Use a more accurate timer than setInterval

[pintassilgo]

I don't know anything about F.LF's code, I'm just creating this ticket after some reading.

1. F.LF is performing bad in Firefox since version 55 (mid 2017!), at least on Windows machines:
   https://bugzilla.mozilla.org/show_bug.cgi?id=1683560

2. It seems that 1 is a thing because "the game relies on setTimeout setInterval for precise frame scheduling. This is not a good idea in general, because by default, the timer resolution on Windows is really bad". Source:
   https://bugzilla.mozilla.org/show_bug.cgi?id=1683560#c5

3. If Chromium (Blink) based browsers handles this well, Firefox must fix this, of course. But the point made in 2 may still be valid for optimization. Maybe you can get something from here:
   https://stackoverflow.com/questions/196027/is-there-a-more-accurate-way-to-create-a-javascript-timer-than-settimeout

[teohhanhui]

https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame

[pintassilgo]

Replacing this line:

F.LF/LF/match.js

Line 207 in 661b1bc

$.time.timer = network.setInterval(function () { return $.frame() }, 1000 / Global.gameplay.framerate)

By

      let frame = -1;

      function loop (timestamp) {
        let seg = Math.floor(timestamp / (1000 / Global.gameplay.framerate));
        if (seg > frame) {
          frame = seg;
          $.frame();
        }
        requestAnimationFrame(loop)
      }

      requestAnimationFrame(loop);

Fixes F.LF for Firefox, the game runs smoothly at 30fps. Even ignoring this Firefox bug, using requestAnimationFrame instead of setInterval is the right choice for controlling framerate.

Of course this is just a prototype, other things must be changed in the code, but this is enough for 30fps local gameplay/demo.

Even in Blink browsers like Chrome, current F.LF is stable at 30fps for 99% of the time, but I see some rare spikes of 31fps, 32fps, 28fps. With requestAnimationFrame is 100% stable at 30fps.

[pintassilgo]

I just opened project-f.github.io on Firefox on Linux and it runs at 30fps. This bug is Firefox&Windows-only. But anyway requestAnimationFrame should be used instead of setInterval.