How to Rotate on Y Axis by 90 degrees left or right?

Questions & Answers
1

I created this code but it doesn’t work and i don’t understand why. In the Debug.Log everything seems fine but the while loops are true for ever. Is there a better way to Rotate the gameobject by 90 degrees left and right?

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour {

	//Public
	public float rotateSpeed = 150f;
	public bool isMoving = false;

	//Private
	private Rigidbody myRigidbody;


	void Start () {
	
		myRigidbody = GetComponent<Rigidbody> ();
	}

	void Update() {

		Quaternion originalRotation = this.transform.rotation;

		if (!isMoving) {
			
			
			if (Input.GetButtonDown ("PlayerRotateRight")) {

				//Rotate Right
				StartCoroutine (PlayerRotateRight (originalRotation));

			} else if (Input.GetButtonDown ("PlayerRotateLeft")) {

				//Rotate Left
				StartCoroutine (PlayerRotateLeft (originalRotation));
			}
		}

	}
    
	IEnumerator PlayerRotateRight(Quaternion originalRotation) {

		Quaternion targetRotation = originalRotation;
		targetRotation *= Quaternion.AngleAxis (90, Vector3.up);

		while (this.transform.rotation.y != targetRotation.y) {

			Debug.Log ("Current: " + this.transform.rotation.y);
			Debug.Log ("Target: " + targetRotation.y);

			isMoving = true;
			transform.rotation = Quaternion.RotateTowards (transform.rotation, targetRotation, rotateSpeed * Time.deltaTime);
			yield return null;
		}

		isMoving = false;
	}

	IEnumerator PlayerRotateLeft(Quaternion originalRotation) {

		Quaternion targetRotation = originalRotation;
		targetRotation *= Quaternion.AngleAxis (90, Vector3.down);

		while (this.transform.rotation.y != targetRotation.y) {

			Debug.Log ("Current: " + this.transform.rotation.y);
			Debug.Log ("Target: " + targetRotation.y);

			isMoving = true;
			transform.rotation = Quaternion.RotateTowards (transform.rotation, targetRotation, rotateSpeed * Time.deltaTime);
			yield return null;
		}

		isMoving = false;
	}
}
2

The simplest way to rotate by 90 degrees (in world axis) is to do the following transform.rotation *= Quaternion.Euler(0, 90f * rotateSpeed * Time.deltaTime, 0).

The quaternions will not be the same since they are using floating points and that is their nature. You need to use something like Quaternion.Angle to check if they are “close enough”.