【Unity3D】Tags和Layers

Tags和Layers分别表示是Unity引擎里面的标签和层，他们都是用来对GameObject进行标识的属性，Tags常用于单个GameObject，Layers常用于一组的GameObject。添加Tags和Layers的操作如下：

"Edit" -> "Project Settings" -> "Tags and Layers"来打开设置面板。

    tag可以理解为一类元素的标记，如hero、enemy、apple-tree等。通过设置tag，可以方便地通过GameObject.FindWithTag()来寻找对象。GameObject.FindWithTag()只返回一个对象，要想获取多个tag为某值的对象，GameObject.FindGameObjectsWithTag()。

    每个GameObject的Inspector面板最上方都也有个Layer选项，就在Tag旁边，unity已经有了几个层，我们新建个层，也叫UI，点击Add Layer，可以看到从Layer0到Layer7都灰掉了，那是不能用的，从第八个起可以用，Layer和tag还有一个很大的区别就是layer最多只能有32个层。

    在使用过程中，使用Culling Mask、Layer Mask的地方实际指的就是layer。下面我们来看一段使用layer来检测碰撞的代码：

Ray ray1 = nguiCamera.camera.ScreenPointToRay(Input.mousePosition);  
RaycastHit hit1; 
LayerMask mask = 1 << LayerMask.NameToLayer("UI"); if (Physics.Raycast(ray1, out hit1, 600, mask.value)) 
{ return;
} 

  LayerMask的NameToLayer是通过层的名称返回该层的索引，如果是8，然后1<<8换算成LayerMask值，再用LayerMask的value就可以了。注意也必须设置collider才能接收碰撞，这里才能判断到。LayerMask实际上是一个位码操作，在Unity中Layers一共有32层，这个是不能增加或者减少的:     1 << LayerMask.NameToLayer("UI") 这一句实际上表示射线查询只在UI所在这个层级查找是返回的该名字所定义的层的层索引，注意是从0开始。

下面我们来看一个玩家控制的脚本，利用 Physics2D.Linecast检测物体是否碰撞到地面。

using UnityEngine;
using System.Collections;public class PlayerControl : MonoBehaviour
{[HideInInspector]public bool facingRight = true;            // For determining which way the player is currently facing.
    [HideInInspector]public bool jump = false;                // Condition for whether the player should jump.public float moveForce = 365f;            // Amount of force added to move the player left and right.public float maxSpeed = 5f;                // The fastest the player can travel in the x axis.public AudioClip[] jumpClips;            // Array of clips for when the player jumps.public float jumpForce = 1000f;            // Amount of force added when the player jumps.public AudioClip[] taunts;                // Array of clips for when the player taunts.public float tauntProbability = 50f;    // Chance of a taunt happening.public float tauntDelay = 1f;            // Delay for when the taunt should happen.private int tauntIndex;                    // The index of the taunts array indicating the most recent taunt.private Transform groundCheck;            // A position marking where to check if the player is grounded.private bool grounded = false;            // Whether or not the player is grounded.private Animator anim;                    // Reference to the player's animator component.void Awake(){// Setting up references.// 在子对象里面找到groundCheckgroundCheck = transform.Find("groundCheck");// 获取当前的动画控制器anim = GetComponent();}void Update(){// 是为能随时检测到groundCheck这个物体，添加一个名叫Ground的Layer，然后把场景中的所有代表地面的物体的Layer设为Ground// 这里用到了2D射线检测Physics2D.Linecast()// LayerMask实际上是一个位码操作，在Unity3d中Layers一共有32层，这个是不能增加或者减少的:// 1 << LayerMask.NameToLayer("Ground") 这一句实际上表示射线查询只在Ground所在这个层级查找 是返回的该名字所定义的层的层索引，注意是从0开始// 每个GameObject的Inspector面板最上方都也有个Layer选项，就在Tag旁边，unity3d已经有了几个层，我们新建个层，也叫UI，点击Add Layer，可以看到从Layer0到Layer7都灰掉了，那是不能用的，从第八个起可以用，所以在第八个建个UI的层。// 一般情况下我们只用前两个参数，distance表示射线距离，默认是无限远，重点是最后一个参数layerMask，专门处理layer过滤的，是个整型，怎么用呢，是靠layer的二进制位来操作的// LayerMask的NameToLayer是通过层的名称返回该层的索引，这里是8，然后1<<8换算成LayerMask值，再用LayerMask的value就可以了。// 注意也必须设置collider才能接收碰撞，这里才能判断到。grounded = Physics2D.Linecast(transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Ground"));  // If the jump button is pressed and the player is grounded then the player should jump.// 如果点击了跳的按键，并且已经着陆，那么就可以跳起来if(Input.GetButtonDown("Jump") && grounded)jump = true;}// 因为主角游戏对象要使用到刚体力，所以一定要写在FixedUpdate里面，不能放在Update上void FixedUpdate (){// Cache the horizontal input.// 换取水平方向的移动距离float h = Input.GetAxis("Horizontal");// The Speed animator parameter is set to the absolute value of the horizontal input.// 设置动画的速度变量anim.SetFloat("Speed", Mathf.Abs(h));// 给物体添加一个水平的力，让它移动的时候会产生惯性的效果// If the player is changing direction (h has a different sign to velocity.x) or hasn't reached maxSpeed yet...// 如果速度小于最大的速度 if(h * rigidbody2D.velocity.x < maxSpeed)// ... add a force to the player.rigidbody2D.AddForce(Vector2.right * h * moveForce);// If the player's horizontal velocity is greater than the maxSpeed...if(Mathf.Abs(rigidbody2D.velocity.x) > maxSpeed)// ... set the player's velocity to the maxSpeed in the x axis.rigidbody2D.velocity = new Vector2(Mathf.Sign(rigidbody2D.velocity.x) * maxSpeed, rigidbody2D.velocity.y);// 转身// If the input is moving the player right and the player is facing left...if(h > 0 && !facingRight)// ... flip the player.
            Flip();// Otherwise if the input is moving the player left and the player is facing right...else if(h < 0 && facingRight)// ... flip the player.
            Flip();// If the player should jump...if(jump){// Set the Jump animator trigger parameter.// 触发跳的动画anim.SetTrigger("Jump");// Play a random jump audio clip.int i = Random.Range(0, jumpClips.Length);AudioSource.PlayClipAtPoint(jumpClips[i], transform.position);// Add a vertical force to the player.// 添加一个垂直的力rigidbody2D.AddForce(new Vector2(0f, jumpForce));// Make sure the player can't jump again until the jump conditions from Update are satisfied.jump = false;}}// 转身void Flip (){// Switch the way the player is labelled as facing.facingRight = !facingRight;// Multiply the player's x local scale by -1.Vector3 theScale = transform.localScale;theScale.x *= -1;transform.localScale = theScale;}public IEnumerator Taunt(){// Check the random chance of taunting.float tauntChance = Random.Range(0f, 100f);if(tauntChance > tauntProbability){// Wait for tauntDelay number of seconds.yield return new WaitForSeconds(tauntDelay);// If there is no clip currently playing.if(!audio.isPlaying){// Choose a random, but different taunt.tauntIndex = TauntRandom();// Play the new taunt.audio.clip = taunts[tauntIndex];audio.Play();}}}int TauntRandom(){// Choose a random index of the taunts array.int i = Random.Range(0, taunts.Length);// If it's the same as the previous taunt...if(i == tauntIndex)// ... try another random taunt.return TauntRandom();else// Otherwise return this index.return i;}
}

转载于:https://www.cnblogs.com/qiuxiangmuyu/p/5826418.html

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