Transport Hub building

Forgejo #18, part 5 of #12. The building only - the vessels that do the
hauling are #19. Placeable, costed at 30, gated behind a new "Freight
Handling" research node hanging off Logistics, with its own info popup,
build-menu glyph and map marker.

Drawn as an octagonal dock ring with berth arms and a squared-off freight
core: deliberately radial-but-flat so it does not read as a small
mothership, which is the only structure with swept arms. Its stationed
transports are NeonPiece children of one rotating holder, per #10 - the
geometry is rasterised once and only the holder's rotation changes, so
the traffic costs no redraws.

Building._draw()'s match has a catch-all that renders anything
unrecognised as a ship crafter, so a missing case is silent and looks
almost right. The test checks for the hub's own _hub_traffic holder
rather than trusting that something plausible appeared - which caught
exactly that: a _ready() patch had silently not applied and the hub was
rendering through the crafter branch.

The build menu grew a third row. Every button, label and price moved:
the old row occupied 332px against a 372px pitch, and three of those do
not fit above a 1280px screen. Rows are now shorter (128px buttons, 40px
price digits) at a 290px pitch, ending at y=1176. Rendered and looked at
- the first attempt tightened the pitch alone and left every price
overlapping the row beneath it, which no headless test would have seen.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/_build_menu_preview.gd

@@ -0,0 +1,20 @@
+extends Node2D
+
+# Preview, not a test. Opens the build menu itself, so the three-row layout
+# added for the Transport Hub (#18) can be checked for fit on the real phone
+# viewport - every button, label and price moved, and a bad offset is
+# invisible to a headless test.
+#
+#   bash tests/screenshot.sh res://tests/_build_menu_preview.tscn /tmp/menu.png 20 720x1280
+
+
+func _ready() -> void:
+	GameState.buildings.clear()
+	GameState.extractors.clear()
+	GameState.rocks = 500
+	# Everything researched, so nothing is greyed out and the whole menu is
+	# legible at full strength.
+	GameState.unlocked = ["shipyards", "logistics", "freight", "coordination"]
+	var main: Node = load("res://Main.tscn").instantiate()
+	add_child(main)
+	main.get_node("UI/BuildMenu").visible = true

tests/_build_menu_preview.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://tests/_build_menu_preview.gd" id="1"]
+
+[node name="BuildMenuPreview" type="Node2D"]
+script = ExtResource("1")

tests/_ingame_buildings_preview.gd

@@ -13,8 +13,9 @@ func _ready() -> void:
 	GameState.buildings.clear()
 	GameState.extractors.clear()
 	GameState.reset_formation()
-	GameState.add_building(GameState.BUILDING_MOTHERSHIP, Vector2(-230.0, 0.0))
-	GameState.add_building(GameState.BUILDING_SHIP_CRAFTER, Vector2(240.0, 0.0))
+	GameState.add_building(GameState.BUILDING_MOTHERSHIP, Vector2(-330.0, 0.0))
+	GameState.add_building(GameState.BUILDING_SHIP_CRAFTER, Vector2(140.0, 0.0))
+	GameState.add_building(GameState.BUILDING_TRANSPORT_HUB, Vector2(480.0, 0.0))
 
 	var main: Node = load("res://Main.tscn").instantiate()
 	add_child(main)
@@ -24,4 +25,4 @@ func _ready() -> void:
 	# far enough to see them whole.
 	main.get_node("Fleet").move_to(Vector2(0.0, 210.0))
 	var cam: Camera2D = main.get_node("Camera2D")
-	cam.zoom = Vector2(1.35, 1.35)
+	cam.zoom = Vector2(1.0, 1.0)

tests/test_transport_hub_building.gd

@@ -0,0 +1,157 @@
+extends SceneTree
+
+# Headless gameplay test: run with
+#   godot --headless -s res://tests/test_transport_hub_building.gd
+# Forgejo #18 (part 5 of #12): the Transport Hub is a placeable building of
+# its own. Only the building here - the vessels that do the hauling are #19.
+#
+# Verifies:
+#   1. it is gated behind its research node, like every other structure
+#   2. researching it makes it buildable, and placing it charges its cost
+#   3. it is drawn as ITSELF, not as the crafter - Building._draw()'s match
+#      has a catch-all that renders anything unrecognised as a ship crafter,
+#      so a missing case is silent and looks almost right
+#   4. its geometry is rasterised ONCE however long it animates (#10), and
+#      its stationed transports really do move
+#   5. it has its own build-menu icon and its own map marker rather than
+#      borrowing another building's - the menu was once unreadable because
+#      two buildings shared a glyph
+
+var game_state: Node
+var scene: Node
+var field: Node
+var controller: Node
+var map_content: Node2D
+var hub: Node2D
+var stage: int = 0
+var elapsed: float = 0.0
+var spin_at_start: float = 0.0
+
+const HUB_AT: Vector2 = Vector2(700.0, 0.0)
+
+
+func _initialize() -> void:
+	game_state = root.get_node("GameState")
+	game_state.buildings.clear()
+	game_state.extractors.clear()
+	game_state.reset_progression()
+	game_state.rocks = 500
+	game_state.fleet_cargo = 0
+	scene = load("res://Main.tscn").instantiate()
+	root.add_child(scene)
+	field = scene.get_node("BuildingField")
+	controller = scene.get_node("BuildController")
+	map_content = scene.get_node("UI/WorldMap/MapContent")
+
+
+func _process(delta: float) -> bool:
+	elapsed += delta
+	match stage:
+		0:
+			scene.get_node("AsteroidField").set_process(false)
+			scene.get_node("EnemySpawner").set_process(false)
+
+			# --- 1. locked until researched ------------------------------
+			if game_state.is_building_unlocked(GameState.BUILDING_TRANSPORT_HUB):
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (buildable with no research at all)")
+				quit(1)
+				return true
+			var gate: String = game_state.research_for_building(GameState.BUILDING_TRANSPORT_HUB)
+			if gate == "":
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (no research node gates it)")
+				quit(1)
+				return true
+			print("locked behind research: '%s'" % gate)
+
+			# --- 5. its own icon, distinct from every other building -----
+			var icons: Dictionary = {}
+			for type in [GameState.BUILDING_MOTHERSHIP, GameState.BUILDING_SHIP_CRAFTER,
+					GameState.BUILDING_COMMAND_CENTER, GameState.BUILDING_TRANSPORT_HUB]:
+				var icon: int = controller._action_icon_for(type)
+				if icons.has(icon):
+					print("TEST_TRANSPORT_HUB_BUILDING: FAIL (%s and %s share an icon)" % [type, icons[icon]])
+					quit(1)
+					return true
+				icons[icon] = type
+			print("action icons distinct across %d buildings" % icons.size())
+
+			# --- 2. research it, then build it ---------------------------
+			game_state.unlocked = ["shipyards", "logistics", "freight"]
+			if not game_state.is_building_unlocked(GameState.BUILDING_TRANSPORT_HUB):
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (still locked after researching '%s')" % gate)
+				quit(1)
+				return true
+			var before: int = game_state.rocks
+			field.place(GameState.BUILDING_TRANSPORT_HUB, HUB_AT)
+			game_state.spend(controller.cost_of(GameState.BUILDING_TRANSPORT_HUB))
+			if game_state.rocks != before - GameState.TRANSPORT_HUB_COST:
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (cost %d charged, expected %d)" % [
+					before - game_state.rocks, GameState.TRANSPORT_HUB_COST
+				])
+				quit(1)
+				return true
+			print("researched and placed for %d ore" % GameState.TRANSPORT_HUB_COST)
+			elapsed = 0.0
+			stage = 1
+			return false
+		1:
+			if elapsed < 0.3:
+				return false
+			for b in field.spawned:
+				if is_instance_valid(b) and b.building_type == GameState.BUILDING_TRANSPORT_HUB:
+					hub = b
+			if hub == null:
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (never spawned)")
+				quit(1)
+				return true
+
+			# --- 3. drawn as itself, not via the crafter catch-all -------
+			# _hub_traffic only exists if _ready() took the transport-hub
+			# branch; a missing case falls through to the crafter and would
+			# leave it null while still rendering something plausible.
+			if hub._hub_traffic == null:
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (rendered through the crafter catch-all, not as a hub)")
+				quit(1)
+				return true
+
+			# --- 5. its own map marker ----------------------------------
+			var markers: Array = map_content.building_markers()
+			var found: bool = false
+			for m in markers:
+				if m.type == GameState.BUILDING_TRANSPORT_HUB:
+					found = true
+					if m.color == map_content.CRAFTER_MARKER_COLOR \
+							or m.color == map_content.MOTHERSHIP_MARKER_COLOR \
+							or m.color == map_content.COMMAND_MARKER_COLOR:
+						print("TEST_TRANSPORT_HUB_BUILDING: FAIL (map marker reuses another building's colour)")
+						quit(1)
+						return true
+			if not found:
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (no map marker - see #11)")
+				quit(1)
+				return true
+			print("has its own map marker")
+
+			spin_at_start = hub._hub_traffic.rotation
+			elapsed = 0.0
+			stage = 2
+			return false
+		2:
+			# --- 4. animates without ever redrawing (#10) ----------------
+			if elapsed < 2.0:
+				return false
+			print("rasterisations after %.1fs: %d" % [elapsed, hub.draw_count])
+			if hub.draw_count != 1:
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (redrew its geometry %d times to animate)" % hub.draw_count)
+				quit(1)
+				return true
+			var spun: float = absf(hub._hub_traffic.rotation - spin_at_start)
+			print("stationed transports turned %.3f rad" % spun)
+			if spun < 0.05:
+				print("TEST_TRANSPORT_HUB_BUILDING: FAIL (nothing moved - a frozen hub trivially passes the redraw check)")
+				quit(1)
+				return true
+			print("TEST_TRANSPORT_HUB_BUILDING: PASS")
+			quit(0)
+			return true
+	return false