nuclear@1: /************************************************************************************
nuclear@1: 
nuclear@1: Filename    :   OVR_Timer.cpp
nuclear@1: Content     :   Provides static functions for precise timing
nuclear@1: Created     :   September 19, 2012
nuclear@1: Notes       : 
nuclear@1: 
nuclear@1: Copyright   :   Copyright 2012 Oculus VR, Inc. All Rights reserved.
nuclear@1: 
nuclear@1: Use of this software is subject to the terms of the Oculus license
nuclear@1: agreement provided at the time of installation or download, or which
nuclear@1: otherwise accompanies this software in either electronic or hard copy form.
nuclear@1: 
nuclear@1: ************************************************************************************/
nuclear@1: 
nuclear@1: #include "OVR_Timer.h"
nuclear@1: 
nuclear@1: #if defined (OVR_OS_WIN32)
nuclear@1: #include <windows.h>
nuclear@1: 
nuclear@1: #else
nuclear@1: #include <sys/time.h>
nuclear@1: #endif
nuclear@1: 
nuclear@1: namespace OVR {
nuclear@1: 
nuclear@1: //-----------------------------------------------------------------------------------
nuclear@1: // ***** Timer Class
nuclear@1: 
nuclear@1: UInt64 Timer::GetProfileTicks()
nuclear@1: {
nuclear@1:     return (GetRawTicks() * MksPerSecond) / GetRawFrequency();
nuclear@1: }
nuclear@1: double Timer::GetProfileSeconds()
nuclear@1: {
nuclear@1:     static UInt64 StartTime = GetProfileTicks();
nuclear@1:     return TicksToSeconds(GetProfileTicks()-StartTime);
nuclear@1: }
nuclear@1: 
nuclear@1: 
nuclear@1: //------------------------------------------------------------------------
nuclear@1: // *** Win32 Specific Timer
nuclear@1: 
nuclear@1: #if (defined (OVR_OS_WIN32))
nuclear@1: 
nuclear@1: CRITICAL_SECTION WinAPI_GetTimeCS;
nuclear@1: volatile UInt32  WinAPI_OldTime = 0;
nuclear@1: volatile UInt32  WinAPI_WrapCounter = 0;
nuclear@1: 
nuclear@1: 
nuclear@1: UInt32 Timer::GetTicksMs()
nuclear@1: {
nuclear@1:     return timeGetTime();
nuclear@1: }
nuclear@1: 
nuclear@1: UInt64 Timer::GetTicks()
nuclear@1: {
nuclear@1:     DWORD  ticks = timeGetTime();
nuclear@1:     UInt64 result;
nuclear@1: 
nuclear@1:     // On Win32 QueryPerformanceFrequency is unreliable due to SMP and
nuclear@1:     // performance levels, so use this logic to detect wrapping and track
nuclear@1:     // high bits.
nuclear@1:     ::EnterCriticalSection(&WinAPI_GetTimeCS);
nuclear@1: 
nuclear@1:     if (WinAPI_OldTime > ticks)
nuclear@1:         WinAPI_WrapCounter++;
nuclear@1:     WinAPI_OldTime = ticks;
nuclear@1: 
nuclear@1:     result = (UInt64(WinAPI_WrapCounter) << 32) | ticks;
nuclear@1:     ::LeaveCriticalSection(&WinAPI_GetTimeCS);
nuclear@1: 
nuclear@1:     return result * MksPerMs;
nuclear@1: }
nuclear@1: 
nuclear@1: UInt64 Timer::GetRawTicks()
nuclear@1: {
nuclear@1:     LARGE_INTEGER li;
nuclear@1:     QueryPerformanceCounter(&li);
nuclear@1:     return li.QuadPart;
nuclear@1: }
nuclear@1: 
nuclear@1: UInt64 Timer::GetRawFrequency()
nuclear@1: {
nuclear@1:     static UInt64 perfFreq = 0;
nuclear@1:     if (perfFreq == 0)
nuclear@1:     {
nuclear@1:         LARGE_INTEGER freq;
nuclear@1:         QueryPerformanceFrequency(&freq);
nuclear@1:         perfFreq = freq.QuadPart;
nuclear@1:     }
nuclear@1:     return perfFreq;
nuclear@1: }
nuclear@1: 
nuclear@1: void Timer::initializeTimerSystem()
nuclear@1: {
nuclear@1:     timeBeginPeriod(1);
nuclear@1:     InitializeCriticalSection(&WinAPI_GetTimeCS);
nuclear@1: 
nuclear@1: }
nuclear@1: void Timer::shutdownTimerSystem()
nuclear@1: {
nuclear@1:     DeleteCriticalSection(&WinAPI_GetTimeCS);
nuclear@1:     timeEndPeriod(1);
nuclear@1: }
nuclear@1: 
nuclear@1: #else   // !OVR_OS_WIN32
nuclear@1: 
nuclear@1: 
nuclear@1: //------------------------------------------------------------------------
nuclear@1: // *** Standard OS Timer     
nuclear@1: 
nuclear@1: UInt32 Timer::GetTicksMs()
nuclear@1: {
nuclear@1:     return (UInt32)(GetProfileTicks() / 1000);
nuclear@1: }
nuclear@1: // The profile ticks implementation is just fine for a normal timer.
nuclear@1: UInt64 Timer::GetTicks()
nuclear@1: {
nuclear@1:     return GetProfileTicks();
nuclear@1: }
nuclear@1: 
nuclear@1: void Timer::initializeTimerSystem()
nuclear@1: {
nuclear@1: }
nuclear@1: void Timer::shutdownTimerSystem()
nuclear@1: {
nuclear@1: }
nuclear@1: 
nuclear@1: UInt64  Timer::GetRawTicks()
nuclear@1: {
nuclear@1:     // TODO: prefer rdtsc when available?
nuclear@1: 
nuclear@1:     // Return microseconds.
nuclear@1:     struct timeval tv;
nuclear@1:     UInt64 result;
nuclear@1: 
nuclear@1:     gettimeofday(&tv, 0);
nuclear@1: 
nuclear@1:     result = (UInt64)tv.tv_sec * 1000000;
nuclear@1:     result += tv.tv_usec;
nuclear@1: 
nuclear@1:     return result;
nuclear@1: }
nuclear@1: 
nuclear@1: UInt64 Timer::GetRawFrequency()
nuclear@1: {
nuclear@1:     return MksPerSecond;
nuclear@1: }
nuclear@1: 
nuclear@1: #endif  // !OVR_OS_WIN32
nuclear@1: 
nuclear@1: 
nuclear@1: 
nuclear@1: } // OVR
nuclear@1: