Camera Rotation every 45 degrees

func _process(delta):
    if Input.is_action_pressed("ui_up"):
        if Input.is_action_pressed("ui_right"):
            rot_y = rotation.y - PI/4
        elif Input.is_action_pressed("ui_left"):
            rot_y = rotation.y + PI/4
        else:
            rot_y = rotation.y
    elif Input.is_action_pressed("ui_down"):
        if Input.is_action_pressed("ui_right"):
            rot_y = (rotation.y - PI/4) - PI/2
        elif Input.is_action_pressed("ui_left"):
            rot_y = (rotation.y + PI/4) + PI/2
        else:
            rot_y = rotation.y - PI
    elif Input.is_action_pressed("ui_right"):
        if Input.is_action_pressed("ui_up"):
            rot_y = rotation.y - PI/4
        elif Input.is_action_pressed("ui_down"):
            rot_y = (rotation.y - PI/4) - PI/2
        else:
            rot_y = rotation.y - PI/2
    elif Input.is_action_pressed("ui_left"):
        if Input.is_action_pressed("ui_up"):
            rot_y = rotation.y + PI/4
        elif Input.is_action_pressed("ui_down"):
            rot_y = (rotation.y + PI/4) + PI/2
        else:
            rot_y = rotation.y + PI/2