How can I create custom shaped buttons in C++?


I am creating my game menu and managed to create custom shaped buttons using blueprints , as shown below :

These give me nice looking transparent buttons with rounded edges , but , I want to utilize this texture to get the same effect in my C++ code , how to do this?, The code I wrote gives rectangular transparent button , I need to use this materials/textures with opacity , with proper rounded edges. A part of my current code is shown below :

		+ SOverlay::Slot()
			.ShadowOffset(FIntPoint(-1, 1))
			.Font(FSlateFontInfo(FPaths::EngineContentDir() / TEXT("/EngineFonts/Barbarian.ttf"), 48))
			.Text(FText::FromString("The Forgotten Realm"))

		+ SOverlay::Slot().Padding(FMargin(GameButtonLeftMargin, GameButtonTopMargin, GameButtonRightMargin, GameButtonBottomMargin))
			+ SHorizontalBox::Slot()
				SAssignNew(GameButton, SButton)
				//	.OnClicked(this, &SDDFileTree::RefreshButtonPressed)
					//Colored Background
						SAssignNew(GameButtonText, STextBlock)
						.Text(FString("New Game"))
				     /*.Font(FSlateFontInfo(FPaths::EngineContentDir() / TEXT("Slate/Fonts/Roboto-Bold.ttf"), 16))*/
						.ShadowOffset(FIntPoint(1, -1))