platformTimer.h

Engine/source/platform/platformTimer.h

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Detailed Description

  1
  2//-----------------------------------------------------------------------------
  3// Copyright (c) 2012 GarageGames, LLC
  4//
  5// Permission is hereby granted, free of charge, to any person obtaining a copy
  6// of this software and associated documentation files (the "Software"), to
  7// deal in the Software without restriction, including without limitation the
  8// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  9// sell copies of the Software, and to permit persons to whom the Software is
 10// furnished to do so, subject to the following conditions:
 11//
 12// The above copyright notice and this permission notice shall be included in
 13// all copies or substantial portions of the Software.
 14//
 15// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 18// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 21// IN THE SOFTWARE.
 22//-----------------------------------------------------------------------------
 23
 24#ifndef _PLATFORM_PLATFORMTIMER_H_
 25#define _PLATFORM_PLATFORMTIMER_H_
 26
 27#include "platform/platform.h"
 28#include "core/util/journal/journaledSignal.h"
 29
 30/// Platform-specific timer class.
 31///
 32/// This exists primarily as support for the TimeManager, but may be useful
 33/// elsewhere.
 34class PlatformTimer
 35{
 36protected:
 37   PlatformTimer();
 38public:
 39   virtual ~PlatformTimer();
 40   
 41   /// Get the number of MS that have elapsed since creation or the last
 42   /// reset call.
 43   virtual const S32 getElapsedMs()=0;
 44   
 45   /// Reset elapsed ms back to zero.
 46   virtual void reset()=0;
 47   
 48   /// Create a new PlatformTimer.
 49   static PlatformTimer *create();
 50};
 51
 52/// Utility class to fire journalled time-delta events at regular intervals.
 53///
 54/// Most games and simulations need the ability to update their state based on
 55/// a time-delta. However, tracking time accurately and sending out well-conditioned
 56/// events (for instance, allowing no events with delta=0) tends to be platform
 57/// specific. This class provides an abstraction around this platform mojo.
 58///
 59/// In addition, a well behaved application may want to alter how frequently
 60/// it processes time advancement depending on its execution state. For instance,
 61/// a game running in the background can significantly reduce CPU usage
 62/// by only updating every 100ms, instead of trying to maintain a 1ms update
 63/// update rate.
 64class TimeManager
 65{
 66   PlatformTimer *mTimer;
 67   S32 mForegroundThreshold, mBackgroundThreshold;
 68   bool mBackground;
 69   
 70   void _updateTime();
 71
 72public:
 73
 74   TimeManagerEvent timeEvent;
 75   
 76   TimeManager();   
 77   ~TimeManager();
 78   
 79   void setForegroundThreshold(const S32 msInterval);
 80   const S32 getForegroundThreshold() const;
 81   
 82   void setBackgroundThreshold(const S32 msInterval);
 83   const S32 getBackgroundThreshold() const;
 84
 85   void setBackground(const bool isBackground) { mBackground = isBackground; };
 86   const bool getBackground() const { return mBackground; };
 87
 88};
 89
 90class DefaultPlatformTimer : public PlatformTimer
 91{
 92   S32 mLastTime, mNextTime;
 93   
 94public:
 95   DefaultPlatformTimer()
 96   {
 97      mLastTime = mNextTime = Platform::getRealMilliseconds();
 98   }
 99   
100   const S32 getElapsedMs()
101   {
102      mNextTime = Platform::getRealMilliseconds();
103      return (mNextTime - mLastTime);
104   }
105   
106   void reset()
107   {
108      mLastTime = mNextTime;
109   }
110};
111
112#endif
113