1 /* ResidualVM - A 3D game interpreter
2 *
3 * ResidualVM is the legal property of its developers, whose names
4 * are too numerous to list here. Please refer to the AUTHORS
5 * file distributed with this source distribution.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 *
21 */
22
23 #include "engines/stark/gfx/framelimiter.h"
24
25 #include "common/util.h"
26
27 namespace Stark {
28 namespace Gfx {
29
FrameLimiter(OSystem * system,const uint framerate)30 FrameLimiter::FrameLimiter(OSystem *system, const uint framerate) :
31 _system(system),
32 _speedLimitMs(0),
33 _startFrameTime(0),
34 _lastFrameDurationMs(_speedLimitMs) {
35 // The frame limiter is disabled when vsync is enabled.
36 _enabled = !_system->getFeatureState(OSystem::kFeatureVSync) && framerate != 0;
37
38 if (_enabled) {
39 _speedLimitMs = 1000 / CLIP<uint>(framerate, 0, 100);
40 }
41 }
42
startFrame()43 void FrameLimiter::startFrame() {
44 uint currentTime = _system->getMillis();
45
46 if (_startFrameTime != 0) {
47 _lastFrameDurationMs = currentTime - _startFrameTime;
48 }
49
50 _startFrameTime = currentTime;
51 }
52
delayBeforeSwap()53 void FrameLimiter::delayBeforeSwap() {
54 uint endFrameTime = _system->getMillis();
55 uint frameDuration = endFrameTime - _startFrameTime;
56
57 if (_enabled && frameDuration < _speedLimitMs) {
58 _system->delayMillis(_speedLimitMs - frameDuration);
59 }
60 }
61
pause(bool pause)62 void FrameLimiter::pause(bool pause) {
63 if (!pause) {
64 // Make sure the frame duration value is consistent when resuming
65 _startFrameTime = 0;
66 }
67 }
68
getLastFrameDuration() const69 uint FrameLimiter::getLastFrameDuration() const {
70 return _lastFrameDurationMs;
71 }
72
73 } // End of namespace Gfx
74 } // End of namespace Stark
75