feat: add animated net gathering

tests/gathering_marker_surface_validation.gd

@@ -0,0 +1,66 @@
+extends SceneTree
+
+const PlayerScene: PackedScene = preload("res://player/player.tscn")
+const GatheringControllerType = preload(
+	"res://gathering/gathering_controller.gd"
+)
+
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+
+func _run() -> void:
+	var player := PlayerScene.instantiate() as Player
+	root.add_child(player)
+	player.set_process(false)
+	player.set_physics_process(false)
+
+	var controller := GatheringControllerType.new()
+	root.add_child(controller)
+	controller.set("_player", player)
+
+	var wall := _make_surface(
+		Vector3(2.0, 2.0, 0.1),
+		Vector3(0.0, 0.9, -1.5),
+	)
+	root.add_child(wall)
+	await physics_frame
+	controller.call("_update_marker_target")
+	var marker := controller.get("_marker") as MeshInstance3D
+	assert(marker != null)
+	assert(bool(controller.get("_marker_has_surface")))
+	assert(marker.global_basis.y.dot(Vector3.BACK) > 0.99)
+
+	wall.queue_free()
+	await process_frame
+	var floor := _make_surface(
+		Vector3(10.0, 0.2, 10.0),
+		Vector3(0.0, -0.1, -1.7),
+	)
+	root.add_child(floor)
+	await physics_frame
+	controller.call("_update_marker_target")
+	assert(bool(controller.get("_marker_has_surface")))
+	assert(marker.global_basis.y.dot(Vector3.UP) > 0.99)
+	assert(is_equal_approx(absf(marker.global_basis.determinant()), 1.0))
+
+	floor.queue_free()
+	controller.queue_free()
+	player.queue_free()
+	await process_frame
+	print("Gathering marker surface validation: PASS")
+	quit()
+
+
+func _make_surface(size: Vector3, position: Vector3) -> StaticBody3D:
+	var body := StaticBody3D.new()
+	body.position = position
+	body.collision_layer = 1
+	body.collision_mask = 0
+	var collision := CollisionShape3D.new()
+	var shape := BoxShape3D.new()
+	shape.size = size
+	collision.shape = shape
+	body.add_child(collision)
+	return body