Now, it's really cool that we have a player, but it'll get really boring if all we can do is move around and shoot some lasers in the dark. Next, we'll introduce some simple enemies that will move toward the player that we'll be able to shoot later. Perform the following steps:
Assets
folder; move the enemy.png
file into our Sprites
folder.MoveTowardsPlayer
. Go to MonoDevelop
and use the following code:using UnityEngine; using System.Collections; public class MoveTowardsPlayer : MonoBehaviour { private Transform player; public float speed = 2.0f; // Use this for initialization void Start () { player = GameObject.Find("playerShip").transform; } // Update is called once per frame void Update () { Vector3 delta = player.position - transform.position; delta.Normalize(); float moveSpeed = speed * Time.deltaTime; transform.position = transform.position + (delta * moveSpeed); } }
In the beginning of the game, I find the player ship and get his Transform
component. Then, in every frame of the project, we move the enemy from where it currently is to the direction where the player is at.
The GameObject.Find
function is very useful as it allows us to access objects at any time, but is computationally expensive, so don't put it in a function that gets called often (such as Update) when you can just save a reference to it. It's also important to note that the spelling of the parameter has to be exactly the same as the object's name in the hierarchy; so be sure to double check when you use it.
Enemy
..455
, and run the game. Have a look at the following screenshot:Now, you'll see that the enemy will always move toward you! But if we shoot it, nothing happens. Let's fix that as follows:
EnemyBehaviour
. Go to MonoDevelop
(your IDE of choice,), and use the following code:using UnityEngine; // MonoBehaviour public class EnemyBehaviour : MonoBehaviour { // How many times should I be hit before I die public int health = 2; void OnCollisionEnter2D(Collision2D theCollision) { // Uncomment this line to check for collision //Debug.Log("Hit"+ theCollision.gameObject.name); // this line looks for "laser" in the names of // anything collided. if(theCollision.gameObject.name.Contains("laser")) { LaserBehaviour laser = theCollision.gameObject.GetComponent("LaserBehaviour") as LaserBehaviour; health -= laser.damage; Destroy (theCollision.gameObject); } if (health <= 0) { Destroy (this.gameObject); } } }
Now, you will notice that we have commented a line of code calling the function Debug.Log
. This function when called will print something onto your console (in this case, name the object that we collided with), which may help you when debugging your own code in the future.
It's also important to note the reason we ask if the name contains Laser instead of is equal to is because when you create an object using Instantiate, by default it will add " (Clone)" to the end of the name of the object.
OnCollisionEnter2D
to be called.Enemy
object and then select Component | 2D Physics | Rigidbody 2D. From there, change the GravityScale value to 0 so that the object will not fall down by default due to gravity.EnemyBehaviour
behavior to your enemy object, save your project, and run the game. If all went well, we should have something like the following screenshot:Now, whenever we hit the enemy with our bullets twice, it will die. Nice!