Using Colliders to Send Messages to the Object Collided With

Questions & Answers
1

I have been having a huge amount of trouble figuring out how to call an ApplyDamage function when a “Bullet” prefab rigid body collides with an other object. Each of these objects collided with have a C# script attatched called CharHealth which is this:

using UnityEngine;
using System.Collections;

public class CharHealth : MonoBehaviour {

	public float maxHealth = 100f;
	public float health = 100f;
	public float minHealth = 0;

	void Start(){
		health = maxHealth;
	}
	public void ApplyDamage(float damageTotal)
	{
		health -= damageTotal;
		Debug.Log ("Damage " + damageTotal + " was applied");
		if (health <= 0)
		{
			health = minHealth;
			Death();
		}
	}
	void Death()
	{
		Destroy (gameObject);
	}
}

I know this script works because I have a melee range enemy that already calls it sucessfully based around how close they are to the player. The problem I have been having is where do I assign a collider script to? The rigid body bullet? or the characters being fired upon.

This is the script I have applied to the bullet for now which isn’t working:

public class CollidingScript : MonoBehaviour {
	
	void OnColliding(Collider col){ // col is a reference to the collider hit
		if (col.gameObject.name == "TargetCube"){ // if the collider belongs to the Player...
			//col.SendMessage("ApplyDamage", 5); // send the message to its owner
			Debug.Log ("Collision Detected");
			Destroy (col.gameObject);
		}
	}
}

I was using this API as reference https://unity3d.com/learn/tutorials/modules/beginner/physics/on-collision-enter and having very little luck. It was erroring with the message “On Colliding has to be of type collider” or somethign along those lines. Follow up question: does this OnColliding() function need to be called in an update, or is it automatic?

2

Here is the corrected class. It takes the name of the target as a public string and then destroys that object.

public class CollidingScript : MonoBehaviour {
public string name;

	void OnCollisionEnter(Collision col){ // col is a reference to the collider hit
		if (col.gameObject.name == name){ // if the collider belongs to the Player...
			//col.SendMessage("ApplyDamage", 5); // send the message to its owner
			Debug.Log ("Collision Detected");
			Destroy (col.gameObject);
		}
	}