2 * Copyright (c) 2011 Sveriges Television AB <info@casparcg.com>
4 * This file is part of CasparCG (www.casparcg.com).
6 * CasparCG is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * CasparCG is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with CasparCG. If not, see <http://www.gnu.org/licenses/>.
19 * Author: Robert Nagy, ronag89@gmail.com
24 #include "prec_timer.h"
26 #include "os/windows/windows.h"
32 prec_timer::prec_timer()
37 // Author: Ryan M. Geiss
38 // http://www.geisswerks.com/ryan/FAQS/timing.html
39 void prec_timer::tick(double interval)
41 tick_millis(static_cast<int64_t>(interval * 1000.0));
44 void prec_timer::tick_millis(int64_t ticks_to_wait)
46 auto t = ::timeGetTime();
53 auto ticks_passed = t - time_;
54 auto ticks_left = ticks_to_wait - ticks_passed;
56 if (t < time_) // time wrap
58 if (ticks_passed >= ticks_to_wait)
63 // if > 0.002s left, do Sleep(1), which will actually sleep some
64 // steady amount, probably 1-2 ms,
65 // and do so in a nice way (cpu meter drops; laptop battery spared).
66 // otherwise, do a few Sleep(0)'s, which just give up the timeslice,
67 // but don't really save cpu or battery, but do pass a tiny
72 for (int i = 0; i < 10; ++i)
73 Sleep(0); // causes thread to give up its timeslice