scummvm/engines/bladerunner/framelimiter.h
2019-09-01 22:22:57 +03:00

89 lines
2.8 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 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.
*
*/
#ifndef BLADERUNNER_FRAMELIMITER_H
#define BLADERUNNER_FRAMELIMITER_H
#include "bladerunner/bladerunner.h"
namespace BladeRunner {
enum FramelimiterFpsRate {
kFramelimiterDisabled = 0,
kFramelimiter15fps = 1,
kFramelimiter25fps = 2,
kFramelimiter30fps = 3,
kFramelimiter60fps = 4,
kFramelimiter120fps = 5
};
class BladeRunnerEngine;
class Framelimiter {
friend class Debugger;
public:
static const FramelimiterFpsRate kDefaultFpsRate = kFramelimiter60fps;
static const bool kDefaultUseDelayMillis = true;
private:
BladeRunnerEngine *_vm;
bool _forceScreenUpdate;
uint32 _speedLimitMs;
// A pass is when a tick or while loop that contains a potential screen update is repeated
// it's essentially when the check is made for a screen update
// Not every pass will necessarily result in a screen update (because that's the purpose of the frame limiter)
// So the "_startFrameTime" is not always equal to "_timeOfCurrentPass"
uint32 _timeOfLastPass;
uint32 _timeOfCurrentPass;
uint32 _startFrameTime; // is updated and valid, only if the current pass will result in a screen update (see method: shouldExecuteScreenUpdate())
uint32 _lastFrameDurationMs; // can be used for average FPS calculation and display purposes when frame limiter is enabled
bool _enabled;
bool _useDelayMs; // true: will use calls to delayMillis(), false: will use non-blocking software timer instead
public:
Framelimiter(BladeRunnerEngine *vm, FramelimiterFpsRate framerateMode, bool useDelayMs);
~Framelimiter();
// void pause(bool pause);
void init(bool forceScreenUpdate = true);
uint32 getLastFrameDuration() const;
uint32 getTimeOfCurrentPass() const;
uint32 getTimeOfLastPass() const;
bool shouldExecuteScreenUpdate();
void postScreenUpdate();
private:
void reset();
};
} // End of namespace BladeRunner
#endif