class RenderLoop {
	constructor() {
		this.renderQue = new Queue();
		this.rendering = null;	// loop処理呼び出し済み判定用
	}

	// 描画用callback関数登録要求
	// 引数のcallbackを1回呼び出します
	// callback: function callback(time)
	requestRenderFunc(callback) {
		console.log('Request render function = ' + (callback ? callback.name : 'null'));
		if (null != callback){
			this.renderQue.enqueue(callback);

			// 描画loop
			(function renderloop(time) {
				if (0 < this.renderQue.size()) {
					this.renderQue.dequeue()(time);
					console.log('render func size=' + this.renderQue.size());
					requestAnimationFrame(renderloop.bind(this));
				}
			}.call(this,window.performance.now()));
		}
	}
}