game_timer.cpp

自己写的一个D3D游戏Dome。实现了基本的游戏功能

#include "..\Include\Game_Timer.h"

Game_Timer::Game_Timer(){
	ticksPerSec  = 0;

	lastTime = 0;
	baseTime = 0;

	LARGE_INTEGER qwTicksPerSec;
	QueryPerformanceFrequency( &qwTicksPerSec );
	ticksPerSec = qwTicksPerSec.QuadPart;
}

void Game_Timer::Start(){
	// Get the current time
	LARGE_INTEGER qwTime;
	QueryPerformanceCounter( &qwTime );

	lastTime = qwTime.QuadPart;
	baseTime = qwTime.QuadPart;
}

double Game_Timer::GetRunTime(){
	LARGE_INTEGER qwTime;
	QueryPerformanceCounter( &qwTime );

	double fTime = (qwTime.QuadPart - baseTime) / (double) ticksPerSec;

	return fTime;
}

double Game_Timer::GetElapsedTime(){
	if (baseTime == 0) Start();

	LARGE_INTEGER qwTime;
	QueryPerformanceCounter( &qwTime );

	double fElapsedTime = (double) ( qwTime.QuadPart - lastTime ) / (double) ticksPerSec;
	lastTime = qwTime.QuadPart;

	if( fElapsedTime < 0.0f )
		fElapsedTime = 0.0f;

	return fElapsedTime;
}