Monster.cs

using UnityEngine;
using System.Collections;

public class Monster : MonoBehaviour {
	
	/* Enum of states for FSM. Few more states should be add ie. for animation :HURTED */
	public enum MONSTER_STATE {PATROL = 0, CHASE = 1, ATTACK = 2};
	/* Current state of monster */
	public MONSTER_STATE ActiveState = MONSTER_STATE.PATROL;
	/* Current health of monster. It's independ with enemy protection, only show % of health, wchih should be
	printed above enemy head, or could be overwrite in child class */
	public int Health = 100;
	/* Reference to active Player */
	protected GameObject Player = null;
	/* Monster cached transform */
	protected Transform ThisTransform = null;
	/* Reference to Player Transform */
	protected Transform PlayerTransform = null;
	/* Reference to NavMesh Agent component */
	protected UnityEngine.AI.NavMeshAgent Agent = null;
	/* Area of monster sight */
	/* DISCLAIMER::: Here and below random values: to elaborate*/
	protected float Sight_distance = 10f; 
	protected float Sight_Angle = 10f;
	/* Area of monster hearing */
	protected float Hearing_distance = 10f;
	/* Area of monster patrol */
	protected float Patrol_distance = 10f;
	/* Area of head twist */
	protected float Twist_angle = 10f;
	protected float Twist_speed = 10f;
	/* Area of monster attack */ 
	/* DISCLAMIER::: Should be overwrite in child class depending on weapon, */
	/* now its mock value refering to min distance between monster and player.*/
	protected float Attack_distance = 0.5f; 
	
	
	
	void Start () {
		Player = GameObject.FindWithTag("Player");
		PlayerTransform = Player.transform;
		ThisTransform = transform;
		Agent = GetComponent<UnityEngine.AI.NavMeshAgent>();
	}
	
	protected bool canISeePlayer() {
		UnityEngine.AI.NavMeshHit hit;
		bool blocked = UnityEngine.AI.NavMesh.Raycast(ThisTransform.position, PlayerTransform.position, out hit, 1);
		if(!blocked && hit.distance <= Sight_distance &&
		Vector3.Angle(ThisTransform.forward, PlayerTransform.position - ThisTransform.position) <= Sight_Angle)/* right Angle */
				return true;
		return false;
	}
	
	protected bool canIHerePlayer() {
		UnityEngine.AI.NavMeshHit hit;
		UnityEngine.AI.NavMesh.Raycast(ThisTransform.position, PlayerTransform.position, out hit, 1);
		if(hit.distance <= Hearing_distance)
			return true;
		return false;
	}
	
	/* Now its just mock function. Its should be return true, if monster is hit by player.*/
	protected bool canIFeelPlayer() {
		return false;
	}
	
	/* Later could be add more circumstances like shell or something...*/
	protected bool canIAttackPlayer() {
		return Vector3.Distance(ThisTransform.position, PlayerTransform.position) <= Attack_distance; 
	}
	
	protected void chase() {
		Agent.SetDestination(PlayerTransform.position);
		Agent.updateRotation = true;
	}
	
	/* Err = feature. Last solution lay on assumption, that we extend states set to "idle", becouse we want that monster could take few-baby step */
	/* in some direction. Idle states would-be called when monster isnt in chase state and have no destination. Now before we establish new patrol point */
	/* , we just check if monster is walking--> thats mean if monster lost sight of player its go to last destination, when player been seen. Last solution */
	/* donst support that behaviour.*/
	protected void patrol() {
		/* Nothing to go afrter - idle. Establish new random patrol point */
		if(!Agent.hasPath) {
			/* Get random destination on map */
			Vector3 randomPoint = Random.insideUnitSphere * Patrol_distance;
			/* Add as offset from current position */
			randomPoint += ThisTransform.position;
			/* Get nearest valid position */
			UnityEngine.AI.NavMeshHit hit;
			UnityEngine.AI.NavMesh.SamplePosition(randomPoint, out hit, Patrol_distance, 1);
			/* Set destination */
			Agent.SetDestination(hit.position);			
		}
			/*DISCLAIMER::: I'm not sure if rotation of all monster body to "symulate look around" is good idea- maybe just head should dance */
			/* Make sure thats flag is set in any other state */
			/* Btw it can product some undefined bevahiour*/
			Agent.updateRotation = false;
			/* Fuck this shit... work-around: sinus is periodic and in some point symmetrical, so can be used to symulate any periodic movement */
			float currentOffsetAngle = Twist_angle * (2 * Mathf.Sin(Time.time * Twist_speed) - 1);
			/* Obtain vector which make currentOffSetAngle with verocity vector*/
			Vector3 lookAtPosition = Quaternion.Euler(0, currentOffsetAngle, 0) * Agent.velocity;
			/* What happen when velocity == 0 ? */
			ThisTransform.LookAt(lookAtPosition);
	}
	
	protected void attack() {
		/* Bite */
	}
	
	/* Dealing monster state */
	void Update() {
		/* Elaborate states */
		if(canISeePlayer() || canIHerePlayer() || canIFeelPlayer())
			ActiveState = MONSTER_STATE.CHASE;
		if(ActiveState == MONSTER_STATE.CHASE && canIAttackPlayer())
			ActiveState = MONSTER_STATE.ATTACK;
		
		/* Call state function and animation launch */
		switch (ActiveState){
			case MONSTER_STATE.CHASE:
				chase();
				break;
			case MONSTER_STATE.PATROL:
				patrol();
				break;
			case MONSTER_STATE.ATTACK:
				attack();
				break;
			default:
				break;
		}
	}
}