Raycast - do something once

Unity Engine
1

I have a raycast on my character. When a specific trigger is in sight, I want to do something once. It is happening every frame. How do I limit the response to just happen once? Thanks.

		if(Physics.Raycast(transform.position, Vector3.right, out hit))
		{
			if(hit.transform.name == "East")
				Instantiate(prefab, new Vector3(0, 0, 9.75f), Quaternion.identity);
		}
2

You can use a boolean variable to only instantiate the prefab when it is true and
be sure to make it false in the statement following the call. Something like this:

if(Physics.Raycast(transform.position, Vector3.right, out hit)) {

   if(hit.transform.name == "East")

      if(instantiatePrefab) {

         InstantiatePrefab();

         instantiatePrefab = false;
      }
   }
}

void InstantiatePrefab() {

   Instantiate(prefab, new Vector3(0, 0, 9.75f), Quaternion.identity);
}
3

A slight modification to Ingot’s answer… for a little more efficiency you can move the bool check to the outermost scope so you don’t even perform the raycast unless you need to.