60 FPS limit in linux?

60 FPS limit in linux?

Frank Drebin

Member #2,987

December 2002

I noticed that when running any Allegro 5 program in linux, I can't get more than 60 FPS - even though al_clear_to_color(al_map_rgb(0,0,0)) only is called and nothing is drawn. How does that come?

BTW: I am using the Allegro 5 version that can be found in the Ubuntu PPAs

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Eric Johnson

Member #14,841

January 2013

1. Are you using a timer? If so, what is it set to?

2. How are you measuring FPS?

3. Is v-sync enabled?

4. Can you post the code?

Frank Drebin

Member #2,987

December 2002

3. I don't know. At least I didn't enable it myself...
1., 2., and 4.:

#SelectExpand
  1#include <stdio.h>
  2#include <allegro5/allegro.h>
  3
  4#define duration 5
  5
  6int frames=0;
  7bool quit=0;
  8
  9int main(int argc,char** argv)
 10{
 11    if (!al_init()) return -1;
 12
 13    ALLEGRO_DISPLAY* display=al_create_display(640,480);
 14    if (!display) return -1;
 15
 16    ALLEGRO_EVENT event;
 17    ALLEGRO_EVENT_QUEUE* queue=al_create_event_queue();
 18    ALLEGRO_TIMER* timer=al_create_timer(duration);
 19    al_start_timer(timer);
 20    al_register_event_source(queue,al_get_timer_event_source(timer));
 21
 22    while (!quit)
 23    {
 24       if (al_wait_for_event_timed(queue,&event,0)) quit=1;
 25
 26       if (al_is_event_queue_empty(queue))
 27       {
 28          al_clear_to_color(al_map_rgb(0,0,0));
 29          al_flip_display();
 30          frames++;
 31       }
 32    }
 33
 34    printf("FPS: %i\n",frames/duration);
 35
 36    al_destroy_display(display);
 37    al_destroy_event_queue(queue);
 38    al_destroy_timer(timer);
 39
 40    return 0;
 41}

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Edgar Reynaldo

Major Reynaldo

May 2007

The Fine Manual entry on al_set_new_display_option said:

ALLEGRO_VSYNC
Set to 1 to tell the driver to wait for vsync in al_flip_display, or to 2 to force vsync off. The default of 0 means that Allegro does not try to modify the vsync behavior so it may be on or off. Note that even in the case of 1 or 2 it is possible to override the vsync behavior in the graphics driver so you should not rely on it.

Eagle and Allegro 5 binaries | Older Allegro 4 and 5 binaries | Allegro 5 compile guide
King Piccolo will make it so Then I could just flip it with some sweet, sweet matrix math. In either case, I’ll ride this wagon until the wheels fall off. Thanks to those that keep it running

Frank Drebin

Member #2,987

December 2002

Thanks - didn't know that vsync was enabled...

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Chris Katko

Member #1,881

January 2002

You can also configure VSYNC on the driver level.

There's at least two ways, google it. I've posted before in these forums but I don't recall the command line arguments. nVidia has one set. And there's one universal set too. It's like VSYNC=1/2/3/4. With 4 maybe being adaptive vsync.

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