求教关于射线的问题，如何让射线只与某层上的物件碰撞

求教关于射线的问题，如何让射线只与某层上的物件碰撞

c#:
using UnityEngine;
using System.Collections;

public class Pathing : MonoBehaviour {

private int LayerGround;
private bool CastRays = true;

void Start () {
LayerGround = LayerMask.NameToLayer("Ground");
}

void Update () {
if (CastRays) {

Ray ray = Camera.mainCamera.ScreenPointToRay (Input.mousePosition);
RaycastHit hit;

// Raycast
if (Physics.Raycast(ray, out hit, Mathf.Infinity)) {

if (hit.transform.gameObject.layer == LayerGround) {
Debug.Log("Ground");//这里和指定层碰撞
} else {
Debug.Log("Other Objects");
}
}
}
}
}

js:

private var LayerGround;
private var CastRays : boolean = true;

function Start () {
LayerGround = LayerMask.NameToLayer("Ground");
}

function Update () {
if (CastRays) {

var ray = Camera.mainCamera.ScreenPointToRay (Input.mousePosition);
var hit : RaycastHit;

// Raycast
if (Physics.Raycast(ray, hit, Mathf.Infinity)) {

if (hit.transform.gameObject.layer == LayerGround) {
Debug.Log("Ground");//这里和指定层碰撞
} else {
Debug.Log("Other Objects");
}
}
}
}