scummvm/engines/bladerunner/framelimiter.cpp
2021-12-26 18:48:43 +01:00

75 lines
2.0 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "bladerunner/framelimiter.h"
#include "bladerunner/bladerunner.h"
#include "bladerunner/time.h"
#include "common/debug.h"
#include "common/system.h"
namespace BladeRunner {
Framelimiter::Framelimiter(BladeRunnerEngine *vm, uint fps) {
_vm = vm;
reset();
if (fps > 0) {
_enabled = true;
_speedLimitMs = 1000 / fps;
} else {
_enabled = false;
}
_timeFrameStart = _vm->_time->currentSystem();
}
void Framelimiter::wait() {
// TODO: when vsync will be supported, use it
if (!_enabled) {
return;
}
uint32 timeNow = _vm->_time->currentSystem();
uint32 frameDuration = timeNow - _timeFrameStart;
if (frameDuration < _speedLimitMs) {
uint32 waittime = _speedLimitMs - frameDuration;
if (_vm->_noDelayMillisFramelimiter) {
while (_vm->_time->currentSystem() - timeNow < waittime) { }
} else {
_vm->_system->delayMillis(waittime);
}
timeNow += waittime;
}
// debug("frametime %i ms", timeNow - _timeFrameStart);
// using _vm->_time->currentSystem() here is slower and causes some shutters
_timeFrameStart = timeNow;
}
void Framelimiter::reset() {
_timeFrameStart = 0u;
}
} // End of namespace BladeRunner