mpri-graphics-project/periodic_updates.cpp

#include "periodic_updates.hpp"

#include <ctime>
#include <chrono>
#include <GL/glut.h>

static Ball* _ball = nullptr;
static std::chrono::time_point<std::chrono::steady_clock>
    _last_time, _init_clocks;

void init_periodic_static(Ball* ball) {
    _last_time = std::chrono::steady_clock::now();
    _init_clocks = std::chrono::steady_clock::now();
    _ball = ball;
}

double ellapsed_double(
        std::chrono::time_point<std::chrono::steady_clock> beg,
        std::chrono::time_point<std::chrono::steady_clock> end)
{
    std::chrono::duration<double> ellapsed_db = end - beg;
    return ellapsed_db.count();
}

void periodic_update() {
    auto now = std::chrono::steady_clock::now();
    _ball->update_pos(ellapsed_double(_last_time, now));

    fprintf(stderr, "dt = %lf, tot = %lf; center: %.2lf, %.2lf, %.2lf\n",
            ellapsed_double(_last_time, now),
            ellapsed_double(_init_clocks, now),
            _ball->getCenter().x,
            _ball->getCenter().y,
            _ball->getCenter().z);

    _last_time = now;
    glutPostRedisplay();
}