Iterating through all static meshes of an actor?

Development Programming & Scripting C++
1

Hey, so I have an actor where I wish to override the colors of all its materials at certain events. (EG flashing a damaged entity red when hurt)
Currently I accomplish that like this:

	TArray<class UMaterialInterface*> materials = GetMesh()->GetMaterials();
	for (int i = 0; i < materials.Num(); i++)
	{
		UMaterialInstanceDynamic* matInstance = UMaterialInstanceDynamic::Create(materials[i], this);

		matInstance->SetVectorParameterValue("ColorEffect", StatusColor);
		GetMesh()->SetMaterial(i, matInstance);
	}

However, in addition to multiple materials, the actors can also have a variable amount of static meshes, and not necessarily just one.

How would you suggest that I also get and iterate through all the actors meshes so that I can apply the color universally, and not just to the base mesh?

1 Like
2

This is theoretical; it hasn’t been tested. If you must make modifications, please post them to help the community.

This should loop through all static mesh components:

TArray<UStaticMeshComponent*> MeshComponents;
GetComponents<UStaticMeshComponent>(MeshComponents);
for (UStaticMeshComponent* MyMesh : MeshComponents) {
    // Loops through the MeshComponents, with MyMesh as the component
}

Note: GetComponents is an AActor member function.

Hope this helps!

2 Likes
3

I recommend this approach. The above is fine, but doing this avoids any copying and creating a temporary array.

for (UActorComponent* CompItr : Actor->GetOwnedComponents())
{
	if (UStaticMeshComponent* Mesh = Cast<UStaticMeshComponent>(CompItr))
	{
		Mesh.DoStuff()
	}
}
3 Likes
4

Thanks for the suggestions! I was able to use them to figure out a way to use them to get all the meshes of and entitity and arrange all their materials into a single array so that I can modify them universally on the fly.

I ended up with this:

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

       // other stuff

	int MeshMatIndex = 0;
	int TempI = 0;
	for (UActorComponent* CompItr : this->GetComponents())
	{
		if (UStaticMeshComponent* Mesh = Cast<UStaticMeshComponent>(CompItr))
		{
			TArray<class UMaterialInterface*> materials = Mesh->GetMaterials();
			for (int i = 0; i < materials.Num(); i++)
			{
				DynaMats.Add(UMaterialInstanceDynamic::Create(materials[i], this));
				
				Mesh->SetMaterial(i, DynaMats[i + MeshMatIndex]);
				TempI = i; //get final material index of this mesh to add to total materials for entity
			}
			MeshMatIndex = MeshMatIndex + TempI + 1; //add one to account for arrays starting at index 0 when counting materials
		}
	}



}

void AWinstickPawn::DoColor(FColor color, float DeltaSeconds)
{
	FTimerHandle Timer;
	for (int i = 0; i < DynaMats.Num(); i++)
	{
		DynaMats[i]->SetVectorParameterValue("ColorEffect", color);
	}
	if (DeltaSeconds != 0)
	GetWorldTimerManager().SetTimer(Timer, this, &AWinstickPawn::UndoColor, DeltaSeconds, false);
}

void AWinstickPawn::UndoColor()
{
	DoColor(FColor(0,0,0,0), 0.0f);
}
5

Cool! One thing though… You’re creating a new material for every mesh. Why can’t you just create one DynamicMaterialInstance, and then assign that to every mesh?

6

Because my meshes use multiple different materials with different textures, etc. But I want them all to be affected the same from some universal things.

7

Okay. I should have noticed that from the code :stuck_out_tongue_closed_eyes:

8

Just one thing to flag - this code is making a local copy of that materials array. You should use const ref here!

10

Just one thing to flag - this code is making a local copy of that materials array. You should use const ref here!

Ah, right! Thanks! I’ve been learning from doing a lot and keep forgetting about these kinds of things!