新入生に見せるため突貫で作った弾避けゲー

Main.cpp

#include<Siv3D.hpp>
#include<chrono>
namespace sch = std::chrono;

void Main()
{
	s3d::Window::Resize(360, 480);
	std::pair<s3d::Circle, bool> enemy[25 * 8]{};
	constexpr int s = 4;
	s3d::Circle player(180, 240, s);
	std::mt19937 random{ std::random_device()() };
	std::uniform_int_distribution<int> uni(0, 360);
	auto start = sch::system_clock::now();
	s3d::Optional<sch::time_point<sch::system_clock>> end;
	std::pair<s3d::Key, s3d::Point> keys[4] =
	{
		std::make_pair(s3d::Input::KeyUp,s3d::Point(0,-1)),
		std::make_pair(s3d::Input::KeyDown,s3d::Point(0,1)),
		std::make_pair(s3d::Input::KeyRight,s3d::Point(1,0)),
		std::make_pair(s3d::Input::KeyLeft,s3d::Point(-1,0))
	};
	int n{};
	s3d::Font const font(32);
	while (s3d::System::Update())
	{
		for (auto& p : enemy)
		{
			if (p.second)
				p.first.draw(s3d::Palette::Red);
		}
		if (end)
		{
			font(L"ゲームオーバー:\n", sch::duration_cast<sch::milliseconds>(*end - start)).draw();
			continue;
		}
		++n;
		if (n % 20 == 0)
		{
			for (int i{};i < 8;++i)
			{
				for (auto& a : enemy)
				{
					if (!a.second)
					{
						a.first.center = s3d::Vec2(uni(random), -s);
						a.first.setSize(s);
						a.second = true;
						break;
					}
				}
			}
		}

		if (std::any_of(std::begin(enemy), std::end(enemy), 
			[&](auto const& p)
		{
			return p.second&& p.first.intersects(player);
		}))
			end = sch::system_clock::now();
		for (auto& p : enemy)
		{
			if (p.second)
			{
				p.first.y += 1;
				if (p.first.y > 480 + s)
				{
					p.second = false;
				}
			}
		}
		for (auto const& p : keys)
		{
			if (p.first.pressed)
			{
				player.center += p.second;
			}
		}
		player.draw(s3d::Palette::White);
		
	}
}