RaycastHit2D.distance

説明

原点からヒットしたオブジェクトの距離

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
	public Vector2 direction;

	void Update()
	{
		//Cast a ray in the direction specified in the inspector.
		RaycastHit2D hit = Physics2D.Raycast(this.gameObject.transform.position,direction);

		//If something was hit.
		if ( hit.collider != null )
		{
			//If the object hit is less than or equal to 6 units away from this object.
			if(hit.distance <= 6.0f)
			{
				Debug.Log("Enemy In Range!");
			}
		}
	}
}