FPS

FPS

Anne M

Member #3,421

April 2003

How can I get the FPS my game in Allegro is running on?

Evert

Member #794

November 2000

At each frame drawn, increment a variable (your frame counter) by one.
Install a timer that gets called once every second. It should store the value of the frame counter in a different variable, say frame counter 2, and then it should set the frame counter to 0.
Display the value of frame counter 2 somewhere during your draw loop. You now have the number of frames drawn in the last second.

There are other ways (measure the time it takes to draw x frames and display x/time, for instance), but this is how I do it.

miran

Member #2,407

June 2002

Or if you code in C++ you can use my FPS class:

1//fps.h
2#ifndef    FPS_H
3#define    FPS_H
4 
5#include <allegro.h>
6 
7class FPS {
8  protected:
9    int frames[256];
10    int samples;
11    int curSample;
12  
13  public:
14    FPS();
15  
16    void Init(int fps);
17    void Update(int f);
18    int Get();
19    void Draw(BITMAP *buffer);
20};
21 
22#endif    //FPS_H

1//fps.cpp
2#include "fps.h"
3 
4FPS::FPS() : samples(0), curSample(0) {
5}
6 
7 
8void FPS::Init(int fps) {
9  samples = fps;
10  for (int i=0; i<samples; i++) {
11    frames<i> = 0;
12  }
13  curSample = 0;
14}
15 
16 
17void FPS::Update(int f) {
18  frames[curSample] = f;
19  ++curSample;
20  curSample %= samples;
21}
22    
23 
24int FPS::Get() {
25  int ret = 0;
26  for (int i=0; i<samples; ++i) {
27    ret += frames<i>;
28  }
29  return ret;
30}
31 
32void FPS::Draw(BITMAP *buffer) {
33  textprintf(buffer, font, 0, 0, makecol(255,255,255), "%d FPS", Get());
34}

You use it in your main loop like this:

1void Game::Run() {
bool done = false;
bool needToRedraw = true;
4 
// need to store the number of drawn frames
// between logic updates
int fpsCount = 0;

FPS fps;
fps.Init(50);   // pass you logic framerate here
timer = 0;
while (!done) {
  while (timer && !done) {
    --timer;
    done = UpdateLogic();
    needToRedraw = true;
17 
    // update the fps
    fps.Update(fpsCount);
20 
    // reset the fps counter
    fpsCount = 0;
  }
  
  if (needToRedraw || Params::unlimitedFPS) {
    DrawScene();
    DrawDoubleBuffer();
    needToRedraw = false;
29 
    // update the fps counter
    ++fpsCount;
32 
    // if you want to display the FPS
    // you can use this
    fps.Draw(buffer);
36 
    // or this
    int currentFPS = fps.Get();
    texprintf(..., "FPS = %d", currentFPS);
  }
}
42}

I know it's not optimal but it works just fine for me...

--
sig used to be here

Trezker

Member #1,739

December 2001

A class for fps! That's something I'd call overkill.

[My github]

StevenVI

Member #562

July 2000

Quote:

A class for fps! That's something I'd call overkill.

I know, eewwwwwwww!!! Reusable code! Yick!!! GET IT AWAY FROM ME!!!!!!!! How else are you supposed to count frames? Get out a stopwatch and start counting on your fingers?

Alternatively, and I think much more efficiently, if you're using Windows, and wanna say "Screw portability" because you're evil like that, you can look up the QueryPerformanceCounter function on MSDN (I think that's what it's called.. if not, it's something very very similar .)

-Steve

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