fix(hud): have game mode hand HUD its target ship instead of group lookup

HUDController found its ship via get_first_node_in_group("ship"), a group
that has 2+ members once a match has an AI opponent — it only worked
because the player ship happened to spawn first. spawn_camera_rig now
wires the HUD's ship the same way it already wires the camera rig's
target.

CLAUDE.md

@@ -59,7 +59,7 @@ The structure was deliberately chosen so an RL-trained AI opponent and, later, m
 - **Ship physics**: all movement is force/torque-based (`_integrate_forces`), not kinematic — inputs become world-space forces/torques relative to ship orientation, with manual drag and speed clamps per tick. Physics formulas are commented inline; see `FLIGHT_MANUAL.md` for the player-facing flight model. Physics properties (mass, inertia, friction material) live in `objects/ship.tscn`, not in `_ready` overrides — keep the scene truthful; RL tuning depends on it.
 - **Surface pull (wall/ceiling grav-plating)**: `ArenaBoundary.get_surface_pull()` is a wall+ceiling-only proximity force field (the floor stays plain default gravity) that `Ship` and `Ball` (`scripts/ball.gd`) each apply in their own `_integrate_forces` with independently-tuned strength/range, discovered via the `"arena_boundary"` group — enabling wall-rides and ceiling shots with no collision-shape changes. Because it runs inside `Ship`'s shared `_integrate_forces`, it reaches trained bots too; see `TRAINING.md` for the retrain this warrants.
 - **Camera** (`scenes/ship_camera_rig.tscn`, `scripts/ship_camera.gd`, group `"ship_camera"`) is spawned by the game mode and given a `target` ship — ships have no camera/HUD dependency, so headless RL runs work (`godot --headless`).
-- **HUD / telemetry pattern**: `Ship` emits flight data via signals only when values change past thresholds (`_last_*` fields, `*_THRESHOLD` constants). `HUDController` (`scripts/HUDController.gd` on `scenes/HUD.tscn`, instanced by each mode's scene) discovers the ship, camera rig, and game mode via groups (`"ship"`, `"ship_camera"`, `"game"`), connects to signals, and only updates labels — no polling. Follow this discovery-by-group + signal-push pattern for new instruments or cross-node communication, not hardcoded `get_node` paths or per-frame polling.
+- **HUD / telemetry pattern**: `Ship` emits flight data via signals only when values change past thresholds (`_last_*` fields, `*_THRESHOLD` constants). `HUDController` (`scripts/HUDController.gd` on `scenes/HUD.tscn`, instanced by each mode's scene) discovers the camera rig and game mode via groups (`"ship_camera"`, `"game"`) but receives its target ship directly from the game mode via `GameMode.spawn_camera_rig` (mirroring the camera rig's `target`, not group lookup — the `"ship"` group can have 2+ members), connects to signals, and only updates labels — no polling. Follow this discovery-by-group + signal-push pattern for new instruments or cross-node communication, not hardcoded `get_node` paths or per-frame polling.
 - **Input actions** are defined in `Game/project.godot` under `[input]` (`move_forward`, `turn_left`, `turbo`, `reset_ball`, etc.) and read only by `PlayerShipController` (plus mode-level `_unhandled_input` for `reset_ball`/`ui_cancel`) — add new controls there rather than hardcoding key checks.
 - Physics engine is Jolt (`Game/project.godot`, `[physics] 3d/physics_engine="Jolt Physics"`).
 

Game/scripts/HUDController.gd

@@ -1,7 +1,9 @@
-# HUD Controller - discovers the ship/camera/game mode via groups and routes
-# their signals to the display widgets. All flight data is rendered by
-# aircraft-style instruments (attitude indicator, heading tape, bar gauges) —
-# this node is only the wiring hub; the instruments are dumb displays.
+# HUD Controller - receives its target ship from the game mode (see
+# GameMode.spawn_camera_rig), discovers the camera rig/game mode via groups,
+# and routes their signals to the display widgets. All flight data is
+# rendered by aircraft-style instruments (attitude indicator, heading tape,
+# bar gauges) — this node is only the wiring hub; the instruments are dumb
+# displays.
 extends CanvasLayer
 class_name HUDController
 
@@ -33,10 +35,11 @@ func _ready():
 	_initialize_hud()
 
 func _initialize_hud():
-	# Find the ship
-	ship = get_tree().get_first_node_in_group("ship")
+	# `ship` is assigned by the game mode (GameMode.spawn_camera_rig) before
+	# this runs — not discovered via group, since the "ship" group can have
+	# 2+ members and there's no reliable way to tell which one is "ours".
 	if not ship:
-		push_error("HUDController: No ship found in 'ship' group")
+		push_error("HUDController: No ship assigned")
 		return
 
 	print("HUDController: Found ship: ", ship.name)

Game/scripts/game_mode.gd

@@ -13,6 +13,7 @@ extends Node3D
 const CAMERA_RIG_SCENE = preload("res://scenes/ship_camera_rig.tscn")
 
 var arena: Arena
+var hud: HUDController
 var ball: RigidBody3D
 var ships: Array[Ship] = []
 var _ship_spawn_transforms := {}
@@ -30,7 +31,8 @@ func _ready():
 	for child in get_children():
 		if child is Arena:
 			arena = child
-			break
+		elif child is HUDController:
+			hud = child
 	if not arena:
 		var path := _get_arena_scene_path()
 		if not path.is_empty():
@@ -99,6 +101,10 @@ func spawn_camera_rig(target: Ship) -> ShipCameraRig:
 	var rig: ShipCameraRig = CAMERA_RIG_SCENE.instantiate()
 	add_child(rig)
 	rig.target = target
+	# Also wires the scene's static HUD (if any) to the same ship, rather
+	# than letting it guess via the "ship" group.
+	if hud:
+		hud.ship = target
 	return rig
 
 

TODO.md

@@ -19,7 +19,7 @@ Bugs found in an adversarial review. None are gameplay- or physics-affecting, so
 - [ ] 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. Derive the aperture constants from the goal's collision shape, the way `goal.gd:53` already measures its own visuals.
 - [x] `match_mode.gd`: full time can fire mid-kickoff-countdown, and the stalled coroutine resumes into the dying scene (can re-emit `kickoff_countdown` / unfreeze bodies for a frame). Guard `_run_kickoff_countdown` with a match-over flag.
 - [x] `match_mode.gd` emits `timer_updated` every frame for a value that changes once a second; the HUD re-formats and re-shapes the label each time. Emit only on change, matching `ship.gd`'s threshold-gated telemetry discipline.
-- [ ] `HUDController` binds to `get_first_node_in_group("ship")` in a group that always has 2+ members — works only because the player ship happens to spawn first. Have the game mode hand the HUD its target ship.
+- [x] `HUDController` binds to `get_first_node_in_group("ship")` in a group that always has 2+ members — works only because the player ship happens to spawn first. Have the game mode hand the HUD its target ship.
 - [ ] Reuse a member `ShipAction` in `ship.gd` (controllerless path) and `player_ship_controller.gd` instead of allocating one per physics tick; `ai_ship_controller.gd` already does this correctly.
 - [ ] Delete the duplicate 1 MB texture — `assets/textures/planet_surface.png` and `assets/models/nebula_planet_planet_surface.png` are byte-identical.