1 files changed, 7 insertions, 1 deletions
diff --git a/source/blender/windowmanager/intern/wm_window.c b/source/blender/windowmanager/intern/wm_window.c
index a1854a8ed86..a7b5b9bddda 100644
--- a/source/blender/windowmanager/intern/wm_window.c
+++ b/source/blender/windowmanager/intern/wm_window.c
@@ -1483,7 +1483,11 @@ static bool wm_window_timer(const bContext *C)
       wt->delta = time - wt->ltime;
       wt->duration += wt->delta;
       wt->ltime = time;
-      wt->ntime = wt->stime + wt->timestep * ceil(wt->duration / wt->timestep);
+
+      wt->ntime = wt->stime;
+      if (wt->timestep != 0.0f) {
+        wt->ntime += wt->timestep * ceil(wt->duration / wt->timestep);
+      }
 
       if (wt->event_type == TIMERJOBS) {
         wm_jobs_timer(wm, wt);
@@ -1596,6 +1600,7 @@ void WM_event_timer_sleep(wmWindowManager *wm,
 wmTimer *WM_event_add_timer(wmWindowManager *wm, wmWindow *win, int event_type, double timestep)
 {
   wmTimer *wt = MEM_callocN(sizeof(wmTimer), "window timer");
+  BLI_assert(timestep >= 0.0f);
 
   wt->event_type = event_type;
   wt->ltime = PIL_check_seconds_timer();
@@ -1615,6 +1620,7 @@ wmTimer *WM_event_add_timer_notifier(wmWindowManager *wm,
                                      double timestep)
 {
   wmTimer *wt = MEM_callocN(sizeof(wmTimer), "window timer");
+  BLI_assert(timestep >= 0.0f);
 
   wt->event_type = TIMERNOTIFIER;
   wt->ltime = PIL_check_seconds_timer();