Hey if anyone is interested in how to make enemy AI with random movement (And this code will allow an enemy to crawl a maze if that’s what you want). I also go over line casting, and briefly explain layer mask. The enemy will look at the player and fire in his direction upon detection.
Enemy Bullet Script
using UnityEngine;
public class EnemyBullet01 : MonoBehaviour
{
private void OnTriggerEnter2D(Collider2D collision)
{
if (collision.tag == "Wall")
{
Destroy(gameObject);
}
if (collision.tag == "Player")
{
Destroy(gameObject);
}
}
}
Player Detection Script
@vakabaka Thanks for your help on this! You are mentioned in the video, amigo!
using UnityEngine;
public class PlayerDetection : MonoBehaviour
{
public Transform origin, end, player;
public float radarSpd;
public bool playerDetected;
public static bool playerIsDetected;
private int playerLayer = 1 << 8;
private Rigidbody2D enemyRb;
private Vector3 facePlayer;
private void Start()
{
enemyRb = GetComponentInParent<Rigidbody2D>();
playerIsDetected = false;
}
private void Update()
{
PlayerDetector();
if (playerDetected == false)
{
Radar();
}
else { PlayerIsDetected(); }
}
void PlayerDetector()
{
Debug.DrawLine(origin.position, end.position, Color.red);
playerDetected = Physics2D.Linecast(origin.position, end.position, playerLayer);
}
void Radar()
{
end.RotateAround(origin.position, Vector3.forward, radarSpd * Time.deltaTime);
playerIsDetected = false;
}
void PlayersPosition()
{
facePlayer = player.position - enemyRb.transform.GetChild(0).GetChild(0).position;
enemyRb.transform.GetChild(0).GetChild(0).up = -facePlayer;
}
void PlayerIsDetected()
{
if(playerDetected == true)
{
playerIsDetected = true;
end.position = player.position;
PlayersPosition();
}
}
}
Wall Detection Script
using UnityEngine;
public class EnemyDetection : MonoBehaviour
{
public Transform originPointDown, endPointDown, originPointLeft,
endPointLeft, originPointRight, endPointRight,
originPointUp, endPointUp;
public bool wallDetectedDown, wallDetectedLeft, wallDetectedRight, wallDetectUp;
public static bool pathOpenDown, pathOpenLeft, pathOpenRight, pathOpenUp;
private int wallLayer = 1 << 10;
private void Update()
{
WallDetector();
}
void WallDetector()
{
Debug.DrawLine(originPointDown.position, endPointDown.position, Color.green);
Debug.DrawLine(originPointLeft.position, endPointLeft.position, Color.green);
Debug.DrawLine(originPointRight.position, endPointRight.position, Color.green);
Debug.DrawLine(originPointUp.position, endPointUp.position, Color.green);
wallDetectedDown = Physics2D.Linecast(originPointDown.position, endPointDown.position, wallLayer);
wallDetectedLeft = Physics2D.Linecast(originPointLeft.position, endPointLeft.position, wallLayer);
wallDetectedRight = Physics2D.Linecast(originPointRight.position, endPointRight.position, wallLayer);
wallDetectUp = Physics2D.Linecast(originPointUp.position, endPointUp.position, wallLayer);
CheckResults();
}
void CheckResults()
{
if( wallDetectedDown == true)
{
pathOpenDown = false;
}
else { pathOpenDown = true; }
if ( wallDetectedLeft == true)
{
pathOpenLeft = false;
}
else { pathOpenLeft = true; }
if ( wallDetectedRight == true)
{
pathOpenRight = false;
}
else { pathOpenRight = true; }
if(wallDetectUp == true)
{
pathOpenUp = false;
}
else { pathOpenUp = true; }
}
}
Enemy Movement Script
using System.Collections;
using UnityEngine;
public class Enemy01Move : MonoBehaviour
{
[Header("Enemy Weapon Field")]
public GameObject eBul;
public Transform eBulSpawn;
private Rigidbody2D enemyRb;
private float enemySpd = 5f;
private float bulSpd = 20f;
private float shootTimer = 1.0f;
private int moveDir;
private int curDir; // You can store your current direction here but I'm not using it in this code. This is how you would do it though
private bool canChange;
private bool canFire;
private bool readyTofire;
private Vector2 moveDirection;
private void Start()
{
enemyRb = GetComponent<Rigidbody2D>();
moveDir = Random.Range(1, 5); // 1-4 -- 1=down 2=left 3=right 4=up
if(moveDir < 1 || moveDir > 4)
{
while(moveDir < 1 || moveDir > 4) { moveDir = Random.Range(1, 5); }
}
canChange = true; // Allows the enemy to pick a random direction when true
canFire = false; // Enemy can only fire if this is true
readyTofire = false; // When true, it will set canFire true. To properly set the fire rate
}
private void Update()
{
if (PlayerDetection.playerIsDetected == false)
{
MovementHandler();
readyTofire = false;
shootTimer = 1.0f;
}
else
{
StopMoving();
}
if(readyTofire == true)
{
shootTimer -= Time.deltaTime;
// Debug.Log(shootTimer);
if (shootTimer > 0f && canFire == true)
{
StartCoroutine(FireRate());
}
if(shootTimer < -1f)
{
shootTimer = 1.0f;
}
}
}
private void FixedUpdate()
{
enemyRb.MovePosition(enemyRb.position + (moveDirection * enemySpd) * Time.fixedDeltaTime);
}
void ChangeDirection()
{
// Can move in any direction
if (EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1, 5); // 1-4 -- 1=down 2=left 3=right 4=up
if (moveDir < 1 || moveDir > 4)
{
while (moveDir < 1 || moveDir > 4)
{
moveDir = Random.Range(1, 5);
if (moveDir == curDir)
{
moveDir = Random.Range(1, 5);
}
}// End of While loop
}// End of IF moveDir statement
} // End of all paths open IF statement
// Cannot move right
else if(EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1, 5); // 1-4 -- 1=down 2=left 3=right 4=up
while(moveDir < 1 || moveDir > 4 || moveDir == 3)
{
moveDir = Random.Range(1, 5);
}// End of While loop
}// End of Right path closed all other paths open Statement
// Cannot move Left or Right
else if(EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1, 5);
while(moveDir < 1 || moveDir > 4 || moveDir == 2 || moveDir == 3)
{
moveDir = Random.Range(1, 5);
}// End of While Loop
}// End of Up or Down path open IF Statement
// Can only move up
else if(EnemyDetection.pathOpenDown == false && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == true)
{
moveDir = 4;
} // End of Up movement only IF statement
// Can only move Up or Right
else if(EnemyDetection.pathOpenDown == false && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1,5);// 1-4 -- 1=down 2=left 3=right 4=up
while (moveDir < 3 || moveDir > 4) // can only be 3 or 4
{
moveDir = Random.Range(1, 5);
}
}// End of Up or Right Movement IF statement
// Can move Left, Right or Up
else if(EnemyDetection.pathOpenDown == false && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1, 5);
while (moveDir > 4 || moveDir < 2) // Cannot be 1
{
moveDir = Random.Range(1, 5);
}
}// End of Left,Right,Up IF statement
// Can only move Left or Up
else if(EnemyDetection.pathOpenDown == false && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1, 5); // 1 = down 2 = left 3 = right 4 = up
while (moveDir < 1 || moveDir > 4 || moveDir == 1 || moveDir == 3)
{
moveDir = Random.Range(1, 5);
}
}// End of Left/Up IF statement
// Cannot move left
else if(EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == true)
{
moveDir = Random.Range(1, 5);
while(moveDir < 1 || moveDir > 4 || moveDir == 2)
{
moveDir = Random.Range(1, 5);
}
}// End of Down, Right, Up IF statement
// Can move any direction except Up
else if(EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == false)
{
moveDir = Random.Range(1, 5);
while(moveDir < 1 || moveDir > 3)
{
moveDir = Random.Range(1, 5);
}
}// End of any direction BUT Up statement
// Cannot move Right or Up
else if(EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == false)
{
moveDir = Random.Range(1, 5); // 1 = down 2 = left 3 = right 4 = up
while(moveDir < 1 || moveDir > 2)
{
moveDir = Random.Range(1, 5);
}
}// End of can't move Right or Up statement
// Cannot move Left or Up
else if (EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == false)
{
moveDir = Random.Range(1, 5);
while(moveDir < 1 || moveDir > 3)
{
moveDir = Random.Range(1, 5);
}
}// End of Can't move Left or Up statement
// Can only move Down
else if (EnemyDetection.pathOpenDown == true && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == false)
{
moveDir = 1;
} // End of can only move Down statement
// Can only move Left
else if (EnemyDetection.pathOpenDown == false && EnemyDetection.pathOpenLeft == true && EnemyDetection.pathOpenRight == false &&
EnemyDetection.pathOpenUp == false)
{
moveDir = 2;
} // End of can only move Left statement
// Can only move Right
else if (EnemyDetection.pathOpenDown == false && EnemyDetection.pathOpenLeft == false && EnemyDetection.pathOpenRight == true &&
EnemyDetection.pathOpenUp == false)
{
moveDir = 3;
} // End of can only move Right
else { moveDir = 4; } // In case we forgot a scenario or since we didn't add move up only, we'll move Up by default
}
void MoveLeft()
{
curDir = 2;
enemyRb.transform.GetChild(0).GetChild(0).eulerAngles = new Vector3(0, 0, -90);
moveDirection = Vector2.left;
}
void MoveRight()
{
curDir = 3;
enemyRb.transform.GetChild(0).GetChild(0).eulerAngles = new Vector3(0, 0, 90);
moveDirection = Vector2.right;
}
void MoveUp()
{
curDir = 4;
enemyRb.transform.GetChild(0).GetChild(0).eulerAngles = new Vector3(0, 0, 180);
moveDirection = Vector2.up;
}
void MoveDown()
{
curDir = 1;
enemyRb.transform.GetChild(0).GetChild(0).eulerAngles = new Vector3(0, 0, 0);
moveDirection = Vector2.down;
}
void StopMoving()
{
moveDirection = Vector2.zero;
if (shootTimer >= 1.0f)
{
readyTofire = true;
canFire = true;
}
}
void StartShooting()
{
GameObject eBull = Instantiate(eBul, eBulSpawn.position, eBulSpawn.rotation);
Rigidbody2D eBulRb = eBull.GetComponent<Rigidbody2D>();
eBulRb.AddForce(eBulSpawn.up * bulSpd, ForceMode2D.Impulse);
Destroy(eBull, 3f);
}
void MovementHandler()
{
if (moveDir == 1)
{
if (EnemyDetection.pathOpenDown == true)
{
MoveDown();
}
else { ChangeDirection(); }
}
else if (moveDir == 2)
{
if (EnemyDetection.pathOpenLeft == true)
{
MoveLeft();
}
else { ChangeDirection(); }
}
else if (moveDir == 3)
{
if (EnemyDetection.pathOpenRight == true)
{
MoveRight();
}
else { ChangeDirection(); }
}
else if (moveDir == 4)
{
if (EnemyDetection.pathOpenUp == true)
{
MoveUp();
}
else { ChangeDirection(); }
}
if (canChange == true)
{
StartCoroutine(RandomMovement());
}
}
IEnumerator RandomMovement()
{
canChange = false;
var timer = Random.Range(0.5f, 2.5f);
yield return new WaitForSeconds(timer);
ChangeDirection();
yield return new WaitForSeconds(0.5f);
canChange = true;
}
IEnumerator FireRate()
{
canFire = false;
float fireRate = 0.25f;
yield return new WaitForSeconds(fireRate);
StartShooting();
yield return new WaitForSeconds(fireRate);
canFire = true;
}
private void OnCollisionEnter2D(Collision2D collision)
{
if(collision.gameObject.tag == "Wall")
{
ChangeDirection();
}
}
}
