import numpy as np

class MovingEntity:
    """Embedded entity in the world with a position."""

    def __init__(self, world):
        self.world = world
        self.pos = np.array((0.0, 0.0, 0.0))  # (x, y, z) in local untilted coordinates

    def get_pos_rotated(self):
        """Return position rotated by world's tilt around y-axis."""
        return self.world.rotate_point_y(self.pos)

    def move(self, dx=0, dy=0, dz=0):
        self.pos = (self.pos[0] + dx, self.pos[1] + dy, self.pos[2] + dz)

class Target(MovingEntity):
    def __init__(self, world, pos=(0.0, 0.0, 0.0)):
        super().__init__(world)
        self.pos = np.array(pos) # Store everything in numpy

class Source(MovingEntity):
    def __init__(self, world, pos=(10.0, 10.0, 10.0)):
        super().__init__(world)
        self.pos = np.array(pos)