Question

所以我读了http://www.koonsolo.com/news/dewitters-gameloop/comment-page-2/#comments上的着名文章，该文章描述了实现游戏循环的不同方法。我试图实现Javascript文章中描述的最终方法（暂时忽略插值）：

var Timer = {
        pastTime : 0,
        currentTime : 0,
        started : false,
        //starts the timer
        start: function(){
            if(!this.started){
                this.started = true;
                this.pastTime = new Date().getTime();
            }
        },
        //gets the time in MILLSECONDS
        getTime: function(){
            return new Date().getTime() - this.pastTime;
        },
        //stops the timer but does not reset it (i.e. getTime() can still be     
          called to get the time between start() and end())
        end: function(){
            if(this.started){
                this.currentTime = new Date().getTime();
                this.started = false;
                return this.currentTime - this.pastTime;
            }
        },
        //resets the timer
        reset: function(){
            this.pastTime = 0;
            this.currentTime = 0;
            this.started = false;
}

var maxFrameSkip = 5;
var nextTick = new Date().getTime();
var TICKS_PER_SECOND = 25;
var tickTimeMillis = 1000 / TICKS_PER_SECOND;

var ticksPerSecondReal = 0;
var ticksCounter = 0;

var timer = Object.create(Timer);

var loops = 0;

function gameLoop(){         
        loops = 0;          

        timer.start(); 

        while(new Date().getTime() > nextTick && loops < maxFrameSkip){
            update();  
            ticksCounter++;
            nextTick += tickTimeMillis;
            loops++;
        }

        draw();      

        if(timer.getTime() >= 1000){
            ticksPerSecondReal = ticksCounter;
            ticksCounter = 0;
            timer.reset();
        } 

        console.log(ticksPerSecondReal);   

        window.requestAnimationFrame(gameLoop);
    }

gameLoop();

所以我遇到的问题是console.log（ticksPerSecondReal）应该总是给我25，因为这是我想要和设置的每秒常数滴答。我最终获得的是一个25和26的交替数字。所以定期（约1秒）它将是25然后是26然后是25，依此类推。当它应该恒定在25时，它会不停地来回切换。这里有什么问题？

固定时间步长给出每秒交替的刻度

0 个答案: