Netcode升级到1.2.0网络变量的变化的变化

1 概述

最近工程升级到Netcode For Gameobject 1.2.0版本
运行会出现部分报错，查看原因后发现是网络变量模块构造方法出现的问题

2 继承网络变量 NetworkVariable，派生类构造出错的问题

2.1 代码描述

【1.1.0+版本 标记以下类为过时】
【1.0.2-版本 以下类可用】
/// <summary>
/// 网络变量 - 基类【重写】
/// </summary>
/// 
/// <remarks>
/// <list type="number">
/// <item> 加入构造函数，可以new新元素加入链表</item>
/// <item>网络变量可以用作静态字段，但是RPC不可以</item>
/// </list>/// </remarks>
[Serializable]
public class NetVar<T> : NetworkVariable<T> where T : unmanaged
{public NetVar(T value = default,NetworkVariableReadPermission readPerm = DefaultReadPerm,NetworkVariableWritePermission writePerm = DefaultWritePerm) : 
base(value, readPerm, writePerm){Value = value;}
}[Obsolete("1.0.2-版本可用，1.1+版本使用-NetworkVariable")]
[Serializable] public class NetVar_Int : NetVar<int>
{public NetVar_Int(int value = 0,NetworkVariableReadPermission readPerm = DefaultReadPerm,NetworkVariableWritePermission writePerm = DefaultWritePerm) : base(value, readPerm, writePerm){Value = value;}
}

2.2 问题记录

1 自己定义的类继承网络变量【NetworkVariable】
1.1使用自定义的类，构造时会直接报错，新版本的网络变量内部有改动

NetVar<int> nv_hp = new NetVar<int>();  **[1.0版本以前可用]**

2.3 解决办法：使用 NetworkVariable 即可

NetworkVariable<int> nv_hp = new NetworkVariable<int>(); [1.1、1.2版本可用]

3 网络变量 NetworkVariable 类的版本差异比较

3.1 差异说明

显著的变化在T Value赋值的过程，和对T的限定，变得更加安全
比较值得方法不一样，但是均在值比较之后发生变化才赋值，无变化不触发。

3.2 [1.0.2]版本的网络变量

using System;
using System.Runtime.CompilerServices;
using Unity.Collections.LowLevel.Unsafe;
using UnityEngine;namespace Unity.Netcode
{[Serializable]public class NetworkVariable<T> : NetworkVariableBase where T : unmanaged{public delegate void OnValueChangedDelegate(T previousValue, T newValue);public OnValueChangedDelegate OnValueChanged;[SerializeField]private protected T m_InternalValue;public virtual T Value{get{return m_InternalValue;}set{if (!ValueEquals(ref m_InternalValue, ref value)){if ((bool)m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId)){throw new InvalidOperationException("Client is not allowed to write to this NetworkVariable");}Set(value);}}}public NetworkVariable(T value = default(T), NetworkVariableReadPermission readPerm = NetworkVariableReadPermission.Everyone, NetworkVariableWritePermission writePerm = NetworkVariableWritePermission.Server): base(readPerm, writePerm){m_InternalValue = value;}[MethodImpl(MethodImplOptions.AggressiveInlining)]private unsafe static bool ValueEquals(ref T a, ref T b){void* ptr = UnsafeUtility.AddressOf(ref a);void* ptr2 = UnsafeUtility.AddressOf(ref b);return UnsafeUtility.MemCmp(ptr, ptr2, sizeof(T)) == 0;}private protected void Set(T value){SetDirty(isDirty: true);T internalValue = m_InternalValue;m_InternalValue = value;OnValueChanged?.Invoke(internalValue, m_InternalValue);}public override void WriteDelta(FastBufferWriter writer){WriteField(writer);}public override void ReadDelta(FastBufferReader reader, bool keepDirtyDelta){T internalValue = m_InternalValue;NetworkVariableSerialization<T>.Read(reader, out m_InternalValue);if (keepDirtyDelta){SetDirty(isDirty: true);}OnValueChanged?.Invoke(internalValue, m_InternalValue);}public override void ReadField(FastBufferReader reader){NetworkVariableSerialization<T>.Read(reader, out m_InternalValue);}public override void WriteField(FastBufferWriter writer){NetworkVariableSerialization<T>.Write(writer, ref m_InternalValue);}}
}

3.3 [1.2.0]版本的网络变量

using System;
using UnityEngine;namespace Unity.Netcode
{[Serializable]public class NetworkVariable<T> : NetworkVariableBase{public delegate void OnValueChangedDelegate(T previousValue, T newValue);public OnValueChangedDelegate OnValueChanged;[SerializeField]private protected T m_InternalValue;public virtual T Value{get{return m_InternalValue;}set{if (!NetworkVariableSerialization<T>.AreEqual(ref m_InternalValue, ref value)){if ((bool)m_NetworkBehaviour && !CanClientWrite(m_NetworkBehaviour.NetworkManager.LocalClientId)){throw new InvalidOperationException("Client is not allowed to write to this NetworkVariable");}Set(value);}}}public NetworkVariable(T value = default(T), NetworkVariableReadPermission readPerm = NetworkVariableReadPermission.Everyone, NetworkVariableWritePermission writePerm = NetworkVariableWritePermission.Server): base(readPerm, writePerm){m_InternalValue = value;}private protected void Set(T value){SetDirty(isDirty: true);T internalValue = m_InternalValue;m_InternalValue = value;OnValueChanged?.Invoke(internalValue, m_InternalValue);}public override void WriteDelta(FastBufferWriter writer){WriteField(writer);}public override void ReadDelta(FastBufferReader reader, bool keepDirtyDelta){T internalValue = m_InternalValue;NetworkVariableSerialization<T>.Read(reader, ref m_InternalValue);if (keepDirtyDelta){SetDirty(isDirty: true);}OnValueChanged?.Invoke(internalValue, m_InternalValue);}public override void ReadField(FastBufferReader reader){NetworkVariableSerialization<T>.Read(reader, ref m_InternalValue);}public override void WriteField(FastBufferWriter writer){NetworkVariableSerialization<T>.Write(writer, ref m_InternalValue);}}
}