Unity教程（十三）敌人状态机

Unity开发2D类银河恶魔城游戏学习笔记

Unity教程（零）Unity和VS的使用相关内容
Unity教程（一）开始学习状态机
Unity教程（二）角色移动的实现
Unity教程（三）角色跳跃的实现
Unity教程（四）碰撞检测
Unity教程（五）角色冲刺的实现
Unity教程（六）角色滑墙的实现
Unity教程（七）角色蹬墙跳的实现
Unity教程（八）角色攻击的基本实现
Unity教程（九）角色攻击的改进

Unity教程（十）Tile Palette搭建平台关卡
Unity教程（十一）相机
Unity教程（十二）视差背景

Unity教程（十三）敌人状态机
Unity教程（十四）敌人空闲和移动的实现

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Unity开发2D类银河恶魔城游戏学习笔记目录

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前言

本文为Udemy课程The Ultimate Guide to Creating an RPG Game in Unity学习笔记，如有错误，欢迎指正。

本节实现敌人状态机。创建实体类，派生出敌人和玩家。

对应b站视频：
【Unity教程】从0编程制作类银河恶魔城游戏P47
【Unity教程】从0编程制作类银河恶魔城游戏P48
【Unity教程】从0编程制作类银河恶魔城游戏P49

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一、概述

本节我们开始在游戏中添加敌人。
由于敌人很多部分与玩家相似，于是抽象出实体类Entity来复用二者都有的部分。
敌人和玩家都继承自Entity。
敌人的种类有很多，我们在敌人类Enemy的基础上，创建一个骷髅小怪Enemy_Skeleton。
此外与玩家的实现对应，我们还需要敌人状态基类EnemyState，和敌人状态机EnemyStateMechine。

二、实体类Entity的创建和继承

（1）创建实体类

先整理一下文件，把之前的玩家相关脚本放在同一文件夹Player下，把视差背景脚本拖入Scripts文件夹。

我们考虑Player和Enemy共有的必须的功能。
首先可以先包含，Awake()、 Start()、Update()三个基本函数。对于一个最简单的来回踱步的小怪，碰撞、翻转和速度设置也是它们共有的基础功能。对应共有的组件要包括刚体和动画师。
在Entity中给需要在子类中重写的函数添加virtual设置为虚函数。
Entity应如下所示：

代码为

//Entity:实体类
using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.UI;public class Entity : MonoBehaviour
{[Header("Flip Info")]protected bool facingRight = true;public int facingDir { get; private set; } = 1;[Header("Collision Info")][SerializeField] protected Transform groundCheck;[SerializeField] protected float groundCheckDistance;[SerializeField] protected Transform wallCheck;[SerializeField] protected float wallCheckDistance;[SerializeField] protected LayerMask whatIsGround;#region 组件public Rigidbody2D rb { get; private set; }public Animator anim { get; private set; }#endregionprotected virtual void Awake(){}//获取组件protected virtual void Start(){rb= GetComponent<Rigidbody2D>();anim= GetComponentInChildren<Animator>();}// 更新protected virtual void Update(){}#region 速度设置//速度置零public void ZeroVelocity() => rb.velocity = new Vector2(0, 0);//设置速度public void SetVelocity(float _xVelocity, float _yVelocity){rb.velocity = new Vector2(_xVelocity, _yVelocity);FlipController(_xVelocity);}#endregion#region 翻转//翻转实现public virtual void Flip(){facingDir = -1 * facingDir;facingRight = !facingRight;transform.Rotate(0, 180, 0);}//翻转控制public virtual void FlipController(float _x){if (_x > 0 && !facingRight)Flip();else if (_x < 0 && facingRight)Flip();}#endregion#region 碰撞//碰撞检测public virtual bool isGroundDetected() => Physics2D.Raycast(groundCheck.position, Vector2.down, groundCheckDistance, whatIsGround);public virtual bool isWallDetected() => Physics2D.Raycast(wallCheck.position, Vector2.right * facingDir, wallCheckDistance, whatIsGround);//绘制碰撞检测protected virtual void OnDrawGizmos(){Gizmos.DrawLine(groundCheck.position, new Vector3(groundCheck.position.x, groundCheck.position.y - groundCheckDistance));Gizmos.DrawLine(wallCheck.position, new Vector3(wallCheck.position.x + wallCheckDistance, wallCheck.position.y));}#endregion
}

（2）派生Player类与Enemy类

抽象出Entity后我们改为由它派生出Player

//Player:玩家
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class Player : Entity
{[Header("Attack details")]public Vector2[] attackMovement;public bool isBusy { get; private set; }[Header("Move Info")]public float moveSpeed = 8f;public float jumpForce = 12f;[Header("Dash Info")][SerializeField] private float dashCoolDown;private float dashUsageTimer;public float dashSpeed=25f;public float dashDuration=0.2f;public float dashDir { get; private set; }#region 状态public PlayerStateMachine StateMachine { get; private set; }public PlayerIdleState idleState { get; private set; }public PlayerMoveState moveState { get; private set; }public PlayerJumpState jumpState { get; private set; }public PlayerAirState airState { get; private set; }public PlayerDashState dashState { get; private set; }public PlayerWallSlideState wallSlideState { get; private set; }public PlayerWallJumpState wallJumpState { get; private set; }public PlayerPrimaryAttackState primaryAttack { get; private set; }  #endregion//创建对象protected override void Awake(){base.Awake();StateMachine = new PlayerStateMachine();idleState = new PlayerIdleState(StateMachine, this, "Idle");moveState = new PlayerMoveState(StateMachine, this, "Move");jumpState = new PlayerJumpState(StateMachine, this, "Jump");airState = new PlayerAirState(StateMachine, this, "Jump");dashState = new PlayerDashState(StateMachine, this, "Dash");wallSlideState = new PlayerWallSlideState(StateMachine, this, "WallSlide");wallJumpState = new PlayerWallJumpState(StateMachine, this, "Jump");primaryAttack = new PlayerPrimaryAttackState(StateMachine, this, "Attack");}// 设置初始状态protected override void Start(){base.Start();StateMachine.Initialize(idleState);}// 更新protected override void Update(){base.Update();StateMachine.currentState.Update();CheckForDashInput();}public IEnumerator BusyFor(float _seconds){isBusy = true;yield return new WaitForSeconds(_seconds);isBusy = false;}//设置触发器public void AnimationTrigger() => StateMachine.currentState.AnimationFinishTrigger();//检查冲刺输入public void CheckForDashInput(){dashUsageTimer -= Time.deltaTime;if (Input.GetKeyDown(KeyCode.LeftShift) && dashUsageTimer<0){dashUsageTimer = dashCoolDown;dashDir = Input.GetAxisRaw("Horizontal");if (dashDir == 0)dashDir = facingDir;StateMachine.ChangeState(dashState);}}}

修改完后运行一下，检查是否破坏原有功能


接着我们创建敌人Enemy类，

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class Enemy : Entity
{public EnemyStateMachine stateMachine;protected override void Awake(){base.Awake();stateMachine = new EnemyStateMachine();}protected override void Update(){base.Update();stateMachine.currentState.Update();}
}

三、敌人状态基类和状态机

（1）敌人状态基类

敌人状态基类和玩家状态基类也基本相似，其中具有状态可能共同用到的变量，状态的构造函数，和状态的进入更新和退出。

//EnemyState:敌人状态基类
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class EnemyState
{protected EnemyStateMachine stateMachine;protected Enemy enemyBase;private string animBoolName;protected float stateTimer;protected bool triggerCalled;//构造函数public EnemyState(EnemyStateMachine _stateMachine, Enemy _enemyBase, string _animBoolName){this.stateMachine = _stateMachine;this.enemyBase = _enemyBase;this.animBoolName = _animBoolName;}public virtual void Enter(){triggerCalled = false;enemyBase.anim.SetBool(animBoolName, true);}public virtual void Update(){stateTimer-= Time.deltaTime;}public virtual void Exit(){enemyBase.anim.SetBool(animBoolName, false);}
}

（2）敌人状态机

敌人状态机中包含当前状态，和初始化状态机和改变状态的函数

//EnemyStateMachine：状态机
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class EnemyStateMachine
{//当前状态public EnemyState currentState { get; private set; }//初始化public void Initialize(EnemyState _startState){currentState = _startState;currentState.Enter();}//改变状态public void ChangeState(EnemyState _newState){currentState.Exit();currentState = _newState;currentState.Enter();}
}

（3）创建SkeletonIdleState和SkeletonMoveState

我们先创建两个类用于骷髅小怪状态机的初始化，至于两个状态的具体内容，将在下一节进行具体实现。
Alt+Enter从子菜单中使用生成构造函数和生成重写。

骷髅小怪的空闲状态：

//SkeletonIdleState:骷髅空闲状态
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class SkeletonIdleState : EnemyState
{public SkeletonIdleState(EnemyStateMachine _stateMachine, Enemy _enemyBase, string _animBoolName) : base(_stateMachine, _enemyBase, _animBoolName){}public override void Enter(){base.Enter();}public override void Exit(){base.Exit();}public override void Update(){base.Update();}
}

骷髅小怪的移动状态：

//SkeletonMoveState:骷髅移动状态
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class SkeletonMoveState : EnemyState
{public SkeletonMoveState(EnemyStateMachine _stateMachine, Enemy _enemyBase, string _animBoolName) : base(_stateMachine, _enemyBase, _animBoolName){}public override void Enter(){base.Enter();}public override void Exit(){base.Exit();}public override void Update(){base.Update();}
}

四、创建骷髅小怪Enemy_Skeleton

我们以Enemy为基类可以派生出各种各样的有各自特点的敌人，在本教程中我们以骷髅Enemy_Skeleton为例制作一类小怪。

参照我们起始时Player创建状态机的过程。我们在Enemy基类中创建了状态机，现在要在Skeleton_Enemy中设置骷髅小怪的起始状态。
在Skeleton_Enemy中创建两个状态空闲和移动两个状态，将空闲状态作为起始状态。

//Enemy_Skeleton:骷髅敌人
using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class Enemy_Skeleton : Enemy
{#region 状态public SkeletonIdleState idleState { get; private set; }public SkeletonMoveState moveState { get; private set; }#endregionprotected override void Awake(){base.Awake();idleState = new SkeletonIdleState(stateMachine,this,"Idle");moveState = new SkeletonMoveState(stateMachine, this, "Move");}protected override void Start(){base.Start();stateMachine.Initialize(idleState);}protected override void Update(){base.Update();}}