |
| Scrolling camera | done | [src/view/game_scene.gd](../src/view/game_scene.gd) |
| Hard fog of war | done | `WorldView._draw_terrain` / `_visible` |
| Per-peer map streaming (anti map-hack) | done | `ServerRuntime._stream_map` |
| Aggro: range **and** line of sight | done | `SimWorld._aggro_target` |
| Cursor-to-world aiming under a scrolling camera | done | `ClientRuntime.screen_to_world` |
| Boss confined to its room | done | `SimWorld._step_boss` clamps to `SimBoss.room`. A no-op while bosses are stationary — established now so Stage 5's movement cannot quietly break it. |
| Actor interest management | done | `NetCodec.encode_snapshot(world, countdown, for_peer)`; per-peer encode in `ServerRuntime`. Bullet spawns filtered separately, see below. |

### The invariants that matter most here

**Maps are streamed per peer, and the generation seed is never sent.** See
[NETCODE.md](NETCODE.md#maps-are-streamed-never-sent). `MAP_STREAM_RADIUS` must
stay wider than `FOG_VIEW_RADIUS`, or the client predicts movement against
terrain it does not have.

**Three radii, deliberately different, and each has a floor it must respect:**

| Radius | Value | Must exceed | Why |
| --- | --- | --- | --- |
| `FOG_VIEW_RADIUS` | 460 | — | What the player can see. |
| `ACTOR_INTEREST_RADIUS` | 800 | fog radius | Enemies beyond it are never sent. Above the fog radius so nothing pops in at the edge of sight. |
| `MAP_STREAM_RADIUS` | 900 | fog radius | Client predicts movement and simulates bullets against terrain it cannot see. |
| `BULLET_INTEREST_RADIUS` | 2200 | longest bullet travel + fog radius | A bullet is announced once at spawn. Withhold one that later flies into view and it becomes invisible damage. `test_interest.gd` computes the floor from real content, so a faster bullet fails a test instead. |

Fog is a *rendering* rule and defends nothing on its own — a modified client
draws whatever it holds. The defence is what the server declines to send.

---

## Art and audio · *first pass done*

Placeholders are gone: terrain, actors and bullets are sprites, and four sounds
play off server events. Enough to prove the pipeline, not a finished look.

| Feature | State | Where |
| --- | --- | --- |
| Atlas/sound table in one place | done | [src/view/art.gd](../src/view/art.gd) |
| Terrain, actors, boss from the 0x72 atlas | done | `WorldView._draw_tile` / `_draw_sprite` |
| Animated bullet sprites, one MultiMesh per kind | done | [src/view/bullet_renderer.gd](../src/view/bullet_renderer.gd) |
| SFX pool driven by server events | done | [src/view/sfx.gd](../src/view/sfx.gd) |
| Rects validated without a display | done | `tests/unit/test_art.gd` |
| Impact/death VFX animation | todo | `Art.IMPACT` is loaded and validated but nothing plays it yet |
| Directional sprites, hit flashes, screen shake | todo | |
| Audio buses and a volume setting | todo | Everything plays on Master at hardcoded dB |
| **In-game credits screen** | **todo** | Not cosmetic: the SFX are CC BY 4.0 and attribution is a licence *requirement*. [CREDITS.md](../CREDITS.md) is not reachable by a player. |
| Replace the two non-redistributable packs | todo | Bullet and FX art is local-only and non-commercial. CC0 replacements would let them into the repo and unblock a commercial release. See [ASSETS.md](ASSETS.md). |

## Stage 2 — Characters, persistence, levels · *done*

| Feature | State | Where |
| --- | --- | --- |
| Steam-shaped identity abstraction | done | [src/meta/auth_provider.gd](../src/meta/auth_provider.gd), [local_auth_provider.gd](../src/meta/local_auth_provider.gd) |
| Character store, JSON, survives restart | done | [src/meta/character_store.gd](../src/meta/character_store.gd) |
| Up to 5 living characters, random colour | done | `CharacterStore.MAX_ACTIVE`, `Character.create` |
| Last-played auto-selected on login | done | `CharacterStore.last_played` |
| Permadeath → retired, never deleted | done | `ServerRuntime._on_player_died` |
| Roster screen: pick or create | done | [src/ui/character_select.gd](../src/ui/character_select.gd) |
| Levels 1–15, +10 max HP each | done | [src/meta/progression.gd](../src/meta/progression.gd) |
| XP from kills, bosses worth far more | done | `ServerRuntime._award_kill` |
| Colour visible in world and on the HUD | done | snapshot carries it; `WorldView._draw_ship` tints |
| Swap character from the hub | done | Esc menu → Change character; refused server-side in a dungeon |
| XP percentage to next level | done | `HUD._draw_xp_bar`, fed live from the snapshot |
| Dead characters hidden from the roster | done | `ServerRuntime._send_characters` sends living only |
| Suggested name when creating | done | `Character.random_name` |
| Passive health regeneration | done | `SimPlayer.regenerate`, 0.5%/s of maximum |

Verified end to end by `tools/diag_progression.tscn`, which drives the real
server through kill → xp → level → health and death → retire → roster. That
path cannot be covered by the bot smoke test, because bots are poor shots.

### Still open in this area

- **The local identity provider is insecure by design.** Any client can claim
  any account id. Fine for a LAN; must be replaced before the game is reachable
  from the internet. Swapping in Steam is one `AuthProvider` subclass and no
  schema change.
- `--account` and `--store` exist so several clients and test runs can coexist
  on one machine. A real provider makes `--account` unnecessary.

## Stage 3 — Inventory and loot · *done*

| Feature | State | Where |
| --- | --- | --- |
| 4 slots, permanently on screen | done | `SimConfig.INVENTORY_SLOTS`, `HUD._draw_inventory` |
| Items defined as data, not code | done | [src/content/items.gd](../src/content/items.gd), [src/actors/items/item_def.gd](../src/actors/items/item_def.gd) |
| Loot tables on enemies and bosses | done | `EnemyDef.loot` / `BossDef.loot`, rolled in `SimWorld._drop_loot` |
| Health potion, rare from trash | done | `Content.TRASH_POTION_CHANCE` = 0.08 |
| …guaranteed from the boss | done | `Content.warden()` loot table, chance 1.0 |
| World-shared loot | done | `SimLoot.owner_peer == 0` |
| Player-instanced loot | done | one `SimLoot` per living player, filtered per peer in `NetCodec.encode_snapshot` |
| Warden's Ration — useless, instanced | done | `Items.wardens_ration()` |
| Pick up, use, drop | done | `SimWorld._try_pickup` / `_use_slot` / `_drop_slot` |
| Inventories persist | done | stored on `Character`, written by `ServerRuntime._persist_inventory` |
| Ground loot drawn with a pickup prompt | done | `WorldView._draw_loot`, `HUD._draw_pickup_prompt` |

Controls: **E** picks up, **1–4** use a slot, **shift+1–4** drop one.

### The decisions worth knowing before touching this

**Item actions ride the input frame; they are not new messages.** `InputFrame`
gained `BTN_USE`, `BTN_DROP` and a slot byte. That buys the redundancy that
covers a dropped packet, the replay guard on `last_input_tick`, ordering against
movement on the same tick, and a natural rate limit of one action per tick — all
of which a separate reliable RPC would have needed bolted back on.

**Item actions are edge-triggered; movement and fire are not.** The client
repeats its last few frames every tick and a starved server coasts on the last
one it was given, so a level-triggered read empties the whole inventory in four
ticks. `SimPlayer.prev_buttons` and `prev_slot` hold the edge, and the *slot* is
part of it — tapping 2 while 1 is held is a second, distinct action.

**Instanced loot is enforced on the wire, not in the client.** A peer is never
told another player's copy exists. That makes it an interest-management rule of
the same kind as `ACTOR_INTEREST_RADIUS`, and it is why the ration is worth
having: every boss kill exercises the path.

**Anything dropped becomes world-shared, even if it arrived instanced.** That is
what makes dropping worth having — a trophy you do not want should be able to
reach someone who does.

**A potion at full health is refused rather than spent.** Nobody drinks one on
purpose at full health, so a mistimed keypress must not do it for them.

**A full bag leaves the item on the floor** and does not block the portal, which
shares the interact key.

### Known gaps

- **Nothing sells items.** Loot only comes from kills; the hub has no source.
  The Stage 4 upgrade NPC is the natural place, and is the reason this is a gap
  rather than a decision.
- **No stacking.** Four potions take four slots. A count byte per slot is cheap
  to add; nothing needed it yet, so the wire, the save record and the HUD all
  stayed simpler for not having one.
- **Ground loot never expires**, it is only capped at
  `SimConfig.MAX_LOOT_PER_INSTANCE` per world, oldest evicted. Dungeons close
  and take their litter with them; only the hub can realistically reach the cap.
- **The ration draws as a gold flask.** The tileset has no food sprite. See
  [ASSETS.md](ASSETS.md).

---

## Stage 4 — Upgrades · *todo, blocked on decisions*

**Do not start this without answering the open questions below.** The damage
formula in particular determines the shape of every upgrade.

### The mechanism

- An NPC in the hub. Each level gained grants one choice.
- The choice offers **3 random upgrades**.
- **Every upgrade also carries a +5% damage buff, additive** ("adaptively
  scaling" in the brief — read as additive, confirm if wrong).
- The choice screen must show that buff **and** all the upgrade's other effects.
- A separate screen lists the upgrades already taken.

### The upgrades, as specified

| Upgrade | Rarity | Effect |
| --- | --- | --- |
| Split shot | common | Hitting an enemy spawns 2 of the same bullet at a 45° angle behind the enemy. A shot cannot split twice unless the upgrade is taken again. |
| Glass cannon | common | +100% damage, −50% health. |
| Spread | common | Adds 2 side projectiles in a cone. −10% damage. |
| Sniper | common | 2× damage (**multiplicative, not additive**), 0.5× fire rate, 2× bullet speed. |
| Doubleshot | rarer than common | Adds 1 projectile firing parallel to the others. −50% damage. |
| Poison | rare | Each projectile deals an additional 50% of its damage over the next 10 seconds. |
| Eraser | legendary | Shots have a 1% chance to delete a projectile they pass through. |

Upgrades stack — "cannot split twice *unless upgraded again*" says so directly.

### What this implies

Damage is currently the constant `SimConfig.PLAYER_BULLET_DAMAGE`. It becomes a
per-player computed stat, so `SimWorld._fire_player_shot` grows a stats block.
Split, spread and doubleshot all change how many bullets a shot produces, so
they belong in the same place.

Two constraints already pinned by tests that upgrades will collide with:

- **Sniper doubles bullet speed.** `test_bullet_speeds_stay_below_the_tunnelling_threshold`
  asserts that even at 2× a bullet stays under one tile per tick. Stacking two
  snipers would break wall collision, so the multiplier needs a ceiling.
- **Longer/faster bullets widen `BULLET_INTEREST_RADIUS`.** `test_interest.gd`
  recomputes the floor from live content; upgrades change bullet travel *per
  player*, which that test does not currently model.

---

## Stage 5 — Boss features and new bosses · *todo*

| Feature | State |
| --- | --- |
| Stationary phases | done — every current phase |
| Boss confined to its room | done — `SimWorld._step_boss` clamps to `SimBoss.room` |
| Roaming / chasing within the boss room | todo |
| Phases that move to preset locations | todo |
| Attacks spawned at a distance with a telegraph indicator | todo — a new event type plus a renderer, and it must survive fog |
| More bosses | partial — `Rooms.choir_vault()` is authored but has no `BossDef` |

The boss format is proven: `tests/unit/test_boss.gd` builds one from scratch and
asserts the simulation needs no changes to run it. Movement is the first thing
that format has not covered, so expect `BossPhase` to gain a movement field
rather than `SimWorld` gaining a per-boss branch.

Remember boss rooms **do not lock** (a settled decision): a player can always
walk out, and the boss cannot follow. Fights cannot rely on trapping anyone.

---

## Deliberate omissions

Not oversights — each was considered and rejected for now, with the reasoning in
[NETCODE.md](NETCODE.md) or [DECISIONS.md](DECISIONS.md):

- **Lag compensation.** Rewinding to a shooter's view means a player who dodged
  still gets hit; wrong trade for this genre.
- **Snapshot delta compression.** Fine at current actor counts.
- **DTLS / encryption.** `ENetMultiplayerPeer` supports it. Required before any
  public server, not before then.
- **Pattern-level bullet replication.** A real bandwidth win that couples the
  client to emitter behaviour.
- **`MultiplayerSynchronizer` / `MultiplayerSpawner`.** Right tools, wrong shape
  for a bullet hell — see [ARCHITECTURE.md](ARCHITECTURE.md).

---

## Open questions for the user

Genuinely unspecified. **Do not guess at these** — each changes the design, and
several have no obvious default.

### Blocking Stage 4 (upgrades)

1. **Damage stacking order.** Sniper is explicitly multiplicative; the +5% per
   upgrade and the ± percentages read as additive. Is it
   `base × (1 + Σ additive) × Π multiplicative`, or something else?
2. **Rarity weights** for common / rarer / rare / legendary.
3. **Split shot geometry** — ±22.5° from the original heading (45° total), or
   45° to each side (90° total)?
4. **Poison stacking** — do applications stack, or does a new hit refresh one
   damage-over-time effect?
5. **Eraser's target** — does it delete *enemy bullets* it passes through?
6. **Do unclaimed level-ups queue?** Reaching level 4 and 5 inside one run:
   two pending choices at the NPC, or one?
7. **Glass cannon's −50% health** — of base HP, or of the character's levelled
   maximum?

### Blocking nothing yet

8. **What advances dungeon depth?** `--depth` is a dev flag; nothing raises it
   in play. Depth drives map size and could drive difficulty and rewards.
9. **Where do items come from outside a dungeon?** Loot only drops from kills.
   If the hub should sell potions, that is the Stage 4 NPC's second job — and
   it needs a currency, which the game does not have.
10. **Should items stack?** Four potions currently take four slots, which makes
    a 4-slot bag small. Stacking is a count byte per slot plus a rule for
    splitting one; neither is hard, but both change the UI.
11. **Attribution for four asset packs.** See [ASSETS.md](ASSETS.md) — two are
    non-redistributable and local-only, and there is no in-game credits screen
    yet, which CC BY 4.0 requires for the audio.