Learn 2D Roguelike tutorial

这篇文章是我通过 2D Roguelike tutorial 项目在学习 Unity 的使用时留下的记录.

官方教程中提供的视频来自 YouTube, 国内有搬运工已经把整套视频搬到 Bilibili 了.

学习成果: 学习成果.mp4

本文内容的更新将第一时间在 Github 项目主页 发布. 更多内容见 个人主页

Rules

通过试玩, 我发现了这个小游戏的一些基础的游戏规则:

1. 回合制游戏, 由玩家移动触发回合.
2. 玩家可以通过 WASD 和 ↑↓←→ 进行移动.
3. 地图中的可移动区域为8x8大小, 四周由外墙 (outerWall) 包围.
4. 可移动区域内会生成位置随机, 数量随机的障碍物 (wall), 水果 (food) 和饮料 (soda).
5. 可移动区域内会生成位置随机, 数量逐渐增多的敌人 (enemy).
6. 玩家 (player) 初始生命值 (foodPoint) 为 100, 碰到水果提升 10 点, 碰到饮料提升 20 点, 被敌人攻击时, 根据敌人类型丢失 10 点或 20 点.
7. 障碍物有 3 点生命值, 被玩家攻击第一次以后会更换材质, 被摧毁后允许玩家和敌人通过.
8. 出口固定在右上角位置.
9. 镜头固定在(x=3.5,y=3.5,z=-10)的位置.
10. 地图全开, 没有迷雾.

File tree

根目录
 ┣ Assets (资产目录, 存放源代码, 素材的地方, 应该被 VCS 管理)
 ┃ ┣ _Complete-Game (完整示例)
 ┃ ┃ ┣ Animation (动画示例)
 ┃ ┃ ┣ Prefabs (预制件示例)
 ┃ ┃ ┣ Scenes (场景示例)
 ┃ ┃ ┣ Scripts (脚本示例)
 ┃ ┃ ┣ _Complete-Game.unity (完整示例的主场景)
 ┃ ┃ ┗ (**.meta (各个文件/文件夹的元数据文件, 由 Unity3D 编译产生, 用来记录 Inspector 中的各种数据))
 ┃ ┣ Audio (音频素材)
 ┃ ┣ Fonts (字体素材)
 ┃ ┣ (Plugins (插件目录))
 ┃ ┣ Sprites (贴图目录)
 ┃ ┣ TutorialInfo (教程目录)
 ┃ ┗ Readme.asset (使用说明对应的资产)
 ┣ Library  (库目录, 存放 Unity3D 编译期产物的地方, 应该被 VCS 忽略)
 ┣ Logs (编译期日志文件夹, )
 ┣ obj (C# 脚本编译产物的地方)
 ┣ Packages (依赖目录? 应该被 VCS 管理)
 ┃ ┗ manifest.json (清单文件, 记录了这个项目的第三方依赖等)
 ┣ ProjectSettings (工程配置, 应该被 VCS 管理)
 ┃ ┣ *.asset (各种资源管理器对应的元数据)
 ┃ ┗ ProjectVersion.txt (目前只记录了 Unity3D 编辑器的版本号)
 ┣ Temp (用途不明的临时文件夹, 应该被 VCS 忽略)
 ┣ *.csproj (Visual studio 编译项目时生产的文件, 应该被 VCS 忽略)
 ┗ *.sln (Visual studio 的项目管理文件, 应该被 VCS 管理)

Version control

第一次接触 Unity 工程, 在做版本控制的时候搜了一些文档, 主要提到了要将 Edit->ProjectSettings->Editor 中的 Version control mode 改为 Visible Meta Files 以及将
Asset serialization mode 改为 Force Text.

仔细调试了一下后, 发现 Visible Meta Files 能够使 Unity 在导入工程的时候生成各种 .meta 后缀的文件. 而 Force Text 则控制着 *.meta 文件里的内容格式, 将各种元数据序列化为可读性较好的 Unity YAML 格式.

后来测试发现这些 *.meta 文件记录着 Inspector 面板中的数据, 是 Unity 的各种组件之间的依赖关系的持久化文件.

Learn by reading

_Complete-Game 目录下包含整个教程完整的示例, 是我学习这个项目的主战场.

Readme.asset

该文件中记录了 TutorialInfo/Scripts/Readme.cs 类对应的元数据. 进一步探索发现这个资产的 Inspector 界面以及顶部工具栏里的 Tutorial 菜单都是通过
TutorialInfo/Scripts/Editor/ReadmeEditor.cs 控制的.

到处改一改, 发现 Unity 插件开发相当的敏捷, 不像 IDEA 的插件, 每次测试插件效果都要重启一个 IDEA 实例. 这个应该也跟编程语言有关系吧.

Main.unity

主场景. 仔细观察了一下发现在 Camera 上挂载着一个 Loader 脚本.

脚本内容很简单, 通过 Inspector 中设置的属性实例化 GameManager 和 SoundManager 对象.

SoundManager.cs

音效管理器. 由于对象在 Unity 环境中托管, 因此在生命周期函数 Awake 中通过判断静态引用的方式实现了单利设计. 利用 AudioSource 类播放本地音频文件, 为了避免听觉疲劳, 使用了随机数调整音效的高低音.

private void Awake() {
    //Check if there is already an instance of SoundManager
    if (Instance == null)
        //if not, set it to this.
        Instance = this;
    //If instance already exists:
    else if (Instance != this)
        //Destroy this, this enforces our singleton pattern so there can only be one instance of SoundManager.
        Destroy(gameObject);

    //Set SoundManager to DontDestroyOnLoad so that it won't be destroyed when reloading our scene.
    DontDestroyOnLoad(gameObject);
    ...
}

GameManger.cs

游戏管理器. 在 Awake 中定义了 Enemy 集合, 并通过 GetComponent<>() 获取到了被托管的 BoardManager 对象完成成员变量的初始化.

//Get a component reference to the attached BoardManager script
_boardScript = GetComponent<BoardManager>();

加下来调用 InitGame 方法控制 UI 层的遮罩以及关卡提示的显示与隐藏, 并调用了 BoardManager 的 SetupScene(int) 初始化了每一级关卡的动态场景.

在生命周期 Update 中, 如果不需要等待玩家移动, 其他敌人移动或者过场的话, 则尝试开启协程移动每一个 Enemy 对象. 全部 Enemy 移动完成后, 允许 Player 移动.

BoardManager.cs

关卡管理器. 没有采用单例设计, 也没有实现生命周期方法.

对外仅暴露部分成员属性用于依赖注入, 以及 SetupScene(int) 方法用于实例化每一级关卡的外墙, 地板, 内墙 (Wall), 食物, 苏打, 敌人以及出口.

具体的实例化方式则是调用 Instantiate(...) 方法, 将指定的预设物实例化在场景中.

//Instantiate the GameObject instance using the prefab chosen for toInstantiate at the Vector3
//corresponding to current grid position in loop, cast it to GameObject. Set the parent of our newly
//instantiated object instance to boardHolder, this is just organizational to avoid cluttering hierarchy.
Instantiate(toInstantiate, new Vector3(x, y, 0f), Quaternion.identity, _boardHolder);

Wall.cs

内墙. 对外暴露 DamageWall(int) 方法, 从实现的功能上来看应该是属于回调类型的方法 (更贴切一点的命名应该是 OnDamage(int) 吧 23333).

内墙被攻击时通过调用 SpriteRenderer 实现了运行时将换贴图替换为受损状态的贴图, hp 低于 0 时将 gameObject 设为失活从而将其从场景中隐藏.

//Set spriteRenderer to the damaged wall sprite.
_spriteRenderer.sprite = dmgSprite;
...
if (_hp > 0) return;
//If hit points are less than or equal to zero, disable the gameObject.
gameObject.SetActive(false);

Enemy.cs

敌人. 继承自 MovingObject 类.

在 Start 生命周期中将自身注册到 GameManager(我觉得这个注册的时机应该由 BoardManager 管理), 并引用玩家的 Transform 对象, 以便在 Update 时向玩家移动.

寻路的算法比较简陋, 简单的判断了一下自身与玩家的水平方向的差距和竖直方向的差距, 然后尝试移动, 没有考虑到撞墙, 绕路等情况.

//MoveEnemy is called by the GameManger each turn to tell each Enemy to 
//try to move towards the player.
public void MoveEnemy() {
    //Declare variables for X and Y axis move directions, these range 
    //from -1 to 1. These values allow us to choose between the cardinal
    //directions: up, down, left and right.
    var xDir = 0;
    var yDir = 0;

    //If the difference in positions is approximately zero (Epsilon) do the following:
    if (Mathf.Abs(_target.position.x - transform.position.x) < float.Epsilon)
        //If the y coordinate of the target's (player) position is greater 
        //than the y coordinate of this enemy's position set y direction 1
        //(to move up). If not, set it to -1 (to move down).
        yDir = _target.position.y > transform.position.y ? 1 : -1;

    //If the difference in positions is not approximately zero (Epsilon) do the following:
    else
        //Check if target x position is greater than enemy's x position,
        //if so set x direction to 1 (move right), if not set to -1 (move left).
        xDir = _target.position.x > transform.position.x ? 1 : -1;

    //Call the AttemptMove function and pass in the generic parameter Player,
    //because Enemy is moving and expecting to potentially encounter a Player
    AttemptMove(xDir, yDir);
}

当遇到玩家导致不能移动时, 则攻击玩家, 触发攻击动画同时播放攻击音效.

//OnCantMove is called if Enemy attempts to move into a space occupied 
//by a Player, it overrides the OnCantMove function of MovingObject 
//and takes a generic parameter T which we use to pass in the component 
//we expect to encounter, in this case Player
protected override void OnCantMove <T> (T component)
{
    //Declare hitPlayer and set it to equal the encountered component.
    Player hitPlayer = component as Player;
    //Call the LoseFood function of hitPlayer passing it playerDamage, 
    //the amount of foodpoints to be subtracted.
    hitPlayer.LoseFood (playerDamage);
    //Set the attack trigger of animator to trigger Enemy attack animation.
    animator.SetTrigger ("enemyAttack");
    //Call the RandomizeSfx function of SoundManager passing in 
    //the two audio clips to choose randomly between.
    SoundManager.instance.RandomizeSfx (attackSound1, attackSound2);
}

MovingObject.cs

可移动的对象. 作为敌人和玩家的父类, 为子类提供了移动方向的碰撞检测和平滑移动能力.

在尝试移动时, 调用 Move(...) 方法进行碰撞检测, 遇到障碍时调用回调方法 OnCannotMove<>(), 否则开启协程进行平滑移动.

//Move returns true if it is able to move and false if not. 
//Move takes parameters for x direction, y direction and a RaycastHit2D to check collision.
protected bool Move(int xDir, int yDir, out RaycastHit2D hit)
{
    ...
    //Cast a line from start point to end point checking collision on blockingLayer.
    hit = Physics2D.Linecast (start, end, blockingLayer);
    ...
    if(hit.transform == null)
    {
        //If nothing was hit, start SmoothMovement co-routine passing in 
        //the Vector2 end as destination
        StartCoroutine(SmoothMovement(end));
        //Return true to say that Move was successful
        return true;
    }
    //If something was hit, return false, Move was unsuccesful.
    return false;
}

Move(...) 方法同时输出了 2 个结果, 一个 bool 类型的返回值, 标志着能否朝指定方向移动, 以及一个 RaycastHit2D 类型的碰撞结果. 我个人感觉布尔类型的返回值有点多余, 通过判断碰撞结果是否为 null 即可.

//The virtual keyword means AttemptMove can be overridden by inheriting classes 
//using the override keyword. AttemptMove takes a generic parameter T 
//to specify the type of component we expect our unit to interact with if blocked 
//(Player for Enemies, Wall for Player).
protected virtual void AttemptMove <T> (int xDir, int yDir)
    where T : Component
{
    //Hit will store whatever our linecast hits when Move is called.
    RaycastHit2D hit;
    //Set canMove to true if Move was successful, false if failed.
    bool canMove = Move (xDir, yDir, out hit);
    //Check if nothing was hit by linecast
    if(hit.transform == null)
        //If nothing was hit, return and don't execute further code.
        return;
    
    //Get a component reference to the component of type T attached to the object that was hit
    T hitComponent = hit.transform.GetComponent <T> ();
    //If canMove is false and hitComponent is not equal to null, meaning 
    //MovingObject is blocked and has hit something it can interact with.
    if(!canMove && hitComponent != null)
        //Call the OnCantMove function and pass it hitComponent as a parameter.
        OnCantMove (hitComponent);
}

AttemptMove(int,int) 判断到能移动时没有执行动作, 这里其实可以把 Move() 方法中开协程进行平滑移动的代码移动到这里来的.

Player.cs

玩家.

玩家类使用宏对运行平台进行了隔离, 移动端判断滑动方向, 桌面端则是判断 WASD 和 ↑↓←→ 进行移动. 不能移动时可以攻击内墙.

private static void HandleInput(out int horizontal, out int vertical) {
            //Check if we are running either in the Unity editor or in a standalone build.
#if UNITY_STANDALONE || UNITY_WEBPLAYER
            //Get input from the input manager, round it to an integer 
            //and store in horizontal to set x axis move direction
            horizontal = (int) Input.GetAxisRaw("Horizontal");
            //Get input from the input manager, round it to an integer 
            //and store in vertical to set y axis move direction
            vertical = (int) Input.GetAxisRaw("Vertical");
            //Check if moving horizontally, if so set vertical to zero.
            if (horizontal != 0) vertical = 0;
            //Check if we are running on iOS, Android, Windows Phone 8 or Unity iPhone
#elif UNITY_IOS || UNITY_ANDROID || UNITY_WP8 || UNITY_IPHONE
            ...
#endif //End of mobile platform dependent compilation section started above with #elif
        }

玩家实现了 OnTriggerEnter2D(Collider2D) 方法, 从而监听到了 2d 碰撞箱的碰撞事件, 对遇到食物和苏打分别进行了不同程度的生命恢复, 遇到出口时则触发场景的重载, 进入下一关卡.

//OnTriggerEnter2D is sent when another object enters a trigger collider attached to this object (2D physics only).
private void OnTriggerEnter2D (Collider2D other)
{
    //Check if the tag of the trigger collided with is Exit.
    if(other.tag == "Exit")
    {
        //Invoke the Restart function to start the next level with a delay of restartLevelDelay (default 1 second).
        Invoke ("Restart", restartLevelDelay);
        //Disable the player object since level is over.
        enabled = false;
    }
    //Check if the tag of the trigger collided with is Food.
    else if(other.tag == "Food")
    {
        //Add pointsPerFood to the players current food total.
        food += pointsPerFood;
        //Update foodText to represent current total and notify player that they gained points
        foodText.text = "+" + pointsPerFood + " Food: " + food;
        //Call the RandomizeSfx function of SoundManager and pass in 
        //two eating sounds to choose between to play the eating sound effect.
        SoundManager.instance.RandomizeSfx (eatSound1, eatSound2);
        //Disable the food object the player collided with.
        other.gameObject.SetActive (false);
    }
    //Check if the tag of the trigger collided with is Soda.
    else if(other.tag == "Soda")
    {
        ...
    }
}

当玩家被敌人攻击时, 回调 OnLossFood(int) 方法, 触发被攻击动画, 移除生命值, 并判断游戏是否结束.

Learn by modifying

至此, Unity 官方教程 2d-roguelike-tutorial 分析完毕, 接下来就是到处改东西, 看看会不会崩了 :).

Resize movable area from 8x8 to random size

想要调整地图尺寸很简单, 在 BoardManager 中修改 _columns 和 _rows 成员变量就行了.

private void BoardSetup(){
    _columns = Random.Range(6, 10);
    _rows = Random.Range(6, 10);
    ...
}

Bad apple

地牢里的水果和饮料总是那么的新鲜, 看起来很诡异, 我决定加入一些烂苹果和腐败的饮料混在其中.

private void OnTriggerEnter2D(Collider2D other) {
    switch (other.tag) {
        case "Food":
            // simulate bad apple
            var randomFoodPoint = Random.Range(-pointsPerFood, pointsPerFood);
            _food += randomFoodPoint;
            ...
    }
}

Superior enemy

精英怪都是会拆墙的.

为了让玩家和敌人能够攻击不同类型的对象, 需要调用 AttemptMove<>(int,int) 方法, 并传入不同的泛型:

...
base.AttemptMove<Wall>(xDir, yDir);
base.AttemptMove<Enemy>(xDir, yDir);
...

但这样写看起来很不简洁, 而且对象会移动多次. 因此需要把泛型从 AttemptMove<>(int,int) 和 OnCannotMove<T>(T) where T : MonoBehavior 中移除.

protected override void OnCantMove(MonoBehavior component) {
    switch (component) {
        case Wall wall:
            wall.DamageWall(Damage);
            break;
    }
    ...
}

Main role

镜头默认位于 (x=3.5,y=3.5,z=-10) 位置, 在地图尺寸随机的情况下, 有时候会看不全. 要使镜头跟随玩家的话, 需要在 Hierarchy 面板中将 MainCamera 移动到 Player 对象内部, 并将 MainCamera 的 position 调整为 (x=0,y=0,z=-10), 确保玩家位于镜头中央.

Fog of war

战争迷雾的缺失, 使得游戏的探索性降低为 0, 玩家只需要在开始行动前规划好路径即可.

要将战争迷雾这一特性加入游戏, 需要改造 BoardManager 和 GameManager:

1. 添加 Fog 预设物以及贴图, 并调整 Sorting layer 为 Units, 确保战争迷雾与玩家同层.
2. 添加 List<GameObject> 到 BoardManager, 用于存放战争迷雾实例.
3. 为 BoardManager 添加方法 public void ClearFogAround(Vector3), 通过控制 GameObject 的 active 属性实现迷雾的显示隐藏, 并延伸到移除指定位置近处的迷雾效果, 恢复远处的迷雾效果.
4. 使 BoardManager 单例化, 以便能够跨组件调用.
5. MovingObject 添加移动结束回调, 以便玩家移动成功时能触发战争迷雾的动态效果.

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