How to use QPC

How to use QPC

Road Runner

Member #7,280

May 2006

I've been wanting to use QueryPerformanceCounter for quite some time, and I checked out the Microsoft documentation hoping to find out everything I need to know, but what I found was a bunch of Windows code that didn't make an ounce of sense.
So I guess I need a little help with figuring out how to use QPC with Allegro.

Just so I don't get scolded for not trying to figure it out myself, I'm a busy high schooler who barely has any free time, and I'm used to reading the Allegro docs, which I find very easy to understand, but the Microsoft docs on the other hand...
Anyway, sorry to pester you all with a dumb question, but I really need help.

Paul whoknows

Member #5,081

September 2004

Take a look at R. Phipps' timer.

____

"The unlimited potential has been replaced by the concrete reality of what I programmed today." - Jordan Mechner.

Road Runner

Member #7,280

May 2006

Thanks, that looks good. I think that's all I really need, but I'm new at programming so I really want to understand how to use QPC myself, so that I can wrap it in whatever code I want. Maybe I should have been more specific in the first place. :-/

23yrold3yrold

Member #1,134

March 2001

1#define WIN_ANIME_TIMERLOOP  0x7fffffffffffffffLL
2__int64   animation_timer;
3__int64   frequency;
4 
5__int64   WinGetAnimationTime() { return animation_timer; }
6 
7void WinInstallAnimationTimer()
8{
9   QueryPerformanceFrequency(( LARGE_INTEGER* )&frequency);
10   // (higher == faster, lower == slower)
11   frequency /= 500;
12   QueryPerformanceCounter(( LARGE_INTEGER* )&animation_timer);
13   animation_timer /= frequency;
14}
15 
16void WinUpdateAnimationTimer()
17{
18   QueryPerformanceCounter(( LARGE_INTEGER* )&animation_timer);
19   animation_timer /= frequency;
20}
21 
22__int64 WinGetRelativeAnimationTime(__int64& oldtime)
23{
24   __int64 t = oldtime;
25   oldtime = animation_timer;
26 
27   if(t > oldtime)
28      return ((WIN_ANIME_TIMERLOOP - t) + oldtime);
29   else
30      return (oldtime - t);
31}

That's more or less how I use it. Shouldn't be hard to decipher. Basically just use QueryPerformanceFrequency() and QueryPerformanceCounter() to make it track the same speed on all systems, and reference it for all your timing needs.

--
Software Development == Church Development
Step 1. Build it.
Step 2. Pray.

Road Runner

Member #7,280

May 2006

I'll just use it until I understand how it works then, and yeah, it's pretty simple code, so it shouldn't take long for me to decipher it.