How to make an object move in only a few directions?

Question

C++ / C#

Good afternoon.
Let's say there is some object, let's call it Player. How to make it move only in 8 directions? In the figure, red lines indicate only those directions in which the Player can move. At the bottom right of the picture, the Player's movement when clicking on point B, bypassing an obstacle (object). Tell me which way to dig? Something similar to:

Vector2 movement_vector = new Vector2 (Input.GetAxisRaw ("Horizontal"), Input.GetAxisRaw ("Vertical"));

But there the axes are read when you press the keys on the keyboard.

Answer 1

How is control actually implemented? at the click point we create a vector to move to this point? or keyboard? it's hard to imagine moving in 8 directions on click
there are some ready-made solutions in 2d https://www.assetstore.unity3d.com/en/#!/content/35803

Answer 2

Code from here

public enum Direction {   
  None, LeftUp, Up, RightUp, Right, RightDown, Down, LeftDown, Left 
}

public Direction GetDirection(double x, double y) {
  double absX = Math.Abs(x);
  double absY = Math.Abs(y);
  if (absX < 0.1 && absY < 0.1) {
    // close to center
    return Direction.None;
  }
  if (absX > absY) {
    // vertical side
    double half = absX * 0.4142;
    if (x > 0) {
      // left side
      if (y > half) return Direction.LeftDown;
      if (y < -half) return Diretion.LeftUp;
      return Direction.Left;
    } else {
      // right side
      if (y > half) return Direction.RightDown;
      if (y < -half) return Direction.RightUp;
      return Direction.Right;
    }
  } else {
    // horisontal side
    double half = absY * 0.4142;
    if (y > 0) {
      // bottom
      if (x > half) return Direction.RightDown;
      if (x < -half) return Direction.LeftDown;
      return Direction.Down;
    } else {
      // top
      if (x > half) return Direction.RightUp;
      if (x < -half) return Direction.LeftUp;
      return Direction.Up;
    }
  }
}