RndNum.cpp

// OpenSiv3D 0.3.1

# include <Siv3D.hpp>

namespace fal::rnd {
	template<class T = void>
	struct Rnd {
		using value_type = T;
		Rnd(const T& from, const T& to) : f(from), t(to) {}
		Rnd() = delete;
		T f, t;
	};
	template<>
	struct Rnd<void> {};
	using All = Rnd<void>;

	template<class V, class W, class X>
	constexpr auto num(const V& v, const W& from, const X& to) {
		return Clamp(v, from, to);
	}

	template<class V, class W, class X>
	auto num(const Rnd<V>& v, const W& from, const X& to) {
		if constexpr (std::is_same_v<Rnd<V>, All>)
			return Random(from, to);
		else
			return Random(Max(v.f, from), Min(v.t, to));
	}
}


using namespace fal::rnd;

template<class A, class B>
auto f(const A& x, const B& y) {
	return Circle(num(x, 0, 320), num(y, 0, 240), 5);
}

void Main() {
	Window::Resize(320, 240);

	while (System::Update()) {
		f(200, 200).draw();
		f(Rnd(100, 150), Rnd(100, 150)).draw(Palette::Pink);
		f(Rnd(), Rnd()).draw(Palette::Red);
	}
}