游戏编程模式05-设计模式-原型模式

设计模式-原型模式

参考章节：https://gpp.tkchu.me/prototype.html

脑内画面

原型模式把"创建一个新对象"变成"复制一个已经配置好的样板"。它像关卡编辑器里的复制粘贴：设计师先做出一只带属性、掉落、AI 参数的怪物样本，生成器以后只负责克隆。
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血量/速度/掉落/AI
实例 A
实例 B
实例 C

它解决的问题

当对象构造过程很复杂，或者类型组合来自数据配置时，继续写一堆 new EnemyA(...)、new EnemyB(...) 会让创建逻辑散落在代码里。原型模式让对象自己知道如何复制自己，生成器只依赖"可克隆"的抽象。

C# 示例

csharp 复制代码

public interface IPrototype<out T>
{
    T Clone();
}

public sealed class Monster : IPrototype<Monster>
{
    public string Name { get; private set; }
    public int Health { get; private set; }
    public List<string> LootTable { get; }

    public Monster(string name, int health, IEnumerable<string> lootTable)
    {
        Name = name;
        Health = health;
        LootTable = new List<string>(lootTable);
    }

    public Monster Clone()
    {
        return new Monster(Name, Health, LootTable);
    }

    public void ScaleForLevel(int level)
    {
        Health += level * 10;
    }
}

public sealed class Spawner
{
    private readonly Monster _prototype;

    public Spawner(Monster prototype)
    {
        _prototype = prototype;
    }

    public Monster Spawn(int level)
    {
        var monster = _prototype.Clone();
        monster.ScaleForLevel(level);
        return monster;
    }
}

什么时候用

创建对象需要大量默认参数。
运行时才知道要创建哪种对象。
数据驱动对象比继承层级更自然。
编辑器里需要复制预制体、技能、单位、任务模板。

使用时的锋利边

C# 里的浅拷贝很诱人，但游戏对象往往包含列表、引用、资源句柄。要明确哪些字段共享，哪些字段深拷贝。资源资产可以共享，运行时状态通常要复制。

原型适合"从样板派生实例"，但不适合隐藏复杂生命周期。对象需要注册系统、申请资源、绑定事件时，克隆后仍要有清晰的初始化阶段。