added linux makefile

modules/oculus_sdk_linux/LibOVR/Src/Kernel/OVR_Timer.cpp

@@ -0,0 +1,287 @@
+/************************************************************************************
+
+Filename    :   OVR_Timer.cpp
+Content     :   Provides static functions for precise timing
+Created     :   September 19, 2012
+Notes       : 
+
+Copyright   :   Copyright 2014 Oculus VR, Inc. All Rights reserved.
+
+Licensed under the Oculus VR Rift SDK License Version 3.1 (the "License"); 
+you may not use the Oculus VR Rift SDK except in compliance with the License, 
+which is provided at the time of installation or download, or which 
+otherwise accompanies this software in either electronic or hard copy form.
+
+You may obtain a copy of the License at
+
+http://www.oculusvr.com/licenses/LICENSE-3.1 
+
+Unless required by applicable law or agreed to in writing, the Oculus VR SDK 
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+************************************************************************************/
+
+#include "OVR_Timer.h"
+#include "OVR_Log.h"
+
+#if defined (OVR_OS_WIN32)
+#include <windows.h>
+#elif defined(OVR_OS_ANDROID)
+#include <time.h>
+#include <android/log.h>
+
+#else
+#include <sys/time.h>
+#endif
+
+namespace OVR {
+
+// For recorded data playback
+bool   Timer::useFakeSeconds  = false; 
+double Timer::FakeSeconds     = 0;
+
+
+//------------------------------------------------------------------------
+// *** Timer - Platform Independent functions
+
+// Returns global high-resolution application timer in seconds.
+double Timer::GetSeconds()
+{
+	if(useFakeSeconds)
+		return FakeSeconds;
+
+    return double(Timer::GetTicksNanos()) * 0.000000001;
+}
+
+
+#ifndef OVR_OS_WIN32
+
+// Unused on OSs other then Win32.
+void Timer::initializeTimerSystem()
+{
+}
+void Timer::shutdownTimerSystem()
+{
+}
+
+#endif
+
+
+
+//------------------------------------------------------------------------
+// *** Android Specific Timer
+
+#if defined(OVR_OS_ANDROID)
+
+UInt64 Timer::GetTicksNanos()
+{
+    if (useFakeSeconds)
+        return (UInt64) (FakeSeconds * NanosPerSecond);
+
+    // Choreographer vsync timestamp is based on.
+    struct timespec tp;
+    const int       status = clock_gettime(CLOCK_MONOTONIC, &tp);
+
+    if (status != 0)
+    {
+        OVR_DEBUG_LOG(("clock_gettime status=%i", status ));
+    }
+    const UInt64 result = (UInt64)tp.tv_sec * (UInt64)(1000 * 1000 * 1000) + UInt64(tp.tv_nsec);
+    return result;
+}
+
+
+//------------------------------------------------------------------------
+// *** Win32 Specific Timer
+
+#elif defined (OVR_OS_WIN32)
+
+
+// This helper class implements high-resolution wrapper that combines timeGetTime() output
+// with QueryPerformanceCounter.  timeGetTime() is lower precision but drives the high bits,
+// as it's tied to the system clock.
+struct PerformanceTimer
+{
+    PerformanceTimer()
+        : OldMMTimeMs(0), MMTimeWrapCounter(0), PrefFrequency(0),
+          LastResultNanos(0), PerfMinusTicksDeltaNanos(0)
+    { }
+    
+    enum {
+        MMTimerResolutionNanos = 1000000
+    };
+   
+    void    Initialize();
+    void    Shutdown();
+
+    UInt64  GetTimeNanos();
+
+
+    UINT64 getFrequency()
+    {
+        if (PrefFrequency == 0)
+        {
+            LARGE_INTEGER freq;
+            QueryPerformanceFrequency(&freq);
+            PrefFrequency = freq.QuadPart;
+        }        
+        return PrefFrequency;
+    }
+    
+
+    CRITICAL_SECTION TimeCS;
+    // timeGetTime() support with wrap.
+    UInt32          OldMMTimeMs;
+    UInt32          MMTimeWrapCounter;
+    // Cached performance frequency result.
+    UInt64          PrefFrequency;
+    
+    // Computed as (perfCounterNanos - ticksCounterNanos) initially,
+    // and used to adjust timing.
+    UInt64          PerfMinusTicksDeltaNanos;
+    // Last returned value in nanoseconds, to ensure we don't back-step in time.
+    UInt64          LastResultNanos;
+};
+
+PerformanceTimer Win32_PerfTimer;
+
+
+void PerformanceTimer::Initialize()
+{
+    timeBeginPeriod(1);
+    InitializeCriticalSection(&TimeCS);
+    MMTimeWrapCounter = 0;
+    getFrequency();
+}
+
+void PerformanceTimer::Shutdown()
+{
+    DeleteCriticalSection(&TimeCS);
+    timeEndPeriod(1);
+}
+
+UInt64 PerformanceTimer::GetTimeNanos()
+{
+    UInt64          resultNanos;
+    LARGE_INTEGER   li;
+    DWORD           mmTimeMs;
+
+    // On Win32 QueryPerformanceFrequency is unreliable due to SMP and
+    // performance levels, so use this logic to detect wrapping and track
+    // high bits.
+    ::EnterCriticalSection(&TimeCS);
+
+    // Get raw value and perf counter "At the same time".
+    mmTimeMs = timeGetTime();
+    QueryPerformanceCounter(&li);
+
+    if (OldMMTimeMs > mmTimeMs)
+        MMTimeWrapCounter++;
+    OldMMTimeMs = mmTimeMs;
+
+    // Normalize to nanoseconds.
+    UInt64  mmCounterNanos     = ((UInt64(MMTimeWrapCounter) << 32) | mmTimeMs) * 1000000;
+    UInt64  frequency          = getFrequency();
+    UInt64  perfCounterSeconds = UInt64(li.QuadPart) / frequency;
+    UInt64  perfRemainderNanos = ( (UInt64(li.QuadPart) - perfCounterSeconds * frequency) *
+                                   Timer::NanosPerSecond ) / frequency;
+    UInt64  perfCounterNanos   = perfCounterSeconds * Timer::NanosPerSecond + perfRemainderNanos;
+
+    if (PerfMinusTicksDeltaNanos == 0)
+        PerfMinusTicksDeltaNanos = perfCounterNanos - mmCounterNanos;
+ 
+
+    // Compute result before snapping. 
+    //
+    // On first call, this evaluates to:
+    //          resultNanos = mmCounterNanos.    
+    // Next call, assuming no wrap:
+    //          resultNanos = prev_mmCounterNanos + (perfCounterNanos - prev_perfCounterNanos).        
+    // After wrap, this would be:
+    //          resultNanos = snapped(prev_mmCounterNanos +/- 1ms) + (perfCounterNanos - prev_perfCounterNanos).
+    //
+    resultNanos = perfCounterNanos - PerfMinusTicksDeltaNanos;    
+
+    // Snap the range so that resultNanos never moves further apart then its target resolution.
+    // It's better to allow more slack on the high side as timeGetTime() may be updated at sporadically 
+    // larger then 1 ms intervals even when 1 ms resolution is requested.
+    if (resultNanos > (mmCounterNanos + MMTimerResolutionNanos*2))
+    {
+        resultNanos = mmCounterNanos + MMTimerResolutionNanos*2;
+        if (resultNanos < LastResultNanos)
+            resultNanos = LastResultNanos;
+        PerfMinusTicksDeltaNanos = perfCounterNanos - resultNanos;
+    }
+    else if (resultNanos < (mmCounterNanos - MMTimerResolutionNanos))
+    {
+        resultNanos = mmCounterNanos - MMTimerResolutionNanos;
+        if (resultNanos < LastResultNanos)
+            resultNanos = LastResultNanos;
+        PerfMinusTicksDeltaNanos = perfCounterNanos - resultNanos;
+    }
+
+    LastResultNanos = resultNanos;
+    ::LeaveCriticalSection(&TimeCS);
+
+	//Tom's addition, to keep precision
+	static UInt64      initial_time = 0;
+	if (!initial_time) initial_time = resultNanos;
+	resultNanos -= initial_time;
+
+
+    return resultNanos;
+}
+
+
+// Delegate to PerformanceTimer.
+UInt64 Timer::GetTicksNanos()
+{
+    if (useFakeSeconds)
+        return (UInt64) (FakeSeconds * NanosPerSecond);
+
+    return Win32_PerfTimer.GetTimeNanos();
+}
+void Timer::initializeTimerSystem()
+{
+    Win32_PerfTimer.Initialize();
+
+}
+void Timer::shutdownTimerSystem()
+{
+    Win32_PerfTimer.Shutdown();
+}
+
+#else   // !OVR_OS_WIN32 && !OVR_OS_ANDROID
+
+
+//------------------------------------------------------------------------
+// *** Standard OS Timer     
+
+UInt64 Timer::GetTicksNanos()
+{
+    if (useFakeSeconds)
+        return (UInt64) (FakeSeconds * NanosPerSecond);
+
+    // TODO: prefer rdtsc when available?
+	UInt64 result;
+
+    // Return microseconds.
+    struct timeval tv;
+
+    gettimeofday(&tv, 0);
+
+    result = (UInt64)tv.tv_sec * 1000000;
+    result += tv.tv_usec;
+
+    return result * 1000;
+}
+
+#endif  // OS-specific
+
+
+
+} // OVR
+