From: "Al Amzeen (Alexandr Amzin)" <amzeen AT mtu-net DOT ru>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: games speed ?
Date: Thu, 6 Apr 2000 21:48:11 +0400
Organization: Fidolook Express page http://fidolook.da.ru
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Greetings, Yannick Benoit <yannick DOT benoit AT dr DOT cgocable DOT ca>! You wrote:
> hi,
> i made some part of a game and after testing it on few diferent pcs, i
found
> out that the speed is never the same, sometimes it lags and sometimes its
> too fast...
>
> is there a way to make it the same on every pcs?
I think it is better to begin code optimizations. btw, vsync() is slightly
unregular procedure when we are talking about run time.


Allegro FAQ about subj:
How can I make my game run at the same speed on any computer?
You need to make sure the game logic gets updated at a regular rate, but
skip the screen refresh every now and then if the computer is too slow to
keep up. This can be done by installing a timer handler that will increment
a global variable at your game logic speed, eg:

      volatile int speed_counter = 0;

      void increment_speed_counter()
      {
         speed_counter++;
      }

      END_OF_FUNCTION(increment_speed_counter);

      void play_the_game()
      {
         LOCK_VARIABLE(speed_counter);
         LOCK_FUNCTION(increment_speed_counter);

         install_int_ex(increment_speed_counter, BPS_TO_TIMER(60));

         while (!game_over) {
            while (speed_counter > 0) {
               update_game_logic();
               speed_counter--;
            }

            update_display();
         }
      }