Engine directory for ticket #1

Engine/source/platform/platformTimer.h

@@ -0,0 +1,111 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2012 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#ifndef _PLATFORM_PLATFORMTIMER_H_
+#define _PLATFORM_PLATFORMTIMER_H_
+
+#include "platform/platform.h"
+#include "core/util/journal/journaledSignal.h"
+
+/// Platform-specific timer class.
+///
+/// This exists primarily as support for the TimeManager, but may be useful
+/// elsewhere.
+class PlatformTimer
+{
+protected:
+   PlatformTimer();
+public:
+   virtual ~PlatformTimer();
+   
+   /// Get the number of MS that have elapsed since creation or the last
+   /// reset call.
+   virtual const S32 getElapsedMs()=0;
+   
+   /// Reset elapsed ms back to zero.
+   virtual void reset()=0;
+   
+   /// Create a new PlatformTimer.
+   static PlatformTimer *create();
+};
+
+/// Utility class to fire journalled time-delta events at regular intervals.
+///
+/// Most games and simulations need the ability to update their state based on
+/// a time-delta. However, tracking time accurately and sending out well-conditioned
+/// events (for instance, allowing no events with delta=0) tends to be platform
+/// specific. This class provides an abstraction around this platform mojo.
+///
+/// In addition, a well behaved application may want to alter how frequently
+/// it processes time advancement depending on its execution state. For instance,
+/// a game running in the background can significantly reduce CPU usage
+/// by only updating every 100ms, instead of trying to maintain a 1ms update
+/// update rate.
+class TimeManager
+{
+   PlatformTimer *mTimer;
+   S32 mForegroundThreshold, mBackgroundThreshold;
+   bool mBackground;
+   
+   void _updateTime();
+
+public:
+
+   TimeManagerEvent timeEvent;
+   
+   TimeManager();   
+   ~TimeManager();
+   
+   void setForegroundThreshold(const S32 msInterval);
+   const S32 getForegroundThreshold() const;
+   
+   void setBackgroundThreshold(const S32 msInterval);
+   const S32 getBackgroundThreshold() const;
+
+   void setBackground(const bool isBackground) { mBackground = isBackground; };
+   const bool getBackground() const { return mBackground; };
+
+};
+
+class DefaultPlatformTimer : public PlatformTimer
+{
+   S32 mLastTime, mNextTime;
+   
+public:
+   DefaultPlatformTimer()
+   {
+      mLastTime = mNextTime = Platform::getRealMilliseconds();
+   }
+   
+   const S32 getElapsedMs()
+   {
+      mNextTime = Platform::getRealMilliseconds();
+      return (mNextTime - mLastTime);
+   }
+   
+   void reset()
+   {
+      mLastTime = mNextTime;
+   }
+};
+
+#endif