taisei/src/hirestime.c
Andrei Alexeyev 513d613387
Consistent indentation: indent with tabs, align with spaces (#104)
I would've preferred to just go with 4-spaces for indent and no tabs,
but lao is a bit conservative about it. :^)

Still, this is a ton better than mixing different styles all over the
place, especially within the same file.
2018-01-12 20:26:07 +02:00

88 lines
2.2 KiB
C

/*
* This software is licensed under the terms of the MIT-License
* See COPYING for further information.
* ---
* Copyright (c) 2011-2018, Lukas Weber <laochailan@web.de>.
* Copyright (c) 2012-2018, Andrei Alexeyev <akari@alienslab.net>.
*/
#include "taisei.h"
#include "util.h"
#include "hirestime.h"
static bool use_hires;
static hrtime_t time_current;
static hrtime_t time_offset;
static uint64_t prev_hires_time;
static uint64_t prev_hires_freq;
static SDL_mutex *paranoia;
static void time_update(void) {
bool retry;
do {
retry = false;
uint64_t freq = SDL_GetPerformanceFrequency();
uint64_t cntr = SDL_GetPerformanceCounter();
if(freq != prev_hires_freq) {
log_debug("High resolution timer frequency changed: was %"PRIu64", now %"PRIu64". Saved time offset: %.16Lf", prev_hires_freq, freq, time_offset);
time_offset = time_current;
prev_hires_freq = freq;
prev_hires_time = SDL_GetPerformanceCounter();
retry = true;
continue;
}
hrtime_t time_new = time_offset + (hrtime_t)(cntr - prev_hires_time) / freq;
if(time_new < time_current) {
log_warn("BUG: time went backwards. Was %.16Lf, now %.16Lf. Possible cause: your OS sucks spherical objects. Attempting to correct this...", time_current, time_new);
time_offset = time_current;
time_current = 0;
prev_hires_time = SDL_GetPerformanceCounter();
retry = true;
} else {
time_current = time_new;
}
} while(retry);
}
void time_init(void) {
use_hires = getenvint("TAISEI_HIRES_TIMER", 1);
if(use_hires) {
if(!(paranoia = SDL_CreateMutex())) {
log_warn("Not using the system high resolution timer: SDL_CreateMutex() failed: %s", SDL_GetError());
return;
}
log_info("Using the system high resolution timer");
prev_hires_time = SDL_GetPerformanceCounter();
prev_hires_freq = SDL_GetPerformanceFrequency();
} else {
log_info("Not using the system high resolution timer: disabled by environment");
return;
}
}
void time_shutdown(void) {
if(paranoia) {
SDL_DestroyMutex(paranoia);
paranoia = NULL;
}
}
hrtime_t time_get(void) {
if(use_hires) {
SDL_LockMutex(paranoia);
time_update();
hrtime_t t = time_current;
SDL_UnlockMutex(paranoia);
return t;
}
return SDL_GetTicks() / 1000.0;
}