glfw/src/win32/win32_time.c
2010-09-12 16:26:00 +02:00

115 lines
3.9 KiB
C

//========================================================================
// GLFW - An OpenGL framework
// Platform: Win32/WGL
// API version: 3.0
// WWW: http://www.glfw.org/
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2010 Camilla Berglund <elmindreda@elmindreda.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would
// be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
// be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
// distribution.
//
//========================================================================
#include "internal.h"
//////////////////////////////////////////////////////////////////////////
////// GLFW internal API //////
//////////////////////////////////////////////////////////////////////////
//========================================================================
// Initialise timer
//========================================================================
void _glfwInitTimer(void)
{
__int64 freq;
// Check if we have a performance counter
if (QueryPerformanceFrequency((LARGE_INTEGER*) &freq))
{
// Performance counter is available => use it!
_glfwLibrary.Win32.timer.HasPerformanceCounter = GL_TRUE;
// Counter resolution is 1 / counter frequency
_glfwLibrary.Win32.timer.Resolution = 1.0 / (double) freq;
// Set start time for timer
QueryPerformanceCounter((LARGE_INTEGER*) &_glfwLibrary.Win32.timer.t0_64);
}
else
{
// No performace counter available => use the tick counter
_glfwLibrary.Win32.timer.HasPerformanceCounter = GL_FALSE;
// Counter resolution is 1 ms
_glfwLibrary.Win32.timer.Resolution = 0.001;
// Set start time for timer
_glfwLibrary.Win32.timer.t0_32 = _glfw_timeGetTime();
}
}
//////////////////////////////////////////////////////////////////////////
////// GLFW platform API //////
//////////////////////////////////////////////////////////////////////////
//========================================================================
// Return timer value in seconds
//========================================================================
double _glfwPlatformGetTime(void)
{
double t;
__int64 t_64;
if (_glfwLibrary.Win32.timer.HasPerformanceCounter)
{
QueryPerformanceCounter((LARGE_INTEGER*) &t_64);
t = (double)(t_64 - _glfwLibrary.Win32.timer.t0_64);
}
else
t = (double)(_glfw_timeGetTime() - _glfwLibrary.Win32.timer.t0_32);
// Calculate the current time in seconds
return t * _glfwLibrary.Win32.timer.Resolution;
}
//========================================================================
// Set timer value in seconds
//========================================================================
void _glfwPlatformSetTime(double t)
{
__int64 t_64;
if (_glfwLibrary.Win32.timer.HasPerformanceCounter)
{
QueryPerformanceCounter((LARGE_INTEGER*) &t_64);
_glfwLibrary.Win32.timer.t0_64 = t_64 - (__int64) (t / _glfwLibrary.Win32.timer.Resolution);
}
else
_glfwLibrary.Win32.timer.t0_32 = _glfw_timeGetTime() - (int)(t * 1000.0);
}