Modifying Homing Missiles for Enemies

Unity Engine
1

Hi everyone,

I’d like to attempt… if not succeed at modifying Joachims homing missile script (see below) to work on my enemy robots, currently seem here -

www.willgoldstone.com/robotest

At the moment they use this script to shoot at the player when you walk in front of them -

Attached to the GUN -

var fieldOfViewShoot = 10.0;
var enemyBullet : Rigidbody;
var shootFreq = 0.3;
var enemyShootSpeed = 10.0;
var enemyProx = 50;
var timer : float;

function Start () {
	
	timer = 0.0;	
	
}

function Update () {
		
		timer += Time.deltaTime;
		
	var targetPoint = GameObject.FindWithTag("Player").transform.position;
	var forward = transform.TransformDirection(Vector3.forward);
	var targetDirection = targetPoint - transform.position;
	

	if(Vector3.AngleBetween(forward, targetDirection) * Mathf.Rad2Deg < fieldOfViewShoot) {
	
		if((Vector3.Distance(transform.position, targetPoint) < enemyProx)  (timer > shootFreq)) {
		
			timer = 0.0;
	
		var thingIshot : Rigidbody = Instantiate (enemyBullet, transform.position, transform.rotation);
		
			thingIshot.velocity = transform.TransformDirection(Vector3(0,0, enemyShootSpeed));
		
			Physics.IgnoreCollision(thingIshot.collider, transform.root.collider);
			Physics.IgnoreCollision(thingIshot.collider, GameObject.FindWithTag("Destructible").transform.root.collider);
			
			
		}
	}
	
}

Attached to the BULLET’S prefab -

var BulletTimeout = 6.0;
var homingSpeed = 0.5;

function Start() {
Invoke("Kill", BulletTimeout);
}

function Kill(){       
Destroy(gameObject);
}

function Update () {
		
	var targetPoint = GameObject.FindWithTag("Player").transform.position;
	
	// forward direction in enemy's coordinate space
	var forward = transform.TransformDirection(Vector3.forward);
	var targetDirection = targetPoint - transform.position;
	
	if((Vector3.Distance(transform.position, targetPoint) < 500)) {
	
		//5 is the field of view angle checking for player
		var theAngleBetween = Vector3.AngleBetween(forward, targetDirection) * Mathf.Rad2Deg;
		
		if(theAngleBetween < 40) {
			
			var rot = Quaternion.LookRotation(targetPoint - transform.position, Vector3.up);
       // homingSpeed is the speed it turns
       		rot = Quaternion.Slerp(transform.rotation, rot, Time.deltaTime * homingSpeed);
       
			rigidbody.angularVelocity = rot * rigidbody.angularVelocity;
		}
		
		
	}
	
}

And i’ve just started looking at Joachims homing missile script and would like to use elements of it in order to make the enemy bots bullets lean toward the player - at the moment if you play the game you’ll notice theyre easy to avoid.

The first prob with the script hes posted is that its for a player, and therefore is only triggered on fire, as opposed to mine which is triggered a lot - therefore enemies would be firing rays at all sorts of things, rather than looking for the player.

So, my main question I suppose is, what is the theory behind using the part of Joachims script that homes in on a ray selected object, and how can I use this to make the bullets my enemies fire head toward the player. I attempted to make this happen in my own script (see the one attached to BULLET above) but this doesnt really work.

I know this is a big question… well to me anyway! Any help much appreciated as always, see Joachim’s Homing missile for FPS controller below -

/*
  The homing missile every frame simply rotates towards the target
 
 The actual physics is done by setting up the drag in the rigidbody (5 works well)
 and a relative force along the zaxis in the constanct force (
relative.z = 50 works well)
*/

var target : Transform;
var rotationSpeed = 50.0;

private var relativeTargetPoint = Vector3.zero;
private var absoluteTargetPoint = Vector3.zero;

function Start ()

{
	rigidbody.freezeRotation = true;
}

function Update () {

	// Update the target point
	if (target)
		absoluteTargetPoint = target.TransformPoint(relativeTargetPoint);

	// Rotate towards the target	

	var oldDirection = transform.TransformDirection(Vector3.forward);
	var direction = absoluteTargetPoint - transform.position;

	direction = Vector3.RotateTowards(oldDirection, direction, rotationSpeed * Mathf.Deg2Rad
 * Time.deltaTime, 1);
	transform.rotation = Quaternion.LookRotation(direction);
}

function SetTarget (t : Transform) {
	target = t;
}

function SetTargetAbsolutePosition (position : Vector3) {

	absoluteTargetPoint = position;
	if (target)
		relativeTargetPoint = target.InverseTransformPoint(absoluteTargetPoint);
}

@script RequireComponent(Rigidbody, ConstantForce, Rocket)

Cheers

Will
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