/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// Frame schedulers: executing a frame's worth of mutation, and possibly
// waiting for a later frame. (These schedulers will halt the main thread,
// allowing background threads to continue working.)
var Scheduler =
class {
constructor(perfMonitor) {
this._perfMonitor = perfMonitor;
}
start(loadMgr, timestamp) {
return loadMgr.start(timestamp);
}
tick(loadMgr, timestamp) {}
wait_for_next_frame(t0, tick_start, tick_end) {}
};
// "Sync to vsync" scheduler: after the mutator is done for a frame, wait until
// the beginning of the next 60fps frame.
var VsyncScheduler =
class extends Scheduler {
tick(loadMgr, timestamp) {
this._perfMonitor.before_mutator(timestamp);
gHost.start_turn();
const completed = loadMgr.tick(timestamp);
gHost.end_turn();
this._perfMonitor.after_mutator(timestamp);
return completed;
}
wait_for_next_frame(t0, tick_start, tick_end) {
// Compute how long until the next 60fps vsync event, and wait that long.
const elapsed = (tick_end - t0) / 1000;
const period = 1 / FPS;
const used = elapsed % period;
const delay = period - used;
gHost.suspend(delay);
this._perfMonitor.after_suspend(delay);
}
};
// Try to maintain 60fps, but if we overrun a frame, do more processing
// immediately to make the next frame come up as soon as possible.
var OptimizeForFrameRate =
class extends Scheduler {
tick(loadMgr, timestamp) {
this._perfMonitor.before_mutator(timestamp);
gHost.start_turn();
const completed = loadMgr.tick(timestamp);
gHost.end_turn();
this._perfMonitor.after_mutator(timestamp);
return completed;
}
wait_for_next_frame(t0, tick_start, tick_end) {
const next_frame_ms = round_up(tick_start, 1000 / FPS);
if (tick_end < next_frame_ms) {
const delay = (next_frame_ms - tick_end) / 1000;
gHost.suspend(delay);
this._perfMonitor.after_suspend(delay);
}
}
};
