Polygon::calculateBuffer(), calculateRoundBuffer() が失敗することがある

[Reputeless]

# include <Siv3D.hpp>

void Main()
{
	Scene::SetBackground(ColorF{ 0.6, 0.8, 0.7 });

	const Font font{ 100, Typeface::Bold };

	Array<Polygon> polygons;
	{
		Vec2 penPos{ 0, 0 };

		for (const auto& glyph : font.renderPolygons(U"Hello, world!"))
		{
			for (const auto& polygon : glyph.polygons)
			{
				polygons << polygon.movedBy(penPos + glyph.getOffset()).calculateRoundBuffer(5);

				polygons << polygon.movedBy(penPos + glyph.getOffset() + Vec2{ 0, 120 }).calculateBuffer(5);
			}

			penPos.x += glyph.xAdvance;
		}
	}

	while (System::Update())
	{
		for (const auto& polygon : polygons)
		{
			polygon.draw();
		}

		Triangle{ 200, 300, 400, 400, 100, 400 }.draw().asPolygon().calculateBuffer(10).draw(ColorF{ 1.0, 0.0, 0.0, 0.4 });

		Triangle{ 600, 400, 700, 500, 400, 500 }.draw().asPolygon().calculateRoundBuffer(10).draw(ColorF{ 1.0, 0.0, 0.0, 0.4 });
	}
}

[Reputeless]

v0.6.7 で修正完了。