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Date: Mon, 10 Oct 2005 13:09:32 +0300 From: Tommi Kyntola <tommi.kyntola@ray.fi> To: sdl@libsdl.org Subject: [SDL] [RFC] get_ticks broken on linux It uses gettimeofday to calculate the timedifference. Gettimeofday returns current time which is seldom monotonous. This breaks SDL timer subsystem. (time callbacks and all that get borked when the time difference ms is suddenly ~ 2^32) I posted a message about this earlier but got no response. Some thoughts on this matter would be appreciated. (Or even an explanation for the lack of interest.) A patch below would use the posix timers that have been around since posix 93 and do provide a good source of monotonous time on linux boxes (and on few others too). The following patch is also availabe at: http://www.hut.fi/u/tkyntola/SDL-1.2.9-clockfix.patch It's against 1.2.9, but I can easily rediffit against the cvs branch is needed. cheers, Tommi Kyntola tommi.kyntola@ray.fi
author Ryan C. Gordon <icculus@icculus.org>
date Tue, 11 Oct 2005 18:16:12 +0000
parents 355632dca928
children
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<HTML
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>Time Examples</TITLE
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>Time Examples</H1
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>Time based game loop</H2
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>#define TICK_INTERVAL    30

static Uint32 next_time;

Uint32 time_left(void)
{
    Uint32 now;

    now = SDL_GetTicks();
    if(next_time &#60;= now)
        return 0;
    else
        return next_time - now;
}


/* main game loop */

    next_time = SDL_GetTicks() + TICK_INTERVAL;
    while ( game_running ) {
        update_game_state();
        SDL_Delay(time_left());
        next_time += TICK_INTERVAL;
    }&#13;</PRE
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