Get the count per second of the high resolution counter.
Uint64 SDL_GetPerformanceFrequency(void);Returns a platform-specific count per second.
This function is available since SDL 3.0.0.
#include "SDL.h"
#define DEFAULT_RESOLUTION 1
static int ticks = 0;
static Uint32 SDLCALL
ticktock(Uint32 interval, void *param)
{
++ticks;
return (interval);
}
static Uint32 SDLCALL
callback(Uint32 interval, void *param)
{
SDL_Log("Timer %d : param = %d", interval, (int) (uintptr_t) param);
return interval;
}
int
main(int argc, char *argv[])
{
int i, desired;
SDL_TimerID t1, t2, t3;
Uint32 start32, now32;
Uint64 start, now;
/* Enable standard application logging */
SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
if (SDL_Init(SDL_INIT_TIMER) < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s", SDL_GetError());
return (1);
}
/* Start the timer */
desired = 0;
if (argv[1]) {
desired = SDL_atoi(argv[1]);
}
if (desired == 0) {
desired = DEFAULT_RESOLUTION;
}
t1 = SDL_AddTimer(desired, ticktock, NULL);
/* Wait 10 seconds */
SDL_Log("Waiting 10 seconds");
SDL_Delay(10 * 1000);
/* Stop the timer */
SDL_RemoveTimer(t1);
/* Print the results */
if (ticks) {
SDL_Log("Timer resolution: desired = %d ms, actual = %f ms",
desired, (double) (10 * 1000) / ticks);
}
/* Test multiple timers */
SDL_Log("Testing multiple timers...");
t1 = SDL_AddTimer(100, callback, (void *) 1);
if (!t1)
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,"Could not create timer 1: %s", SDL_GetError());
t2 = SDL_AddTimer(50, callback, (void *) 2);
if (!t2)
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,"Could not create timer 2: %s", SDL_GetError());
t3 = SDL_AddTimer(233, callback, (void *) 3);
if (!t3)
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,"Could not create timer 3: %s", SDL_GetError());
/* Wait 10 seconds */
SDL_Log("Waiting 10 seconds");
SDL_Delay(10 * 1000);
SDL_Log("Removing timer 1 and waiting 5 more seconds");
SDL_RemoveTimer(t1);
SDL_Delay(5 * 1000);
SDL_RemoveTimer(t2);
SDL_RemoveTimer(t3);
start = SDL_GetPerformanceCounter();
for (i = 0; i < 1000000; ++i) {
ticktock(0, NULL);
}
now = SDL_GetPerformanceCounter();
SDL_Log("1 million iterations of ticktock took %f ms", (double)((now - start)*1000) / SDL_GetPerformanceFrequency());
SDL_Log("Performance counter frequency: %"SDL_PRIu64"", (unsigned long long) SDL_GetPerformanceFrequency());
start32 = SDL_GetTicks();
start = SDL_GetPerformanceCounter();
SDL_Delay(1000);
now = SDL_GetPerformanceCounter();
now32 = SDL_GetTicks();
SDL_Log("Delay 1 second = %d ms in ticks, %f ms according to performance counter", (now32-start32), (double)((now - start)*1000) / SDL_GetPerformanceFrequency());
SDL_Quit();
return (0);
}