最简单的 UE 4 C++ 教程 —— C++ 中添加静态网格文件【三】

心已赠人 2022-08-31 14:17 198阅读 0赞

**【原教程是基于 UE 4.18，我是基于 UE 4.25】**

[英文源地址][Link 1]

接上一节的教程，让我们首先创建一个名为 **AddMeshFromFile** 的新 Actor 子类。

我们不需要在头文件中做任何事情。

下面是创建新类时生成的默认头文件。

### AddMeshFromFile.h ###

#pragma once
    
    #include "CoreMinimal.h"
    #include "GameFramework/Actor.h"
    #include "AddMeshFromFile.generated.h"
    
    UCLASS()
    class UNREALCPP_API AAddMeshFromFile : public AActor
    {
    	GENERATED_BODY()
    	
    public:	
    	// Sets default values for this actor's properties
    	AAddMeshFromFile();
    
    protected:
    	// Called when the game starts or when spawned
    	virtual void BeginPlay() override;
    
    public:	
    	// Called every frame
    	virtual void Tick(float DeltaTime) override;
    };

为了以编程方式添加一个特定的网格，我们必须包含 **ConstructorHelpers.h** 文件【**此处修订原英文教程的编译错误**】。

代码如下，在 Actor 子类头文件后包含该头文件。

#include "AddMeshFromFile.h"
    // add constructor header
    #include "UObject/ConstructorHelpers.h"

接下来，在 Actor 子类的构造函数中，我们将设置要添加到 actor 中的网格的默认值。创建一个**UStaticMeshComponent** 指针，并将其设置为 **RootComponent** 。

AAddMeshFromFile::AAddMeshFromFile()
    {
     	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    	PrimaryActorTick.bCanEverTick = true;
    
    	// add Cylinder to root
        UStaticMeshComponent* Cylinder = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("VisualRepresentation"));
        Cylinder->SetupAttachment(RootComponent);
    
    }

在我们的初始化设置之后，下一步是添加我们想要的网格到我们的角色。我们将使用**ConstructorHelpers** 中地方法 **FObjectFinder** 来定位我们的网格。在这个例子中，我构造并调用了变量 **CylinderAsset**，并传入了由初学者内容提供的圆柱体形状的路径。我们传入的路径是 **/Game/StarterContent/Shapes/Shape\_Cylinder.Shape\_Cylinder** 。

接下来，让我们做一个错误检查，以确保我们成功地获得网格。

if (CylinderAsset.Succeeded()) {}

如果该检查语句通过的话，让我们接着在圆柱体组件上执行下面三句话

*  SetStaticMesh
 *  SetRelativeLocation
 *  SetWorldScale3D

if (CylinderAsset.Succeeded()) 
    {
        Cylinder->SetStaticMesh(CylinderAsset.Object);
        Cylinder->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f));
        Cylinder->SetWorldScale3D(FVector(1.f));
    }

最后完整的 cpp 如下所示

#include "AddMeshFromFile.h"
    // add constructor header
    #include "UObject/ConstructorHelpers.h"
    
    
    // Sets default values
    AAddMeshFromFile::AAddMeshFromFile()
    {
     	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    	PrimaryActorTick.bCanEverTick = true;
    
    	// add Cylinder to root
        UStaticMeshComponent* Cylinder = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("VisualRepresentation"));
        Cylinder->SetupAttachment(RootComponent);
    
        static ConstructorHelpers::FObjectFinder<UStaticMesh> CylinderAsset(TEXT("/Game/StarterContent/Shapes/Shape_Cylinder.Shape_Cylinder"));
    
    	if (CylinderAsset.Succeeded())
        {
            Cylinder->SetStaticMesh(CylinderAsset.Object);
            Cylinder->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f));
            Cylinder->SetWorldScale3D(FVector(1.f));
    	}
    
    }
    
    // Called when the game starts or when spawned
    void AAddMeshFromFile::BeginPlay()
    {
    	Super::BeginPlay();
    	
    }
    
    // Called every frame
    void AAddMeshFromFile::Tick(float DeltaTime)
    {
    	Super::Tick(DeltaTime);
    
    }

最后的结果如下

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BhbmRhMTIzNGxlZQ_size_16_color_FFFFFF_t_70][] 将新建的 actor 子类拖入场景中

[Link 1]: https://unrealcpp.com/add-mesh-from-file/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3BhbmRhMTIzNGxlZQ_size_16_color_FFFFFF_t_70]: /images/20220829/b3a36eccc2bc47bf994f103e7230b940.png