1 files changed, 156 insertions, 0 deletions
diff --git a/LibOVR/Src/Kernel/OVR_Timer.cpp b/LibOVR/Src/Kernel/OVR_Timer.cpp
new file mode 100644
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+++ b/LibOVR/Src/Kernel/OVR_Timer.cpp
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+/************************************************************************************
+
+Filename    :   OVR_Timer.cpp
+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.
+
+************************************************************************************/
+
+#include "OVR_Timer.h"
+
+#if defined (OVR_OS_WIN32)
+#include <windows.h>
+
+#else
+#include <sys/time.h>
+#endif
+
+namespace OVR {
+
+//-----------------------------------------------------------------------------------
+// ***** Timer Class
+
+UInt64 Timer::GetProfileTicks()
+{
+    return (GetRawTicks() * MksPerSecond) / GetRawFrequency();
+}
+double Timer::GetProfileSeconds()
+{
+    static UInt64 StartTime = GetProfileTicks();
+    return TicksToSeconds(GetProfileTicks()-StartTime);
+}
+
+
+//------------------------------------------------------------------------
+// *** Win32 Specific Timer
+
+#if (defined (OVR_OS_WIN32))
+
+CRITICAL_SECTION WinAPI_GetTimeCS;
+volatile UInt32  WinAPI_OldTime = 0;
+volatile UInt32  WinAPI_WrapCounter = 0;
+
+
+UInt32 Timer::GetTicksMs()
+{
+    return timeGetTime();
+}
+
+UInt64 Timer::GetTicks()
+{
+    DWORD  ticks = timeGetTime();
+    UInt64 result;
+
+    // On Win32 QueryPerformanceFrequency is unreliable due to SMP and
+    // performance levels, so use this logic to detect wrapping and track
+    // high bits.
+    ::EnterCriticalSection(&WinAPI_GetTimeCS);
+
+    if (WinAPI_OldTime > ticks)
+        WinAPI_WrapCounter++;
+    WinAPI_OldTime = ticks;
+
+    result = (UInt64(WinAPI_WrapCounter) << 32) | ticks;
+    ::LeaveCriticalSection(&WinAPI_GetTimeCS);
+
+    return result * MksPerMs;
+}
+
+UInt64 Timer::GetRawTicks()
+{
+    LARGE_INTEGER li;
+    QueryPerformanceCounter(&li);
+    return li.QuadPart;
+}
+
+UInt64 Timer::GetRawFrequency()
+{
+    static UInt64 perfFreq = 0;
+    if (perfFreq == 0)
+    {
+        LARGE_INTEGER freq;
+        QueryPerformanceFrequency(&freq);
+        perfFreq = freq.QuadPart;
+    }
+    return perfFreq;
+}
+
+void Timer::initializeTimerSystem()
+{
+    timeBeginPeriod(1);
+    InitializeCriticalSection(&WinAPI_GetTimeCS);
+
+}
+void Timer::shutdownTimerSystem()
+{
+    DeleteCriticalSection(&WinAPI_GetTimeCS);
+    timeEndPeriod(1);
+}
+
+#else   // !OVR_OS_WIN32
+
+
+//------------------------------------------------------------------------
+// *** Standard OS Timer     
+
+UInt32 Timer::GetTicksMs()
+{
+    return (UInt32)(GetProfileTicks() / 1000);
+}
+// The profile ticks implementation is just fine for a normal timer.
+UInt64 Timer::GetTicks()
+{
+    return GetProfileTicks();
+}
+
+void Timer::initializeTimerSystem()
+{
+}
+void Timer::shutdownTimerSystem()
+{
+}
+
+UInt64  Timer::GetRawTicks()
+{
+    // TODO: prefer rdtsc when available?
+
+    // Return microseconds.
+    struct timeval tv;
+    UInt64 result;
+
+    gettimeofday(&tv, 0);
+
+    result = (UInt64)tv.tv_sec * 1000000;
+    result += tv.tv_usec;
+
+    return result;
+}
+
+UInt64 Timer::GetRawFrequency()
+{
+    return MksPerSecond;
+}
+
+#endif  // !OVR_OS_WIN32
+
+
+
+} // OVR
+