# Plugin05

**Repository Path**: weekend/Plugin05

## Basic Information

- **Project Name**: Plugin05
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2025-07-24
- **Last Updated**: 2025-08-01

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README


## UnLua 快速入门
> `"EngineAssociation": "4.27"`

1. 获取UnLua, `git clone https://github.com/Tencent/UnLua.git`
2. 将UnLua下的Plugins/UnLua拷贝到当前工程的Plugins目录下，重新打开编辑器后就可以得到一个UnLua菜单
3. 新建蓝图类并点UnLua/Bind生成Interface: GetModuleName, 设置一个名字作为脚本名
4. 点击 UnLua/CreateLuaTemplate 自动生成Lua脚本，位于Content/Script目录
5. 增加一些Lua代码，并将此蓝图添加到地图，运行查看

```lua
-- BP_LuaActor.lua
function M:ReceiveBeginPlay()
  print('BP_LuaActor: ReceiveBeginPlay')
end

function M:ReceiveEndPlay()
  print('BP_LuaActor: ReceiveEndPlay')
end

--[[ 运行日志
LogUnLua: BP_LuaActor: ReceiveBeginPlay
LogUnLua: BP_LuaActor: ReceiveEndPlay
--]]
```

## Tick, 默认Tick是被禁用的
> 只有当蓝图中的Tick事件启用时，Lua中的Tick才会执行。这个是UE自己的设计，开启Tick有两种方法，一种是在C++中把 `bCanEverTick` 设为true，另一种就是在蓝图中创建 `Event Tick` 节点，可见 `FKismetCompilerContext::SetCanEverTick()` 函数。

* Enable Tick
```diff
@@ -2,10 +2,7 @@ Begin Object Class=/Script/BlueprintGraph.K2Node_Event Name="K2Node_Event_2"
    EventReference=(MemberParent=Class'"/Script/Engine.Actor"',MemberName="ReceiveTick")
    bOverrideFunction=True
    NodePosY=416
-   EnabledState=Disabled
    bCommentBubblePinned=True
-   bCommentBubbleVisible=True
-   NodeComment="This node is disabled and will not be called.\nDrag off pins to build functionality."
    NodeGuid=742D17A34014F52F7FD4D29169D3CB4C
    CustomProperties Pin (PinId=19D924324AFCA1078486F2AC6A66A017,PinName="OutputDelegate",Direction="EGPD_Output",PinType.PinCategory="delegate",PinType.PinSubCategory="",PinType.PinSubCategoryObject=None,PinType.PinSubCategoryMemberReference=(MemberParent=Class'"/Script/Engine.Actor"',MemberName="ReceiveTick"),PinType.PinValueType=(),PinType.ContainerType=None,PinType.bIsReference=False,PinType.bIsConst=False,PinType.bIsWeakPointer=False,PinType.bIsUObjectWrapper=False,PersistentGuid=00000000000000000000000000000000,bHidden=False,bNotConnectable=False,bDefaultValueIsReadOnly=False,bDefaultValueIsIgnored=False,bAdvancedView=False,bOrphanedPin=False,)
    CustomProperties Pin (PinId=EFF4856C4619B0C6CAE73A96C1920144,PinName="then",Direction="EGPD_Output",PinType.PinCategory="exec",PinType.PinSubCategory="",PinType.PinSubCategoryObject=None,PinType.PinSubCategoryMemberReference=(),PinType.PinValueType=(),PinType.ContainerType=None,PinType.bIsReference=False,PinType.bIsConst=False,PinType.bIsWeakPointer=False,PinType.bIsUObjectWrapper=False,PersistentGuid=00000000000000000000000000000000,bHidden=False,bNotConnectable=False,bDefaultValueIsReadOnly=False,bDefaultValueIsIgnored=False,bAdvancedView=False,bOrphanedPin=False,)
```

```lua
-- BP_LuaActor.lua
function M:ReceiveTick(DeltaSeconds)
  print('BP_LuaActor: ReceiveTick', DeltaSeconds)
end

--[[ 运行日志
LogUnLua: BP_LuaActor: ReceiveTick    0.016666699200869
LogUnLua: BP_LuaActor: ReceiveTick    0.016666699200869
LogUnLua: BP_LuaActor: ReceiveTick    0.016666699200869
LogUnLua: BP_LuaActor: ReceiveTick    0.016666699200869
--]]
```

## LUA访问c++静态函数(BlueprintCallable)
1. 新建继承自UBlueprintFunctionLibrary的c++类，并定义蓝图可访问的静态函数 `UMyBlueprintFunctionLibrary::GetMaxHealth`
```cpp
UCLASS()
class PLUGIN05_API UMyBlueprintFunctionLibrary : public UBlueprintFunctionLibrary
{
  GENERATED_BODY()

public:
  UFUNCTION(BlueprintCallable)
    static int GetMaxHealth() { return 100; };
};
```

2. 从LUA访问这个函数 `UE4.UMyBlueprintFunctionLibrary.GetMaxHealth`
```lua
function M:ReceiveBeginPlay()
  print('BP_LuaActor: ReceiveBeginPlay')
  print('BP_LuaActor: The Max Health: ', UE4.UMyBlueprintFunctionLibrary.GetMaxHealth())
end

--[[ 运行日志
LogUnLua: BP_LuaActor: ReceiveBeginPlay
LogUnLua: BP_LuaActor: The Max Health:    100
--]]
```

## LUA访问c++成员函数(member function, BlueprintCallable)
1. 基于 AActor 创建c++类 AMyActor
2. 添加一些成员函数, BlueprintCallable
```cpp
public:	
  UFUNCTION(BlueprintCallable)
  int GetHealth() { return health; }

  UFUNCTION(BlueprintCallable)
  void SetHealth(int h) { health = h; }
private:
	int health {0};
```
3. 基于 AMyActor 创建蓝图类 BP_MyActor，并绑定脚本
4. 测试 c++ 成员函数调用，注意这里要用冒号，会隐式将self作为参数传进去，成员函数需要这个self参数
```lua
function M:ReceiveBeginPlay()
  print('BP_MyActor: ReceiveBeginPlay')
  self:SetHealth(UE4.UMyBlueprintFunctionLibrary.GetMaxHealth())
end

function M:ReceiveEndPlay()
  print('BP_MyActor: ReceiveEndPlay', self:GetHealth())
end
```

## LUA访问蓝图成员变量/函数
```lua
-- 这里会覆盖蓝图的 Event Construct
function M:Construct()
  -- 启动就播放一次动画
  self:PlayAnimation(self.NewAnimation, 0.0, 1, UE4.EUMGSequencePlayMode.Forward, 1.0)

  -- 调用蓝图函数Init
  self:Init()

  -- 蓝图按钮事件绑定，这里不会覆盖蓝图的 OnPressed
  self.Button_Power.OnPressed:Add(self, function()
    print('Button_Power pressed')
    
    -- 访问蓝图变量并调用其成员函数
    self.TextBlock_Power:SetText('Lua Power On')

    -- 调用蓝图函数 PowerTriggered
    self:PowerTriggered()

    -- 也可以直接调 Event
    -- self:CustomEvent_0()
  end)
end
```

## LUA访问c++ UPROPERTY成员, 动态加载蓝图资产
```cpp
public:
  UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "MyActor")
  FString SpecialName;
```

```lua
function M:PowerPressed()
  print('PowerPressed')
  self.TextBlock_Power:SetText('Lua Power On')

  local World = self:GetWorld()
  if not World then
    return
  end

  -- 动态加载Actor, 注意这里多一个后缀 _C
  local MyActorClass = UE4.UClass.Load("/Game/BP_MyActor.BP_MyActor_C")
  local MyTmpActor = World:SpawnActor(MyActorClass, UE.FVector(), UE4.ESpawnActorCollisionHandlingMethod.AlwaysSpawn, self, self, "")
  print(MyTmpActor.SpecialName)
end
```

## LUA 覆盖重写 BlueprintImplementableEvent/BlueprintNativeEvent c++函数
> 直接提供同名函数即可覆写

```h
// MyActor.h
public:
	// c++不（不能）提供实现，蓝图中提供实现
    UFUNCTION(BlueprintImplementableEvent, BlueprintCallable)
    void OnSpecialNameChanged(const FString &NewName);

	// c++可以（必须）提供实现，蓝图中可以重写
    UFUNCTION(BlueprintNativeEvent, BlueprintCallable)
    void OnSpecialNameChangedNative(const FString &NewName);
```

```cpp
// MyActor.cpp
void AMyActor::OnSpecialNameChangedNative_Implementation(
    const FString &NewName) {
  UE_LOG(LogTemp, Warning, TEXT("Health changed to: %s"), *NewName);
  // 如果需要，蓝图中没重写也能调用
  OnSpecialNameChanged(NewName);
}
```

```lua
-- BP_LuaActor.lua
-- 重写BlueprintImplementableEvent, 这里不需要_Implementation后缀
function M:OnSpecialNameChanged()
  self.SpecialName = "LuaSpecialName"
end

-- 重写BlueprintNativeEvent, 这里也不需要_Implementation后缀
function M:OnSpecialNameChanged()
  self.SpecialName = "LuaSpecialNameNative"
end
```

## LUA 覆盖重写蓝图事件
```lua
-- BP_LuaActor.lua
-- 覆写 CustomEvent_0
function M:CustomEvent_0(NewName)
  print('LUA CustomEvent_0 called with NewName:', NewName)
end
```

![](image01.gif)


## 参考
* [UnLua快速入门示例](https://github.com/Tencent/UnLua/blob/master/Docs/CN/Quickstart_For_UE_Newbie.md)
* [制作UMG控件动画](https://dev.epicgames.com/documentation/zh-cn/unreal-engine/animating-umg-widgets-in-unreal-engine)