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authorBrad Davis <[email protected]>2013-06-27 11:25:32 -0800
committerBrad Davis <[email protected]>2013-06-28 10:47:29 -0700
commitebefcc885f74461cd0e3f19b5ae3622dc6cf6dbc (patch)
tree2b16db7350fce54c2e6c1b1c4020d67419cb1164 /LibOVR/Src/Kernel/OVR_Timer.h
parent0ade748e1845694c5cbe562fb823e56f09773e27 (diff)
SDK 0.2.2
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+/************************************************************************************
+
+PublicHeader: OVR
+Filename : OVR_Timer.h
+Content : Provides static functions for precise timing
+Created : September 19, 2012
+Notes :
+
+Copyright : Copyright 2012 Oculus VR, Inc. All Rights reserved.
+
+Use of this software is subject to the terms of the Oculus license
+agreement provided at the time of installation or download, or which
+otherwise accompanies this software in either electronic or hard copy form.
+
+************************************************************************************/
+
+#ifndef OVR_Timer_h
+#define OVR_Timer_h
+
+#include "OVR_Types.h"
+
+namespace OVR {
+
+//-----------------------------------------------------------------------------------
+// ***** Timer
+
+// Timer class defines a family of static functions used for application
+// timing and profiling.
+
+class Timer
+{
+public:
+ enum {
+ MsPerSecond = 1000, // Milliseconds in one second.
+ MksPerMs = 1000, // Microseconds in one millisecond.
+ MksPerSecond = MsPerSecond * MksPerMs
+ };
+
+
+ // ***** Timing APIs for Application
+ // These APIs should be used to guide animation and other program functions
+ // that require precision.
+
+ // Returns ticks in milliseconds, as a 32-bit number. May wrap around every
+ // 49.2 days. Use either time difference of two values of GetTicks to avoid
+ // wrap-around. GetTicksMs may perform better then GetTicks.
+ static UInt32 OVR_STDCALL GetTicksMs();
+
+ // GetTicks returns general-purpose high resolution application timer value,
+ // measured in microseconds (mks, or 1/1000000 of a second). The actual precision
+ // is system-specific and may be much lower, such as 1 ms.
+ static UInt64 OVR_STDCALL GetTicks();
+
+
+ // ***** Profiling APIs.
+ // These functions should be used for profiling, but may have system specific
+ // artifacts that make them less appropriate for general system use.
+ // On Win32, for example these rely on QueryPerformanceConter may have
+ // problems with thread-core switching and power modes.
+
+ // Return a hi-res timer value in mks (1/1000000 of a sec).
+ // Generally you want to call this at the start and end of an
+ // operation, and pass the difference to
+ // TicksToSeconds() to find out how long the operation took.
+ static UInt64 OVR_STDCALL GetProfileTicks();
+
+ // More convenient zero-based profile timer in seconds. First call initializes
+ // the "zero" value; future calls return the difference. Not thread safe for first call.
+ // Due to low precision of Double, may malfunction after long runtime.
+ static double OVR_STDCALL GetProfileSeconds();
+
+ // Get the raw cycle counter value, providing the maximum possible timer resolution.
+ static UInt64 OVR_STDCALL GetRawTicks();
+ static UInt64 OVR_STDCALL GetRawFrequency();
+
+
+ // ***** Tick and time unit conversion.
+
+ // Convert micro-second ticks value into seconds value.
+ static inline double TicksToSeconds(UInt64 ticks)
+ {
+ return static_cast<double>(ticks) * (1.0 / (double)MksPerSecond);
+ }
+ // Convert Raw or frequency-unit ticks to seconds based on specified frequency.
+ static inline double RawTicksToSeconds(UInt64 rawTicks, UInt64 rawFrequency)
+ {
+ return static_cast<double>(rawTicks) * rawFrequency;
+ }
+
+private:
+ friend class System;
+ // System called during program startup/shutdown.
+ static void initializeTimerSystem();
+ static void shutdownTimerSystem();
+};
+
+
+} // Scaleform::Timer
+
+#endif