Simple FPS Character Controller for Unity

SimpleCharacterController.cs

using UnityEngine;

public sealed class SimpleCharacterController : MonoBehaviour
{
	[SerializeField] private float speed;
	[SerializeField] private float jumpSpeed;

	private Vector3 _velocity;

	[SerializeField] private CharacterController characterController;

	[SerializeField] private float xSensitivity;
	[SerializeField] private float ySensitivity;

	[SerializeField] private float xMin;
	[SerializeField] private float xMax;

	[SerializeField] private Transform fpsCamera;

	private Vector3 _fpsCameraEulerAngles;

	private bool _isFrozen;

	private void Update()
	{
		if (Input.GetKeyDown(KeyCode.Escape))
		{
			_isFrozen = !_isFrozen;

			Cursor.visible = _isFrozen;

			Cursor.lockState = _isFrozen ? CursorLockMode.None : CursorLockMode.Locked;
		}

		Move();

		LookAround();
	}

	private void Move()
	{
		var x = Input.GetAxis("Horizontal");
		var z = Input.GetAxis("Vertical");

		var desiredVelocity = ((transform.right * x) + (transform.forward * z)) * (_isFrozen ? 0.0f : speed);

		desiredVelocity = Vector3.ClampMagnitude(desiredVelocity, speed);

		_velocity.x = desiredVelocity.x;
		_velocity.z = desiredVelocity.z;

		if (characterController.isGrounded)
		{
			_velocity.y = 0.0f;

			if (!_isFrozen && Input.GetKey(KeyCode.Space))
			{
				_velocity.y = jumpSpeed;
			}
		}
		else
		{
			_velocity.y += Physics.gravity.y * Time.deltaTime;
		}

		characterController.Move(_velocity * Time.deltaTime);
	}

	private void LookAround()
	{
		var multiplier = _isFrozen ? 0.0f : 1.0f;

		var x = Input.GetAxis("Mouse X") * multiplier;
		var y = Input.GetAxis("Mouse Y") * multiplier;

		_fpsCameraEulerAngles.x = Mathf.Clamp(_fpsCameraEulerAngles.x - y * ySensitivity, xMin, xMax);

		transform.Rotate(0.0f, x * xSensitivity, 0.0f);

		fpsCamera.localEulerAngles = _fpsCameraEulerAngles;
	}
}