javascript - Node.js: alternative to setInterval which is more precise for game loop - Stack Overflow

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My setup is a multiplayer game, with sockets to async transfer data.

Now because of the nature of a game, I have a game loop which should tick every 500ms to do player updating (e.g. position, appearance,...).

var self = this;

this.gameLoop = setInterval(function()
{   
    for (var i = 0; i < playerSize; i++)
    {
        self.players.get(i).update();
    };
}, 500);

I'm currently using setInterval but when i did some benchmarks with about 200 connections, setInterval drifted away to 1000ms instead of 500ms, which makes the whole game appear laggy. Also it's not accurate enough unfortunately with a little amount of players. (note that the update calls only take about 100ms maximum)

So to me after researching, there seems to be no other option then to spawn a process which only handles the timining mechanism? Or are there other options?

Anyone has done this before or can give some fundamental ideas/solutions on how to do this?

Full code:

Game.prototype.start = function()
{
    var average = 0;
    var cycles = 10;
    var prev = Date.now();

    this.thread = setInterval(function()
    {       
        console.log("interval time="+(Date.now() - prev));
        prev = Date.now();

        var s = Date.now();

        // EXECUTE UPDATES
    for (var i = 0; i < playerSize; i++)
    {
        self.players.get(i).update();
    };

        average += (Date.now() - s);

        cycles--;
        if(cycles == 0)
        {
            console.log("average update time: " + (average/10) + "ms");
            average = 0;
                cycles = 10;
            }
    }, 500);
}

My setup is a multiplayer game, with sockets to async transfer data.

Now because of the nature of a game, I have a game loop which should tick every 500ms to do player updating (e.g. position, appearance,...).

var self = this;

this.gameLoop = setInterval(function()
{   
    for (var i = 0; i < playerSize; i++)
    {
        self.players.get(i).update();
    };
}, 500);

I'm currently using setInterval but when i did some benchmarks with about 200 connections, setInterval drifted away to 1000ms instead of 500ms, which makes the whole game appear laggy. Also it's not accurate enough unfortunately with a little amount of players. (note that the update calls only take about 100ms maximum)

So to me after researching, there seems to be no other option then to spawn a process which only handles the timining mechanism? Or are there other options?

Anyone has done this before or can give some fundamental ideas/solutions on how to do this?

Full code:

Game.prototype.start = function()
{
    var average = 0;
    var cycles = 10;
    var prev = Date.now();

    this.thread = setInterval(function()
    {       
        console.log("interval time="+(Date.now() - prev));
        prev = Date.now();

        var s = Date.now();

        // EXECUTE UPDATES
    for (var i = 0; i < playerSize; i++)
    {
        self.players.get(i).update();
    };

        average += (Date.now() - s);

        cycles--;
        if(cycles == 0)
        {
            console.log("average update time: " + (average/10) + "ms");
            average = 0;
                cycles = 10;
            }
    }, 500);
}

• javascript
• node.js
• timer
• game-loop

Share Improve this question Follow edited Sep 15, 2015 at 15:27 Captain Obvious asked Sep 15, 2015 at 13:55 Captain ObviousCaptain Obvious 78533 gold badges1818 silver badges3939 bronze badges 6

• You said update() only takes about 100ms. How did you benchmark this? And does it mean the whole loop with 200 players only takes 100ms or one single call of update takes 100ms? – basilikum Commented Sep 15, 2015 at 14:26
• Hi, all the updates of the players takes less than 100ms, my point was just to make note that it is not more than the interval time. I measured it with a Date.now() difference – Captain Obvious Commented Sep 15, 2015 at 15:05
• Can you maybe show, in code, how you measured it? I am not sure, but considering these huge differences (from 500ms to 1000ms), I would assume, that the benchmark is maybe incorrect and that your loop actually takes more time then 500ms to execute which make the intervals bee longer and possible overlapping. – basilikum Commented Sep 15, 2015 at 15:15
• I've updated my post. – Captain Obvious Commented Sep 15, 2015 at 15:28
• Ok, looks good. Could it maybe have something to do with this: stackoverflow./questions/5927284/… – basilikum Commented Sep 15, 2015 at 15:42

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2 Answers 2

Sorted by: Reset to default 3

Here is an article on creating an accurate node.js game loop using a bination of setTimeout() and setImmediate so things are accurate but don't use up too much CPU.

The nanoTimer timing library might work for you. From the readme it sounds like it uses a similar approach. I don't know if it's been designed with games in mind but it should be worth a try!

Although I don't work with games, there is a better alternative than setInterval, as shown here. It worked well for me in a business application. I hope this helps.

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