Support gas cargo transfers

BuildController.gd

@@ -133,6 +133,8 @@ var lab_building_id: int = 0
 @onready var to_fleet_batch_button: IconButton = get_node("../UI/TransferMenu/ToFleetBatchButton")
 @onready var to_fleet_batch_label: Label = get_node("../UI/TransferMenu/ToFleetBatchLabel")
 @onready var to_fleet_all_button: IconButton = get_node("../UI/TransferMenu/ToFleetAllButton")
+@onready var gas_to_building_button: IconButton = get_node("../UI/TransferMenu/GasToBuildingButton")
+@onready var gas_to_fleet_button: IconButton = get_node("../UI/TransferMenu/GasToFleetButton")
 
 # Every building menu carries the same header (#24). Held as a list because
 # the only thing any of them needs is to be told which building it is
@@ -253,6 +255,8 @@ func _ready() -> void:
 	to_building_all_button.pressed.connect(_on_transfer.bind(true, ALL))
 	to_fleet_batch_button.pressed.connect(_on_transfer.bind(false, GameState.CARGO_LOAD_BATCH))
 	to_fleet_all_button.pressed.connect(_on_transfer.bind(false, ALL))
+	gas_to_building_button.pressed.connect(_on_gas_transfer.bind(true))
+	gas_to_fleet_button.pressed.connect(_on_gas_transfer.bind(false))
 
 	formation_close_button.pressed.connect(func(): formation_menu.visible = false)
 	formation_reset_button.pressed.connect(_on_reset_formation)
@@ -1002,6 +1006,11 @@ func _on_transfer(to_building: bool, amount: int) -> void:
 		transfer_status.text = "Loaded %d ore into the fleet" % moved
 	_refresh_transfer()
 
+func _on_gas_transfer(to_building: bool) -> void:
+	var moved: int = GameState.transfer_gas_to_building(transfer_building_id, ALL) if to_building else GameState.transfer_gas_to_fleet(transfer_building_id, ALL)
+	transfer_status.text = "Moved %d gas" % moved if moved > 0 else "No gas available on that side"
+	_refresh_transfer()
+
 
 func _transfer_place_name() -> String:
 	var b: Dictionary = GameState.find_building(transfer_building_id)
@@ -1037,6 +1046,10 @@ func _refresh_transfer() -> void:
 	for button in [to_building_batch_button, to_building_all_button,
 			to_fleet_batch_button, to_fleet_all_button]:
 		button.queue_redraw()
+	gas_to_building_button.enabled = GameState.fleet_gas_cargo > 0
+	gas_to_fleet_button.enabled = GameState.building_gas_holdings(transfer_building_id) > 0
+	gas_to_building_button.queue_redraw()
+	gas_to_fleet_button.queue_redraw()
 
 
 func _refresh_queue() -> void:

GameState.gd

@@ -42,10 +42,14 @@ var gas: int = 0
 # down and rebuilt on every trip to a planet's surface - and cargo mined ON a
 # surface would otherwise be dropped the moment the player took off.
 var fleet_cargo: int = 0
+var fleet_gas_cargo: int = 0
 
 func collect_cargo(amount: int = 1) -> void:
 	fleet_cargo += amount
 
+func collect_gas_cargo(amount: int = 1) -> void:
+	fleet_gas_cargo += amount
+
 
 # The batch size the transfer menu offers, next to "All". A batch rather
 # than only all-or-nothing: the hold is the part that can be lost, and
@@ -73,6 +77,11 @@ func building_holdings(id: int) -> int:
 		return rocks
 	return int(b.get("stock", 0))
 
+func building_gas_holdings(id: int) -> int:
+	var b: Dictionary = find_building(id)
+	if b.is_empty(): return 0
+	return gas if b.type == BUILDING_MOTHERSHIP else int(b.get("gas_stock", 0))
+
 
 func transfer_to_building(id: int, amount: int) -> int:
 	# Hold -> this building. Returns how much actually moved, which is capped
@@ -108,6 +117,24 @@ func transfer_to_fleet(id: int, amount: int) -> int:
 	fleet_cargo += moved
 	return moved
 
+func transfer_gas_to_building(id: int, amount: int) -> int:
+	var b: Dictionary = find_building(id)
+	if b.is_empty(): return 0
+	var moved := mini(amount, fleet_gas_cargo)
+	fleet_gas_cargo -= moved
+	if b.type == BUILDING_MOTHERSHIP: gas += moved
+	else: b.gas_stock = int(b.get("gas_stock", 0)) + moved
+	return moved
+
+func transfer_gas_to_fleet(id: int, amount: int) -> int:
+	var b: Dictionary = find_building(id)
+	if b.is_empty(): return 0
+	var moved := mini(amount, building_gas_holdings(id))
+	if b.type == BUILDING_MOTHERSHIP: gas -= moved
+	else: b.gas_stock = int(b.get("gas_stock", 0)) - moved
+	fleet_gas_cargo += moved
+	return moved
+
 const MOTHERSHIP_COST: int = 20
 const SHIP_CRAFTER_COST: int = 12
 const SHIP_COST: int = 6

GasVentField.gd

@@ -12,7 +12,7 @@ func _process(delta: float) -> void:
 		if fleet.get_centroid().distance_to(vent) < 90.0:
 			progress += delta
 			if progress >= 1.0:
-				GameState.gas += int(progress)
+				GameState.collect_gas_cargo(int(progress))
 				progress = fmod(progress, 1.0)
 			return
 	progress = 0.0

IconButton.gd

@@ -26,6 +26,7 @@ enum Icon {
 	UPGRADE_SHIELD_HITS, UPGRADE_SHIELD_RECHARGE, UPGRADE_CARGO,
 	UPGRADE_ENGINES, UPGRADE_UNLOCK_SHIELD,
 	ACTION_MENU,
+	GAS,
 }
 
 # Size the glyphs were originally drawn against. Every glyph dimension is
@@ -200,6 +201,8 @@ func _draw() -> void:
 			_draw_upgrade_unlock_shield(center, pulse, s)
 		Icon.ACTION_MENU:
 			_draw_action_menu(center, pulse, s)
+		Icon.GAS:
+			_draw_gas(center, pulse, s)
 
 
 func _draw_close(center: Vector2, pulse: float, s: float) -> void:
@@ -334,6 +337,15 @@ func _draw_action_menu(center: Vector2, pulse: float, s: float) -> void:
 			center + Vector2(-15, y + 2) * s,
 		]), _active_color(), pulse, core_color)
 
+func _draw_gas(center: Vector2, pulse: float, s: float) -> void:
+	# Three drifting bubbles: the visual language for gaseous resources.
+	for data in [[Vector2(-6,-3), 6.0], [Vector2(6,4), 8.0], [Vector2(4,-9), 4.0]]:
+		var ring := PackedVector2Array()
+		for i in range(10):
+			var a := TAU * float(i) / 10.0
+			ring.append(center + (data[0] + Vector2(cos(a), sin(a)) * data[1]) * s)
+		NeonDraw.draw_glowing_polygon(self, ring, _active_color(), pulse, core_color)
+
 
 func _draw_build(center: Vector2, pulse: float, s: float) -> void:
 	# A plus inside a frame - "add a structure".

Main.tscn

@@ -1615,6 +1615,38 @@ script = ExtResource("10")
 icon = 1
 glow_color = Color(1, 0.78, 0.25, 1)
 
+[node name="GasToBuildingButton" type="Control" parent="UI/TransferMenu"]
+anchor_left = 0.5
+anchor_right = 0.5
+offset_left = -180
+offset_right = -32
+offset_top = 1020
+offset_bottom = 1168
+script = ExtResource("10")
+icon = 25
+glow_color = Color(0.85, 0.52, 1, 1)
+
+[node name="GasToFleetButton" type="Control" parent="UI/TransferMenu"]
+anchor_left = 0.5
+anchor_right = 0.5
+offset_left = 32
+offset_right = 180
+offset_top = 1020
+offset_bottom = 1168
+script = ExtResource("10")
+icon = 25
+glow_color = Color(0.85, 0.52, 1, 1)
+
+[node name="GasTransferLabel" type="Label" parent="UI/TransferMenu"]
+mouse_filter = 2
+anchor_right = 1.0
+offset_top = 1172
+offset_bottom = 1222
+text = "GAS: unload all                 load all"
+horizontal_alignment = 1
+theme_override_colors/font_color = Color(0.85, 0.52, 1, 1)
+theme_override_font_sizes/font_size = 22
+
 [node name="FormationMenu" type="Control" parent="UI" groups=["modal_menus"]]
 visible = false
 mouse_filter = 2

ResourceBar.gd

@@ -93,7 +93,7 @@ func _layout() -> void:
 
 
 func _process(_delta: float) -> void:
-	_gas_caption.text = "GAS %d" % GameState.gas
+	_gas_caption.text = "GAS %d / %d / %d" % [GameState.gas, GameState.fleet_gas_cargo, GameState.building_gas_holdings(building_id)]
 	_numbers[0].set_amount(GameState.rocks)
 	_numbers[1].set_amount(GameState.fleet_cargo)
 

tests/test_gas_system.gd

@@ -51,6 +51,11 @@ func _process(delta: float) -> bool:
 		game_state._arrive(game_state.transporters[0])
 		if game_state.gas != game_state.transporter_load_limit() or game_state.rocks != 0:
 			return _fail("gas delivery banked gas=%d ore=%d" % [game_state.gas, game_state.rocks])
+		var mothership_id: int = int(game_state.buildings[0].id)
+		if game_state.transfer_gas_to_fleet(mothership_id, 7) != 7 or game_state.fleet_gas_cargo != 7:
+			return _fail("could not load banked gas into fleet cargo")
+		if game_state.transfer_gas_to_building(2, 7) != 7 or game_state.building_gas_holdings(2) != 7:
+			return _fail("could not unload fleet gas into a building")
 		print("gas giant animated; transporter banked %d gas without creating ore" % game_state.gas)
 		print("TEST_GAS_SYSTEM: PASS")
 		quit(0)