2D TOP DOWN - W A S D as direction

Hello I need here really a help

I am making a top down 2d tank shooter game. The direction should based on keys WASD. So if I want to go right the Z rotiation should be zero. If I go to left so it should be 270. So I don’t know really how to calculate it. Because the Quaternion gives me headache.

When I used old engine it was without Quaternion. I just made Direction.ToAngle() and I got the angle were I could use .setAngle(angle). For smooth I just did SmoothAng = currentAng - (angle - CurrentAng) *0.1f (it hadn’t lerp)
In Unity it needs to Vectors to get an angle which confusing me while in old engine I used just one Vector like Quaternion.Euler.

Quaternion seems more complex. There is LookRotation or something else. Don’t know really how these do the culculation. So I hope you can help me :S

Important!! It needs to be a smooth rotation.

While this can easily be done with Quaternions, it also can be easily done just using eulerAngles. Given you are rotating around ‘y’ axis, you can do something like this:

#pragma strict

var speed = 3.0;
private var angleTo = 0.0;
private var angle = 0.0;
function Update() {
	if (Input.GetKeyDown(KeyCode.A))
		angleTo = -90.0;
	if (Input.GetKeyDown(KeyCode.S))
		angleTo = 180.0;
	if (Input.GetKeyDown(KeyCode.D)) 
		angleTo = 90.0;
	if (Input.GetKeyDown(KeyCode.W))
		angleTo = 0.0;
	angle = Mathf.Lerp(angle, angleTo, Time.deltaTime * speed);
	transform.eulerAngles = Vector3(0.0, angle, 0.0);

A couple things to note here. First, I never read from eulerAngles. I keep my own variable (angle) and just write to them. Second, I’m using Time.deltaTime instead of 0.1. Since the time of each frame varies, you cannot used a fixed value in Update(). You could use a fixed value if you wanted to use FixedUpdate().

Well, I think this is solution (sorry because it is in C#):

rb.MovePosition(rb.position + new Vector2(Input.GetAxis("Horizontal"), Input.GetAxis("Vertical")) * [speed of character, for example 5] * Time.fixedDeltaTime);