cutinfx.cpp

#include <Siv3D.hpp>

struct ScrollLines
{
	Array<RectF> lines;
	int frame = 0;
	
	const int duration;
	const int fade;

	ScrollLines(const int duration, const int fade) : duration(duration), fade(fade)
	{
	}

	void update()
	{
		if (InRange(frame, 0, duration))
		{
			// Generate lines
			if (frame % 2 == 0)
			{
				const double length = Random(40.0, 200.0);
				const double width = Random(0.5, 1.5);
				const Vec2 pos = Vec2(-length, Random(Window::Height()));
				lines.emplace_back(pos, length, width);
			}

			// Move lines
			for (auto& r : lines)
			{
				r.moveBy(r.w * 0.3, 0);
			}

			// Remove lines
			Erase_if(lines, [](auto& r) { return r.x > Window::Width(); });


			int alpha = 255;
			if (frame < fade) alpha = 255 * frame / (double)fade;
			if (frame > duration - fade) alpha -= 255 * (frame - (duration - fade)) / (double)fade;

			// Draw BG
			Window::ClientRect().draw(Color(0, alpha / 3));

			// Draw lines
			for (auto& r : lines)
			{
				for (int i : step(3))
				{
					r.movedBy(-r.w * 0.3 * (i + 1), 0).draw(Alpha(alpha / (i + 1)));
				}
				r.draw(Alpha(alpha));
			}
		}

		++frame;
	}
};

struct Banner
{
	int frame = 0;
	const int duration;
	const int bannerOpen = 16;
	const int bannerClose = 16;
	const String text;
	const Font font{ 32, Typeface::Bold, FontStyle::Italic };

	Banner(const int duration, const String& text) : duration(duration), text(text)
	{
	}

	void update()
	{
		if (InRange(frame, 0, duration))
		{
			// Open / Close banner

			double width = 70.0;

			if (InRange(frame, 0, bannerOpen))
			{
				width *= EaseOut<Easing::Cubic>(frame / (double)bannerOpen);
			}

			if (InRange(frame, duration - bannerClose, duration))
			{
				width *= 1.0 - EaseIn<Easing::Cubic>((frame - (duration - bannerClose)) / (double)bannerClose);
			}

			RectF(0, Window::Height() / 2 - width / 2, Window::Width(), width).draw(Palette::Deepskyblue);


			// mini lines

			if (frame > bannerOpen)
			{
				const double y1 = 5 * (frame - bannerOpen);
				const double y2 = 5 * (frame - bannerOpen - 16);
				const double baseY = Window::Center().y;

				for (int i : step(4))
				{
					const double Y1 = 50.0 * (i + 1);
					const double Y2 = 50.0 * (i + 1) + (20.0 - i * 4.5);

					if (y1 > Y1 && y2 < Y2)
					{
						RectF(0, Min(baseY + y1, baseY + Y2), Window::Width(), Max(baseY + y2, baseY + Y1) - Min(baseY + y1, baseY + Y2)).draw(Palette::Royalblue);
						RectF(0, Max(baseY - y1, baseY - Y2), Window::Width(), Min(baseY - y2, baseY - Y1) - Max(baseY - y1, baseY - Y2)).draw(Palette::Royalblue);
					}
				}
			}


			// Text

			const int wait = 8;
			const int durationText = duration - wait * 2;

			const Rect region = font.region(text);
			const double startX = -region.center.x;
			const double moveDist = Window::Width() + region.w;
			const Vec2 textPos(
				startX + moveDist * (EaseIn<Easing::Expo>((frame - wait) / (double)durationText) + EaseOut<Easing::Expo>((frame - wait) / (double)durationText)) / 2.0,
				Window::Center().y);

			font(text).drawCenter(textPos.movedBy(2, 2), Palette::Dodgerblue);
			font(text).drawCenter(textPos);
		}

		++frame;
	}
};

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

	const int scrollLinesStart = 30;
	const int scrollLinesDuration = 180;
	const int scrollLinesFade = 32;
	const int bannerWait = 16;
	const int bannerStart = scrollLinesStart + bannerWait;

	ScrollLines scrollLines(scrollLinesDuration, scrollLinesFade);
	Banner banner(scrollLinesDuration - bannerWait * 2, L"SIV3D CUT IN EFFECT");

	int frame = 0;

	auto reset = [&]() {
		frame = 0;
		scrollLines.frame = 0;
		banner.frame = 0;
	};

	while (System::Update())
	{
		if (Input::KeyEnter.clicked)
		{
			reset();
		}

		if (frame > scrollLinesStart)
		{
			scrollLines.update();
		}

		if (frame > bannerStart)
		{
			banner.update();
		}

		++frame;
	}
}