CODEWITHSUNDEEP
c#unity-game-enginegame-physics
drpelz
drpelz

Reputation: 811

How to stop raycast when hitting an object in Unity?

In my Unity game (top-down 2D shooter) there are some enemies flying along a path (via DOTween). My player casts a ray into the scene in order to get an enemy-object right in front of the player. So far so good.

Now the problem is that I want only one enemy-object as a result, i.e. the raycast should stop when it hits an enemy-object for the very first time. How do I achieve this?

I need only one enemy-object hit by the raycast because there is a crosshair in my game and when the raycast starts and the enemies fly along the path the crosshair jumps forth and back (and I don't want this - the crosshair should stay at the first enemy hit by the raycast).

Raycast video

This is my code (attached to the player):

void FixedUpdate() {
    
    //crosshair: Cast a ray straight up.
    float _size = 12f;
        Vector2 _direction = this.transform.up;
        RaycastHit2D _hit = Physics2D.Raycast(this.transform.position, _direction, _size);

    if (_hit.collider != null && _hit.collider.tag == "EnemyShipTag") {

        // We touched something!

        Vector2 target = new Vector2(_hit.collider.gameObject.transform.position.x, _hit.collider.gameObject.transform.position.y);

        const float moveTime = 0.1f;
        float step;

        step = Vector2.Distance(crosshairGO.transform.position, target);
        crosshairGO.transform.position = Vector2.MoveTowards(crosshairGO.transform.position, target, step / moveTime * Time.deltaTime);

        Vector2 _pos3 = new Vector2(this.transform.position.x, crosshairGO.transform.position.y);
        crosshairGO.transform.position = _pos3;
        crosshairBegin = false;
    } else {
        // Nothing hit

        Vector2 _pos2 = new Vector2(this.transform.position.x, 4.5f);
        if (crosshairBegin) {
            crosshairGO.transform.position = _pos2;
        } else {
            Vector2 _pos4 = new Vector2(this.transform.position.x, crosshairGO.transform.position.y);
            crosshairGO.transform.position = _pos4;
        }
    }


}

Upvotes: 0

Views: 2932

Answers (1)

Motion Brain
Motion Brain

Reputation: 21

If I understand you right. You could create a bool value and set it true after you hit something.

For example:

Vector2 _pos3 = new Vector2(this.transform.position.x, crosshairGO.transform.position.y);
    crosshairGO.transform.position = _pos3;
    crosshairBegin = false;
    youHitSomething = true;

Before you create the ray you could write an if

if(!youHitSomething)
{
    float _size = 12f;
    Vector2 _direction = this.transform.up;
    RaycastHit2D _hit = Physics2D.Raycast(this.transform.position, _direction, _size);

     if (_hit.collider != null && _hit.collider.tag == "EnemyShipTag") 
     {
        // We touched something!
        // your Code 
        youHitSomething = true; 
     } 
     else 
    {
    // Nothing hit
    // your code
    }   
}

To let the ray cast again you could create a new method

public void ActivateRay()
{
   youHitSomething = false;
}

Upvotes: 2

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