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 initialization
void 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 frame
void 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 initialization
void 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 frame
void 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")))