# TODO

Deferred work, in rough priority order. The current architecture (ShipAction/ShipController seam, Arena/GameMode split, code-driven spawning, group-tagged ball/goals) was chosen specifically so these bolt on without rework.

## AI opponent (reinforcement learning)

The training pipeline is built — see `TRAINING.md` (self-play PPO via the vendored godot_rl_agents bridge, JSON policy export, in-game GDScript inference, eval ladder). Remaining:

- [ ] Long training runs on the Linux/3090 box to produce actually-good bots; promote further checkpoints into `Game/bots/promoted/` as `medium`/`hard` tiers once they clear `easy.json` in `evaluate.py`.
- [ ] Frozen-opponent league: train the live policy against a *pool* of past exported checkpoints, sampled per-episode (today's `--opponent-mode=frozen` only supports one fixed model per run) to prevent self-play strategy collapse on long runs.
- [ ] Richer state setter / curriculum: aerial states, wall plays, rebound scenarios as skill grows (beyond the score/defend/draw staging already in place).

## Correctness

Bugs found in an adversarial review. None are gameplay- or physics-affecting, so all are safe to land against the current `Game/bots/` checkpoints.

- [x] ~~Goal scoring volume (3.5 x 1.5, `objects/goal.tscn`) is smaller than the drawn mouth (3.7 x 1.65, `ArenaBoundary.GOAL_APERTURE_*`) — a ball crossing the visible edge doesn't score.~~ Fixed: `GOAL_APERTURE_HALF_WIDTH`/`HEIGHT` now match the sensor exactly (1.75/1.5).
- [ ] Delete the duplicate 1 MB texture — `assets/textures/planet_surface.png` and `assets/models/nebula_planet_planet_surface.png` are byte-identical.

## Performance

- [ ] Measure `nebula_dust.gdshader`'s per-fragment depth-texture sample across 500 large soft billboards before adding more particle work.
- [x] ~~Bake `ArenaBoundary`'s ~160 runtime-generated `CollisionShape3D` nodes into the scene.~~ Done: `ArenaBoundary.bake_colliders()` + `Game/tools/bake_arena_boundary.gd` (re-run after any future geometry change). `_ready()` self-heals — skips regenerating when a bake already matches the current `goal_mode`, regenerates at runtime otherwise (e.g. the `_elevated` arena variants, not yet baked).

## Presentation / AAA polish

The largest gap between this and a AAA-feeling product is presentation, not code. Sequenced after the above for pragmatic reasons, but this is the highest impact per hour.

- [ ] **Audio — there is none.** Zero sound files, zero `AudioStreamPlayer` nodes, no bus layout. Needs: engine hum pitched to throttle, turbo whoosh, ball impacts scaled by collision impulse, wall scrapes, goal explosion, crowd bed, UI clicks, countdown beeps, music. Can be driven off `Ship`'s existing telemetry signals.
- [ ] SSAO/SSIL in the arena Environments — cheapest single perceived-quality win available; grounds the ships against the deck and gives the fillets and goal recesses real depth.
- [ ] VFX on anything that moves: `EngineGlowL/R` are static meshes that don't respond to throttle. No thruster plume, turbo flame, ball trail, impact sparks or goal burst. `arena_02` is the only scene with any particles at all.
- [ ] Impact feedback — screen shake, hit-stop, flash, controller rumble on ball contact.
- [ ] Camera feel in `ship_camera.gd` — fixed distance/height/FOV today. Speed-based FOV widening, turbo kick, impact shake.
- [ ] Goal celebration sequence: today it's a `print()` and a label scale-pop. Wants an explosion, team-tinted screen flash, camera cut, slow-mo, title card. `HUDController`'s `ResultOverlay` animation is a reasonable template.
- [ ] Local lighting / LightmapGI bake — two directional lights and low ambient, no local lights anywhere. `arena_deck.gdshader`'s `hull_fill` uniform is explicitly a "stand-in for bounce light", i.e. the shader is compensating for lighting that isn't there. The arena is fully static, so a bake is viable; retire `hull_fill` afterwards.
- [ ] Dress `arena_03` — its `Decoration` node is empty, while `arena_02` has stations, debris, a planet and volumetric dust.
- [ ] Custom font + a real `Theme` resource for the HUD. The procedural instruments are well-engineered, but `ThemeDB.fallback_font` at 10-13 px reads as a debug overlay.
- [ ] Post-processing beyond glow: DoF, motion blur, vignette, chromatic aberration on turbo.

## Resolved — trained-bot compatibility (2026-08-05 retrain-from-scratch reset)

The four items below all took their architecturally-correct form instead of their zero-risk form, since `Game/bots/promoted/*.json` are being retrained from scratch anyway (those two checkpoints are left in place and are expected to go stale, not migrated). Scoped up further mid-implementation to a genuine 5v5 ceiling with a proportionally resized arena, since the observation-space plumbing is the expensive part to redo twice.

- [x] **Per-tick drag** (`ship.gd`) — delta-scaled via `_tick_scaled(k, state.step)`, invariant to `physics_ticks_per_second`.
- [x] **Goal aperture** — real navigable hole cut into each end wall's collision (`ArenaBoundary._build_end_wall_colliders`), sized to the actual scoring sensor and correct for both FLOOR and ELEVATED goal modes.
- [x] **Collider bake** — done alongside the geometry changes above (see Performance).
- [x] **Beyond 1v1** — `ShipObservations` now takes padded teammate/opponent arrays (`MAX_TEAMMATES=4`, `MAX_OPPONENTS=5`, `SIZE=83`), ordered by a new persistent `Ship.spawn_index` so slots never reorder mid-match. `training_mode.gd`/`match_mode.gd` gained a `team_size` export (default 1, so existing 1v1 behaviour is unchanged) and the arena was resized 1.5x to fit 5v5. This pass is plumbing only: no 2v2+ curriculum, no team-play reward design, and no match-mode UI to pick team size — those are still open work.

## Multiplayer (long term)

- [ ] `RemoteShipController extends ShipController` — feeds replicated `ShipAction`s from a network peer into the local ship simulation.
- [ ] Networked `GameMode` subclass: per-peer ship spawning (MultiplayerSpawner or custom), authoritative server for ball/score.
- [ ] C# backend / online servers per README roadmap (not started).
- [ ] Possible v0.2 split-screen: spawn one `ship_camera_rig` + viewport per local player (camera is already outside the ship scene to allow this).