CODE:

# include 

void Main()
{
		//SystemInit
	/*************************************************/
	Graphics::SetBackground(Palette::Black);
	Graphics::SetVSyncEnabled(true);
	Window::Resize(1280, 720);
	Window::SetTitle(L"The MiniGame");

	Font px64(64);
	Font px32(32);

	int SEvol = 0;
	int BGMvol = 0;

	int scene = 0; //Manage Scenes

	enum
	{
		TITLE,
		GAMEMAIN,
		OPTION,
		EXIT,
		RESULT,
	};



		//TitleInit
	/*************************************************/


	const Sound titlemusic(L""); //オプションと共有

	const String title00 = L"The MiniGame";
	const String title01 = L"GameStart!";
	const Rect pos_t1 = px32(title01).regionCenter({ 640, 400 });
	const String title02 = L"Option";
	const Rect pos_t2 = px32(title02).regionCenter({ 640, 480 });
	const String title03 = L"Result";
	const Rect pos_t3 = px32(title03).regionCenter({ 640, 560 });
	const String title04 = L"Exit";
	const Rect pos_t4 = px32(title04).regionCenter({ 640, 640 });

		//OptionInit
	/*************************************************/

	//Siv3D標準装備のGUIをつかってみる

	GUI optionGUI(GUIStyle::Default);
	optionGUI.setCenter({ 320, 320 });

	optionGUI.add(GUIText::Create(L"SE Volume   "));
	optionGUI.addln(L"SE Volume", GUISlider::Create(0, 128, 100, 480, true));
	optionGUI.add(GUIText::Create(L"BGM Volume"));
	optionGUI.addln(L"BGM Volume", GUISlider::Create(0, 128, 100, 480, true));

	optionGUI.show(false);

		//GameMainInit
	/*************************************************/
	const int BALLMAX = 128;

	typedef struct Ball{
		double x, y;
		double vx, vy;
		double g;
		Color color;
		int r;
		int life;
		bool flag;
	};

	Ball ball[BALLMAX];
	int score;
	Circle effect[20];
	int cntB=1;

	for (int i = 0; i < BALLMAX; i++)
		ball[i].flag = false;

	

		//ExitInit
	/*************************************************/

	bool exit = false;



	while (System::Update())
	{

		switch (scene)
		{
			case TITLE:
			{
					//マウスとの接触？
				const bool hit1 = pos_t1.mouseOver;
				const bool hit2 = pos_t2.mouseOver;
				const bool hit3 = pos_t3.mouseOver;
				const bool hit4 = pos_t4.mouseOver;

					//クリックされてたらそれぞれシーンへと飛ぶ
				if (pos_t1.leftClicked)scene = GAMEMAIN;
				if (pos_t2.leftClicked)scene = OPTION;
				if (pos_t3.leftClicked)scene = RESULT;
				if (pos_t4.leftClicked)scene = EXIT;

					//タイトルの描画
				px64(title00).drawCenter({ 640, 128 }, HSV(System::FrameCount() % 100 * 3.6));
				px32(title01).drawCenter({ 640, 400 }, hit1 ? Color(Random() * 255, Random() * 255, Random() * 255) : Palette::White);
				px32(title02).drawCenter({ 640, 480 }, hit2 ? Color(Random() * 255, Random() * 255, Random() * 255) : Palette::White);
				px32(title03).drawCenter({ 640, 560 }, hit3 ? Color(Random() * 255, Random() * 255, Random() * 255) : Palette::White);
				px32(title04).drawCenter({ 640, 640 }, hit4 ? Color(Random() * 255, Random() * 255, Random() * 255) : Palette::White);

				break;
			}


			case GAMEMAIN:
			{

					//5秒に一回ほどボールを生成する
				if (System::FrameCount() % 300 == 0)cntB++;
				for (int i = 0; i < cntB; i++)
				{
						//空きを見つけて初期化
					if (ball[i].flag == false)
					{
						const double rand = Random();

						ball[i].r = (rand+1) * 30;

						ball[i].x = rand * 1280;
						ball[i].y = -60;
						ball[i].vx = 0;
						ball[i].vy = 0;
						ball[i].g = (rand+1)/8;
						ball[i].life = 0;
						ball[i].color = HSV(Random() * 360);
						ball[i].flag = true;
					}
				}


				for (int i = 0; i < cntB; i++)
				{
						//フラグ立ってたら計算と描画
					if (ball[i].flag == true)
					{
						ball[i].vy += ball[i].g;
						ball[i].life++;
						ball[i].x = ball[i].x + ball[i].vx;
						ball[i].y = ball[i].y + ball[i].vy;

						Circle(ball[i].x, ball[i].y, ball[i].r).draw(ball[i].color);
					}
				}



				if (Input::KeyT.clicked)scene = TITLE;

				break;
			}


			case OPTION:
			{
				optionGUI.show(true);

				px32(L"Press T to return Title").draw(0, 0);
				SEvol = optionGUI.slider(L"SE Volume").valueInt;
				BGMvol = optionGUI.slider(L"BGM Volume").valueInt;
				Println(BGMvol);
				if (Input::KeyT.clicked)
				{
					scene = TITLE;
					optionGUI.show(false);
				}

				break;
			}

			case RESULT:
			{
				px32(L"さーせんまだ未実装です＾＾\n　Tキーを押してタイトルへ戻る。").draw(0, 0);
				if (Input::KeyT.clicked)scene = TITLE;

				break;
			}

			case EXIT:
			{
				exit = true; //終了のフラグを立てる
				break;
			}


			default:
			{
				Println(L"Error:定義されていないシーンが呼ばれました。");
				break;
			}
		}
		if (exit == true) break; //終わり
	}
	
}