live-game-day1.cpp

#include <Siv3D.hpp>

void Main() {
	Graphics::SetTargetFrameRateHz(60);
	Window::SetTitle(U"五月祭 TSGLIVE 5! day-1 ライブゲームプログラミング");

	Scene::SetBackground(Palette::Lightblue);
	Window::Resize({ 500, 800 });

	constexpr double timeDelta = 1 / 60.0;

	constexpr double mag = 1 / 20.0;

	Camera2D camera(Vec2::Zero(), 1/mag, Camera2DParameters::NoControl());

	P2World world(9.8);

	P2Body ceiling = world.createStaticRect(Vec2{ 0.0, 10.0 }, SizeF{ 25, 1.5 });

	Array<P2Body> wall = {
		world.createStaticRect(
			Vec2{-(Window::ClientWidth() - 1.5) / 2 * mag, 0.0 },
			SizeF{ 1.5, 100 }
		),
		world.createStaticRect(
			Vec2{ (Window::ClientWidth() - 1.5) / 2.0 * mag, 0.0 },
			SizeF{ 1.5, 100 }
		)
	};

	const Polygon arrow({
		{ 0.0, 1.0 },
		{ 0.3, 0.7 },
		{ 0.1, 0.8 },
		{ 0.0, 0.0 },
		{-0.1, 0.8 },
		{-0.3, 0.7 },
	});

	double outer = 0.75;
	
	Array<P2Body> playerBodies;
	for (auto i : step(8))
		playerBodies << world.createCircle(
			Circular(outer / Sin(Math::Pi / 8), i * Math::TwoPi / 8),
			outer
		);

	Array<P2PivotJoint> playerPivots;
	auto resetPivots = [&](Vec2 center) {
		for (auto i : step(playerBodies.size()))
			playerPivots << world.createPivotJoint(
				playerBodies[i],
				playerBodies[(i + 1) % playerBodies.size()],
				center + Circular(
					outer / Tan(Math::Pi / playerBodies.size()),
					(i + 0.5) * Math::TwoPi / playerBodies.size()
				)
			).setLimits(-40.0_deg, 40.0_deg).setLimitEnabled(true);
	};
	resetPivots(Vec2::Zero());

	Optional<Vec2> grabOrigin;

	Font scoreFont(60);
	Font highScoreFont(30);

	double highScore = 0.0;
	
	Optional<double> hitInterval = none;

	Array<P2Body> objects;

	std::unordered_set<int> objectIds;
	bool isGameover = false;

	while (System::Update()) {
		Cursor::RequestStyle(CursorStyle::Hand);

		camera.update();

		const Vec2 playerCenter = playerBodies.reduce(
			[](auto&& acc, auto&& body) {
				return acc + body.getPos();
			}, Vec2::Zero()
		) / static_cast<double>(playerBodies.size());

		if (!hitInterval) {
			for (auto&& [pair, col] : world.getCollisions()) {
				if (objectIds.contains(pair.a) || objectIds.contains(pair.b)) {
					playerPivots.clear();
					if (playerBodies.size() <= 3) {
						for (auto&& [i, b] : IndexedRef(playerBodies))
							b.applyLinearImpulse(Circular(5.0, Random(Math::TwoPi)));

						isGameover = true;
						break;
					}

					playerBodies.pop_back();
					for (auto&& [i, b] : IndexedRef(playerBodies))
						b.setPos(playerCenter + Circular(outer / Sin(Math::Pi / playerBodies.size()), i * Math::TwoPi / playerBodies.size()));

					resetPivots(playerCenter);
					
					hitInterval = 0.0;

					break;
				}
			}
		}
		else {
			*hitInterval += 1.0;
			if (*hitInterval >= 200)
				hitInterval = none;
		}

		const Vec2 rawCursor = Cursor::PosRaw();

		const double gazeY = Min(0.0, playerCenter.y);

		if (!isGameover) {
			camera.setTargetCenter({ 0.0, gazeY });

			wall[0].setPos({ -11.75, gazeY });
			wall[1].setPos({ 11.75, gazeY });

			if (MouseL.down())
				grabOrigin = rawCursor;

			if (grabOrigin && MouseL.up()) {
				for (auto&& body : playerBodies)
					body.applyLinearImpulse((*grabOrigin - rawCursor) / 5.0);

				grabOrigin = none;
			}

			highScore = Max(highScore, -gazeY);
		}

		constexpr double interval = 10.0;
		const Quad tekiQuad({ 1.5, 0.0 }, { 0.0, 1.5 }, { -1.5, 0.0 }, { 0.0, -1.5 });
		while (highScore + 5 * interval >= static_cast<double>(objects.size()) * interval) {
			objects << world.createStaticQuad(
				{
					Random(-9.0, 9.0),
					-static_cast<double>(objects.size() + 1) * interval
				},
				tekiQuad
			);
			objectIds.insert(objects.back().id());
		}

		world.update();

		// 描画

		{
			const auto transformer = camera.createTransformer();

			ceiling.draw();
			wall.each([](auto&& w) { w.draw(); });

			objects.each([](auto&& o) { o.draw(); });

			playerBodies.each([&](auto&& b) { b.draw(hitInterval ? Palette::Blue.lerp(Palette::Red, *hitInterval / 250) : Palette::Red); });
		}

		if (isGameover) {
			Rect(Window::ClientSize()).draw(ColorF(Palette::Black, 0.5));

			scoreFont(U"ハイスコア").drawAt(Window::ClientCenter().moveBy(0, -30));
			scoreFont(U"{:.1f}m"_fmt(highScore)).drawAt(Window::ClientCenter().moveBy(0, 30));

			continue;
		}

		if (grabOrigin && MouseL.pressed()) {
			Vec2 v = rawCursor - *grabOrigin;

			auto _ = Transformer2D(
				Mat3x2::Rotate(-v.getAngle({ 0.0, -1.0 }))
				* Mat3x2::Scale(v.length())
				* Mat3x2::Translate(*grabOrigin)
			);

			arrow.draw();
		}

		scoreFont(U"{:.1f}m"_fmt(Max(0.0, -gazeY))).drawAt({ Window::ClientWidth() / 2, 50 }, Palette::Black);
		highScoreFont(U"ハイスコア: {:.1f}m"_fmt(highScore)).drawAt({ Window::ClientWidth() / 2, 100 }, Palette::Black);
	}

	playerPivots.clear();
}