unreal-c++教程-第十章:c++和Unlua的交互

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c++和Unlua的交互

1. 背景2. 基本思路

2.1 (GlobalTable函数的交互)在c++定义暴露给UnLua的静态函数

2.1.1 该函数的基本需求：2.1.2 该函数的基本实现思路

2.2 (FLuaTable的交互)在c++定义暴露给UnLua的静态函数

2.2.1 该函数的基本需求2.2.2 该函数的实现思路



3. 完整的c++代码4. 注意

4.1 添加Lua的搜索路径4.2 缺少Lua库

1. 背景

1. 我们希望频繁变动的脚本是通过lua来完成的，因此我们引入了tx的UnLua(开源库)
2. 我们会在c++中完成socket层面的处理，然后过滤出proto的字节流，这个字节流会从
3. c++传递给lua，然后在lua中完成proto消息的处理

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2. 基本思路

1. 1. 定义c++的静态函数
2. 2. 在lua中访问该静态函数

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2.1 (GlobalTable函数的交互)在c++定义暴露给UnLua的静态函数

1. UFUNCTION(BlueprintCallable, meta =(DisplayName ="CallLuaByGlobalTable", Category ="UnLua Tutorial"))staticvoidCallLuaByGlobalTable();

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然后我们就可以在lua中调用该c++的函数了

在这里需要进修UnLua的入门教程
2.1.1 该函数的基本需求：

1. 1. 我们在TestReceiveCpp.lua中定义了一个函数叫做：CallMe的函数

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1. function TestReceiveCpp.CallMe(a, b)
2.     local ret = a + b
3.     local msg = string.format("c++ call a = %f,b = %f,ans = %f", a, b, ret)
4.     Screen.Print(msg)return

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1. 2. 我们希望在c++中去调用这个CallMe函数

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2.1.2 该函数的基本实现思路

1. 1. 拿到对应lua脚本的闭包，并用变量TRC保留该闭包的引用

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1.         UnLua::FLuaEnv Env;constauto bSuccess = Env.DoString("TRC = require 'TestReceiveCpp'");check(bSuccess);

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1. 显然，到这里，我们其实就是将定义的TestReceiveCpp的lua脚本加载到当前Env的内存当中

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1. 2. 调用该闭包的CallMe函数

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1. constauto RetValues = UnLua::CallTableFunc(Env.GetMainState(),"TRC","CallMe",1.1f,2.2f);check(RetValues.Num()==1);

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1. 3. 完整的函数

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1. void AClient::CallLuaByGlobalTable(){       
2.         UnLua::FLuaEnv Env;constauto bSuccess = Env.DoString("TRC = require 'TestReceiveCpp'");check(bSuccess);constauto RetValues = UnLua::CallTableFunc(Env.GetMainState(),"TRC","CallMe",1.1f,2.2f);check(RetValues.Num()==1);}

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2.2 (FLuaTable的交互)在c++定义暴露给UnLua的静态函数

2.2.1 该函数的基本需求

见2.1.1
2.2.2 该函数的实现思路

1. 1. 利用UnLua自带的FLuaFuntion去加载require函数

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1. constauto Require = UnLua::FLuaFunction(&Env,"_G","require");

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1. 2. 利用requre函数获取TestReceiveCpp的闭包(加载到内存并返回引用)

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1. constauto RetValues1 = Require.Call("TestReceiveCpp");check(RetValues1.Num()==2);

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1. 3. 获取函数Table

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1. constauto RetValue = RetValues1[0];constauto LuaTable = UnLua::FLuaTable(&Env, RetValue);

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1. 4. 调用CallMe函数

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1. constauto RetValues2 = LuaTable.Call("CallMe",3.3f,4.4f);check(RetValues2.Num()==1);

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1. 5. 从lua函数的返回中解析目标值

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1. constauto Msg = FString::Printf(TEXT("[C++]收到来自Lua的返回，结果=%f"), RetValues2[0].Value<float>());PrintScreen(Msg);

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3. 完整的c++代码

.h

1. // Fill out your copyright notice in the Description page of Project Settings.#pragmaonce#include"CoreMinimal.h"#include"GameFramework/Actor.h"#include"Client.generated.h"UCLASS()
2. class LUAX_API AClient : public AActor
3. {GENERATED_BODY()
4.        
5. public:// Sets default values for this actor's propertiesAClient();
7. protected:// Called when the game starts or when spawned
8.         virtual voidBeginPlay() override;
10. public:// Called every frame
11.         virtual voidTick(float DeltaTime) override;UFUNCTION(BlueprintCallable, meta =(DisplayName ="CallLuaByGlobalTable",
12.         Category ="UnLua Tutorial"))staticvoidCallLuaByGlobalTable();UFUNCTION(BlueprintCallable, meta =(DisplayName ="CallLuaByFLuaTable", Category ="UnLua Tutorial"))staticvoidCallLuaByFLuaTable();UFUNCTION(BlueprintCallable, meta =(DisplayName ="SetupCustomLoader", Category ="UnLua Tutorial"))staticvoidSetupCustomLoader(int Index);UFUNCTION(BlueprintNativeEvent, Category ="Switch Functions")voidOnReceiveMsg(float val);voidOnReceiveMsg_Implementation(float val);};

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.cpp

1. // Fill out your copyright notice in the Description page of Project Settings.#include"Client.h"#include"UnLua.h"#include"Kismet/KismetSystemLibrary.h"//#include "UnLua/"//#include "UnLua/"// Sets default values
2. AClient::AClient(){// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
3.         PrimaryActorTick.bCanEverTick = true;}// Called when the game starts or when spawned// Called every framevoid AClient::Tick(float DeltaTime){
4.         Super::Tick(DeltaTime);OnReceiveMsg(DeltaTime);}void AClient::OnReceiveMsg_Implementation(float val){}staticvoidPrintScreen(const FString& Msg){
5.         UKismetSystemLibrary::PrintString(nullptr, Msg, true, false,FLinearColor(0,0.66,1),100);}void AClient::CallLuaByGlobalTable(){       
6.         UnLua::FLuaEnv Env;constauto bSuccess = Env.DoString("TRC = require 'TestReceiveCpp'");check(bSuccess);constauto RetValues = UnLua::CallTableFunc(Env.GetMainState(),"TRC","CallMe",1.1f,2.2f);check(RetValues.Num()==1);}void AClient::CallLuaByFLuaTable(){PrintScreen(TEXT("[C++]CallLuaByFLuaTable 开始"));
7.         UnLua::FLuaEnv Env;constauto Require = UnLua::FLuaFunction(&Env,"_G","require");constauto RetValues1 = Require.Call("TestReceiveCpp");check(RetValues1.Num()==2);constauto RetValue = RetValues1[0];constauto LuaTable = UnLua::FLuaTable(&Env, RetValue);constauto RetValues2 = LuaTable.Call("CallMe",3.3f,4.4f);check(RetValues2.Num()==1);constauto Msg = FString::Printf(TEXT("[C++]收到来自Lua的返回，结果=%f"), RetValues2[0].Value<float>());PrintScreen(Msg);PrintScreen(TEXT("[C++]CallLuaByFLuaTable 结束"));}
9. bool CustomLoader1(UnLua::FLuaEnv& Env,const FString& RelativePath, TArray<uint8>& Data, FString& FullPath){constauto SlashedRelativePath = RelativePath.Replace(TEXT("."),TEXT("/"));
10.         FullPath = FString::Printf(TEXT("%s%s.lua"),*GLuaSrcFullPath,*SlashedRelativePath);if(FFileHelper::LoadFileToArray(Data,*FullPath, FILEREAD_Silent))return true;
12.         FullPath.ReplaceInline(TEXT(".lua"),TEXT("/Index.lua"));if(FFileHelper::LoadFileToArray(Data,*FullPath, FILEREAD_Silent))return true;return false;}
14. bool CustomLoader2(UnLua::FLuaEnv& Env,const FString& RelativePath, TArray<uint8>& Data, FString& FullPath){constauto SlashedRelativePath = RelativePath.Replace(TEXT("."),TEXT("/"));constauto L = Env.GetMainState();lua_getglobal(L,"package");lua_getfield(L,-1,"path");constchar* Path =lua_tostring(L,-1);lua_pop(L,2);if(!Path)return false;
16.         TArray<FString> Parts;FString(Path).ParseIntoArray(Parts,TEXT(";"), false);for(auto& Part : Parts){
17.                 Part.ReplaceInline(TEXT("?"),*SlashedRelativePath);
18.                 FPaths::CollapseRelativeDirectories(Part);if(FPaths::IsRelative(Part))
19.                         FullPath = FPaths::ConvertRelativePathToFull(GLuaSrcFullPath, Part);else
20.                         FullPath = Part;if(FFileHelper::LoadFileToArray(Data,*FullPath, FILEREAD_Silent))return true;}return false;}void AClient::SetupCustomLoader(int Index){switch(Index){case0:
21.                 FUnLuaDelegates::CustomLoadLuaFile.Unbind();break;case1:
22.                 FUnLuaDelegates::CustomLoadLuaFile.BindStatic(CustomLoader1);break;case2:
23.                 FUnLuaDelegates::CustomLoadLuaFile.BindStatic(CustomLoader2);break;}}void AClient::BeginPlay(){
24.         Super::BeginPlay();SetupCustomLoader(1);}

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4. 注意

4.1 添加Lua的搜索路径

1. bool CustomLoader1(UnLua::FLuaEnv& Env,const FString& RelativePath, TArray<uint8>& Data, FString& FullPath){constauto SlashedRelativePath = RelativePath.Replace(TEXT("."),TEXT("/"));
2.         FullPath = FString::Printf(TEXT("%s%s.lua"),*GLuaSrcFullPath,*SlashedRelativePath);if(FFileHelper::LoadFileToArray(Data,*FullPath, FILEREAD_Silent))return true;
4.         FullPath.ReplaceInline(TEXT(".lua"),TEXT("/Index.lua"));if(FFileHelper::LoadFileToArray(Data,*FullPath, FILEREAD_Silent))return true;return false;}

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4.2 缺少Lua库

如果报以下错误：

这是因为缺少Lua库
可以在.Build.cs中

添加