Controlling player with a mouse

I’m making a top down 2.5d game where the player controls a tank and uses the WASD keys to move and the mouse to aim. What I want is for the take turret to point towards wherever the mouse cursor is. The turret is attached to the tank body and moves wherever the body moves to. Here’s what I have:

	void Update () {
		Vector3 mouseWorldPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition + Vector3.forward * 10f);
		float angle = AngleBetweenPoints(transform.position, mouseWorldPosition);
		Vector3 mousePos = Input.mousePosition;

		//To make mousePos relative to center of screen
		mousePos.x -= Screen.width / 2;
		mousePos.y -= Screen.height / 2;

		//To make mousePos relative to transform
		mousePos += transform.position;
		angle = Vector3.Angle(mousePos, Vector3.up);

		//For 360 degree angle
		if (mousePos.x > 0)
			angle = 360 - angle;

		transform.rotation = Quaternion.Euler(0, -angle, 0);
		if (Input.GetKeyDown (KeyCode.Mouse0)) {
			Instantiate(bullet, bulletPosition.transform.position, transform.rotation);
		}
	}

	float AngleBetweenPoints(Vector2 a, Vector2 b) {
		return Mathf.Atan2(a.y - b.y, a.x - b.x) * Mathf.Rad2Deg;
	}

Now this works when the tank is in the center of the screen however when the tank is at one side of the screen then it doesn’t work anymore. So how can I make the mouse aim work no matter where the player is on screen?

This should work:

var worldUp = transform.TransformDirection(Vector3.up);
var rotation = Quaternion.LookRotation(mouseWorldPosition  - transform.position, worldUp); 
transform.rotation = new Quaternion(0, 0, rotation.z, rotation.w);

You Could Import the first person or third person character assets from the default assests