gistfile1.cs

using UnityEngine;
using System.Collections;

public class Checkpoint : MonoBehaviour {
	
	void OnTriggerEnter2D(Collider2D col)
	{
		Player p = col.GetComponent<Player>();
		if( p != null) {
			// Player touched pickup
			renderer.material.SetColor("_Color", Color.green);
			p.HitCheckpoint(this);
		}
	}
}