Unity LayerMask 与位运算

Unity是用 int32来表示32个Layer层，int32用二进制来表示一共有32位。

0000 0000 0000 0000 0000 0000 0000 0000

31                                                            0

看几个例子：

开启layer 2

LayerMask mask = 1<<2;

其中 <<左边的 1表示有[开启碰撞]，0表示没有该layer[忽略碰撞] 。右边的2表示左移2位即是 layer2层的位置。

开启layer 0和layer 2

LayerMask mask = 1 << 0 |  1 << 2;

开启Layer0 并关闭 Layer2

LayerMask mask = 1 << 0 | 0 << 2

开启Layer Default

LaserMask mask=1 << LayserMask.NameToLayer(“Default”);

下面是一个脚本例子，把它绑定在Camera上

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(Camera))]
public class LayerMaskTest : MonoBehaviour {

    //打开Npc层，变1 或 运算符
    private void Show()
    {
        //camera.cullingMask |= 1 << LayerMask.NameToLayer("Npc");
        camera.cullingMask = (int) 1<<LayerMask.NameToLayer("Npc");//写法二
    }

    // 关闭Npc层，变0 按位与 &  按位取反 ~
    private void Hide()
    {
        camera.cullingMask &= ~(1 << LayerMask.NameToLayer("Npc"));
    }

    // 开关Npc层，按位异或    ^
    private void Toggle()
    {
        camera.cullingMask ^= 1 << LayerMask.NameToLayer("Npc");
    }

    void OnGUI()
    {
        if (GUILayout.Button("Show")) Show();
        if (GUILayout.Button("Hide")) Hide();
        if (GUILayout.Button("Toggle")) Toggle();
    }
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

Unity的碰撞检测API：

static bool Raycast(Vector3 origin, Vector3 direction, float distance = Mathf.Infinity, int layerMask = DefaultRaycastLayers);

我在项目中进行物理碰撞互斥：

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

    float bounds = 2;
      LayerMask mask = 1 << (int)GameLayerDef.Npc;
      RaycastHit2D raycastHit = Physics2D.CircleCast(transform.position, bounds, Vector2.right, Mathf.Infinity, mask.value);

注：部分内容参考自: 【风宇冲】二进制：四 Unity

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

Unity LayerMask 与位运算