FpsAnalysis.js

// 原本的用法，可以將變數包起來，並用return 決定要開那些介面
Framework.FpsAnalysis = function () {
	if (!(this instanceof arguments.callee)) return new arguments.callee();
  	var timeData = new Array(50);
	var fpsData = new Array(50);
	for (var i = 0; i < fpsData.length; i++) {
		timeData[i] = 0;
		fpsData[i] = 0;
	}
	var currentPoint = 1;
	var fps = 0;
	timeData[0] = (new Date()).getTime();
	return {
		update: function () {
			timeData[currentPoint] = (new Date()).getTime();
			fps -= fpsData[currentPoint];
			fpsData[currentPoint] = timeData[currentPoint] - (currentPoint == 0 ? timeData[timeData.length - 1] : timeData[currentPoint - 1]);
			fps += fpsData[currentPoint];
			currentPoint = (++currentPoint) % fpsData.length;
		},
		getUpdateFPS: function () {
			return Math.floor(1000 / (fps / fpsData.length));
		}
	};
};

//改用 Klass 的方式就不能將變數包起來決定要開那些介面，
Framework.FpsAnalysis = Klass({
    _timeData: [],
    _fpsData: [],
    _currentPoint: 0,
    _fps: 0,
    // __construct 為自訂的建構子
    __construct: function(){
        this._timeData = new Array(50);
        this._fpsData = new Array(50);
        for(var i=0;i<this._fpsData.length;i++){
            this._timeData[i] = 0;
            this._fpsData[i] = 0;
        }
        this._currentPoint = 1;
        this._fps = 0;
        this._timeData[0] = (new Date()).getTime();
    },
    update: function(){
        this._timeData[this._currentPoint] = (new Date()).getTime();
        this._fps -= this._fpsData[this._currentPoint];
        this._fpsData[this._currentPoint] = this._timeData[this._currentPoint] - (this._currentPoint === 0 ? this._timeData[this._timeData.length-1] : this._timeData[this._currentPoint -1]);
        this._fps += this._fpsData[this._currentPoint];
        this._currentPoint = (++this._currentPoint) % this._fpsData.length;
    },
    getUpdateFPS: function(){
        return Math.floor(1000 / (this._fps / this._fpsData.length));
    }
});