SierpinskiCarpet

//激重なのでリリースでの実行を推奨

# include <Siv3D.hpp>

void DrawCarpet(int left, int top, int size);

void Main()
{
	Graphics::SetBackground(Palette::Black);

	int size = Window::Width();

	while (System::Update())
	{
		DrawCarpet(0, 0, size);
		size *= 1.02;
		if (size > Window::Width() * 3)size /= 3;
	}
}

void DrawCarpet(int left, int top, int size){
	//再帰的に白い正方形を描いていくだけ
	Rect(left + size / 3, top + size / 3,size / 3,size / 3).draw(Palette::White);
	if (size < 3)return;

	DrawCarpet(left, top, size / 3);
	if (size / 3 < Window::Width())
	{
		DrawCarpet(left + size / 3, top, size / 3);
		DrawCarpet(left, top + size / 3, size / 3);
		if (size * 2 / 3 < Window::Width())
		{
			DrawCarpet(left + size * 2 / 3, top, size / 3);
			DrawCarpet(left + size * 2 / 3, top + size / 3, size / 3);
			DrawCarpet(left, top + size * 2 / 3, size / 3);
			DrawCarpet(left + size / 3, top + size * 2 / 3, size / 3);
			DrawCarpet(left + size * 2 / 3, top + size * 2 / 3, size / 3);
		}
		
	}
	
}