Raycasting completely cancelling instantiation.

Question

In a retro space-invaders styled game, I am attempting to use raycasting to stop the enemies on the upper rows from killing the enemies beneath them. However, instead of doing this, my script stops the enemies from firing projectiles at all. It looks something like this:

 #pragma strict
 var enemyShot : Transform;
 
 var nextRowLayer : int;
 
 var layerMask = 1 << nextRowLayer;
 
 var shotTime = 1000;
 var timeToShot = 0;
 
 var castDistance : float;
 
 var hit : RaycastHit;
 
 function Start () {
 
 }
 
 function Update () {
 
 timeToShot ++;
 
 if (timeToShot == shotTime)
     {
     if (Physics.Raycast (transform.position, transform.TransformDirection (Vector3.down), hit, Mathf.Infinity, layerMask))
         {
         Instantiate(enemyShot, transform.position, transform.rotation);
         Debug.Log("shoot");
         }
         timeToShot = 0;
     } 
 }

I have tried converting it to Physics2D, but it gives me nothing but a barrage of errors. Feel free to ask for any additional information. Please include code samples in your answers if possible.

Answer 1

Answer by Dakwamine · Nov 28, 2016 at 04:44 PM

Your logic is not taking into account every possibility.

 if (timeToShot == shotTime)
 {
     Debug.Log("It's time to shoot!");
     if (Physics.Raycast (transform.position, transform.TransformDirection (Vector3.down), hit) ) 
     {
         Debug.Log("I have seen something in front of me...");
         if (hit.transform.tag != "Enemy")
         {
             Debug.Log("It was not an Enemy! FIRE!!!!!");
             Instantiate(enemyShot, transform.position, transform.rotation);
         }
         else
         {
             Debug.Log("Oh it's just a friendly Enemy.");
         }
     }
     else
     {
         Debug.Log("Nothing ahead! FIRE!!!!! For the Empire!");
         Instantiate(enemyShot, transform.position, transform.rotation);
     }
     timeToShot = 0;
 }

If Enemy never finds something from the raycast, you may want to verify the ray info such as the layers, ray directions, colliders... I would advise you to use a layer mask as a public inspector value:

 public var enemyLayerMask : LayerMask;

... and set the value in the inspector by checking "Enemy" only and uncheck everything else. And then, you can use this:

 if (timeToShot == shotTime)
 {
     Debug.Log("It's time to shoot!");
     if (Physics.Raycast (transform.position, transform.TransformDirection (Vector3.down), hit, Mathf.Infinity, enemyLayerMask) )
     {
         Debug.Log("There is a friendly Enemy somewhere in my sight. Let's shoot later.");
     }
     else
     {
         Debug.Log("There is no friendly Enemy! FIRE!!!!! For the Empire!");
         Instantiate(enemyShot, transform.position, transform.rotation);
     }
     timeToShot = 0;
 }

The second script is lighter from a performance perspective. Only Enemy objects are tested.

But it differs from the first script's logic: in the first, if something with a collider passes between two enemies, the Enemy above will still fire because, as every object is checked in the Raycast, the hit will tell "this is not an Enemy".

In the second script, only Enemies which are at the lowest row of their column will fire. And I think this is what you expected as a behaviour.

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Ian9921 · Nov 29, 2016 at 03:52 AM 0

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Unfortunately, I'm still having a problem. The enemies are firing, but they are killing the enemies beneath them. I'm currently using the second script you posted and I have tried the first one, with the same results. Looks like this has come full circle...

Dakwamine Ian9921 · Nov 30, 2016 at 11:52 PM 0

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What the log says?

Ian9921 Dakwamine · Dec 01, 2016 at 12:08 AM 1

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The log says "It's time to shoot" and "There is no freindly in my sight! Fire! For the empire!"

Here is my exact code:

 #pragma strict
 var enemyShot : Transform;
 
 var shotTime = 1000;
 var timeToShot = 0;
 
 public var enemyLayerMask : LayerMask;
 
 var castDistance : float;
 
 function Start () {
 
 }
 
 function Update () {
 
 var hit : RaycastHit;
 
 timeToShot ++;
 
 if (timeToShot == shotTime)
     {
     Debug.Log("It's time to shoot");
     if (Physics.Raycast (transform.position, transform.TransformDirection (Vector3.down), hit, Mathf.Infinity, enemyLayerMask) ){
             Debug.Log("There is a freindly in my sight. I'll shoot later");
         } else {
             Debug.Log("There is no freindly in my sight! Fire! For the empire!");
             Instantiate(enemyShot, transform.position, transform.rotation);
         }
     timeToShot = 0;
     }
 }

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Ian9921 · Dec 01, 2016 at 12:46 AM 1

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@roman_sedition Yes I have, by inserting this code:

 Debug.DrawRay(transform.position, Vector3.down, Color.red, 1);

immediately above the line where the ray is cast

roman_sedition Ian9921 · Dec 01, 2016 at 12:59 AM 1

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Then maybe there's something wrong outside of the scope of what you are showing us, enemies on wrong layers, enemies without tags, raycasting on wrong layers, enemies without colliders, triggers on colliders are set etc. If you are following somebody else's tutorial for making a space invader's game, maybe there was an error you made in reproducing the code. If you aren't, then probably look at some tutorials of similar games and find out why yours doesn't work out.

Dakwamine Ian9921 · Dec 01, 2016 at 11:06 AM 0

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Then could you update your raycast for peace of mind?

 if (Physics.Raycast (transform.position, Vector3.down, hit, Mathf.Infinity, enemyLayerMask) )

Dakwamine Ian9921 · Dec 01, 2016 at 11:09 AM 0

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And is the Enemy prefab on the enemy layer? ^^

Raycasting completely cancelling instantiation.

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