Newbie learning

Development Programming & Scripting C++
1

Hi all, I’m a bit stuck trying to add a material to static mesh using an actor component class.

In begin play function I’ve tried the following.

UStaticmeshcomponent* objmesh = Cast<UStaticmeshcomponent>(GetOwner()) ;

//from the upropery umaterial in class

objmesh->setmaterial(0,mat);

This just crashes and my material pointer in not null.

I’m obviously applying it to the wrong object.

2

The Static Mesh Component is part of an Actor but you are Casting Directly to UStaticMeshComponent, The Owner Can’t be a StaticMesh in this Case but an Actor.
It should Cast To AActor then from that Actor you need to access its StaticMesh and Change its Material.

3

MyActor.h




    UPROPERTY(BlueprintReadOnly, VisibleAnywhere, Category = "Mesh")
    class UStaticMeshComponent* StaticMesh;


    //This is a quick function for getting mesh in case you put variables in private (I would suggest FORCEINLINE but that can get a bit different for new people but still take a look at those
    UFUNCTION()
    class UStaticMeshComponent* GetStaticMeshFromActor();

MyActor.cpp




#include "Materials/MaterialInterface.h"
#include "Components/StaticMeshComponent.h"


AMyActor::AMyActor()
{
    //Constructor
    StaticMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("StaticMesh"));
    SetRootComponent(StaticMesh);

}

//The Getter Function in case you made the Variable private/protected
UStaticMeshComponent* AApplyMaterialQuestion::GetStaticMeshFromActor()
{
    return StaticMesh;
}

Now The Component

ChangeMaterialComponent.h



    UPROPERTY(EditDefaultsOnly, Category = "Material")
    class UMaterialInterface* NewMat;

ChangeMaterialComponent.cpp



#include "Materials/MaterialInterface.h"
#include "NewProject/MyActor.h"
#include "Components/StaticMeshComponent.h"

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

    // ...

    AMyActor* MeshofMyActor = Cast<AMyActor>(GetOwner());
    if (MeshofMyActor)
    {
        UStaticMeshComponent* SMComp = MeshofMyActor->GetStaticMeshFromActor();
        if (NewMat && SMComp)
        {
            SMComp->SetMaterial(0, NewMat);
        }
    }

}