basic game logic with simple translation animation

timer.c

@@ -0,0 +1,58 @@
+#include <sys/time.h>
+#include <stdlib.h>
+
+#include "timer.h"
+
+struct timeval start_time;
+
+double get_time(void) {
+  struct timeval current_time;
+  gettimeofday(&current_time, NULL);
+
+  return (double)(current_time.tv_sec - start_time.tv_sec) + (double)(current_time.tv_usec - start_time.tv_usec) / 1000000.0;
+}
+
+void start_internal_timer(void) {
+  gettimeofday(&start_time, NULL);
+}
+
+bool timer_ended(Timer *timer) {
+  if (timer->state == TIMER_STOPPED) return false;
+
+  return get_time() - timer->start >= timer->duration;
+}
+
+void timer_start(Timer *timer, float duration) {
+  timer->start = get_time();
+  timer->elapsed = 0;
+  timer->duration = duration;
+  timer->state = TIMER_RUNNING;
+}
+
+void timer_stop(Timer *timer) {
+  timer->state = TIMER_STOPPED;
+}
+
+void timer_reset(Timer *timer) {
+  timer->start = get_time();
+  timer->elapsed = 0;
+  timer->state = TIMER_RUNNING;
+}
+
+double timer_remaining(Timer *timer) {
+  return timer->duration - (get_time() - timer->start);
+}
+
+double timer_elapsed(Timer *timer) {
+  return get_time() - timer->start + timer->elapsed;
+}
+
+void timer_pause(Timer *timer) {
+  timer->state = TIMER_PAUSED;
+  timer->elapsed = get_time() - timer->start + timer->elapsed;
+}
+
+void timer_resume(Timer *timer) {
+  timer->state = TIMER_RUNNING;
+  timer->start = get_time();
+}