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/* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include "bladerunner/framelimiter.h"
#include "bladerunner/bladerunner.h"
#include "bladerunner/time.h"
#include "common/system.h"
namespace BladeRunner {
Framelimiter::Framelimiter(BladeRunnerEngine *vm, FramelimiterFpsRate framerateMode, bool useDelayMs) {
_vm = vm;
// // FUTURE: The frame limiter is disabled when vsync is enabled.
// _enabled = !_system->getFeatureState(OSystem::kFeatureVSync);
_enabled = true;
_useDelayMs = useDelayMs;
_speedLimitMs = 0u;
uint32 framerate = 1u; // dummy init
switch (framerateMode) {
case kFramelimiter15fps:
framerate = 15u;
break;
case kFramelimiter25fps:
framerate = 25u;
break;
case kFramelimiter30fps:
framerate = 30u;
break;
case kFramelimiter60fps:
framerate = 60u;
break;
case kFramelimiter120fps:
framerate = 120u;
break;
case kFramelimiterDisabled:
// fall through
default:
_enabled = false;
break;
}
if (_enabled) {
_speedLimitMs = 1000 / CLIP<uint32>(framerate, 1, 120);
}
reset();
}
Framelimiter::~Framelimiter() { }
void Framelimiter::init(bool forceScreenUpdate) {
reset();
_timeOfLastPass = _vm->_time->currentSystem();
_forceScreenUpdate = forceScreenUpdate;
}
uint32 Framelimiter::getLastFrameDuration() const {
return _lastFrameDurationMs;
}
uint32 Framelimiter::getTimeOfCurrentPass() const {
return _timeOfCurrentPass;
}
uint32 Framelimiter::getTimeOfLastPass() const {
return _timeOfLastPass;
}
bool Framelimiter::shouldExecuteScreenUpdate() {
bool shouldUpdateScreen = true;
_timeOfCurrentPass = _vm->_time->currentSystem();
if (_enabled) {
if (_useDelayMs) {
// _timeOfCurrentPass is used to calculate the duration that the current frame is on screen so far
uint32 frameDuration = _timeOfCurrentPass - _startFrameTime;
if (frameDuration < _speedLimitMs) {
_vm->_system->delayMillis(_speedLimitMs - frameDuration);
// cheaper than calling _vm->_time->currentSystem() again
_timeOfCurrentPass += (_speedLimitMs - frameDuration);
}
}
shouldUpdateScreen = ((_timeOfCurrentPass - _timeOfLastPass) >= _speedLimitMs) || _forceScreenUpdate || _useDelayMs;
if (shouldUpdateScreen) {
if (_forceScreenUpdate) {
_forceScreenUpdate = false;
}
_lastFrameDurationMs = _timeOfCurrentPass - _startFrameTime;
_startFrameTime = _timeOfCurrentPass;
}
}
return shouldUpdateScreen;
}
void Framelimiter::postScreenUpdate() {
_timeOfLastPass = _timeOfCurrentPass;
// if (_enabled) {
// // for debug purposes, this calculates the time between deciding to draw the frame, and the time after drawing the update to the screen
// uint32 endFrameTime = _vm->_time->currentSystem();
// uint32 frameDuration = endFrameTime - _startFrameTime;
// }
}
void Framelimiter::reset() {
_forceScreenUpdate = false;
_timeOfLastPass = 0u;
_timeOfCurrentPass = 0u;
_startFrameTime = 0u;
_lastFrameDurationMs = _speedLimitMs;
}
} // End of namespace BladeRunner
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