view test/testtimer.c @ 1157:baf35853ad54

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 be9c9c8f6d53
children b2b476a4a73c
line wrap: on
line source


/* Test program to check the resolution of the SDL timer on the current
   platform
*/

#include <stdlib.h>
#include <stdio.h>

#include "SDL.h"

#define DEFAULT_RESOLUTION	1

static int ticks = 0;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
	SDL_Quit();
	exit(rc);
}

static Uint32 ticktock(Uint32 interval)
{
	++ticks;
	return(interval);
}

static Uint32 callback(Uint32 interval, void *param)
{
  printf("Timer %d : param = %d\n", interval, (int) param);
  return interval;
}

int main(int argc, char *argv[])
{
	int desired;
	SDL_TimerID t1, t2, t3;

	if ( SDL_Init(SDL_INIT_TIMER) < 0 ) {
		fprintf(stderr, "Couldn't load SDL: %s\n", SDL_GetError());
		return(1);
	}

	/* Start the timer */
	desired = 0;
	if ( argv[1] ) {
		desired = atoi(argv[1]);
	}
	if ( desired == 0 ) {
		desired = DEFAULT_RESOLUTION;
	}
	SDL_SetTimer(desired, ticktock);

	/* Wait 10 seconds */
	printf("Waiting 10 seconds\n");
	SDL_Delay(10*1000);

	/* Stop the timer */
	SDL_SetTimer(0, NULL);

	/* Print the results */
	if ( ticks ) {
		fprintf(stderr,
		"Timer resolution: desired = %d ms, actual = %f ms\n",
					desired, (double)(10*1000)/ticks);
	}
	
	/* Test multiple timers */
	printf("Testing multiple timers...\n");
	t1 = SDL_AddTimer(100, callback, (void*)1);
	if(!t1)
	  fprintf(stderr,"Could not create timer 1: %s\n", SDL_GetError());
	t2 = SDL_AddTimer(50, callback, (void*)2);
	if(!t2)
	  fprintf(stderr,"Could not create timer 2: %s\n", SDL_GetError());
	t3 = SDL_AddTimer(233, callback, (void*)3);
	if(!t3)
	  fprintf(stderr,"Could not create timer 3: %s\n", SDL_GetError());
	
	/* Wait 10 seconds */
	printf("Waiting 10 seconds\n");
	SDL_Delay(10*1000);

	printf("Removing timer 1 and waiting 5 more seconds\n");
	SDL_RemoveTimer(t1);

	SDL_Delay(5*1000);

	SDL_RemoveTimer(t2);
	SDL_RemoveTimer(t3);

	SDL_Quit();
	return(0);
}