改寫原本的 Day 06 的 ScenesManger
switch scence with ScenesManager by ts

• private: 私有屬性
• public: 公有屬性
• void: 用於function的回傳值定義，代表這個function不會回傳任何值
• function(arg): Type{} : 代表這個 function 回傳值為這個 type
  ex: public goToScene(id: string): bool { ... return false} 回傳布林值

class ScenesManager {
	private static scenes: any = {}; // should be hashmap but a JS object is fine too :)
  public static currentScene: Scene;

	public create(width: number, height: number, scale:bool=false) {
			// requestAnimFrame(ScenesManager.loop);
			var canvas = document.getElementById('canvas')
			canvas.width = width
			canvas.height = height
			return this;
	}
	public createScene(id: string, TScene: void) {
		console.log('id: ', id)
				console.log('TScene: ', TScene)
			if (ScenesManager.scenes[id]) return undefined;
			// if (ScenesManager.scenes[id]) return undefined;

			// var scene = new TScene();

		ScenesManager.scenes[id] = TScene;
		console.log('ScenesManager.scenes: ', ScenesManager.scenes)

			// return scene;
	}

  public clearScene() {
		var canvas = document.getElementById('canvas')
		var ctx = canvas.getContext('2d');
		ctx.clearRect(0, 0, canvas.width, canvas.height);
	}
	public goToScene(id: string): bool {
		this.clearScene()
		if (ScenesManager.scenes[id]) {
				// if (ScenesManager.currentScene) ScenesManager.currentScene.pause();
				ScenesManager.currentScene = ScenesManager.scenes[id];
				// ScenesManager.currentScene.resume();
				ScenesManager.scenes[id]()
				return true;
		}
		return false;
		}
}