fix: stabilize mouse camera dragging

tests/camera_drag_validation.gd

@@ -0,0 +1,57 @@
+extends SceneTree
+
+const PlayerScene: PackedScene = preload("res://player/player.tscn")
+
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+
+func _run() -> void:
+	root.size = Vector2i(1280, 720)
+	var player := PlayerScene.instantiate() as Player
+	root.add_child(player)
+	await process_frame
+	player.local_control_enabled = true
+	player.set_camera_input_enabled(true)
+	Input.mouse_mode = Input.MOUSE_MODE_VISIBLE
+
+	var press := InputEventMouseButton.new()
+	press.button_index = MOUSE_BUTTON_RIGHT
+	press.button_mask = MOUSE_BUTTON_MASK_RIGHT
+	press.pressed = true
+	player.call("_input", press)
+	assert(bool(player.get("_camera_dragging")))
+	if DisplayServer.get_name() != "headless":
+		assert(Input.mouse_mode == Input.MOUSE_MODE_VISIBLE)
+
+	var yaw := player.get_node("%CameraYaw") as Node3D
+	var previous_yaw: float = yaw.rotation.y
+	var motion := InputEventMouseMotion.new()
+	motion.button_mask = MOUSE_BUTTON_MASK_RIGHT
+	motion.relative = Vector2(18.0, -4.0)
+	motion.screen_relative = motion.relative
+	player.call("_input", motion)
+	assert(not is_equal_approx(yaw.rotation.y, previous_yaw))
+	await process_frame
+	assert(bool(player.get("_camera_dragging")))
+	if DisplayServer.get_name() != "headless":
+		assert(Input.mouse_mode == Input.MOUSE_MODE_CAPTURED)
+
+	var release := InputEventMouseButton.new()
+	release.button_index = MOUSE_BUTTON_RIGHT
+	release.pressed = false
+	player.call("_input", release)
+	assert(not bool(player.get("_camera_dragging")))
+	if DisplayServer.get_name() != "headless":
+		assert(Input.mouse_mode == Input.MOUSE_MODE_VISIBLE)
+
+	player.call("_input", press)
+	assert(bool(player.get("_camera_dragging")))
+	player.notification(NOTIFICATION_APPLICATION_FOCUS_OUT)
+	assert(not bool(player.get("_camera_dragging")))
+
+	player.queue_free()
+	await process_frame
+	print("Camera drag validation: PASS")
+	quit()

tests/camera_drag_validation.gd.uid

@@ -0,0 +1 @@
+uid://dku3kyarg3fxu