Unity－Physics.Raycast

关于API看一下链接

http://game.ceeger.com/Script/Physics/Physics.Raycast.html

• static function Raycast (origin : Vector3, direction : Vector3, out hitInfo : RaycastHit, distance : float = Mathf.Infinity, layerMask : int = kDefaultRaycastLayers) : bool

Parameters参数

• origin
  The starting point of the ray in world coordinates.
  在世界坐标，射线的起始点。
• direction
  The direction of the ray.
  射线的方向。
• distance
  The length of the ray
  射线的长度。
• hitInfo
  If true is returned, hitInfo will contain more information about where the collider was hit (See Also: RaycastHit).
  如果返回true，hitInfo将包含碰到器碰撞的更多信息。
• layerMask
  A Layer mask that is used to selectively ignore colliders when casting a ray. 
  只选定Layermask层内的碰撞器，其它层内碰撞器忽略。
  
  

今天， 我讨论两个问题 

1.注意：如果从一个球型体的内部到外部用光线投射，返回为假

2.layerMask层的选择和屏蔽

首先 看第一个 如果一个点在碰撞体内部，向外部射，

先写一个脚本

using UnityEngine;using System.Collections;public class Demo2 : MonoBehaviour {public float XStartPos = 0f;public float YStartPos = 0f;public float ZStartPos = 0f;public float XEndPos = 0f;public float YEndPos = 0f;public float ZEndPos = 0f;private Vector3 startPos;private Vector3 endPos;private Vector3 direction;private float distance;// Use this for initializationvoid Start () {startPos = new Vector3 (XStartPos, YStartPos, ZStartPos);endPos = new Vector3 (XEndPos, YEndPos, ZEndPos);direction = (endPos - startPos).normalized;distance = Vector3.Distance (startPos, endPos);}// Update is called once per framevoid Update () {Debug.DrawLine (startPos, endPos, Color.red);RaycastHit hit;if (!Physics.Raycast (startPos, direction, out hit, distance)) {Debug.Log ("false");} else{Debug.Log ("yes   " + hit.collider.name);}}}

建一个cube1，绑定脚本，设置startPos在cube内endPos在cube外，运行结果表明 false

再建一个cube2，startPos依然在cube1内，但endPos在cube2内，运行结果表明 yes  cube2

也就是说  射线由内部向外部射 是不识别自己的碰撞体，但是识别其他的碰撞体。

第二个问题关于射线层的选择和屏蔽

修改一下脚本

using UnityEngine;using System.Collections;public class Demo3 : MonoBehaviour {public float XStartPos = 0f;public float YStartPos = 0f;public float ZStartPos = 0f;public float XEndPos = 0f;public float YEndPos = 0f;public float ZEndPos = 0f;private Vector3 startPos;private Vector3 endPos;private Vector3 direction;private float distance;// Use this for initializationvoid Start () {startPos = new Vector3 (XStartPos, YStartPos, ZStartPos);endPos = new Vector3 (XEndPos, YEndPos, ZEndPos);direction = (endPos - startPos).normalized;distance = Vector3.Distance (startPos, endPos);}// Update is called once per framevoid Update () {Debug.DrawLine (startPos, endPos, Color.red);RaycastHit hit;LayerMask l = 1 << LayerMask.NameToLayer("cube1");if (Physics.Raycast (startPos, direction, out hit, distance, l)) {Debug.Log ("yes   " + hit.collider.name);} else{Debug.Log ("false");}}}

自行比对

只与cube1层碰撞

Physics.Raycast (startPos, direction, out hit, distance, l)

与除cube1层以外的层碰撞

Physics.Raycast (startPos, direction, out hit, distance, ~l)

与cube2 cube3层碰撞

Physics.Raycast (startPos, direction, out hit, distance, 1 << LayerMask.NameToLayer("cube2") | 1 << LayerMask.NameToLayer("cube3"))

与除cube2 cube3层碰撞

Physics.Raycast (startPos, direction, out hit, distance,~(1 << LayerMask.NameToLayer("cube2") | 1 << LayerMask.NameToLayer("cube3")))