Trouble editing Dynamic Material param at Runtime

Development Asset Creation
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1

Hi all,

I am struggling with an issue editing a parameter of a Material at runtime via C++. The premise is thus: I am implementing Chess and trying to set up an OnClick Highlight effect (using a simple Fresnel) so the player knows what piece they’ve selected. The material on the pieces looks as follows:

137862-material.jpg
137862-material.jpg1070×632 76.9 KB

I modify the Tint successfully on creation of the piece in the world (I’m spawning the board and pieces programmatically), with the following code

//Initialize Piece
void APiece::InitializePiece(bool bPlayer)
{
	TArray<UStaticMeshComponent*> Components;

	if (bPlayer)
	{
		PieceColor = FLinearColor::Black;
	}
	else
	{
		PieceColor = FLinearColor::White;
	}

	GetComponents<UStaticMeshComponent>(Components);

	//Get the Static Mesh Component
	DynamicMaterial = UMaterialInstanceDynamic::Create(Components[0]->GetMaterial(0), this);

	//Set the tint parameter to Black or White
	DynamicMaterial->SetVectorParameterValue("Tint", PieceColor);
	Components[0]->SetMaterial(0, DynamicMaterial);

	bIsHighlighted = false;
}

This all works fine, it changes the base color of the pieces and sets them to white/black correctly. I have an OnClick event that calls the following function, which is where it seems to be going wrong:

void APiece::ChangeHighlight()
{
	TArray<UStaticMeshComponent*> Components;

	GetComponents<UStaticMeshComponent>(Components);

	DynamicMaterial = UMaterialInstanceDynamic::Create(Components[0]->GetMaterial(0), this);

	//If piece is not highlighted, highlight it, else remove highlight
	if (!bIsHighlighted)
	{
		DynamicMaterial->SetScalarParameterValue("Intensity", 1.0f);
		bIsHighlighted = true;
		UE_LOG(LogTemp, Warning, TEXT("Setting Highlight"));
	}
	else
	{
		DynamicMaterial->SetScalarParameterValue("Intensity", 0.0f);
		bIsHighlighted = false;
		UE_LOG(LogTemp, Warning, TEXT("Removing Highlight"));
	}

	Components[0]->SetMaterial(0, DynamicMaterial);

}

When I click the actor, it turns the entire actor dark gray permanently. I’m not sure what I’m doing wrong here, but I’m pretty sure it’s in the ChangeHighlight function, as I have traced through all the other code to make sure it’s firing. Help figuring this out would be greatly appreciated!

2

Thats Probably because you already Converted it to a Dynamic Material (Init Function) and trying to Convert it again to a Dynamic Material (Highlight Function). That will Probaly Fail :stuck_out_tongue_winking_eye:

Since you already have a Dynamic Material use it right away without creating a new one. Cast to UMaterialInstanceDynamic if necessary. You also dont need to reassign the Material to the Mesh at the end.

3

That was exactly it. Thank you so much, I’d been struggling with this for a while. =)