Smooth boosted fleet travel

vessels/Fleet.gd

@@ -230,6 +230,7 @@ func teleport_to(world_pos: Vector2) -> void:
 		ship.move_target += displacement
 		ship.velocity = Vector2.ZERO
 		ship.fleet_velocity = Vector2.ZERO
+		ship.reset_physics_interpolation()
 	steer_direction = Vector2.ZERO
 	dash_remaining = 0.0
 	dash_direction = Vector2.ZERO
@@ -242,7 +243,7 @@ func teleport_to(world_pos: Vector2) -> void:
 
 
 func move_in_direction(direction: Vector2) -> void:
-	# Joystick steering. Sets the heading; _process advances the anchor.
+	# Joystick steering. Sets the heading; _physics_process advances the anchor.
 	#
 	# This used to park a target 2000 units ahead and let the ships chase
 	# it. That made formation changes barely register while flying: with
@@ -275,7 +276,13 @@ func is_dashing() -> bool:
 	return dash_remaining > 0.0
 
 
-func _process(delta: float) -> void:
+func is_using_speed_boost() -> bool:
+	return GameState.fleet_speed_multiplier > 1.0 \
+		and steer_direction != Vector2.ZERO and not is_dashing() \
+		and not ships.is_empty()
+
+
+func _physics_process(delta: float) -> void:
 	# #158: a building may pay a local cost out of the hold when the fleet is
 	# actually standing at it, and the autoload has no other way to know
 	# where that is. Written before the early return below - a parked fleet

vessels/Ship.tscn

@@ -6,6 +6,7 @@
 radius = 16.0
 
 [node name="Ship" type="Area2D"]
+physics_interpolation_mode = 1
 script = ExtResource("1")
 
 [node name="CollisionShape2D" type="CollisionShape2D" parent="."]