What am I doing wrong when trying to spawn a class 4.8?

Development Programming & Scripting C++
1

I am trying to spawn a sphere in the scene I created a new C++ class and attached it to the spawn category in the details tab,



ASpawnFactory.cpp:
ASpawnFactory::ASpawnFactory()
{
   FVector NewLocation =  FVector(0.f, 0.f, 0.f);
   ASpawnFactory* Spawned_Actor = GetWorld()->SpawnActor<ASpawnFactory>(MySpawn, NewLocation, FRotator::ZeroRotator);
}

ASpawnFactory.h:
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = spawn)
AActor* MySpawn;

Why is this not working? What am i doing wrong? How can I get “MyClass” to spawn a simple sphere?!

2

i73, if you haven’t looked already, may be what I posted on this thread will help:

If you read down to the third post in the thread, it shows how to spawn an asset that is set in the editor. Not sure if it applies to what you are trying to do but it does look similar.

3

Okay so I understand that
ItemStaticMesh = CreateDefaultSubobject<UStaticMeshComponent>(FName(“ItemStaticMesh”));

Will create a “Class” That spawns this mesh component, so how do I call it? with Spawn Actor? What did I do wrong? and how can I make it work with what I have?

4

I’m not sure about all of this but between what you provided and what Visual Studio intellisense provides:



    FVector spawnLocation = FVector(0.0, 0.0f, 0.0f);
    FRotator spawnRotation = FRotator::ZeroRotator;
    UStaticMeshComponent* staticMesh = CreateDefaultSubobject<UStaticMeshComponent>(FName("ItemStaticMesh"));
    UStaticMeshComponent* aircraft = GetWorld()->SpawnActor<UStaticMeshComponent>(staticMesh->GetClass(), spawnLocation, spawnRotation);

The question is, how do you get a sphere?

I’m looking now. . .

5

I just want to spawn a sphere *Cries into his laptop

Ill keep looking, thank you. I assumed it was to just spawn a class with a Mesh on it…

6

I’m not sure if this will help you or not but hopefully it will at least point you in the right direction. First the end results:

4c071f91faaa2435d3cbf2b2870c659c1c08cd02.jpeg
4c071f91faaa2435d3cbf2b2870c659c1c08cd02.jpeg1286×750 186 KB

This is a class that replicates itself, that is, you add this to your scene and press Play. The class initially will spawn 8 of the same (itself), and instruct the eight to spawn 4 each, then the four to spawn 2, and finally once more for a total of 168 spheres spawned from the main sphere (the sphere you added to the scene manually).

.h



#pragma once

#include "Engine/StaticMeshActor.h"
#include "MyStaticMeshActor.generated.h"


UCLASS()
class YOURPROJECTNAMEHERE_API AMyStaticMeshActor : public AStaticMeshActor
{
	GENERATED_BODY()

public:

    AMyStaticMeshActor(const FObjectInitializer& ObjectInitializer);

    virtual void BeginPlay() override;
    virtual void Tick(float DeltaSeconds) override;

protected:

    UStaticMesh* SphereMesh;

private:

    //  first mesh creates 8                     8
    //  second tier creates 4 x 8               32
    //  forth tier creates 2 x 32               64
    //  fifth tier creates 1 x 64               64
    const int32 DefaultSpawnCount = 8;
    const float DefaultSpawnDelta = 3.0f;

    bool isDone;

    int32 spawnCount;
    int32 numberSpawned;

    float spawnDelta;
    float spawnTime;
};

.cpp



#include "YourProjectNameHere.h"
#include "MyStaticMeshActor.h"


AMyStaticMeshActor::AMyStaticMeshActor(const FObjectInitializer& ObjectInitializer) : Super(ObjectInitializer)
{
    GetStaticMeshComponent()->SetMobility(EComponentMobility::Movable);

    static ConstructorHelpers::FObjectFinder<UStaticMesh> SphereMeshAsset(TEXT("StaticMesh'/Engine/BasicShapes/Sphere.Sphere'"));
    SphereMesh = SphereMeshAsset.Object;

    PrimaryActorTick.bCanEverTick = true;

    isDone = false;
    numberSpawned = 0;
    spawnCount = DefaultSpawnCount;
    spawnDelta = DefaultSpawnDelta;
}


void AMyStaticMeshActor::BeginPlay()
{
    Super::BeginPlay();

    spawnTime = spawnDelta;
}


void AMyStaticMeshActor::Tick(float DeltaSeconds)
{
    const int32 newKEY = -1;

    if (numberSpawned < spawnCount)
    {
        spawnTime -= DeltaSeconds;
        if (spawnTime <= 0.0f)
        {
            spawnTime = spawnDelta;

            FVector spawnLocation = FVector(FMath::FRandRange(-500.0f, 500.0f), FMath::FRandRange(-500.0f, 500.0f), FMath::FRandRange(80.0f, 250.0f));
            FRotator spawnRotation = FRotator::ZeroRotator;

            AMyStaticMeshActor* mesh = GetWorld()->SpawnActor<AMyStaticMeshActor>(this->GetClass(), spawnLocation, spawnRotation);

            if (mesh != nullptr)
            {
                numberSpawned++;
                mesh->spawnCount = spawnCount >> 1;
                mesh->spawnDelta = FMath::FRandRange(1.5f, 4.5f);

                mesh->StaticMeshComponent->SetMobility(EComponentMobility::Movable);
                mesh->StaticMeshComponent->SetStaticMesh(SphereMesh);

                FString msgText(TEXT("spawnSphere: "));
                int32 msgNum = 0;
                msgNum++;
                GEngine->AddOnScreenDebugMessage(newKEY, 15.0f, FColor::White, msgText + FString("<") + FString::SanitizeFloat(spawnLocation.X)
                    + FString(", ") + FString::SanitizeFloat(spawnLocation.Y)
                    + FString(", ") + FString::SanitizeFloat(spawnLocation.Z)
                    + FString(">"));
            }
            else
            {
                FString msgText(TEXT("failed to spawn sphere"));
                int32 msgNum = 0;
                msgNum++;
                GEngine->AddOnScreenDebugMessage(newKEY, 15.0f, FColor::Red, msgText);
            }
        }
    }
    else if (!isDone)
    {
        isDone = true;

        FString msgText(TEXT("spawn complete."));
        int32 msgNum = 0;
        msgNum++;
        GEngine->AddOnScreenDebugMessage(newKEY, 15.0f, FColor::Green, msgText);
    }
}

There isn’t much error checking going on, and I’m certain better formatting of the spawned location exits, and certainly no optimizations. Notice the SpawnActor<>(this->GetClass(),. . .), and also the SetMobility call. You could create a SphereManager class, move the code to it, and SpawnActor<AMyStaticMeshActor>(AMyStaticMeshActor::StaticClass(),. . .).

Secondly, the SetMobility is probably a gem I’ll need later on. . .but will forget about it. It is my understanding that this call allows you to change material and other properties of static classes.