Glass_spheres

# include <Siv3D.hpp> // OpenSiv3D v0.1.5

struct Glass
{
	Glass(const Vec2& _pos, const double& _n, const double& _r)
		: pos(_pos), n(_n), r(_r) {}
	Vec2 pos;
	double n;
	double r;

	Circle circle() const { return Circle(pos, r); }
};

struct Lazer
{
	Lazer(const Vec2& _pos, const Vec2& _ang)
		: pos(_pos), ang(_ang) {}
	Vec2 pos;
	Vec2 ang;
};

void Main()
{
	Graphics::SetBackground(Color(11, 22, 33));
	Window::SetTitle(L"ガラス球の光学特性");
	Window::Resize(1280, 720);

	const Font font(24);

	Array<Glass> glass;
	Array<Lazer> lazer;
	double n = 1;

	Mat3x2 transform(Mat3x2::Identity());

	for (int i = 0; i < 100; i++)
		glass.emplace_back(Vec2(0, i * 33), 1.5, 16);

	for (int x = 0; x < 10; x++)
		for (int y = 0; y < 10; y++)
			glass.emplace_back(Vec2(0, -700) + Vec2(x*1.73*0.5, y + (x % 2)*0.5) * 64, 1.5, 31);

	for (int i = 0; i < 10; i++)
		lazer.emplace_back(Vec2(64, 0 + i * 8), Vec2(1.0, 0.0));
	for (int i = 0; i < 30; i++)
		lazer.emplace_back(Vec2(64, 512 + i * 4), Vec2(1.0, 0.0));
	for (int i = 0; i < 100; i++)
		lazer.emplace_back(Vec2(64, 1024 + i * 8), Vec2(1.0, 0.0));


	Glass* selectedGlass = NULL;
	Lazer* rSelectedLazer = NULL;
	Lazer* lSelectedLazer = NULL;

	while (System::Update())
	{
		if (!KeyControl.pressed() && !KeyShift.pressed()) transform = transform.scale((10 - Mouse::Wheel()) / 10.0, Cursor::PosF());
		else
		{
			const Transformer2D t1(transform, true);
			for (auto& g : glass)
			{
				if (g.circle().mouseOver())
				{
					if (KeyShift.pressed()) g.n = Max(1.0, Min(5.0, g.n + Mouse::Wheel() / 10.0));
					else g.r *= (10 - Mouse::Wheel()) / 10.0;
				}
			}
		}
		{
			const Transformer2D t1(transform, true);
			if (MouseL.up()) selectedGlass = NULL;
			if (selectedGlass != NULL) selectedGlass->pos = Cursor::PosF();
			if (MouseL.up()) lSelectedLazer = NULL;
			if (lSelectedLazer != NULL) lSelectedLazer->pos = Cursor::PosF();

			if (MouseR.up()) rSelectedLazer = NULL;
			if (rSelectedLazer != NULL && !(Cursor::PosF() - rSelectedLazer->pos).isZero()) rSelectedLazer->ang = (Cursor::PosF() - rSelectedLazer->pos).normalized();
		}
		for (;;)
		{
			bool flag = false;
			for (auto& g1 : glass)
			{
				for (auto& g2 : glass)
				{
					if (&g1 != &g2 && g1.circle().intersects(g2.circle()))
					{
						if (&g1 != selectedGlass) g1.pos += (g1.pos - g2.pos).normalized();
						if (&g2 != selectedGlass) g2.pos += (g2.pos - g1.pos).normalized();
						flag = true;
					}
				}
			}
			if (!flag) break;
		}

		for (auto& l : lazer)
		{
			const Transformer2D t1(transform, true);

			double len = 4096;
			Vec2 pos = l.pos;
			Vec2 ang = l.ang;
			Glass* nowGlass = NULL;
			for (auto& g : glass) if (g.circle().intersects(l.pos)) nowGlass = &g;

			for (;;)
			{
				Vec2 nearPos;
				Glass* nearGlass = NULL;
				const auto ray = Line(pos, pos + ang * len);
				for (auto& g : glass)
				{
					auto list = g.circle().intersectsAt(ray);
					if (list)
					{
						for (auto& i : list.value())
						{
							if (!(i - ray.begin).isZero() && (nearGlass == NULL || (i - ray.begin).length() < (nearPos - ray.begin).length()))
							{
								nearGlass = &g;
								nearPos = i;
							}
						}
					}
				}
				if (nowGlass == NULL)
				{
					if (nearGlass != NULL)
					{
						Circle(nearPos, 4).draw(ColorF(Palette::Red, 1.0));
						Line(pos, nearPos).draw(2, ColorF(Palette::Red, 1.0));
						auto a = n / nearGlass->n* (nearGlass->pos - nearPos).normalized().cross(ang);
						ang = Vec2::Right().rotated(atan2(nearGlass->pos.y - nearPos.y, nearGlass->pos.x - nearPos.x) + asin(a));
						len -= (nearPos - pos).length();
						pos = nearPos + ang*0.01;
						nowGlass = nearGlass;
					}
					else
					{
						ray.draw(2, ColorF(Palette::Red, 1.0));
						break;
					}
				}
				else
				{

					if (nearGlass != NULL)
					{

						Circle(nearPos, 4).draw(ColorF(Palette::Red, 1.0));
						Line(pos, nearPos).draw(2, ColorF(Palette::Red, 1.0));
						auto a = nowGlass->n / n* (nearGlass->pos - nearPos).normalized().cross(ang);
						if (abs(a) <= 1)
						{
							ang = Vec2::Right().rotated(atan2(nearPos.y - nearGlass->pos.y, nearPos.x - nearGlass->pos.x) - asin(a));
							nowGlass = NULL;
						}
						else
						{
							ang.rotate(-(atan2(ang.y, ang.x) - atan2(nearPos.y - nearGlass->pos.y, nearPos.x - nearGlass->pos.x)) * 2);
							ang = -ang;
						}
						len -= (nearPos - pos).length();
						pos = nearPos + ang*0.01;
					}
					else
					{
						ray.draw(2, ColorF(Palette::Red, 1.0));
						break;
					}
				}
			}
		}

		for (auto& g : glass)
		{
			const Transformer2D t1(transform, true);

			g.circle().draw(ColorF(Palette::Skyblue, (g.n - 1) / 8.0)).drawFrame(2.0, ColorF(Palette::Skyblue, g.circle().mouseOver() ? 1.0 : 0.5));
			font(g.n).drawAt(g.pos);
			if (g.circle().leftClicked()) selectedGlass = &g;
		}

		for (auto& l : lazer)
		{
			const Transformer2D t(transform, true);
			Circle(l.pos + l.ang * 8, 4).draw(ColorF(Palette::Red, 1.0));
			auto r = Rect(-8, -3, 16, 6).rotated(atan2(l.ang.y, l.ang.x)).movedBy(l.pos);
			r.draw(Palette::White).drawFrame(1, 0, Palette::Gray);
			if (r.rightClicked()) rSelectedLazer = &l;
			if (r.leftClicked() && selectedGlass == NULL) lSelectedLazer = &l;
		}

	}
}