public class Zombie : MonoBehaviour {
        Animator animator;
        NavMeshAgent agent;
        GameObject player;

        public float visible = 15f;
        public float angleV = 180f;
        public float distance;
        public Quaternion look;

        void Start () {
                animator = GetComponent<Animator> ();
                agent = GetComponent<NavMeshAgent> ();
                player = GameObject.FindGameObjectWithTag ("Player");
        }
       

        void Update () {
                if (player != null) {

                        distance = Vector3.Distance(transform.position, player.transform.position);

                        look = Quaternion.LookRotation(player.transform.position - transform.position);

                        float angle = Quaternion.Angle(transform.rotation, look);

                            if(angle < angleV)
                    {  
                    
                    RaycastHit hit;

                    Ray ray = new Ray(transform.position + Vector3.up*2, player.transform.position - transform.position + Vector3.down);
                    Debug.DrawRay(transform.position + Vector3.up*2, player.transform.position - transform.position + Vector3.down);
                    
                    if(Physics.Raycast(ray, out hit, visible))
                    
                    {
                    if(hit.transform.gameObject == player && distance < visible && distance >= 3.8f)
                    {
                    animator.SetBool ("attack", false);
                    agent.destination = player.transform.position;
                    }

                    if(hit.transform.gameObject == player && distance < 3.8f)
                    {
                    Vector3 pos = player.transform.position;
                    pos.y = transform.position.y;
                    transform.LookAt(pos);
                    agent.stoppingDistance = 3.5f;
                    animator.SetBool ("attack", true);
                    }

                    }

                    }
}
}