C++ 虚幻引擎：如何在循环中创建组件？

我试图使用for循环创建多个

UStaticMeshComponent

，但Unreal引擎一直在

Object.h

中的

CreateDefaultSubobject

上触发断点（不在我的代码中，它来自UE4核心API）。当我创建单个组件时，它工作正常。我对UnrealEngine和C++很陌生，所以我可能会做一些傻事，但是请你不要太在意： 非常感谢你的帮助

标题

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "FlowSphere.generated.h"

UCLASS()
class CPP_PRACTICE_3_API AFlowSphere : public AActor
{
    GENERATED_BODY()

public: 
    // Sets default values for this actor's properties
    AFlowSphere();

protected:
    // Called when the game starts or when spawned
    virtual void BeginPlay() override;

public: 
    // Called every frame
    virtual void Tick(float DeltaTime) override;

private:
    //UPROPERTY()
    //TArray<UStaticMeshComponent*> StaticMeshComponents;

    UStaticMeshComponent* test;

};

---

您对CreateDefaultSubobject的两个不同调用使用了相同的名称

< >我在新的UE4C++项目中运行了代码，并获得以下错误信息：

致命错误： [文件：D:\Build++UE4\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [行：3755]默认子对象StaticMeshComponent球体已存在 FlowSphere/Script/MyProject.Default\uuuu FlowSphere存在

另外，您发布的代码没有编译

item.AttachTo(this->RootComponent);

应该是：

item->AttachTo(this->RootComponent);

您还需要包括“Components/StaticMeshComponent.h”。以下是更正后的代码：

#include "FlowSphere.h"
#include "Components/StaticMeshComponent.h"

// Sets default values
AFlowSphere::AFlowSphere()
{
    int32 amount = 100;

    RootComponent = CreateDefaultSubobject<USceneComponent>("SceneComponent");

    for (int32 i = 0; i < amount; i++) {

        FName name = *FString::Printf(TEXT("Sphere %i"), i);
        UStaticMeshComponent* item = CreateDefaultSubobject<UStaticMeshComponent>(name);
        item->AttachTo(this->RootComponent);

    }

    this->test = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("HELLO"));
    PrimaryActorTick.bCanEverTick = true;

}

#包括“FlowSphere.h”
#包括“组件/StaticMeshComponent.h”
//设置默认值
AFlowSphere:：AFlowSphere（）
{
int32金额=100；
RootComponent=CreateDefaultSubobject（“SceneComponent”）；
对于（int32 i=0；i附件（此->根组件）；
}
此->测试=CreateDefaultSubobject（文本（“HELLO”）；
PrimaryActorTick.bCanEverTick=true；
}

所以我最近不得不做同样的事情，遇到了很多问题，但需要解决的两个主要问题是：

使用UInstancedStaticMesh而不是UStaticMesh

向静态网格添加特性

下面是正确的代码

#include "FlowSphere.h"
#include "Components/StaticMeshComponent.h"
#include "UObject/ConstructorHelpers.h"

// Sets default values
AFlowSphere::AFlowSphere()
{
    int32 amount = 100;

    RootComponent = CreateDefaultSubobject<USceneComponent>("SceneComponent");

    for (int32 i = 0; i < amount; i++) {

        FName name = *FString::Printf(TEXT("Sphere %i"), i);
        FName c_name = *FString::Printf(TEXT("ChildSceneComponent %i"), i);

        UPROPERTY(EditAnywhere)
            USceneComponent* ChildSceneComponent
            = CreateDefaultSubobject<USceneComponent>(c_name);

        // instead of the regular static mesh, create and instance static mesh object with name assigned
        UInstancedStaticMeshComponent* item = CreateDefaultSubobject<UStaticMeshComponent>(name);
        item->RegisterComponent();

        // assign property to mesh if not you'll get a static mesh null property error like i did 
        auto MeshAsset = ConstructorHelpers::FObjectFinder<UStaticMesh>(TEXT("StaticMesh'/Engine/BasicShapes/Sphere.Sphere'"));

        if (MeshAsset.Object != nullptr)
        {
            item->SetStaticMesh(MeshAsset.Object);
        }
        item->SetFlags(RF_Transactional);

        // add instance to actor level
        this->AddInstanceComponent(item);

        // make the scene component for the mesh to be visible
        RootComponent = Root;

        // attach mesh to the scene component of the actor in form of a Hierarchy

        item->AttachToComponent(ChildSceneComponent, FAttachmentTransformRules::KeepWorldTransform, m_name);
        ChildSceneComponent->AttachToComponent(Root, FAttachmentTransformRules::KeepWorldTransform, c_name);

        // set mesh transform based on the ith position
        FTransform t(FVector(250 * i, i, i));

        // activate the new copy of the mesh
        Mesh->AddInstance(t);

        // Offset and scale the child scene from the root scene as a precaution
        ChildSceneComponent->SetRelativeTransform(
            FTransform(FRotator(0, 0, 0),
                FVector(250 * i, i, i),
                FVector(0.1f))
        );


    }


    PrimaryActorTick.bCanEverTick = true;

}



    

#包括“FlowSphere.h”
#包括“组件/StaticMeshComponent.h”
#包括“UObject/ConstructorHelpers.h”
//设置默认值
AFlowSphere:：AFlowSphere（）
{
int32金额=100；
RootComponent=CreateDefaultSubobject（“SceneComponent”）；
对于（int32 i=0；iRegisterComponent（）；
//将属性指定给网格，否则会像我一样出现静态网格null属性错误
auto-MeshAsset=ConstructorHelpers:：FObjectFinder（文本（“StaticMesh'/Engine/BasicShapes/Sphere.Sphere'）；
if（MeshAsset.Object！=nullptr）
{
item->SetStaticMesh（MeshAsset.Object）；
}
项目->设置标志（RF_事务）；
//将实例添加到参与者级别
此->添加组件（项目）；
//使网格的场景组件可见
RootComponent=根；
//将网格以层次的形式附加到角色的场景组件
item->AttachToComponent（ChildSceneComponent，FAttachmentTransformRules:：KeepWorldTransform，m_名称）；
ChildSceneComponent->AttachToComponent（根，FAttachmentTransformRules:：KeepWorldTransform，c_名称）；
//基于第i个位置设置网格变换
f变换t（FVector（250*i，i，i））；
//激活网格的新副本
网格->附加值（t）；
//作为预防措施，从根场景偏移并缩放子场景
ChildSceneComponent->SetRelativeTransform(
F变换（FRotator（0,0,0），
FVector（250*i，i，i），
FVector（0.1f））
);
}
PrimaryActorTick.bCanEverTick=true；
}

#include "FlowSphere.h"
#include "Components/StaticMeshComponent.h"

// Sets default values
AFlowSphere::AFlowSphere()
{
    int32 amount = 100;

    RootComponent = CreateDefaultSubobject<USceneComponent>("SceneComponent");

    for (int32 i = 0; i < amount; i++) {

        FName name = *FString::Printf(TEXT("Sphere %i"), i);
        UStaticMeshComponent* item = CreateDefaultSubobject<UStaticMeshComponent>(name);
        item->AttachTo(this->RootComponent);

    }

    this->test = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("HELLO"));
    PrimaryActorTick.bCanEverTick = true;

}

#include "FlowSphere.h"
#include "Components/StaticMeshComponent.h"
#include "UObject/ConstructorHelpers.h"

// Sets default values
AFlowSphere::AFlowSphere()
{
    int32 amount = 100;

    RootComponent = CreateDefaultSubobject<USceneComponent>("SceneComponent");

    for (int32 i = 0; i < amount; i++) {

        FName name = *FString::Printf(TEXT("Sphere %i"), i);
        FName c_name = *FString::Printf(TEXT("ChildSceneComponent %i"), i);

        UPROPERTY(EditAnywhere)
            USceneComponent* ChildSceneComponent
            = CreateDefaultSubobject<USceneComponent>(c_name);

        // instead of the regular static mesh, create and instance static mesh object with name assigned
        UInstancedStaticMeshComponent* item = CreateDefaultSubobject<UStaticMeshComponent>(name);
        item->RegisterComponent();

        // assign property to mesh if not you'll get a static mesh null property error like i did 
        auto MeshAsset = ConstructorHelpers::FObjectFinder<UStaticMesh>(TEXT("StaticMesh'/Engine/BasicShapes/Sphere.Sphere'"));

        if (MeshAsset.Object != nullptr)
        {
            item->SetStaticMesh(MeshAsset.Object);
        }
        item->SetFlags(RF_Transactional);

        // add instance to actor level
        this->AddInstanceComponent(item);

        // make the scene component for the mesh to be visible
        RootComponent = Root;

        // attach mesh to the scene component of the actor in form of a Hierarchy

        item->AttachToComponent(ChildSceneComponent, FAttachmentTransformRules::KeepWorldTransform, m_name);
        ChildSceneComponent->AttachToComponent(Root, FAttachmentTransformRules::KeepWorldTransform, c_name);

        // set mesh transform based on the ith position
        FTransform t(FVector(250 * i, i, i));

        // activate the new copy of the mesh
        Mesh->AddInstance(t);

        // Offset and scale the child scene from the root scene as a precaution
        ChildSceneComponent->SetRelativeTransform(
            FTransform(FRotator(0, 0, 0),
                FVector(250 * i, i, i),
                FVector(0.1f))
        );


    }


    PrimaryActorTick.bCanEverTick = true;

}