Saturday, March 31, 2012
C++ Timer Class
Hey guys. This my blog on how to create a timer in C++. You can use this in order to get delta time if you like.
include the windows.h file:
#include <windows.h>
you would need to create two variables like so:
float freq_;
unsigned __int64 baseTime_;
You will initialize them in a contructor or initialize function:
unsigned __int64 pf;
QueryPerformanceFrequency( (LARGE_INTEGER *)&pf );
freq_ = 1.0f / (float)pf;
QueryPerformanceCounter( (LARGE_INTEGER *)&baseTime_ );
Basically the QueryPerformanceFrequency will get the high resolution counter's accuracy and
QueryPerformanceCounter is basically the elapsed time since when the program started running
Create a function to get your seconds:
float seconds()
{
unsigned __int64 val;
QueryPerformanceCounter( (LARGE_INTEGER *)&val );
float dt = (float)(val - baseTime_) * freq_ / 60.0f;
baseTime_ = val;
return dt;
}
from this you can also get your milliseconds.
Enjoy :)
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QPC has some wrinkles on some platform/CPU combinations still in use today. If you have boost available, a version that's portable, safe, and with less shady casting:
ReplyDelete#include <boost/date_time/posix_time/posix_time.hpp>
#include <iostream>
int main() {
using namespace std;
using namespace boost::posix_time;
ptime start_time = microsec_clock::universal_time();
do_something();
ptime end_time = microsec_clock::universal_time();
time_duration how_long = end_time - start_time;
cout << how_long.total_nanoseconds() << '\n';
return 0;
}
Thanks for that information. Didn't know that.
Deletebut you dont tell us where to put the code, like some could go before the message loop or after, can you do a tutorial with a window etc and the message loop and timer class?
ReplyDeleteI can just show you where exactly I put it at if you like
Delete